U.S. patent application number 17/186534 was filed with the patent office on 2022-01-20 for methods of inhibiting hiv infections by pre-exposure prophylaxis.
This patent application is currently assigned to THE UNITED STATES OF AMERICA, as represented by the Secretary, Department of Health and Human. The applicant listed for this patent is THE UNITED STATES OF AMERICA, as represented by the Secretary, Department of Health and Human, THE UNITED STATES OF AMERICA, as represented by the Secretary, Department of Health and Human. Invention is credited to Thomas M. Folks, Jose Gerardo Garcia Lerma, Walid Heneine, Robert Janssen, Ronald A. Otten.
Application Number | 20220016139 17/186534 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-20 |
United States Patent
Application |
20220016139 |
Kind Code |
A1 |
Heneine; Walid ; et
al. |
January 20, 2022 |
METHODS OF INHIBITING HIV INFECTIONS BY PRE-EXPOSURE
PROPHYLAXIS
Abstract
A process is provided for protecting a primate host from a
self-replicating infection by an immunodeficiency retrovirus.
Protection is achieved by administering to the primate host a
combination of a pharmaceutically effective amount of a nucleoside
reverse transcriptase inhibitor and a pharmaceutically effective
amount of a nucleotide reverse transcriptase inhibitor prior to
exposure to the immunodeficiency retrovirus. The administration is
effective if provided in a single dose within 24 hours of the
exposure. A regime of regular daily doses is also effective in
providing protection against an immunodeficiency retrovirus
becoming self-replicating after infecting a primate host. A process
for controlling retrovirus transmission within a population
includes the administration to a subpopulation at high risk for
contracting an immunodeficiency retroviral infection the detailed
combination prior to sexual exposure to a source of
immunodeficiency retrovirus so as to preclude the immunodeficiency
retrovirus from becoming self-replicating in a member of the
subpopulation.
Inventors: |
Heneine; Walid; (Atlanta,
GA) ; Folks; Thomas M.; (Helotes, TX) ;
Janssen; Robert; (Atlanta, GA) ; Otten; Ronald
A.; (Villa Rica, GA) ; Garcia Lerma; Jose
Gerardo; (Decatur, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE UNITED STATES OF AMERICA, as represented by the Secretary,
Department of Health and Human |
Bethesda |
MD |
US |
|
|
Assignee: |
THE UNITED STATES OF AMERICA, as
represented by the Secretary, Department of Health and
Human
Bethesda
MD
|
Appl. No.: |
17/186534 |
Filed: |
February 26, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16808135 |
Mar 3, 2020 |
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17186534 |
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16413381 |
May 15, 2019 |
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16808135 |
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15913750 |
Mar 6, 2018 |
10335423 |
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16413381 |
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15406344 |
Jan 13, 2017 |
9937191 |
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15913750 |
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14679887 |
Apr 6, 2015 |
9579333 |
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15406344 |
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11669547 |
Jan 31, 2007 |
9044509 |
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14679887 |
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60764811 |
Feb 3, 2006 |
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International
Class: |
A61K 31/675 20060101
A61K031/675; A61K 31/513 20060101 A61K031/513; A61K 31/7072
20060101 A61K031/7072; A61K 45/06 20060101 A61K045/06; A61K 31/683
20060101 A61K031/683; A61K 9/00 20060101 A61K009/00 |
Goverment Interests
GOVERNMENT INTEREST
[0002] The invention described herein may be manufactured, used,
and licensed by or for the United States Government.
Claims
1. A method, comprising: prohibiting a primate subject from
acquiring an immunodeficiency retrovirus infection by: a.
determining if the primate subject is negative for a detectable
immunodeficiency retrovirus infection; and b. orally administering
a plurality of doses of at least one tablet comprising 200 mg
emtricitabine (FTC) and a pharmaceutically effective amount of a
tenofovir prodrug to the subject if the primate subject is negative
for the immunodeficiency retrovirus infection, wherein at least a
first dose occurs before the primate subject is potentially exposed
to the immunodeficiency retrovirus; and testing the primate subject
after the oral administration to confirm that the subject has
remained negative for the detectable immunodeficiency retrovirus
infection following a plurality of doses.
2. The method of claim 1, wherein the tenofovir prodrug is
tenofovir disoproxil fumarate in an amount of 300 mg.
3. The method of claim 1, wherein orally administering the at least
one tablet comprises orally administering one tablet per day.
4. The method of claim 1, wherein the tenofovir prodrug comprises a
tenofovir ester.
5. The method of claim 1, wherein the oral administration of the at
least one tablet results in an area under the plasma
concentration-time curve (AUC) over a 24 hour interval for
emtricitabine in the primate subject of 6.88 .mu.ghr/mL to 13.12
.mu.ghr/mL.
6. The method of claim 1, wherein the oral administration of the at
least one tablet results in an area under the plasma
concentration-time curve (AUC) over a 24 hour interval for
emtricitabine in the primate subject of 11 .mu.ghr/mL.
7. The method of claim 1, wherein the testing the primate subject
comprises a polymerase chain reaction (PCR) assay to detect the
presence of the immunodeficiency retroviral genome in the primate
subject.
8. The method of claim 1, wherein the oral administration of the at
least one tablet results in an absence of an immunodeficiency
retrovirus seroconversion in the primate subject.
9. The method of claim 1, wherein the primate subject is an adult
human subject.
10. The method of claim 1, wherein the oral administration of the
plurality of doses of the at least one tablet comprises a treatment
regimen over a time period, and wherein the testing of the primate
subject occurs regularly during the time period of the treatment
regimen.
11. The method of claim 1, wherein the oral administration of the
plurality of doses of the at least one tablet prohibits a
subsequent HIV-1 exposure of the primate subject from becoming a
self-replicating HIV-1 infection.
12. A method, comprising inhibiting a human subject who is
uninfected with human immunodeficiency virus 1 (HIV-1) from
becoming infected, by: a. screening the human subject to confirm
that the subject does not have a detectable HIV-1 infection; b.
orally administering a plurality of doses of at least one tablet
comprising 200 mg emtricitabine (FTC) and a pharmaceutically
effective amount of a prodrug of tenofovir to the subject if the
primate subject is confirmed to not have an HIV-1 infection,
wherein the administration occurs before the human subject is
exposed to HIV-1; and c. testing the human after the subject has
been potentially exposed to HIV-1 to confirm that the human subject
does not have an HIV-1 infection.
13. The method of claim 12, wherein the prodrug of tenofovir is
tenofovir disoproxil fumarate in an amount of 300 mg.
14. The method of claim 12, wherein the prodrug of tenofovir is a
tenofovir ester.
15. The method of claim 12, wherein administration of a single dose
of the tablet results in an area under the plasma
concentration-time curve (AUC) for emtricitabine of about 6.88
.mu.ghr/mL to about 13.12 .mu.ghr/mL.
16. The method of claim 12, wherein administration of a single dose
of the tablet results in an area under the plasma
concentration-time curve (AUC) for emtricitabine of 11
.mu.ghr/mL.
17. The method of claim 12, wherein the oral administration is a
daily oral dose of the tablet.
18. The method of claim 17, wherein the daily oral dose of the
tablet inhibits a subsequent HIV-1 exposure of the human subject
from becoming a self-replicating HIV-1 infection.
19. The method of claim 17, wherein the daily oral dose of the
tablet is administered daily for several months, and wherein the
subject is tested for HIV-1 infection during the course of the
several months of administration.
20. The method of claim 19, wherein the daily oral dose of the
tablet results in steady-state plasma levels of emtricitabine and
tenofovir in the primate subject.
21. A pre-exposure prophylactic treatment method for preventing an
exposure of a human subject to human immunodeficiency virus 1
(HIV-1) from becoming a HIV-1 self-replicating infection,
comprising: a. confirming that the human subject is serologically
negative for HIV-1; b. orally administering a plurality of daily
doses of a tablet comprising 200 mg emtricitabine (FTC) and a
pharmaceutically effective amount of a tenofovir prodrug to the
human subject if the human subject is serologically negative for
HIV-1, wherein the administration is initiated before the human
subject has been exposed to HIV-1; and c. testing the human subject
after several months of the oral administration to confirm that the
subject does not have a self-replicating HIV-1 infection.
22. The treatment method of claim 21, wherein the tenofovir prodrug
is tenofovir disoproxil fumarate in an amount of 300 mg.
23. The treatment method of claim 21, wherein the tenofovir prodrug
is a tenofovir ester.
24. The treatment method of claim 23, wherein if the testing
determines that the subject does not have a self-replicating HIV-1
infection after the several months of daily doses of the tablet,
then continuing with the daily doses of the tablet.
25. The method of claim 23, wherein the oral administration of the
daily doses of the tablet results in the human subject being
protected from developing a self-replicating HIV-1 infection
following sexual exposure to an HIV-1-infected subject.
26. A pre-exposure prophylactic treatment method for preventing an
exposure of a human subject to human immunodeficiency virus 1
(HIV-1) from becoming a HIV-1 self-replicating infection,
comprising: a. confirming that the human subject is negative for an
HIV-1 infection; b. orally administering a daily dose of a tablet
comprising 200 mg emtricitabine (FTC) and a tenofovir prodrug to
the human subject for several months if the human subject is
serologically negative for HIV-1; and c. testing the human subject
after the several months of the oral administration to confirm that
the human subject has not developed a self-replicating retroviral
infection.
27. The method of claim 26, wherein the tenofovir prodrug is
tenofovir disoproxil fumarate in an amount of 300 mg.
28. The method of claim 26, wherein the tenofovir prodrug is a
tenofovir ester.
29. The method of claim 26, wherein the oral administration of the
tablet results in an area under the plasma concentration-time curve
(AUC) over a 24 hour interval for emtricitabine in the human
subject of 10.0.+-.3.12 .mu.ghr/mL.
30. The method of claim 26, wherein the oral administration of the
tablet results in an area under the plasma concentration-time curve
(AUC) over a 24 hour interval for emtricitabine in the human
subject of 11 .mu.ghr/mL.
31. A kit, comprising a plurality of doses of a tablet comprising
200 mg emtricitabine (FTC) and a pharmaceutically effective amount
of a tenofovir prodrug, for use in the method of claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No.
16/808,135, filed on Mar. 3, 2020, which is a continuation of U.S.
patent application Ser. No. 16/413,381, filed on May 15, 2019,
which is a continuation of U.S. patent application Ser. No.
15/913,750, filed on Mar. 6, 2018, issued as U.S. Pat. No.
10,335,423, which is a continuation of U.S. patent application Ser.
No. 15/406,344, filed on Jan. 13, 2017, issued as U.S. Pat. No.
9,937,191, which is a continuation of U.S. patent application Ser.
No. 14/679,887, filed on Apr. 6, 2015, issued as U.S. Pat. No.
9,579,333, which is a continuation of U.S. patent application Ser.
No. 11/669,547, filed on Jan. 31, 2007, issued as U.S. Pat. No.
9,044,509, which claims the benefit of U.S. provisional application
60/764,811, filed on Feb. 3, 2006. All of the prior applications
are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0003] The present invention in general relates to a process for
inhibiting initial infection by a retrovirus such as human
immunodeficiency virus (HIV) and in particular to a combination of
a nucleoside reverse transcriptase inhibitor (NRTI) and a
nucleotide reverse transcriptase inhibitor (NtRTI) capable of
preventing self-replicating retroviral infection, even in response
to multiple viral challenges.
BACKGROUND OF THE INVENTION
[0004] Despite the fact that significant progress has been made
slowing the advancement of the symptoms of AIDS associated with HIV
infection, in the absence of an effective vaccine, HIV continues to
spread globally. The spread of HIV persists in part because an
infected individual remains a potential source of injection. It is
clear that current treatment of monitoring viral titer and in
response to a titer exceeding a preselected threshold commencing
treatment with highly active antiretroviral therapy (HAART) has not
prevented new infections.
[0005] An attractive method of controlling the spread of HIV would
be to provide an individual exposed to a potential source of HIV
with a pre-exposure prophylactic treatment. As HIV and, in
particular HIV-1, often begins with a comparatively small
population of retroviral particles being transmitted to a new host
and within a few days self-replicating into a retroviral titer
detectable in host blood serum. If the establishment of a
retroviral could be blocked before the HIV burden expands into a
self-propagating infection, an individual could avoid contraction
of HIV.
[0006] Previous attempts at pre-exposure prophylaxis have met with
limited success.
[0007] Prophylactic activity has been demonstrated with the NtRTI,
tenofovir in monkey models challenged with simian immunodeficiency
virus (SIV)..sup.1-3 Unfortunately, oral daily dosing and
pre-exposure prophylaxis with tenofovir at a dose equivalent to
that used in humans proved to only be partially protective against
rectal SHIV transmission..sup.4
[0008] HAART therapy involves the administration of a combination
including at least three active compounds classified by the mode of
operation as an NRTI, an NtRTIs, a non-nucleoside reverse
transcriptase inhibitors (NNRTIs), protease inhibitor, and an entry
inhibitor. While HAART is effective in lowering retroviral titer in
a host, concerns remain as to the long term toxicity and the
retained potential to infect others. It is also unknown if
initiating HAART therapy in a pre-exposure prophylactic regimen
would be efficacious. As a result, society remains devoid of a
pre-exposure prophylactic regimen to prevent an individual from
developing self-propagating retrovirus infection subsequent to
initial exposure.
[0009] Thus, there exists a need for a chemoprophylactic
composition and dosing regimen effective in blocking early stage
infection by retrovirus in a host founder cell population. There
also exists a need for a chemoprophylactic composition formulated
with a vehicle amenable to user compliance.
SUMMARY OF THE INVENTION
[0010] A process is provided for protecting a primate host from a
self-replicating infection by an immunodeficiency retrovirus.
Protection is achieved by administering to the primate host a
combination of a pharmaceutically effective amount of a nucleoside
reverse transcriptase inhibitor and a pharmaceutically effective
amount of a nucleotide reverse transcriptase inhibitor prior to
exposure to the immunodeficiency retrovirus. The administration is
effective if provided in a single dose prior to the exposure. A
regime of multiple temporally spaced doses prior to retroviral
exposure is also effective in providing protection against an
immunodeficiency retrovirus becoming self-replicating after
infecting a primate host. A process for controlling retrovirus
transmission within a population includes the administration to a
subpopulation at high risk for contracting an immunodeficiency
retroviral infection a combination of a pharmaceutically effective
nucleoside reverse transcriptase inhibitor and a pharmaceutically
effective amount of a nucleotide reverse transcriptase inhibitor
prior to exposure to a source of immunodeficiency retrovirus so as
to preclude the immunodeficiency retrovirus from becoming
self-replicating in a member of the subpopulation.
[0011] A kit is also provided that includes at least one
combination dose of a pharmaceutically effective amount of a
nucleoside reverse transcriptase inhibitor and a pharmaceutically
effective amount of a nucleotide reverse transcriptase inhibitor
sufficient to protect a primate host from developing a
self-replicating retroviral infection along with instructions for
the administration of the at least one dose one prior to and
optionally one additional dose subsequent to a potential exposure
to an immunodeficiency retrovirus along with dosing modifications
associated with subject characteristics and behaviors to further
reduce the risk of contracting a self-replicating immunodeficiency
retrovirus infection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic depicting one study of the present
invention for 4 groups of macaques in which all treated macaques
received known antiretroviral medications 7 to 9 days prior to the
first virus inoculation and continuing throughout the study with
treated animals that remained uninfected throughout the 14 viral
challenges receiving 28 additional days of post-exposure
prophylactics.
[0013] FIG. 2 is a survival curve graph for macaque Groups
1.about.4 per FIG. 1, as well as for animals receiving only
tenofovir disoproxil fumarate (TDF).
[0014] FIG. 3 is a graph depicting a plot of viremia as a function
of time for untreated controls (.smallcircle.) and breakthrough
infections (.cndot.) where each point represents a mean viremia
observed, 0 time indicates peak plasma virus load observed in a
given animal where the arrow bars denote standard error of the mean
(SEM).
[0015] FIG. 4 depicts plots of infection dynamics as a function of
time during the study per FIG. 1 with plots for animals coded as
AG-80, AG-46, AH-04 and AG-07 corresponding to emtricitabine (FTC)
treatment alone, or FTC plus TDF treatment (AI-54 and AG-81). The
arrow indicates the first detectable antibody response. Grey
circles indicate detectable M184V/I mutation; wild type sequences
are shown in as black full circles. Open circles indicate the time
points where no genotype was undertaken.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The present invention has utility in protecting a primate
host from self-propagating immunodeficiency virus infection. The
use of a combination of antiretroviral agents as a prophylactic
dosing regime is also provided for the manufacture of a medicament
is provided for protection against a human immunodeficiency virus
infection developing to a level of self-replicating infection.
Retroviral transmission through most routes entails a new primate
host receiving a small number of viral particles. Common routes of
retrovirus transmission illustratively include sexual intercourse,
medical worker skin puncture inoculation, hypodermic needle
sharing, blood transfusions, birth canal exposure, breastfeeding,
and transplacental contact between individuals. Through the
administration of at least one nucleoside reverse transcriptase
inhibitor (NRTI) and at least one nucleotide reverse transcriptase
inhibitor (NtRTI) prior to a retrovirus exposure protection is
provided against development of a self-replicating retroviral
infection. As the aforementioned exposure routes are characterized
by a small number of retrovirus particles being transferred to the
new primate host, this initial phase of infection represents a
window of opportunity to protect a host from infection. The
inventive chemoprophylactic treatment is provided through a dosing
regimen. A dosing regimen according to the present invention that
provides retroviral protection to a host primate includes at least
one single dose administered prior to initial retroviral exposure.
An inventive dosing regimen also includes a course of multiple
doses administered in advance of exposure to maintain a therapeutic
level of NRTI and NtRTI agents in the primate host. The timing of
the at least one does prior to retroviral exposure is dictated by
the pharmacokinetics of the NRTI and NtRTI components to assure the
presence of a therapeutically effective amount of inventive
composition for at least 20 hours subsequent to the exposure to the
communicated small retroviral particle population. Multiple doses
are administered according to the present invention at regular time
intervals and amounts such as for example like formulated daily
doses for a period of several days, weeks, or months; or are
administered in advance of a likely exposure as a cluster of doses,
with the amount of NRTI and NtRTI components in each dose being
independent of the of amount of NRTI and NtRTI in other doses
within the cluster. While most oral, topical, and parenteral
existing versions of NRTIs and NtRTIs are fully absorbed and
therapeutically active within 1 to 8 hours, it is appreciated that
subcutaneous implants and long acting timed release formulations
allow for a single dose to sustain therapeutically effective
amounts of an inventive prophylactic composition for several days,
weeks, or even months. Representative of sustained release
compositions and implants are provided in the U.S. Pat. Nos.
4,122,129; 4,927,687; 4,996,047; 5,169,642; and 5,656,296.
[0017] The combination of NRTI and NtRTI compounds administered
prophylactically according to the present invention are shown to
provide a dose-dependent inhibition of HIV self-replicating
infection and a therapeutically effective dosing primate host
protection against self-replicating HIV infection is provided, even
in response to multiple viral challenges. While the present
invention is largely detailed with respect to HIV-1 as a
prototypical infectious and pathogenic retrovirus, it is
appreciated that other retroviruses owing to reliance on reverse
transcription for replication are also protected against in a
primate host according to the present invention.
[0018] As used herein, "protection" as used in the context of a
host primate response to an immunodeficiency virus challenge is
defined by the host primate being serologically negative and
negative in response to a polymerase chain reaction (PCR) testing
for viral genome.
[0019] As used herein, the term "retrovirus" is inclusive of any
virus that utilizes reverse transcriptase in the viral replication
cycle and therefore is susceptible to the antiviral activity of
nucleoside or nucleotide analogs specifically inclusive of HIV
(HIV-1 and HIV-2), HTLV-1, HTLV-2, HTLV-3, HTLV-4, and SIV. Also
encompassed are viruses such as HBV that although not technically
classified as retroviruses nonetheless utilize a reverse
transcriptase and are therefore susceptible to the antiviral
activity of nucleoside and/or nucleotide analogs.
[0020] As used herein a "primate host" is defined to include a
monkey, baboon, chimpanzee, gorilla, and a human. Nonhuman primates
are appreciated to themselves be susceptible to infection by
retroviruses and in particular immunodeficiency viruses and
represent well-established animal models as to human response with
an appreciation that physiological differences often require
different doses in milligrams per kilogram for a nonhuman primate
animal model relative to a human.
[0021] The compositions of the present invention include
administration in combination of an NRTI and NtRTI and are readily
compounded by pharmaceutical composition with conventional
pharmaceutically acceptable carriers or diluents. Additionally,
pharmaceutically acceptable derivatives and prodrugs of active
NRTIs and NtRTIs operative in the present invention include salts
such as alkali metal salts; esters such as acetate, butyrate,
octinoate, palmitate, chlorobenzoates, benzoates, Ci-C6 benzoates,
succinates, and mesylate; salts of such esters; and nitrile oxides.
It is appreciated that other analogs of pharmaceutically active
NRTIs or NtRTIs that provide within a primate host an active
antiviral metabolite residue are also suitable as part of an
inventive composition. A pharmaceutically acceptable carrier or
diluent includes agents that are compatible with other ingredients
of a dosage and not injurious to a primate host. The identity and
process for compounding a combination of at least one NRTI and at
least one NtRTI into a dosage form suitable for delivery by a route
with administration by oral, rectal, topical, vaginal or parenteral
routes of administration are provided in Remington's Science and
Practice of Pharmacology, 20.sup.th Edition, Chapters 37-47, pages
681-929, where parenteral injection includes subcutaneous,
intramuscular, intravenous, and intradermal injection.
[0022] As used herein the term "prodrug" is defined to include a
compound that when administered to a primate host generates an
active NRTI or NtRTI as a result of spontaneous reaction under
physiological conditions, enzymatic catalysis, metabolic clearance,
or combinations thereof. An exemplary NtRTI prodrug currently FDA
approved for HAART use is tenofovir disoproxil fumarate (TDF) and
is detailed in U.S. Pat. No. 5,935,946.
[0023] The present invention provides an alternative to
conventional retroviral therapy using HAART, in response to
self-propagating HIV infection by protecting a primate host against
the establishment of self-replicating retroviral infection that
provides an indication for such therapy. Through prophylactic prior
dosing with an inventive combination including at least one NRTI
and one NtRTI, replication of the comparatively low number of viral
particles received by a host primate is prevented.
[0024] To achieve protection against a primate host developing a
retroviral self-replicating infection, at least one dosage of an
NRTI and NtRTI is administered to the primate host prior to
exposure to the retrovirus. Preferably, the at least one NRTI and
at least one NtRTI are administered concurrently. More preferably,
the combination of reverse transcriptase inhibitors is compounded
into a single formulation.
[0025] The process of the present invention demonstrates protection
against retroviral self-replicating infection through
administration of even a single dosage administered prior to the
retroviral exposure. Owing to the known pK rates of specific NRTIs
and NtRTIs, a single dosage is administered to assure a
therapeutically effective amount of NRTI and NtRTI persist in the
primate host for a time of more than 12 hours after viral
challenge. With conventional NRTI and NtRTI formulations, currently
approved for HAART, preferably an inventive dose is administered
within 12 hours prior to retroviral exposure and still more
preferably often within 2 hours prior to retroviral exposure. The
practice of the inventive process involving the administration of a
single dosage in the hours proceeding a likely retroviral exposure
is particularly advantageous in assuring compliant dosing in a
human and also avoids side effects associated with a regular dosing
regime and is particularly well suited for a human engaging in a
sporadic behavior likely to bring the person into retroviral
exposure. Preferably, an additional dose or doses of a combination
of at least one NRTI and at least one NtRTIs is provided subsequent
to the retroviral exposure event to assure adequate antiviral
reverse transcriptase inhibitor concentration during and
immediately subsequent to retroviral infection of the host founder
cell population so as to preclude retroviral self-replication to
assure NRTI and NtRTI incorporation into a replicating virus
genome. Preferably, a dose of an inventive composition taken after
retroviral exposure is administered within 24 hours subsequent to
the exposure, and more preferably within 12 hours subsequent to the
exposure.
[0026] Alternatively, an individual routinely subjected to
retroviral exposure can be protected against the development of a
self-replicating retroviral infection through administration of
regular prophylactic doses of an inventive combination. As a
result, an epidemiological advantage exists in controlling the
outbreak and spread of a retrovirus within a population is provided
through offering routine doses of an inventive composition
prophylactically to high-risk persons such as sex workers and a
short course prophylactic inventive composition to uninfected sex
trade clientele.
[0027] It is appreciated that hybrid dosing regimes of an inventive
composition are also operative herein and include multiple doses
prior to retroviral exposure with multiple doses not being
administered for a duration or with sufficient periodicity to arise
to the level of a routine prophylactic regime.
[0028] The at least one nucleoside reverse transcriptase inhibitor
has the attribute of interfering with in vivo viral replication. An
NRTI operative in an inventive prophylactic process includes
emtricitabine, lamivudine, zalcitabine, zidovudine, azidothymidine,
didanosine, stavudine, abacavir; with the aforementioned specific
NRTIs intended to include pharmaceutically acceptable salts,
esters, ester salts, nitrile oxides, and prodrugs of any of the
active agents.
[0029] An at least one nucleotide reverse transcriptase inhibitor
(NRTI) present in an inventive composition to protect a primate
from developing a self-replicating retroviral infection
illustratively includes tenofovir, adefovir;
2',3'-dideoxy-3'-fluoroadenisine; 2',3'-dideoxy-3'-fluoroguanasine;
3'deoxy-3'-fluoro-5-042-(L-valyloxy)-propionyllguanosine with the
aforementioned specific NtRTIs intended to include pharmaceutically
acceptable salts, esters, ester salts, nitrile oxides, and prodrugs
of any of the active agents.
[0030] Optionally, an inventive composition also includes within an
inventive combination other antiretrovirals such as nonnucleoside
reverse transcriptase inhibitors, protease inhibitors, fusion
inhibitors, and combinations thereof. Representative non-nucleoside
reverse transcriptase inhibitors operative herein illustratively
include delavirdine, efavirenz, nevirapine, and other
diarylpyrimidine (DAPY) derivatives. Representative protease
inhibitors operative herein illustratively include amprenavir,
tipranavir, indinavir, saquinavir, lopinavir, ritonavir,
fosamprenavir calcium, ritonavir, atazanavir sulfate nelfinavir
mesylate, and combinations thereof. An entry inhibitor operative
herein as an optional active ingredient in an inventive composition
illustratively includes enfuvirtide, Schering C (Schering Plough),
S-1360 (Shionogi), and BMS806 (Bristol Myers Squibb).
[0031] The dose of individual active components of an inventive
prophylactic composition is administered to create a therapeutic
concentration of the active composition at the situs of retrovirus
initial founder cell population infection prior to viral exposure.
It is appreciated that establishing a therapeutic concentration at
the time of viral replication for a given NRTI, NtRTI or optional
additional active agent in the target cells, includes factors for
the therapeutic agent such as the route of administration,
pharmacokinetics, absorption rate based on administration route,
effects of food on oral absorption, in vivo distribution, metabolic
pathways, elimination route, race, gender, and age of the subject,
single dose incident side effects, long term administration side
effects, and synergistic effects with co-administered active
agents. Information related to these factors considered in dosing
are available from the United States Food and Drug Administration
(http://www.fda.gov/oashi/aids/virals.html) Preferably, NRTI and
NtRTI prophylactic dosing according to the present invention uses
as a starting point the maximal recommended tolerated dosing levels
for the given active agent combination associated with HAART
treatment protocols.
[0032] An inventive kit is provided that includes a 2-dose package
of oral doses, such as tablets. In an exemplary embodiment of FDA
approved NRTI and NtRTIs, each dose contains between 100 and 2500
milligrams (mg) of emtricitabine and between 100 and 2500 mg of TDF
along with instructions to ingest the first dose approximately 1 to
8 hours prior to potential retroviral exposure and preferably about
2 hours there before, and a second dosage to be ingested 20 to 48
hours after potential retroviral exposure, preferably at about 22
hours thereafter. For an adult human, preferably each of the doses
includes 200 mg of emtricitabine and 300 mg TDF. A non-human
primate dose according to the present invention is typically higher
on a mg per kg animal body weight basis by a factor typically
ranging from 2 to 10. Additional NRTIs, NtRTIs, NNRTIs, protease
inhibitors or entry inhibitors are optionally provided in concert
with either or both of these doses. The kit also includes
instructions as to the timing of doses, contraindications,
modifications associated with food ingestion, and additional
behaviors that the recipient (synonymously described herein as a
human primate host) can undertake to reduce the risk of retrovirus
exposure and initial infection. It is also appreciated that a
carrier illustratively including a gel, jelly, cream, ointment,
film, sponge, foam, suppository, vaginal ring or other delivery
device is provided containing an NRTI such as emtricitabine, alone
or in combination with an NtRTI such as tenofovir or TDF. The
carrier is readily applied to mucosal tissue likely to be exposed
to viral transmission as an added level of protection in concert
with the oral doses.
[0033] An inventive kit is also provided that includes at least one
NRTI and at least one NtRTI compounded as a gel, jelly, cream,
ointment, film, sponge, foam, suppository, or applied to a vaginal
ring or other like antiviral barrier. To prepare such a
pharmaceutical compounded form, an effective amount of each of the
active agents inclusive of at least one NRTI and NtRTI is combined
in admixture with the pharmaceutically acceptable carrier or
applied to a surface of the barrier. It is appreciated that the
residence time of such a pharmaceutical composition is maintained
at the site of administration through the inclusion of an optional
bioadhesive that provides adhesion to mucosal tissue or the dermis.
An inventive composition compounded for application to the dermis
or mucosal tissue is provided along with instructions as to the
timing of doses, contraindications, modifications associated with
food ingestion, and additional behaviors that the person
(synonymously described herein as a human primate host) can
undertake to reduce the risk of retrovirus exposure and initial
infection. Optionally, a kit containing an oral dosage is combined
with a composition compounded for application to the dermis, rectal
mucosa or vaginal mucosa so as to assure a therapeutically
effective combination of NRTI and NtRTI at the mucosal point of
retroviral entry associated with sexual exposure, as well as a
therapeutically effective serum circulating quantity of
prophylactic antiretrovirals.
[0034] The present invention is further detailed with respect to
the following non-limiting examples. These examples are intended to
provide exemplary specific embodiments of the present invention and
are not intended to limit the scope of the appended claims.
EXAMPLES
Example 1--Antiretroviral Drugs and Doses
[0035] A dose of 22 mg/kg of tenofovir disoproxil fumarate (TDF) is
given orally and 20 mg/kg of emtricitabine (FTC) given orally or
subcutaneously to one group of adult male rhesus macaques. The 22
mg/kg TDF dose resulted in an area-under the plasma
concentration-time curve over a 24 h interval (AUC) of 4.49
.mu.g.times.hr/ml which was similar to the value of 5.02
.mu.g.times.hr/ml observed in human receiving 300 mg of TDF. The
dose of 20 mg/kg of FTC resulted in an AUC value (11
.mu.g.times.hr/ml), also similar to that observed in humans
receiving 200 mg of FTC orally (10.0.+-.3.12
.mu.g.times.hr/ml).sup.6. Subcutaneous administration of FTC
results in plasma FTC levels comparable to those achieved during
oral administration, indicating a high FTC absorption in rhesus
macaques.
[0036] Oral administration of FTC and TDF to macaques is by mixing
the drug powders with peanut butter or fruit. Macaques are observed
to ensure ingestion.
Example 2--Virus Inoculations
[0037] A chimeric envelope SHIV.sub.SF162P3 isolate is used to
inoculate the macaques. SHIV.sub.SF162P3 is a construct that
contains the tat, rev, and env coding regions of HIV-1.sub.SF162 in
a background of SIVmac239. This isolate was obtained from the
National Institutes of Health (NIH) AIDS Research and Reference
Reagent Program..sup.7,8 Virus exposures are performed 2 hours
after drug treatment, and involved non-traumatic inoculation of 1
mL of SHIV.sub.SF162P3 (10 TCID.sub.50 or 7.5.times.10.sup.6 viral
RNA copies) into the rectal vault via a sterile gastric feeding
tube..sup.9 Anesthetized macaques remained recumbent for at least
15 min after each intra-rectal inoculation.
Example 3--SHIV Viral Load Assay
[0038] Plasma RNA is quantified using a real-time PCR assay as
previously described..sup.5 This assay has a sensitivity of
detection of 50 RNA copies/ml or 10 copies of a pVp1 plasmid
carrying the SIVmac239 RT gene. HIV-1 RNA is extracted from 1 mL of
plasma using the NucliSens extraction method (bioMerieux). A known
amount of virus particles (3.times.10.sup.5) from an HIV-1 CM240
virus stock is added to each sample prior to extraction to control
for the efficiency of extraction. Reverse transcription is
performed using 10 microliters (.mu.l) of extracted RNA and the
2-step TaqMan Gold reverse-transcriptase (RT)PCR kit (Applied
Biosystems) according to the manufacturer's instructions. PCR
reactions are performed as described using an ABI 7000 Gene
Detection System (Applied Biosystems). Virus loads are calculated
from a standard curve generated with known amount of virus
particles. All primers and probes used for SIVmac239 and HIV-1
CM240 have been reported elsewhere..sup.5 HIV-1 CM240 is obtained
from the National Institutes of Health (NIH) AIDS Research and
Reference Reagent Program.
Example 4--Detection of Genotypic Resistance to FTC and
Tenofovir
[0039] Emergence of FTC and tenofovir resistance is monitored by
sequence analysis of SIV RT (551 bp; amino acids 52 to 234) and by
a more sensitive allele-specific real-time PCR method for the K65R
and M184V mutations. Sequence analysis was done from plasma viruses
using an RT-PCR procedure as previously described..sup.5 The Vector
NTI program (Version 7, 2001) is used to analyze the data and to
determine deduced amino-acid sequences. Detection of low frequency
of K65R and M184V mutants in plasma by real-time PCR is performed
as previously described..sup.10 These assays have a detection limit
of 0.4% of K65R and 0.6% of M184V cloned sequences in a background
of wild type plasmid.
Example 5--Virus-Specific Antibody Responses
[0040] Virus-specific serologic responses (IgG and IgM) are
measured using a synthetic-peptide EIA (Genetic Systems
HIV-1/HIV-2) assay.
Example 6--Statistical Methods
[0041] The exact log-rank test is used for a discrete-time survival
analysis of the treatment and control groups, with use of the
number of inoculations as the time variable. The Cox proportional
hazards model is used to estimate the relative hazard ratio (HR).
Percent protection is calculated from the HR value using the
formula: (1-1/HR).times.100. All statistical analyses for
calculation of the efficacy of the different interventions are
performed using SAS software (version 9.1; SAS Institute) and
StatXact software (version 6.3; Cytel).
Example 7--Routine Dosing Experimental Design
[0042] Macaques are exposed rectally once weekly for up to 14 weeks
to SHIV162p3 which contains an R5 tropic HIV-1 envelope that
resembles naturally transmitted viruses. The SHIV162p3 challenge
dose is 10 TCID.sub.50 or 7.6.times.10.sup.5 RNA copies which is
similar to HIV-1 RNA levels in semen during acute infection in
humans..sup.11 Virus exposures are terminated when a macaque became
infected. FIG. 1 shows the study design and the interventions
evaluated in each group of macaques. Three prophylactic drug
treatments of increasing drug potency are each given once daily to
a group of six macaques. Animals in Group 1 were treated
subcutaneously with 20 mg/kg of FTC alone. Animals in Group 2
received orally a combination of FTC (20 mg/kg) and TDF (22 mg/kg).
Animals in Group 3 had the most protective treatment with
subcutaneous 20 mg/kg of FTC and a 22 mg/kg of tenofovir (PMPA).
The rate of infection in each group is compared with that seen in
18 untreated control macaques (9 real time and 9 historical
controls).
[0043] All treated macaques received the corresponding drugs 7 to 9
days prior to the first virus inoculation to achieve steady-state
plasma levels. Treated animals that remained uninfected during the
14 challenges received 28 days of post-exposure prophylaxis after
the last challenge. Protection was defined as absence of persistent
viremia and seroconversion. Treated animals that became infected
continued treatment for an average of 21 weeks (range=13 to 29) to
monitor for plasma viremia and drug resistance development.
Example 8--Survival Curves
[0044] FIG. 2 shows the survival curves observed for each group of
animals per Example 7. Data with TDF (20 mg/kg) is also provided
for comparison. Untreated macaques are infected after a median of 2
rectal exposures (mean=4). The majority of the animals (13/18 or
72%) are infected during the first 4 challenges (median=2); 4 (22%)
are infected between exposures 8 and 14 (mean=10), and only 1 (6%)
remained uninfected after 14 exposures. The median 2 exposures for
infection in controls suggests that an animal receiving
prophylactic treatment and remaining uninfected after 14 virus
challenges would have been protected against a median of 7 rounds
of transmissions. Treatments of Groups 1-3 are all protective to a
degree with a clear dose-response relationship being observed. All
6 macaques in Group 3 that received the most potent inventive
composition remained uninfected demonstrating that full protection
against repeated challenges is possible. Of the 6 macaques in Group
2, 4 were protected and only 2 (animal reference numbers AI-54 and
AG-81) became infected at exposures 9 and 12. Compared to controls,
infection in this group is reduced by 7.8-fold (Cox proportional
hazard ratio [HR]=7.8, p=0.0075). Infection in both animals is
significantly delayed compared to the untreated controls
(p=0.0004). These 2 macaques became seropositive 2 weeks after the
first detectable viral RNA in plasma and both were proviral DNA
positive at weeks 10 and 12, respectively. Of the 6 macaques in
Group 1 receiving FTC only, 2 remained protected after 14 exposures
and 4 had the first detectable viral RNA at exposures 5 (AG-80), 10
(AG-46), 12 (AH-04), and 13 (AG-07), respectively. Survival
analysis showed a statistically significant difference from
untreated controls (p=0.004). Compared to controls, infection is
reduced 3.8-fold macaques (Cox proportional hazard ratio [HR]=3.8,
p=0.021). Infection in these 4 animals is also confirmed by PCR
amplification of proviral DNA from PBMCs and by serology; antibody
responses are detectable 3, 1, 2, and 6 weeks after the first
detectable RNA, respectively. FIG. 2 also shows that the protection
achieved with FTC alone was higher than that previously seen in 4
animals receiving TDF,.sup.5 consistent with the slightly higher
potency of FTC, although the difference was not statistically
significant (p=0.5).
Example 9--Prophylactic Breakthrough Infections and Drug Resistance
Emergence
[0045] Since the dynamics of breakthrough infections that occur
during inventive prophylaxis and drug resistance emergence are
unknown, the 6 infected animals from Groups 1 and 2 are followed
under continued drug treatment. FIG. 3 compares the virus load
kinetics in the 6 breakthrough infections with those in 12
untreated macaques that had sufficient follow-up samples. The mean
peak viremia in the 6 treated macaques was 4.9.+-.0.5 log.sub.10
RNA copies/ml, 2.0 log.sub.10 lower than in untreated controls
(6.9.+-.0.3 log.sub.10 RNA). FIG. 3 also shows that such
differences in viremia were maintained up to week 11 as indicated
by similar rate of virus load decline seen in the two groups of
animals (-0.23.+-.0.02 log.sub.10/week in treated vs. -0.29.+-.0.02
log.sub.10/week in untreated controls). The individual virus load
kinetics in the 6 breakthrough infections are shown in FIG. 4.
Three FTC (AG-80, AH-04, and AG-07) and one of the FTC/TDF (AG-81)
failures had undetectable virus loads 3, 4, 7, and 11 weeks after
the peak in viremia, respectively; viremia in these animals
remained consistently low or undetectable for up to 20 weeks. In
contrast, all 12 untreated macaques had detectable virus loads
during a median follow-up period of 7 weeks (range=5-36 weeks). The
arrow in FIG. 4 denotes the first detectable antibody response.
Grey circles indicate detectable M184V/I mutation; wild type
sequences are shown in black full circles. Open circles are
provided for data points not genotyped.
[0046] Drug resistance testing showed that wild type virus
initiated all 6 breakthrough infections in Groups 1 and 2
reflecting residual virus replication in target cells not protected
by drugs (FIG. 4). Four animals had no evidence of drug resistance
despite extended treatment (median=23 weeks). Only 2 animals had
detectable M184V (AG-46, FTC-treated) or M1841 (AI-54
FTC/TDF-treated) mutations associated with FTC resistance at week 4
and 10, respectively. The tenofovir-associated K65R mutation is not
detected in the 2 Group 2 animals receiving FTC/TDF. FIG. 4 also
shows that the 2 macaques that selected M184V/I had the highest
peak viremias. Without intending to be bound to a particular
theory, it is hypothesized that more virus replication in these
animals may have facilitated drug resistance selection. Reductions
in acute viremia are proposed to contribute at a population level
to a decrease in virus transmissibility.
Example 10--Single Dosing
[0047] The process of Example 7 is repeated in Group 3 with drugs
only being administered 2 hours prior to and 22 hours subsequent to
each inoculation. The resultant survival curves are comparable to
those detailed in Example 8.
Example 11--Single Dosing with Suppository
[0048] A group of 6 macaques received the drug treatment of Group 3
per Example 7 in the form of a gel inserted rectally containing 300
mg of tenofovir and 300 mg lamuvidine (3-TC) 1 hour before viral
inoculation with observation to assure that the suppository is not
voided. The gel is formed by compounding tenofovir and 3-TC in 2%
by weight hydroxyethyl cellulose (HEC)-based gel in both a vaginal
formulation (pH 4.5) and rectal formulation (pH 6.5) containing
(w/v) 3% tenofovir, and 3% 3-TC. The gels are stable at room
temperature for at least five months with no loss in activity; and
gels retained full activity at both pH 4.5 and pH 6.5 at levels
equivalent to those observed for tenofovir and 3-TC preparations in
water. Using an MT4/MTT phenotypic assay, all gels were tested for
activity against wild-type HIV-1.sub.HXB2, and resistant HIV-1
viruses containing the K65R or M184V mutations. No significant
cytotoxicity is seen in the cervical explant model.
[0049] Viral protection of the macaques is maintained throughout
the study.
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[0061] Patent documents and publications mentioned in the
specification are indicative of the levels of those skilled in the
art to which the invention pertains. These documents and
publications are incorporated herein by reference to the same
extent as if each individual document or publication was
specifically and individually incorporated herein by reference.
[0062] The foregoing description is illustrative of particular
embodiments of the invention, but is not meant to be a limitation
upon the practice thereof. The following claims, including all
equivalents thereof, are intended to define the scope of the
invention.
* * * * *
References