U.S. patent application number 15/352271 was filed with the patent office on 2017-07-06 for immune mediated cancer cell destruction, systems and methods.
The applicant listed for this patent is LAZURE SCIENTIFIC, INC.. Invention is credited to Andrew L. Azure, Larry Azure, Charles E. Hill, Lawrence L. Kunz, Rafael Ponce.
Application Number | 20170189098 15/352271 |
Document ID | / |
Family ID | 57589998 |
Filed Date | 2017-07-06 |
United States Patent
Application |
20170189098 |
Kind Code |
A1 |
Azure; Larry ; et
al. |
July 6, 2017 |
IMMUNE MEDIATED CANCER CELL DESTRUCTION, SYSTEMS AND METHODS
Abstract
Systems and methods for delivering electric fields to a target
tissue of a patient for destruction of cancerous cells so as to
elicit or induce a specific anti-cancerous cell immune response in
the patient.
Inventors: |
Azure; Larry; (Issaquah,
WA) ; Hill; Charles E.; (Issaquah, WA) ;
Azure; Andrew L.; (Issaquah, WA) ; Ponce; Rafael;
(Issaquah, WA) ; Kunz; Lawrence L.; (Issaquah,
WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LAZURE SCIENTIFIC, INC. |
Issaquah |
WA |
US |
|
|
Family ID: |
57589998 |
Appl. No.: |
15/352271 |
Filed: |
November 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13095804 |
Apr 27, 2011 |
9526911 |
|
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15352271 |
|
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|
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61328580 |
Apr 27, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 5/025 20130101;
A61B 18/14 20130101; A61B 2018/00577 20130101; A61B 2017/00867
20130101; A61B 18/1477 20130101; A61N 1/32 20130101; A61B 18/18
20130101; A61B 18/1206 20130101; A61B 2018/0016 20130101; A61B
2018/1432 20130101; A61B 2018/143 20130101; A61N 1/403 20130101;
A61B 2018/1425 20130101; A61B 2018/1475 20130101; A61N 5/0625
20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14; A61N 5/02 20060101 A61N005/02; A61N 1/40 20060101
A61N001/40; A61B 18/18 20060101 A61B018/18; A61B 18/12 20060101
A61B018/12 |
Claims
1. A method for delivering electric fields to a target tissue of a
patient for destruction of cancerous cells, comprising:
establishing an electrical current flow through a volume of the
target tissue so as to preferentially destroy cancerous cells in
the volume and induce a specific anti-cancerous cell immune
response in the host patient.
2. The method of claim 1, wherein the electrical current flow is
selected such that thermal based protein coagulation and
denaturation in the cancerous cells or tissue is substantially
avoided.
3. The method of claim 1, further comprising administering an
immunostimulatory agent or adjuvant.
4. The method of claim 1, wherein the target tissue is heated to
less than about 50 degrees C. during a phase of treatment.
5. The method of claim 1, wherein the electrical current flow
provides a voltage field less than about 50 V/cm.
6. The method of claim 1, wherein the electrical current flow
comprises a frequency between about 50 kHz and about 300 kHz.
7. A method for delivering electric fields to a target tissue of a
patient for destruction of cancerous cells, comprising: identifying
a first target tissue site and a second target tissue site; and
eliciting destruction of cancerous cells of the first target tissue
site comprising establishing an electrical current flow through a
volume of the second target tissue so as to preferentially destroy
cancerous cells in the volume and induce a specific host
anti-cancerous cell immune response so as to control growth of
cancerous cells at a location remote from the second target tissue
that have not directly received electrical current flow.
8. The method of claim 7, wherein cancerous cells have been seeded
at the second target tissue site.
9. The method of claim 7, further comprising systemically or
locally administering an immunostimulatory agent or adjuvant.
10. The method of claim 7, wherein the electrical current flow is
selected such that thermal based protein coagulation and
denaturation in the cancerous cells or tissue is substantially
avoided.
11. The method of claim 7, wherein the second target tissue is
heated to less than about 50 degrees C.
12. The method of claim 7, wherein the electrical current flow
provides a voltage field less than about 50 V/cm.
13. The method of claim 7, wherein the electrical current flow
comprises a frequency between about 50 kHz and about 300 kHz.
14. A system for delivering electric fields to a target tissue of a
patient for destruction of cancerous cells, comprising: a probe
comprising one or more electrodes and configured to establish an
electrical current flow through a volume of the target tissue so as
to preferentially destroy cancerous cells in the volume and induce
a specific anti-cancerous cell immune response in the host
patient.
15. The system of claim 14, wherein the probe is configured to
deliver an electrical current flow selected such that thermal based
protein coagulation and denaturation in the cancerous cells or
tissue is substantially avoided.
16. The system of claim 14, where in the probe further comprises a
delivery unit for administering an immunostimulatory agent or
adjuvant.
17. The system of claim 14, further comprising an energy source
coupled to the probe.
18. The system of claim 14, wherein the probe further comprises an
array of the one or more electrodes defining an ablation
volume.
19. The system of claim 14, wherein the probe is configured to
radiate current radially or in a plurality of different
directions.
20. The system of claim 14, further comprising a biopsy unit for
seeding the target tissue in a patient.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Application Ser. No. 61/328,580 (Attorney Docket No. 91190-770575)
filed Apr. 27, 2010 the full disclosure of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to electric field
delivery to a tissue of a patient. More particularly, the present
invention provides systems and methods for delivering electric
fields to a target tissue of a patient for destruction of cancerous
cells and eliciting or induction of a specific anti-cancerous cell
immune response in the patient.
[0003] The immune system is the body's natural defense against
infection and disease, destroying foreign elements such as harmful
bacteria and viruses that enter the body. In order for the immune
system to provide effective defense against disease, it has to
recognize and label agents that are "foreign" and distinguish
foreign infection from the body's own non-harmful cells and
components. Once this happens, cells in the immune system can
function to eliminate the foreign agents.
[0004] Another important role of the immune system is to identify
and eliminate tumors. The transformed cells of tumors include
proteins or antigens that are not found on normal cells. To the
immune system, these antigens appear foreign, and their presence
causes immune cells to attack the transformed tumor cells. The
antigens produced by tumors can have several sources, and may
include those derived from a foreign infecting agent, such as a
virus, as well as the body's own proteins that have been mutated or
altered, or proteins that occur at low levels in normal cells but
reach high levels in tumor cells.
[0005] One primary response of the immune system to tumors is to
destroy the abnormal cells using so called natural killer T cells,
sometimes with the assistance of other immune cells, such as helper
T cells. Tumor antigens may be processed and presented by immune
cells in a similar way to viral or bacterial antigens. This allows
immune cells such as killer T cells to recognize the tumor cell as
abnormal. In addition, in some instances antibodies are generated
against tumor cells allowing for their destruction by the
complement system.
[0006] While the immune system represents a powerful and vital
defense against cancer, in some cases, tumors evade the immune
system and go on to become cancers. Thus, there is great interest
in cancer immunotherapy treatments and techniques that utilize or
stimulate the body's own immune system to better combat and
eradicate cancerous cells in the body. Cancer immunotherapy aims to
teach the body's own natural defenses to identify cancer cells
correctly and then kill them. There are different types of cancer
immunotherapy, including cancer vaccines and a treatment called
Antigen-Specific Cancer Immunotherapeutics (ASCI).
[0007] While cancer immunotherapy holds tremendous promise, to date
very few effective treatments have been developed. Thus, there is
continued interest in techniques and treatments that can stimulate
a patient's immune system to better combat cancerous cell
growth.
BRIEF SUMMARY OF THE INVENTION
[0008] Systems and methods are provided for delivering electric
fields to a target tissue of a patient for destruction of cancerous
cells so as to elicit or induce a specific anti-cancerous cell
immune response in the patient. Methods include establishing an
electrical current flow through a volume of the target tissue so as
to preferentially destroy cancerous cells in the volume.
[0009] Thus, in one aspect, the present invention includes systems
and related methods for delivering electric fields to a target
tissue of a patient for destruction of cancerous cells, including
establishing an electrical current flow through a volume of the
target tissue so as to preferentially destroy cancerous cells in
the volume and induce a specific host anti-cancerous cell immune
response. The electrical current flow can be selected such that
thermal based protein coagulation and denaturation in the cancerous
cells or tissue is minimized or substantially avoided.
Administering an immunostimulatory agent or adjuvant can further be
accomplished.
[0010] In another aspect, the present invention further includes
methods including identifying a first target tissue site and a
second target tissue site; eliciting destruction of cancerous cells
of the first target tissue site comprising establishing an
electrical current flow through a volume of the second target
tissue so as to preferentially destroy cancerous cells in the
volume and induce a specific host anti-cancerous cell immune
response so as to control growth of cancerous cells at a location
remote from the second target tissue that have not directly
received electrical current flow. In some instances, cancerous
cells will have been seeded at the second target tissue site.
[0011] The present invention further includes systems and methods
for delivering electric fields to a target tissue of a patient for
destruction of cancerous cells, including identifying a first
target tissue site and a second target tissue site; eliciting
destruction of cancerous cells of the first target tissue site
including establishing an electrical current flow through a volume
of the second target tissue so as to preferentially destroy
cancerous cells in the volume; removing tissue or fluid from the
second target tissue following electrical current application;
delivering to the first target tissue site the tissue or fluid
removed from the second target tissue, so as to reduce growth of
cancerous cells at a location remote from the second target tissue
that have not directly received electrical current flow.
[0012] For a fuller understanding of the nature and advantages of
the present invention, reference should be made to the ensuing
detailed description and accompanying drawings. Other aspects,
objects and advantages of the invention will be apparent from the
drawings and detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a method according to an embodiment of
the present invention.
[0014] FIG. 2 illustrates current delivery at a first site and
eliciting a response at a second site, according to an embodiment
of the present invention.
[0015] FIGS. 3A through 3C illustrate seeding cells from a first
site at a second location, according to an embodiment of the
present invention.
[0016] FIG. 4 illustrates a probe or device according to an
embodiment of the present invention.
[0017] FIGS. 5A through 5D illustrate a probe or device according
to another embodiment of the present invention.
[0018] FIGS. 6A through 6D illustrate current or field delivery in
a target tissue according to various embodiments of the present
invention.
[0019] FIGS. 7A and 7B illustrate a system for delivery of electric
fields to a tissue of a patient using a plurality or array of
electrodes.
[0020] FIG. 8 includes a diagram illustrating a system according to
an embodiment of the present invention.
[0021] FIG. 9 shows lymphocyte proliferation data.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention provides methods, and related systems
and devices, for destruction of cancerous cells in a patient.
According to the present invention, an electric field is applied to
a target tissue region for controlled and/or preferential
destruction of cancerous cells, and stimulation in vivo of the
patient's own immune system against cancerous cells in the
patient's body. In particular, application of electric fields or
energy delivery as described herein may be selected to stimulate an
adaptive or specific immune response in the patient for destruction
of cancerous cells in the patient's body, including cancerous cells
at or near the treatment site as well as cancerous cells at
locations in the patient's body separate or remote from the energy
delivery treatment site.
[0023] Energy application and delivery according to the present
invention includes establishing current flow through a target
tissue that can include a controlled low-level tissue heating or
mild hyperthermia. Current flow can be established between
electrodes, e.g., in a bipolar arrangement, with current flow
established and substantially contained between the spaced
electrodes. Tissue heating can be more precisely controlled to
prevent or minimize excessive heating and/or hot spots that can
cause indiscriminate tissue destruction and undesired damage to
healthy or non-target tissues. While heating may occur with energy
application according to the present invention due to tissue
resistance and, to a lesser degree, frictional heating, high
temperature thermal ablation or thermally-induced coagulation,
protein denaturation, and/or cross-linking as is typically present
with conventional high-temperature thermal RF ablation is generally
avoided with the present methods.
[0024] As thermally-induced coagulation/cross-linking is
substantially avoided, antigenic properties of cancerous cell
specific proteins may be better preserved in the current treatment
methods compared to conventional high-temperature thermal ablation
techniques. In addition to disrupting the viability and/or
integrity of cancerous cells, energy delivery treatment according
to the present invention can elicit migration of immune cells to
the treated target tissue region. Histopathology analysis has
identified immune cells such as macrophages increasingly present
about the target tissue following energy application, indicating an
immune cell mediated response is elicited by the current
application. In conjunction with energy application according to
the current methods, degradation (e.g., enzymatic cleavage) and/or
processing (e.g., immune cell mediated processing) of cancerous
cell proteins may lead to generation of an in vivo specific immune
response for further destruction of cancerous cells that may occur
not only at or about the treatment site, but also at locations
remote or removed from the energy delivery site.
[0025] Stimulation of an immune response, including a cancer
specific response, according to the present invention can provide a
powerful tool for treatment and/or targeted destruction of
cancerous cells and tissue in a patient. As such, methods and
structures as described herein can make use of this previously
unrecognized immune mediated action, including treatment planning
tools and approaches, treatment of previously non-accessible or
lesser accessible treatment sites, use of immunostimulating agents
and/or adjuvants, and the like to greatly enhance cancerous cell
destruction approaches.
[0026] Energy delivery as described has been observed to be
surprisingly effective in preferentially damaging and destroying
cancerous cells compared to non-cancerous or healthy cells/tissue.
Preferential destruction, as described herein, refers to
establishing current flow as described herein such that cytotoxic
effects of treatment are, on average or as a whole, more
destructive and/or lethal to cancerous or hyperplastic cells (e.g.,
cells exhibiting or predisposed to exhibiting unregulated growth)
compared to non-cancerous or healthy cells. In some instances,
establishing current flow and induction of low or mild hyperthermia
as described herein is remarkably effective in preferentially
destroying cancerous cells with limited or no observable damage to
non-cancerous tissues.
[0027] Without being bound by any particular theory, electrode
configuration and field application as described in certain
embodiments (e.g., radially and/or in a plurality of different
directions) may take advantage of tumor or mitotic cell physiology
to increase treatment effectiveness, and can include a more optimal
or effective orientation of the applied field with respect to
dividing cells of the target region. For example, energy
application can be accomplished such that current fields are
substantially aligned at some point during energy delivery with
division axes of dividing cells (e.g., cancerous cells), thereby
more effectively disrupting cellular processes or mitotic events
(e.g., mitotic spindle formation and the like). As cancerous cells
are dividing at a higher rate compared to non-cancerous cells,
field application in this manner may preferentially damage
cancerous cells compared to healthy or non-dividing cells. It will
be recognized, however, that energy application according to the
present invention likely has several or numerous cytotoxic effects
on cells of the target region and that such effects may be
cumulatively or synergistically disruptive to a target cell,
particularly to cells disposed or pre-disposed to unregulated
growth (i.e., cancerous cells). Other cytotoxic or disruptive
effects of the energy application as describe herein may occur due,
for example, to application of mild hyperthermia (e.g., mild
heating of tissue between about 40 to 48 degrees C.; or less than
about 50 degrees C.); ion disruption, disruption of membrane
stability, integrity or function; disruption of cellular components
and/or organelles; and the like.
[0028] As noted, the energy delivery according to the present
invention in some instances has been observed to be preferentially
cytotoxic or destructive of cancerous cells while substantially
sparing the non-cancerous cells, such as normal stromal tissue
including fibrous connective tissue, arterioles, capillaries,
veins, lymphatic vessels, smooth muscle stroma, and nerves. The
applied treatment currents are controlled so the tissue within the
treatment array does not substantially include high-temperature,
thermally ablative temperatures, and therefore the proteins of the
cell are not substantially thermally coagulated (denatured by
high-heat induced cross-linking) during current application.
Without being bound by any theory, current application and cell
destruction according to the current methods may elicit the release
from target cells of endogenous enzymes, especially from lysosomes
within the cell, lead to some autodigestion of the cancer cells.
These endogenous enzymes may cleave the cancer cells non-denatured
proteins into fragments that can in turn be taken up by macrophages
and dendritic cells, leading to the stimulation of both a humeral
and cellular immune response against the patients own tumor.
[0029] Further, without being bound by any particular theory,
treatment resulting autodigestion and release of enzymatically
cleaved, non-denatured protein fragments may be taken up and
processed by immune cells, such as taken up by macrophages
initially and subsequentially dendritic cells. These cells continue
the fragmentation of the proteins into antigenic peptides and the
dendritic cells display the antigens on their surfaces.
Antigen-bearing cells, such as dendritic cells, travel to lymph
nodes and the spleen via the lymph system, where they interact with
B cells, which produce antibodies, and killer T cells, which are
directed against the tumors from which the antigens were derived.
In energy application according to the present invention, the
vascular system of the target region typically remains
substantially intact following treatment, including the lymph
vessels, making it easier and more efficient for the cells to
travel to the lymph nodes and spleen, than by treatments that
destroy the vascular system. Antigen presenting cells, such as
dendritic cells, present their antigen-laden MHC molecules to naive
helper T cells. The dendritic cells can program the naive helper T
cells to recognize an antigen as foreign and as a hazard to the
patient's body. The programmed helper T cells then prompt the B
cells to produce antibodies that can bind to surface antigens
expressed by the tumor cells. The dendritic cells and helper cells
also activate killer T cells, which can destroy tumor cells
expressing these surface antigens. Whether the patients immune
system responds with antibodies or killer cells seems to be
determined in part by which subset of dendritic cells conveys the
message and which of two types of immune-stimulating cytokines they
prompt the helper T cells to make.
[0030] Furthermore, it is possible that the current delivery as
described herein alters or disrupts immunotolerogenic signaling in
the patient that permits the cancerous tissue to substantially
escape immunosurveillance in the absence of current treatment as
described. One reason that tumors, in general, may escape
immunosurveillance is that they express tolerogenic signals that
suppress immunity. It is possible that damage associated with
sumor-specific injury resulting from current delivery according to
the present invention will result in an immunogenic response due at
least partially to a change in signaling associated with the form
of cell death induced by the current field. Change in signaling can
include changes to intercellular signaling as well as intra and
extracellular signaling. Moreover, the current field per the
present invention may induce (e.g., directly) certain genomic
changes associated with immunostimulation--e.g., such as heat shock
proteins induced by the current field, which may be implicated in
increasing antigen presentation (e.g., by dendritic cells) or in
interactions between dead/dying cells and dendritic cells. Current
field delivery and stimulation or eliciting of an adaptive or
specific immune response according to the present invention may
include one or more of the mechanisms of action described herein,
or none, and/or may include additional processes not specifically
listed herein.
[0031] Appropriate adjuvants and/or immunostimulants in conjunction
with energy delivery according to the present invention can be used
to increase the type and level of immune response to the tumor
antigens. Tumor cells, being abnormal, may generate aberrant
molecules/peptides and peptides in different amounts, which could
be targeted by the stimulated immune system. Antigens that occur
only on cancerous cells are difficult to find, but several have
been isolated by researchers for some types of cancer. For example,
adjuvants can be injected locally within the tumor at or about the
time of treatment. Adjuvant injection, together with the
non-specific aberrant fragmentation of proteins by autodigestion
non-denatured tumor cell protein fragments produced in response to
energy delivery as described, may increase the in vivo activity of
the immune system against a patients own tumors.
[0032] Thus, the present invention includes methods and related
structures for delivering electric fields to a target tissue of a
patient so as to induce a specific host anti-cancerous cell immune
response. Current delivery as described herein can elicit
destruction of cancerous cells locally or proximate to the current
delivery site, and may further elicit or stimulate a host immune
response that induces a specific immune response further
destructive of cancerous cells at the current delivery site or a
second/remote site, or both. Current delivery methods and
structures can be tailored or configured to take advantage of the
induced immune response. For example, as noted above, current
delivery can be coupled or coordinated with delivery or
administration of an immunostimulatory agent or adjuvant. Further,
immune response induction as described herein can be utilized in
treatment planning or selection of current delivery location.
[0033] Referring to FIG. 1, a method of delivering or administering
an immunostimulatory agent or adjuvant and current is described.
The method includes administering an immunostimulatory agent or
adjuvant (Step 10) and delivering current to a target site (Step
12). Agent administration and current delivery can occur in any
order, may be simultaneous or substantially simultaneous,
immediately successive in time or have some delay between steps.
Current delivery can be accomplished by a number of means,
including those delivery methods and structures described
herein.
[0034] One or more agents, e.g., immunostimulatory agents and/or
adjuvants, can be delivered as described, and may be coupled with
or coordinated with energy or current delivery. An
immunostimulatory agent will generally include agents that increase
a number of T cells (e.g., stained or detectable T cells) as a
result of delivery (e.g., in vitro or in vivo), whereas a decrease
(or lack of increase) in T cell proliferation or number of
detectable T cells will generally indicate that an agent is not
effective as an immunostimulatory agent. An adjuvant or
immunostimulatory agent is a pharmacological or immunological agent
that modifies the effect of immunization of a patient receiving
energy treatment described herein. Adjuvants or agents can be added
to enhance, stimulate, or facilitate the patient's immune response,
including a cancer specific response following energy/current
delivery as described herein. Various adjuvants, including those
known in the art, can be utilized herein with energy or current
delivery techniques. Non-limiting examples of adjuvants include
aluminum salts (e.g., aluminum hydroxide or aluminum phosphate),
Freund's complete adjuvant (FCA) and incomplete adjuvant, or
organic adjuvants (e.g., squalene).
[0035] As indicated, energy or current deliver as described herein
may elicit destruction of cancerous cells locally or proximate to
the current delivery site, and may further elicit or stimulate a
host immune response further destructive of cancerous cells at the
current delivery site or a second/remote site, or both. FIG. 2
illustrates energy delivery at a first site 14 eliciting or
stimulating an immune response 20 at a second site 16. As shown,
energy or current delivery can include positioning one or more
electrodes 18 in tissue at a first target site 14, and delivery of
current to the target tissue (see also, below). As described,
energy delivery can further elicit a host specific immune response
20 further destructive to the cancerous cells. Such an immune
response may not only effect cancerous cell survival at the first
site 14, but may also elicit immune cell mediated destruction of
similar cancerous cells at a second site 20.
[0036] Such a response that is more systemically oriented or not
necessarily limited only to the initial target site of
energy/current delivery can be utilized for selection of current
delivery and/or treatment planning. For example, in some instances
where multiple cancerous tissues or tumors are present, certain
cancerous sites may be more accessible or more sensible targets
than others and may be the initial target of current delivery at a
particular stage of treatment. Thus, a phase of treatment may
include selecting one or more cancerous sites for current/energy
delivery as opposed to others. For example, cancerous sites or
tumors may be present in proximity to sensitive tissues or
difficult to access locations, or otherwise less attractive for
probe placement and/or energy delivery. Treatment planning and
selection of energy delivery can be coupled with other imaging and
detection methods, and may factor in an immune mediate response as
indicated.
[0037] In another embodiment, remote targeting via an immune
mediate response can include biopsy and seeding of cancerous tissue
or cells in a patient, with energy delivery at the seeded site so
as to elicit an immune mediate response at a location remote from
the seeded site. Biopsy and seeding, according to an embodiment of
the present invention, is described with reference to FIGS. 3A
through 3C. Cancerous cells are obtained from a first site (FIG.
3A) and implanted or seeded at a second location (FIG. 3B). Energy
delivery is accomplished in a grown tissue mass at the second
location (FIG. 3C). Energy delivery at the second location may
elicit a more systemic or non-locally constrained immune response
in the patient, which can be destructive of cancerous cells remote
from the second location.
[0038] Various energy delivery systems, which can include a wide
array of selected electrode or probe configurations, can be
utilized according to the present invention for energy or current
delivery. Delivery systems and methods can be utilized, modified,
or tailored to take further advantage of an immune response
elicited following current delivery as described herein. For
example, energy delivery systems may be utilized in conjunction
with systems for administering or delivering an immunostimulatory
agent or adjuvant. Energy delivery systems may further or
alternatively be modified or configured for delivery of both
current to the tissue as well as delivery of an agent or
adjuvant.
[0039] In one embodiment, electrodes can include an array of
needle-type electrodes, which can be fixed to common support (e.g.,
housing) or separately positionable and controlled. Such a
plurality or array of electrodes can include a straight-needle
array including electrically conductive material such as stainless
steel, gold, silver, etc. or combination thereof. An array of
straight-needle electrodes can be coupled to a rigid needle support
or housing that can ensure correct positioning of each individual
needle relative to the others. The needles can be arranged parallel
to one another with opposing rows and/or columns of electrodes
ensuring the field is delivered to and contained within the target
area. Needle length and needle spacing can vary depending on the
actual dimensions of the target tissue. Individual needle placement
can be guided using imaging (e.g., ultrasound, X-ray, etc.) and
relative needle position can be maintained with a rigid grid
support (e.g., housing, template, etc.) that remains outside the
body. The needle assembly will electrically connect to the control
system or module, e.g., via insulated wires and stainless steel
couplings.
[0040] In another embodiment, a probe can include one or more
electrodes that are deployable from an elongate probe housing or
catheter. Such embodiments may be particularly useful for treatment
of target areas more difficult to access with an array of fixed
needles. Such deployable type probes, and others described herein,
can be inserted percutaneously through the skin of the patient and
into the target tissue, or advanced through a body lumen. As above,
appropriate imaging technology can be used to guide the precise
placement of the probe in the target site. In one embodiment, a
deployable type probe can include outer polyurethane sheath housing
pre-shaped deployable shape memory metal tines and a stainless
steel central electrode tip. Conductive surfaces can further be
coated with a highly conductive material.
[0041] Another embodiment of the probe can include one or more
expandable elements (e.g., balloon) that can be individually
positioned around a target area or organ, or advanced in a body
lumen, and then deployed and "inflated" to achieve maximum surface
area and optimal distribution of the therapeutic field. In one
example, an electrically active segment of the expandable element
can include an electrically conductive material (e.g., silver,
gold, etc.) coated or deposited on a mylar balloon. Prior to
deployment and inflation, the expandable element can be contained
inside a flexible catheter that can be guided to the treatment
area. Once the delivery catheter is positioned, the "balloon" can
be deployed and expanded via the circulation of fluid through the
balloon, which can have a selected or controlled temperature and
may act as a heat sink. The therapeutic field can than be delivered
via the silver coating on the mylar balloon. Two or more probes
deployed in this fashion will serve to contain the field within the
treatment area.
[0042] Electrodes and probes of the present invention can be
coupled to control system or control module designed to generate,
deliver, monitor and control the characteristics of the applied
field within the specified treatment parameters. In one embodiment,
a control system includes a power source, an alternating current
(AC) inverter, a signal generator, a signal amplifier, an
oscilloscope, an operator interface and/or monitor and a central
processing unit (CPU). The control unit can manually,
automatically, or by computer programming or control, monitor,
and/or display various processes and parameters of the energy
application through electrodes and to the target tissue of the
patient. While the control system and power source can include
various possible frequency ranges, current frequency delivered to
target tissue will be less than about 300 kHz, and typically about
50 kHz to about 250 kHz (e.g., 100 kHz). Frequencies in this range
have been observed as effective in precisely controlling the energy
application to the target tissue, controlling thermal effects
primarily to mild thermal application, and preferentially
destroying cancerous cells with limited or no observable damage to
non-cancerous tissues.
[0043] Energy application according to the present invention can
include mild or low levels of hyperthermia. In some embodiments,
small changes/elevations in temperature in the target tissue region
may occur, generally ranging from about 0-15 degrees (and any
number therebetween) above pre-treatment tissue temperature.
Typically, temperature elevations will be no more than about 10
degrees C. above body temperature, and may be about 2 degrees to
less than about 10 degrees C. above body temperature (e.g., normal
human body temperature of about 38 degrees C.). Thus, local tissue
temperatures (e.g., average tissue temperature in a volume of
treated tissue) during treatment will typically be less than about
50 degrees C., and typically within a range of about 40-48 degrees
C. In one embodiment, average target tissue temperature will be
selected at about 42-45 degrees C. As target tissue temperatures
rise above about 40-42 degrees C. during treatment, the cytotoxic
effects of energy delivery on cancerous cells of the target region
are observably enhanced, possibly due to an additive and/or
synergistic effect of current field and hyperthermic effects. Where
mild hyperthermic effects are substantially maintained below about
48 degrees C., the energy delivery according to the present
invention appears to more preferentially destroy cancerous cells
compared to healthy or non-cancerous cells of the target tissue
region. Where energy delivery induces tissue heating substantially
in excess of about 45-48 degrees C. (e.g., particularly above 48-50
degrees C.), the preferential cytotoxic effects on cancerous cells
may begin to diminish, with more indiscriminate destruction of
cancerous and non-cancerous cells occurring.
[0044] Tissue temperatures can be selected or controlled in several
ways. In one embodiment, tissue temperatures can be controlled
based on estimated or known characteristics of the target tissue,
such as tissue impedance and tissue volume, blood flow or perfusion
characteristics, and the like, with energy application to the
tissue selected to deliver an approximated controlled mild increase
in tissue temperature. In another embodiment, tissue temperature
can be actively detected or monitored, e.g., by use of a feedback
unit, during treatment, with temperature measurements providing
feedback control of energy delivery in order to maintain a desired
target tissue temperature or range. Temperature control measures
can include electronics, programming, thermosensors and the like,
coupled with or included in a control unit or module of a system of
the invention. Further, use of inflatable/expandable balloons and
circulation heated/cooled inflation media further facilitates
control and delivery of the desired treatment temperature to the
target tissue.
[0045] Energy application and induction of hyperthermia in a target
tissue region according to the present application can include
delivery of various types of energy delivery. As described,
application of generally intermediate frequency range (e.g., less
than about 300 kHz) alternating current in the RF range has been
observed as effective in establishing mild heating and
hyperthermia, as well as current fields in a controlled manner so
as to provide a cytotoxic effect, and in some instances, a
preferential destructive effect to cancerous cells of a target
tissue volume/region. It will be recognized, however, that
additional energy applications and/or ranges may be suitable for
use according to the present invention, and that systems and
methods of the present invention may be amenable to use with other
or additional energy applications. For example, energy application
can include current flow having frequencies found generally in the
RF range, as well as microwave range, including higher frequencies
such as 300-500 kHz and above, and may further be amenable to use
with direct current applications. Applied current can be pulsed
and/or continuously applied, and energy delivery can be coupled
with a feedback-type system (e.g., thermocouple positioned in the
target tissue) to maintain energy application and/or tissue heating
in a desired range.
[0046] In certain embodiments, particularly where energy
application is selected for lower power delivery/ablation, the
control system can be designed to be battery powered and is
typically isolated from ground. AC current is derived from the
integrated power inverter. An intermediate frequency (e.g., less
than 300 kHz; or about 50 kHz to about 250 kHz) alternating
current, sinusoidal waveform signal is produced from the signal
generator. The signal is then amplified, in one non-limiting
example to a current range of 5 mA to 50 mA and voltage of up to 20
Vrms per zone. Field characteristics including waveform, frequency,
current and voltage are monitored by an integrated oscilloscope.
Scope readings are displayed on the operator interface monitor. An
integrated CPU monitors overall system power consumption and
availability and controls the output of the signal generator and
amplifier based on the treatment parameters input by the operator.
The operator can define treatment parameters to include maximum
voltage, maximum current or temperature, maximum power, and the
like.
[0047] Imaging systems and devices can be included in the methods
and systems of the present invention. For example, the target
tissue region can be identified and/or characterized using
conventional imaging methods such as ultrasound, computed
tomography (CT) scanning, X-ray imaging, nuclear imaging, magnetic
resonance imaging (MRI), electromagnetic imaging, and the like. In
some embodiments, characteristics of the tumor, including those
identified using imaging methods, can also be used in selecting
ablation parameters, such as energy application as well as the
shape and/or geometry of the electrodes. Additionally, these or
other known imaging systems can be used for positioning and
placement of the devices and/or electrodes in a patient's
tissues.
[0048] Referring to FIG. 4, a device according to an embodiment of
the present invention is described. The device 30 includes a
delivery member 32 having a distal portion 34 and a proximal
portion 36. The device 30 further includes a proximal portion 38 of
the device that can be coupled (e.g., removably coupled) to the
delivery member 32. Additionally, the device 30 can include
conductive cables 40 electrically coupled to an energy source (not
shown). The device includes a plurality of electrodes 42 at the
distal portion 34 of the delivery member 32. The electrodes 42 can
be positioned or fixed, for example, at the distal end of the
delivery member 32 or positionable and deployable from a lumen of
the delivery member 32 and retractable in and out of the distal end
of the delivery member 32. The electrodes 42 can include a
non-deployed state, where the electrodes 42 can be positioned
within a lumen of the delivery member 32, and a deployed state when
advanced from the distal end of the delivery member 32. Electrodes
42 are advanced out the distal end and distended into a deployed
state substantially defining an ablation volume.
[0049] In another embodiment, a probe can include a plurality of
needle electrodes fixed to or positioned on a body or housing of a
device. FIGS. 5A through 5C show a device having a plurality of
electrodes coupled to a housing, according to another embodiment of
the present invention. As shown, the device 50 includes a plurality
of electrodes extending from the distal portion (e.g., housing) of
the device. FIG. 5A shows a three dimensional side view of the
device having the plurality of electrodes. FIG. 5B shows a top view
of the device illustrating the electrode arrangement. The plurality
includes a centrally positioned electrode 52 and outer electrodes
54, 56, 58 spaced laterally from the central electrode 52. The
illustrated electrodes include substantially linear needle-like
portions or needle electrodes. The electrodes extend from the
distal portion of the device and are oriented to be substantially
parallel with the longitudinal axis of the device 50. Additionally,
each electrode is substantially parallel with other electrodes of
the plurality. The plurality of electrodes substantially define the
ablation volume, with the outer electrodes 54, 56, 58 substantially
defining a periphery of the ablation volume and the electrode 52
positioned within or at about the center point of the defined
periphery. Each of the electrodes can play different roles in the
ablation process. For example, there can be changes in polarity
and/or polarity shifting between the different electrodes of the
device. As with other devices of the invention, electrodes can be
electrically independent and separately addressable electrically,
or two or more electrodes can be electrically connected, for
example, to effectively function as one unit. In one embodiment,
for example, outer electrodes 54, 56, 58 can be electrically
connected and, in operation, include a polarity different from that
of the inner electrode 52. As illustrated in FIG. 5C the electrodes
52 and 54, 56 of the device can include opposing charges (e.g.,
bipolar). In such an instance, the applied electrical current can
provide an electrical field, as illustrated by the arrows,
extending radially outward from the central electrode 52 and toward
the peripherally positioned or outer electrode(s) 54, 56. FIG. 5D
illustrates the concept of a current flow center, where current
flow is established through about a center location of a treatment
volume.
[0050] In some embodiments, electrodes can be deployable from
small, electrode guides or positioning tubes, e.g., microtubes or
microcatheters, positionable in and advanceable from a distal
portion of an ablation probe. The terms catheter or microcatheter,
as used herein, refer generally to an elongate tube having a lumen.
For example, an ablation probe of the present invention can include
a distal portion or a delivery member having a lumen with electrode
aiming/positioning microtubes/microcatheters positioned within the
lumen of the delivery member, with electrodes disposed in the
microcatheters and deployable therefrom. Both microcatheters and
electrodes can include a shape memory metal and include a preformed
shape for deployment.
[0051] Energy delivery between positioned electrodes is further
described with reference to FIGS. 6A through 6C. Electrodes can be
positioned in a target tissue and activated in pairs or groups such
that the desired electric field is delivered to the target tissue
between the electrodes and, in some instances, in a radial
orientation or in a plurality of different directions. FIG. 6A
conceptually illustrates establishment of a current field with two
spaced electrode elements (e.sub.1 and e.sub.2) as a basic field
delivery unit according to an embodiment of the present invention.
As shown, distal portions of two electrodes (e.sub.1 and e.sub.2)
of a plurality positioned in a target tissue and activated as an
electrode pair or circuit, with the applied current substantially
contained between the two. Thus, electrodes can be activated in a
bipolar configuration, with current flowing between electrodes
(e.g., between e.sub.1 and e.sub.2) and the tissue between the
electrodes acting as a flow medium or current pathway between the
electrodes. Positioning and activation of pairs or relatively small
groups of electrodes in this manner allows more precise control of
the current applied to the tissue, containment of the applied field
to the desired location, as well control of heating or limited
temperature increase in the target tissue.
[0052] In some embodiments of therapeutic energy delivery according
to the present invention, electrode positioning and/or device
configuration advantageously allows delivery of field throughout a
target tissue volume in a plurality of different directions, such
as radial field orientation and application through the target
volume. FIGS. 6B through 6D illustrate simplified plan views of
electrode positioning and spacing for field application according
to exemplary embodiments of the present invention. As shown in FIG.
6B, a simple four electrode grouping can be selected for use in
treatment, with an applied field established between groups or
pairs (e.g., different opposing electrode pairs). Groups or pairs
of different electrodes can be differentially activated for field
application in different directions/orientations. Electrode
positioning can further include outer electrodes substantially
defining a volume, and an electrode positioned within the volume.
Electrode activation can include application of current flowing
between a centrally positioned electrode and outer or secondary
electrodes positioned spaced from the inner or center electrode.
Thus, an exemplary delivery unit can include an inner or centrally
located electrode surrounded by spaced electrodes, with the applied
field extending between the central electrode and the outer spaced
electrodes. In this manner, the outer electrodes can essentially
define an ablation volume with the inner/central electrode
positioned within the volume. Field delivery in this way is
advantageously controlled and substantially contained within the
ablation volume. Furthermore, field delivery in this manner
advantageously allows a current field to be established with
current flow in a radial and plurality of different directions
through the treatment volume, e.g., extending through or from a
flow center located about the centrally positioned electrode. FIG.
6C illustrates exemplary electrode positioning including outer
electrodes and an inner or centrally located electrode, for
defining a discrete target tissue volume for treatment and
application of treatment filed extending radially through the
volume. Electrode positioning will not be limited to any particular
configuration, and various arrangements will be possible.
[0053] In another embodiment of the present invention, systems and
methods can include a plurality of electrodes (e.g., needle
electrodes) that can be individually advanced and positioned in the
target tissue, and electrically activated for energy delivery. In
such an embodiment, an array of electrodes can be advanced through
the tissue of the patient and electrically activated (e.g.,
differentially activated) to deliver current field in a plurality
of different directions. An array or plurality as described can
include various numbers of electrodes, and the selected number can
depend, at least partially, on factors such as target tissue
characteristics, treatment region, needle size, and the like. An
array can include a few to several dozen electrodes. In one
example, an array can include about a few electrodes, to about a
dozen or hundred, or more (e.g., 10-100, 5-200, any number
therebetween, or more) electrodes for positioning in the target
tissue region.
[0054] A system and method for delivering electric fields according
to the present invention is described with reference to FIGS. 7A
and 7B. The system includes a plurality of individual needle
electrodes that can be positioned in a target tissue. Elongated
needle electrodes will include a distal portion and a proximal
portion. The proximal portion of each electrode will be
electrically connected to a system control unit or module, which
includes electronics, storage media, programming, etc., as well as
a power generator, for controlled delivery of selected electrical
fields to the target tissue. In use, a plurality of electrodes will
be advanced through the tissue and to a desired position, as shown
in FIG. 7A. Electrode positioning can include, for example,
insertion and advancement through the skin and through the tissue
of the patient. Electrode positioning and arrangement within the
target tissue can be precisely controlled and may occur under the
guidance of tissue imaging methodology (e.g., ultrasound imaging,
X-ray, CT, etc.). FIG. 7B illustrates a cross-section view of a
target tissue having a plurality of positioned needle
electrodes.
[0055] In some embodiments, electrode positioning can be directed
to smaller distances so as to further allow more precise control of
the desired effect of the applied field on the tissue. Factors such
as differential conductive properties and resistance or tissue
impedance (e.g., differences in muscle, adipose, vasculature,
etc.), as well as differential perfusion of blood through
vascularized tissue, can limit the ability to control and/or
predict effects of delivered current field traversing larger
distances through tissue. In the present invention, distances
between activated electrodes can be limited to shorter distances,
such as a few centimeters or less, for improved control and
predictability of current effects (e.g., tissue heating, field
delivery, orientation, etc) on the targeted tissue. Thus, activated
electrodes in a pair or group can be spaced less than about 4 cm
apart. For example, adjacent electrodes of a pair or group will
typically be positioned within about 0.1 cm to about 2 cm of each
other. Distances of about 0.5 cm have been shown to be particularly
effective in providing controlled and predictable field delivery,
controlled tissue heating, as well as substantial therapeutic
effect.
[0056] As described above, a plurality of electrodes can be
positioned in the target tissue of a patient and the electrodes can
be activated in pairs or groups to deliver the therapeutic current
field to destroy cancerous tissue. A particular electrode of an
array need not be confined to a single unit, but can be activated
at different times in conjunction with different electrodes of the
plurality. For example, differential activation can include
activating a specific or selected series of electrode groups in a
particular or predetermined order. In one embodiment, a series of
selected pairs or groups can be activated in seriatim and/or in a
predetermined order, with activation control typically being
determined by operation or instructions (e.g., programming) of a
control system or module. Sequences of group activations can be
controlled and repeated, manually or by automation, as necessary to
deliver an effective or desired amount of energy.
[0057] Such differential activation may advantageously allow
delivery of fields throughout the target tissue and in a plurality
of different directions. As shown above by way of example, a simple
four electrode grouping of an array can be differentially activated
in pairs, with each different pair of electrodes providing a
different field delivery and orientation (possible field
flow/orientations are illustrated by arrows). While activation of
electrodes in discrete pairs provides simplicity, electrodes can be
activated in groups for more diverse field orientation and deliver.
For example, a delivery unit can include a centrally located
electrode surrounded by spaced outer or secondary electrodes, with
the applied field extending between the central electrode and the
outer spaced electrodes. In this manner, the outer electrodes can
essentially define an ablation volume with the inner/central
electrode positioned within the volume. Field delivery in this way
can be controlled and substantially contained within the ablation
volume. Examples described herein illustrate electrode positioning
including outer electrodes and an inner or centrally located
electrode. Electrode positioning will not be limited to any
particular configuration, and various arrangements will be
possible.
[0058] Treatment time according to the present invention can be
selected based on a variety of factors, such as characterization of
the tissue, energy applications selected, patient characteristics,
and the like. Energy application to a target tissue region during
treatment according to the present invention can be selected from a
few minutes to several hours. In some instances, effective
treatment is expected to occur in about 5 minutes to 90 minutes.
Effective preferential destruction of cancerous cells has been
observed in less than one hour, and in many cases about 15-30
minutes of energy application. Treatment can include a single
energy delivery period or dose, or multiple phases or doses of
energy application. As described above, electrodes can be
positioned in a first location and energy delivered, then moved to
subsequent location(s) for subsequent energy delivery. Treatment
can occur in phases or repeated, and/or may be coupled with
additional or alternative treatments or energy delivery
methods.
[0059] A system according to an embodiment of the present invention
is described with reference to FIG. 8. The system 200 can include
incorporated therewith any device of the present invention for
delivery of energy to the patient, and includes a power unit 210
that delivers energy to a driver unit 220 and than to electrode(s)
of an inventive device. The components of the system individually
or collectively, or in a combination of components, can comprise an
energy source for a system of the invention. A power unit 210 can
include any means of generating electrical power used for operating
a device of the invention and applying electrical current to a
target tissue as described herein. A power unit 210 can include,
for example, one or more electrical generators, batteries (e.g.,
portable battery unit), and the like. One advantage of the systems
of the present invention is the low power required for the ablation
process. Thus, in one embodiment, a system of the invention can
include a portable and/or battery operated device. A feedback unit
230 measures electric field delivery parameters and/or
characteristics of the tissue of the target tissue region, measured
parameters/characteristics including without limitation current,
voltage, impedance, temperature, pH and the like. One or more
sensors (e.g., temperature sensor, impedance sensor, thermocouple,
etc.) can be included in the system and can be coupled with the
device or system and/or separately positioned at or within the
patient's tissue. These sensors and/or the feedback unit 230 can be
used to monitor or control the delivery of energy to the tissue.
The power unit 210 and/or other components of the system can be
driven by a control unit 240, which may be coupled with a user
interface 250 for input and/or control, for example, from a
technician or physician. The control unit 240 and system 200 can be
coupled with an imaging system 260 (see above) for locating and/or
characterizing the target tissue region and/or location or
positioning the device during use. The system can further
optionally include a delivery unit or source of one or more
immunostimulatory agents or adjuvants. Such a delivery unit or
source can be wholly separate from other components of the system
or may be incorporated with one or more other components. For
example, a delivery unit or source may be coupled with or
incorporated together with a probe or one or more electrodes of a
probe (e.g., hollowed injection needle or electrode).
[0060] A control unit can include a, e.g., a computer or a wide
variety of proprietary or commercially available computers or
systems having one or more processing structures, a personal
computer, and the like, with such systems often comprising data
processing hardware and/or software configured to implement any one
(or combination of) the method steps described herein. Any software
will typically include machine readable code of programming
instructions embodied in a tangible media such as a memory, a
digital or optical recovering media, optical, electrical, or
wireless telemetry signals, or the like, and one or more of these
structures may also be used to transmit data and information
between components of the system in any wide variety of distributed
or centralized signal processing architectures.
[0061] Components of the system, including the controller, can be
used to control the amount of power or electrical energy delivered
to the target tissue. Energy may be delivered in a programmed or
pre-determined amount or may begin as an initial setting with
modifications to the electric field being made during the energy
delivery and ablation process. In one embodiment, for example, the
system can deliver energy in a "scanning mode", where electric
field parameters, such as applied voltage and frequency, include
delivery across a predetermined range. Feedback mechanisms can be
used to monitor the electric field delivery in scanning mode and
select from the delivery range parameters optimal for ablation of
the tissue being targeted.
[0062] Systems and devices of the present invention can, though not
necessarily, be used in conjunction with other systems, ablation
systems, cancer treatment systems, such as drug delivery, local or
systemic delivery, surgery, radiology or nuclear medicine systems,
and the like. For example, as indicated above, systems and devices
may include immunostimulatory agent or adjuvant delivery, and may
be configured for delivery of such agents in various form (e.g.,
liquid, solid, suspensions, and the like). Another advantage of the
present invention, is that treatment does not preclude follow-up
treatment with other approaches, including conventional approaches
such as surgery and radiation therapy. In some cases, treatment
according to the present invention can occur in conjunction or
combination with therapies such as chemotherapy. Similarly, devices
can be modified to incorporate components and/or aspects of other
systems, such as drug delivery systems, including drug delivery
needles, electrodes, etc.
[0063] The following examples are intended to illustrate but not
limit the invention.
EXAMPLES
Example 1
[0064] Initial testing included treatment of a breast cancer tumor
model in Female Fisher-344 rats (Charles River). Rat breast cancer
cells (MTLn-3) were initially grown in culture and subcutaneous
tumors were produced by implanting cells from cultures into the
abdomen of the animal. Tumors were grown to approximately 1 cm or
greater in diameter followed by low-temperature or mild
hyperthermia ablation treatment. As the MTLn-3 cell line is an
aggressively proliferating cell line, tumors were highly metastatic
and in some cases test animals presented more than one observable
tumor. In animals presenting more than one tumor, one tumor was
selected for direct insertion of electrodes for treatment with
additional tumors left unaddressed by direct electrode insertion
and energy application.
[0065] The probe used was of the triangle configuration with a
central anode and three outer cathodes (e.g., similar to probe
FIGS. 5A-5D). The radius of the probe from anode to cathode was
three millimeters. The electrode probe was coupled to a System
Control Module (SCM) designed to generate, deliver, monitor and
control the therapeutic field within the specified treatment
parameters. The SCM included of an integrated direct current (DC)
battery power source, an alternating current (AC) inverter, a
signal generator, a signal amplifier, an oscilloscope, an operator
interface monitor, and a central processing unit (CPU). The SCM was
battery powered and isolated from ground. AC current was derived
from the integrated power inverter. An intermediate frequency
(about 100 kHz) alternating current, sinusoidal wave form signal
can be produced from the signal generator. Total power output is
less than 1 watt. The treatment parameters are input by the
operator.
[0066] Energy application treatment times included 30 minutes, 90
minutes, and about 3 hours. Effective treatment times of shorter
duration, e.g., about 15 minutes, have been observed in separate
studies. Significant tumor destruction relative to untreated
control group animals was observed in a majority of the rats
subject to treatment.
[0067] The energy application demonstrated a significant, direct
tumor destructive effect on cancerous cells of the target treatment
region. In addition to the direct effect of current application on
cancerous cell viability, several observations suggested additional
tumor cell destruction effects, possibly by an immune system
mediated action including development of an in vivo immune memory
and cancerous cell specific immune mediated effect. First, a
subgroup of the treated animals surprisingly achieved long term
survival and viability, suggesting a systemic remission of cancer
treated. Because the tumor model was a highly metastatic cancerous
cell line, it was expected that even if eradication of a locally
treated tumor could be achieved, long term survival was unlikely as
the highly metastatic cells would be expected to have spread to
other regions of the animals body that were not directly subject to
current application. Those metastatic cells would be expected to
undergo proliferation and relatively rapidly produce lethal tumors,
thereby limiting the possibility of long term survival absent some
systemic response resulting from the localized treatment described
above. Second, as noted above, while several animals in the
treatment group exhibited multiple tumors, in each treated animal,
only one tumor was selected for energy application during the
testing. In several instances, untreated tumors that were remote
from the treatment site appeared to exhibit reduced tumor volume
several days following treatment.
[0068] Third, in one animal exhibiting multiple tumors, fluid
removed from a first tumor subjected to current delivery was
injected into a second tumor (not subjected to local current
delivery), followed by observed volume reduction in the second
tumor. Thus, a first tumor in the animal was selected for energy
application as noted above. Following current delivery to the first
tumor, a further step was performed where a hypodermic syringe was
used to remove fluid from the first tumor treatment site. The
removed fluid was then injected into a second tumor at a second
tumor site remote from the first tumor, where the second tumor had
not been directly subjected to local current delivery. A reduction
in tumor volume at the second tumor following fluid injection was
observed upon follow-up examination.
[0069] Fourth, several animals in the treatment group in which long
term survival was achieved exhibited a reduced susceptibility to
attempted tumor re-introduction and re-implantation following
treatment. As noted above, rats of the treatment group were
initially implanted (prior to energy application) with cancerous
cells and tumors successfully grown. A subset of rats (n=2) of the
treatment group subject to energy application as described
exhibited no observable tumors following treatment, with that
subset achieving surprisingly long term survival (e.g., greater
than 12 months compared to about 3 weeks of expected survival). The
two long-term surviving rats were later subject to cancerous cell
implantation according to the same implantation protocol initially
used. However, cancerous cell implantation following treatment was
unsuccessful in implanting/growing subsequent tumors in those long
term surviving animals, indicating a developed resistance to the
cancerous cell line.
[0070] Fifth, histopathology analysis of tissue of treated animals
has identified immune cells such as macrophages increasingly
present about the target tissue following energy application,
indicating a non-specific immune cell mediated response is at least
initially elicited by the current application. In combination with
other observations, e.g., including those listed above, initial
localized macrophage infiltration and immune system mediated
localized response to treatment suggests initial stages of
development of a adaptive immune response in the host that is
specific to the cancerous tissue treated and facilitated by the
localized current application.
Example 2
[0071] Additional study will address an increased in vivo specific
or adaptive immunological response of an individual subject against
a cancerous cell species following current application treatment
according to the present invention. In one example, a study will
include several groups of animals for experimental groups and
control. A control group (Group 1) can include tumor implantation
(carcinoma tumors such as MTLn3 and MATB3 tumor cell lines in
Fisher 344 rats, or 4T1 tumor cell line in BALB/c mice) into
immunologically intact (normal) rats or mice and the time to death
due to tumor metastasis measured with gross and microscopic
pathological evaluation to document the metastatic sites and
severity. Another group includes subjects where a primary or
treatment site is ablated by low-heat energy application as
described herein and the subjects are monitored for any
reoccurrence of tumors (Group 2). Any subjects in Group 2 that
survived past the time period where 80% of the mice in Group 1 died
or demonstrated clinical signs of metastatic disease will be
further evaluated for development of an immunological response that
at least partially contributed to survival from metastatic spread
of the cancer cells. These surviving subjects will be placed in
Group 3, and the same tumor attempted for implantation into the
subjects for evaluation of rate of acceptance of the transplanted
tumor compared to implantation acceptance rate in the initial Group
2. A group of untreated subject animals with the same age as those
in Group 3, which have no-prior tumor implantation or treatment,
will also be transplanted with the tumor cells (Group 4). Group 4
can control for any decrease in the acceptance rate of tumor
implantation is due to energy application/low-temperature ablation
treatment induced immunity and not age dependant resistance to the
tumor.
[0072] Pathological characterization of metastatic tumor sites and
immunohistological characterization of immune cell (e.g., dendritic
cells, macrophages, etc.) numbers and pattern in follicles of the
tumors regional lymph nodes and the spleen can be used as an
indirect assessment of immunological up-regulation of an immune
response to the tumor following energy application therapy.
Positive direct results of anti-tumor immunity in these studies
would indicate that the current application according to the
present invention not only destroyed the treated tumors directly,
but also inhibited the growth of metastatic and untreated tumor
foci within the animals through the induction of an antitumor
immune response.
Example 3
[0073] Tumor destruction according to the present invention
involves direct and indirect tumor kill, and potentially specific
or adaptive antitumor immunologic effects. To provide evidence for
the potential antitumor immunologic effects, low-heat or mild
hyperthermia inducing current application to a target tissue as
described herein is used to treat primary tumors and examine
prevention of metastases in the tumor model. A tumor model selected
will be an aggressive, spontaneously metastasizing tumor model, and
may include those mirroring human breast cancer, prostate cancer,
liver cancer, brain cancer, pancreatic cancer, or any variety of
tumor models. When grown in an animal, highly metastatic tumors
rapidly metastasize beyond the implantation site, e.g., to lung,
liver, lymph nodes, brain, etc.
[0074] To confirm a specific or adaptive immune mediated tumor
destruction by current application as described herein, tumors are
grown in animals, followed by current application treatment and
monitoring of survival. To determine whether the therapy could
enhance antitumor immunity and reduce metastatic growth, the lymph
node (LN) cells from treated and control animals are transferred to
naive recipient animals. Recipients are challenged with a
tumorigenic dose of the same tumor cells after adoptive transfer
and primary and secondary tumor growth in the recipients was
examined.
[0075] Animals receiving LN cells from treated animals are examined
for significant increased survival when compared to animals
receiving LN cells from control animals. LN cells isolated from
treated animals, but not control animals, are examined for
significantly inhibited primary tumor growth in recipients and
reduction in the number of metastases present after tumor
challenge. Depletion of certain immune cells, such as CD8.sup.+ T
cells, from the LN can be examined for an abolished effect. Results
will indicate whether current application therapy as described
herein not only destroys the treated tumors directly but also
controls growth of untreated tumors through induction of a specific
host antitumor immune response.
Example 4
[0076] In another example, evidence for specific/adaptive
immunologic effects resulting from delivery of current application
to a target tissue as described herein may optionally further
include examination of immuno-compromised animal model(s). For
example, a study may include two groups of animals as experimental
and control groups. A control group (Group 1) can include tumor
implantation (such as 3T3 mouse epithelial tumor cells, CT26 mouse
colorectal tumor cells, or EMT6/AR1 mouse breast cancer cells) into
wild-type (genomically normal) C57Bl/6 mice and the time to death
due to tumor metastasis measured with gross and microscopic
pathological evaluation to document the metastatic sites and
severity. Tumors can be implanted into a second group of C57Bl/6
mice having a genetic deficiency in RAG1 or RAG2 genes (Group 2).
Mice lacking RAG1 or RAG2 completely lack natural killer T, T and B
cells. However, DNA repair mechanisms are intact in nonlymphoid
tissues. The implanted tumors in both groups of mice can be ablated
by low-heat energy application as described herein and the animals
monitored for any reoccurrence of tumors.
[0077] Comparison of clinical and pathological characterization of
the primary tumor and metastatic tumor sites between the two groups
can provide direct evidence regarding the role of underlying
immunocompetence in suppressing tumor growth and development, and
impact on animal well-being. Immunohistological characterization of
tumor-infiltrating immune cells can provide additional information
regarding immune-mediated anti-tumor immunity. Positive direct
results of anti-tumor immunity, delayed tumor growth or metastases,
and improved survival in control animals compared to RAG-deficient
mice would indicate that the current application according to the
present invention not only destroyed the treated tumors directly,
but also inhibited the growth of metastatic and untreated tumor
foci within the animals through the induction of an antitumor
immune response.
Example 5
[0078] In another example, study may optionally further include
examination of immunosuppressed (non-genetically) animal model(s).
A study may include three groups of animals as control and
experimental treatment groups. Tumor cells (such as 3T3 mouse
epithelial tumor cells, CT26 mouse colorectal tumor cells, or
EMT6/AR1 mouse breast cancer cells) can be implanted into each
groups of wild-type C57Bl/6 mice. The implanted tumors in each
group of mice can be ablated by low-heat energy application as
described herein and the animals monitored for any reoccurrence of
tumors. After tumor ablation, animals in the experimental treatment
group (Group 1) can receive a cocktail of antibodies to deplete CD4
and CD8 T cells and IFN-.gamma.. Animals in a separate experimental
treatment group (Group 2) can receive adjuvant (such as Freund's
incomplete adjuvant) after tumor ablation to non-specifically
stimulate an immune response. The response in experimental Group 1
and 2 animals and untreated control animals (Group 3) can be
followed to evaluate time to death due to tumor metastasis measured
with gross and microscopic pathological evaluation to document the
metastatic sites and severity.
[0079] Comparison of clinical and pathological characterization of
the primary tumor and metastatic tumor sites between the
experimental treatment groups compared to controls can provide
direct evidence regarding the role of suppressed immunity (Group 1
vs Group 3) or stimulated immunity (Group 2 vs Group 3) in altering
tumor growth and development, and the associated impact on animal
well-being. Immunohistological characterization of
tumor-infiltrating immune cells can provide additional information
regarding immune-mediated anti-tumor immunity. Positive direct
results of anti-tumor immunity, delayed tumor growth or metastases,
and improved survival among immunostimulated animals (or reduced
performance in immunosuppressed animals) in these studies would
indicate that the current application according to the present
invention not only destroyed the treated tumors directly, but also
inhibited the growth of metastatic and untreated tumor foci within
the animals through the induction of an antitumor immune
response.
Example 6
[0080] Additional study will involve in vitro analysis of an
increased immunological response of an individual subject against a
cancerous cell species following current application treatment
according to the present invention. In one example, a study will
determine whether RF treatment of experimental VX-2T tumors in
rabbit skeletal muscle stimulates immune responses to VX-2T tumor
cells. Activation of a cellular immune response
(lymphoproliferation) will be determined by quantifying T-cell
proliferation to VX-2T cells before and after RF treatment in a
Lymphoproliferation Assay (LPA). Activation of a humoral immune
response (antibody production) will be determined by detection of
specific antibodies to VX-2T in an Enzyme-Linked Immunosorbent
Assay (ELISA). The Experimental design will involve isolation of
PBMCs (peripheral blood mononuclear cells or mixed lymphocytes) and
serum from rabbit blood prior to RF treatment and at two to four
weeks after treatment.
[0081] The LPA is the classic method for assessing lymphocyte
response to stimulation. Lymphocytes proliferate after incubation
in tissue-culture microtiter plates with non-specific mitogens such
as phytohemaglutin A (PHA) or with a specific antigen such as VX-2T
cell lysates. Proliferation can be measured by a number of ways.
For example, proliferation is measured by .sup.3H-thymidine
incorporation. The degree of 3H-thymidine incorporation provides an
indication of general lymphocyte activation to a specific antigen.
Activation is often expressed as the stimulation index:
SI=(.sup.3H-thy incorporation in media containing
antigen)/(.sup.3H-thy incorporation in media alone). FIG. 9 shows
an example of 3 naive rabbit PBMC response to PHA and to VX-2T cell
lysate. The SI to PHA for samples A-C is 3.9, 2.2 and 2.2
respectively. SI of 1.0 or lower indicates no response to VX2T.
Increase of the SI to VX-2T following RF treatment will be
examined.
[0082] The ELISA is a biochemical technique used in immunology to
detect the presence of an antibody or an antigen. In this case, the
analysis will look for antibodies to VX-2T that are generated by
rabbits following RF treatment. VX-2T cell lysate (the antigen) is
immobilized on a solid surface such as a 96-well plastic microtiter
plate. Then samples of diluted rabbit serum obtained before and
after RF treatment are added. Following this, an indicator antibody
(secondary antibody) with an attached enzyme such as goat
anti-rabbit conjugated to horse-radish peroxidase is added.
Thorough washing of wells is done following each incubation step to
remove non-specifically bound proteins. Detection of anti-VX-2T
antibodies generated in rabbits will be seen after addition of
substrate for the enzyme-linked secondary antibody as a visible
color change that can be measured by light absorption. It is
expected that antibodies may be detected after tumor implantation
as often is the case to any foreign proteins but will increase
significantly after RF treatment. These antibodies may play an
ancillary role in tumor clearance.
[0083] It is understood that the examples and embodiments described
herein are for illustrative purposes only and that various
modifications or changes in light thereof will be suggested to
persons skilled in the art and are to be included within the spirit
and purview of this application and scope of the appended claims.
Numerous different combinations, including combinations of
embodiments described herein, are possible, and such combinations
are considered part of the present invention.
* * * * *