U.S. patent application number 12/557099 was filed with the patent office on 2010-05-06 for use of ramoplanin to treat diseases associated with the use of antibiotics.
Invention is credited to Daniela Jabes, Richard F. Labaudiniere, Timothy S. Leach, Giorgio Mosconi, Steven M. Rauscher.
Application Number | 20100112091 12/557099 |
Document ID | / |
Family ID | 29739879 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100112091 |
Kind Code |
A1 |
Jabes; Daniela ; et
al. |
May 6, 2010 |
USE OF RAMOPLANIN TO TREAT DISEASES ASSOCIATED WITH THE USE OF
ANTIBIOTICS
Abstract
The invention features a method of treating or preventing a
disease associated with the use of antibiotics in a patient in need
thereof by administering to the patient ramoplanin in an amount and
for a duration effective to treat said disease. The disease may be
caused, for example, by the presence of a bacterium such as
enterotoxin producing strains of C. difficile, C. perfringens, or
S. aureus.
Inventors: |
Jabes; Daniela; (Cassina
Rizzardi, IT) ; Leach; Timothy S.; (Groton, MA)
; Labaudiniere; Richard F.; (Sherbron, MA) ;
Rauscher; Steven M.; (Lexington, MA) ; Mosconi;
Giorgio; (Wayne, PA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
29739879 |
Appl. No.: |
12/557099 |
Filed: |
September 10, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11906750 |
Oct 3, 2007 |
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12557099 |
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10454998 |
Jun 5, 2003 |
7317001 |
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11906750 |
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60385902 |
Jun 6, 2002 |
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60469803 |
May 12, 2003 |
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Current U.S.
Class: |
424/653 ;
514/2.4; 514/2.9 |
Current CPC
Class: |
A61P 31/04 20180101;
A61K 45/06 20130101; A61K 38/16 20130101; A61K 31/573 20130101;
A61K 31/58 20130101; A61K 38/16 20130101; A61P 1/12 20180101; A61K
2300/00 20130101; A61K 2300/00 20130101; A61K 31/58 20130101; A61K
2300/00 20130101; A61K 31/573 20130101 |
Class at
Publication: |
424/653 ;
514/8 |
International
Class: |
A61K 33/24 20060101
A61K033/24; A61K 38/14 20060101 A61K038/14; A61P 31/04 20060101
A61P031/04 |
Claims
1. A method of treating a disease caused by a bacterial infection
of the colon, said method comprising administering to a patient in
need thereof an effective amount of ramoplanin in a pharmaceutical
formulation that maintains the integrity of the formulation during
passage through the gastrointestinal tract and permits release of
said ramoplanin into the colon or other portion of the
gastrointestinal tract.
2. The method of claim 1, wherein the bacterial infection is a
Clostridium difficile, Staphylococcus aureus, or Clostridium
perfringens infection.
3. The method of claim 2, wherein said Clostridium difficile is
resistant to metronidazole and/or vancomycin.
4. The method of claim 1, further comprising administering to said
patient a corticosteroid.
5. The method of claim 4, wherein said corticosteroid is algestone,
6-alphafluoroprednisolone, 6-alpha-methylprednisolone,
6-alpha-methylprednisolone 21 acetate, 6-alpha-methylprednisolone
21-hemisuccinate sodium salt, 6-alpha,9-alphadifluoroprednisolone
21-acetate 17-butyrate, amcinafal, beclomethasone, beclomethasone
dipropionate, beclomethasone dipropionate monohydrate,
6-betahydroxycortisol, betamethasone, betamethasone-17-valerate,
budesonide, clobetasol, clobetasol propionate, clobetasone,
clocortolone, clocortolone pivalate, cortisone, cortisone acetate,
cortodoxone, deflazacort, 21-deoxycortisol, deprodone, descinolone,
desonide, desoximethasone, dexamethasone, dexamethasone-21-acetate,
dichlorisone, diflorasone, diflorasone diacetate, diflucortolone,
doxibetasol, fludrocortisone, flumethasone, flumethasone pivalate,
flumoxonide, flunisolide, fluocinonide, fluocinolone acetonide,
9-fluorocortisone, fluorohydroxyandrostenedione, fluorometholone,
fluorometholone acetate, fluoxymesterone, flupredidene,
fluprednisolone, flurandrenolide, formocortal, halcinonide,
halometasone, halopredone, hyrcanoside, hydrocortisone,
hydrocortisone acetate, hydrocortisone butyrate, hydrocortisone
cypionate, hydrocortisone sodium phosphate, hydrocortisone sodium
succinate, hydrocortisone probutate, hydrocortisone valerate,
6-hydroxydexamethasone, isoflupredone, isoflupredone acetate,
isoprednidene, meclorisone, methylprednisolone, methylprednisolone
acetate, methylprednisolone sodium succinate, paramethasone,
paramethasone acetate, prednisolone, prednisolone acetate,
prednisolone metasulphobenzoate, prednisolone sodium phosphate,
prednisolone tebutate, prednisolone-21-hemisuccinate free acid,
prednisolone-21-acetate, prednisolone-21 (beta-D-glucuronide),
prednisone, prednylidene, procinonide, tralonide, triamcinolone,
triamcinolone acetonide, triamcinolone acetonide 21-palmitate,
triamcinolone diacetate, or triamcinolone hexacetonide.
6. The method of claim 5, wherein said corticosteroid is
budesonide.
7. The method of claim 1, further comprising administering to said
patient one or more compounds selected from detoprofen, diclofenac,
diflunisal, etodolac, fenoprofen, flurbiprofen, ibuprofen,
indomethacin, ketoprofen, meclofenameate, mefenamic acid,
meloxicam, nabumeone, naproxen sodium, oxaprozin, piroxicam,
sulindac, tolmetin, celecoxib, rofecoxib, aspirin, choline
salicylate, salsalte, cyclosporine, azathioprine, methotrexate,
leflunomide, cyclophosphamide, hydroxychloroquine, sulfasalazine,
D-penicillamine, minocycline, etanercept, infliximab,
sulfasalazine, olsalazine, balsalazide, azathioprine,
6-mercaptopurine, or methotrexate.
8. The method of claim 1, further comprising administering to said
patient bismuth, diphenoxylate, atropine, kaolin, pectin,
loperamide, or paragoric.
9. The method of claim 1, wherein the disease is
antibiotic-associated diarrhea or pseudomembranous colitis.
10. The method of claim 1, wherein said ramoplanin is administered
in an amount between 50 mg and 1 g.
11. The method of claim 10, wherein said ramoplanin is administered
in an amount between 200 and 400 mg once or twice daily.
12. The method of claim 1, wherein said ramoplanin is administered
one to four times daily for three to fifteen days.
13. The method of claim 1, wherein said ramoplanin is administered
orally.
14. The method of claim 1, further comprising administering to said
patient vancomycin, bacitracin, or metronidazole.
15. A method for reducing sporulation of Clostridium difficile or
Clostridium perfringens in a patient, said method comprising
administering to said patient ramoplanin in an amount and for a
duration effective to reduce sporulation of Clostridium difficile
or Clostridium perfringens.
16. The method of claim 15, wherein said Clostridium difficile is
resistant to metronidazole and/or vancomycin.
17. The method of claim 15, wherein said ramoplanin is administered
in an amount between 50 mg and 1 g.
18. The method of claim 15, wherein said ramoplanin is administered
in an amount between 200 and 400 mg once or twice daily.
19. The method of claim 15, wherein said ramoplanin is administered
one to four times daily for three to fifteen days.
20. The method of claim 19, wherein said ramoplanin is administered
orally.
21. The method of claim 15, further comprising administering to
said patient vancomycin, bacitracin, or metronidazole.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/906,750, filed Oct. 3, 2007, which is a divisional of U.S.
application Ser. No. 10/454,998, filed Jun. 5, 2003, which claims
benefit of U.S. Provisional Application Nos. 60/385,902 (filed Jun.
6, 2002) and 60/469,803 (filed May 12, 2003), each of which is
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates to the treatment of diseases
associated with the use of antibiotics, such as colitis,
pseudomembranous colitis, and antibiotic associated diarrhea.
BACKGROUND OF THE INVENTION
[0003] Antibiotic-associated diarrheal diseases are caused by
enterotoxin producing strains of Clostridium difficile,
Staphylococcus aureus and Clostridium perfringens, and represent a
major economic burden to the healthcare system, that is
conservatively estimated at $3-6 billion per year in excess
hospital costs in the U.S. alone.
[0004] Clostridium difficile associated diarrhea (CDAD) is the most
common cause of infectious, hospital-acquired diarrhea in the
United States, and its incidence is increasing. With some estimates
of its incidence as high as 3 million cases/year, it is clearly a
major nosocomial infectious disease. The illness is caused by
Clostridium (C.) difficile, an anaerobic, spore forming,
Gram-positive bacterium that produces two enterotoxins (A and B).
The spectrum of CDAD may range from mild, self-limited diarrhea to
fulminant, life-threatening pseudomembranous colitis.
[0005] The two most important risk factors for CDAD are recent
exposure to an antibiotic and exposure to a toxin-producing strain
of the organism. Patients treated with clindamycin appear to be
highly susceptible to CDAD presumably due to its prolonged effects
on the indigenous anaerobic bowel flora. Host susceptibility also
appears to be a critical factor in the development of CDAD since
asymptomatic colonization is the most common outcome after exposure
to the organism. Indeed, a recent report suggests that increased
serum levels of immunoglobulin G against toxin A are associated
with asymptomatic carriage of the organism post-exposure.
[0006] There are currently two dominant therapies for CDAD:
vancomycin and metronidazole. While only vancomycin is approved by
the Food and Drug Administration (FDA) for this indication,
metronidazole is recommended as initial therapy out of concern for
the promotion and selection of vancomycin resistant gut flora,
especially enterococci. Oral bacitracin has also been used for the
treatment of CDAD, although very infrequently. Recently there have
been reports of C. difficile tolerance or resistance to vancomycin
and metronidazole (Pelaez et al., Antimicrob. Agents Chemother.
46:1617-1618, 2002; Pelaez et al., Antimicrob. Agents Chemother.
46:1647-1650, 2002). While both vancomycin and metronidazole are
generally very well tolerated and effective, allergies,
intolerances, and side effects to both agents do occur.
[0007] Broad spectrum, anti-anaerobic agents such as metronidazole
have also been shown to increase the density of
vancomycin-resistant enterococcus (VRE) in the stool of colonized
patients, and patients with CDAD may be at greater risk for VRE
bacteremia in some populations. Given the limited therapeutic
alternatives for the treatment of CDAD, and incipient reports of
resistance, new therapies are needed.
SUMMARY OF THE INVENTION
[0008] The present invention relates to the treatment and
prevention of antibiotic associated conditions such as colitis,
pseudomembranous colitis, and antibiotic associated diarrhea by the
administration of ramoplanin. Treatment with ramoplanin can be
performed without increasing the concentration of vancomycin
resistant enterococci (VRE) in the gut.
[0009] In one aspect, the invention features a method of treating
or preventing a disease associated with the use of antibiotics in a
patient in need thereof by administering to the patient ramoplanin
in an amount and for a duration effective to treat said disease.
The disease may be caused, for example, by the presence of a
bacterium such as enterotoxin producing strains of C. difficile, C.
perfringens, or Staphylococcus (S.) aureus. Exemplary diseases are
antibiotic-associated diarrhea, colitis, and pseudomembranous
colitis.
[0010] In a related aspect, the invention features a method of
inhibiting onset of an antibiotic-associated condition in a patient
in need thereof by administering to the patient ramoplanin in an
amount and for a duration sufficient to inhibit onset of the
antibiotic-associated condition. The antibiotic-associated
condition may be antibiotic-associated diarrhea, colitis, or
pseudomembranous colitis, or may be another disease caused by the
presence of toxigenic C. difficile, S. aureus, or C.
perfringens.
[0011] In another related aspect, the invention features a method
of inhibiting relapse of antibiotic-associated diarrhea in a
patient by administering ramoplanin in an amount and for a duration
effective to inhibit relapse of antibiotic-associated diarrhea in
the patient.
[0012] The invention also features a method of treating a disease
caused by a bacterial infection of the colon (e.g.,
antibiotic-associated diarrhea or pseudomembranous colitis) by
administering to a patient in need thereof an effective amount of
ramoplanin in a pharmaceutical formulation that permits release of
the ramoplanin into the patient's gastrointestinal tract. This
pharmaceutical formulation can treat gastrointestinal infections
caused by toxigenic strains of C. difficile, S. aureus, and C.
perfringens.
[0013] The invention also features a method for preventing
sporulation of C. difficile in a patient in need thereof by
administering to the patient ramoplanin in an amount and for a
duration effective to prevent sporulation of C. difficile.
[0014] In any of the foregoing methods, ramoplanin is typically
administered in an amount between 50 mg and 1 g, although higher or
lower doses may be required. Administration may be daily (e.g., one
to four times daily) or may be less frequent (e.g., once every
other day or once or twice weekly). In a desired embodiment,
ramoplanin is administered in an amount between 100 and 400 mg once
or twice daily. While the duration of ramoplanin therapy is
determined on a case-by-case basis, typically administration is for
three to fifteen days. Treatment durations shorter than standard
therapies may be warranted with ramoplanin. Oral administration is
preferred.
[0015] The ramoplanin administration may be performed in
conjunction with other therapies. For example, the patient may also
receive a second antibiotic (e.g., vancomycin, bacitracin, or
metronidazole) or an antidiarrheal preparation (e.g., bismuth,
diphenoxylate, atropine, kaolin, pectin, loperamide, or paragoric).
Ramoplanin may be co-formulated with any of the foregoing, or may
be administered separately.
[0016] Ramoplanin may also be formulated or used with
corticosteroids. Corticosteroids include algestone,
6-alpha-fluoroprednisolone, 6-alpha-methylprednisolone,
6-alpha-methylprednisolone 21-acetate, 6-alpha-methylprednisolone
21-hemisuccinate sodium salt, 6-alpha,9-alpha-difluoroprednisolone
21-acetate 17-butyrate, amcinafal, beclomethasone, beclomethasone
dipropionate, beclomethasone dipropionate monohydrate,
6-beta-hydroxycortisol, betamethasone, betamethasone-17-valerate,
budesonide, clobetasol, clobetasol propionate, clobetasone,
clocortolone, clocortolone pivalate, cortisone, cortisone acetate,
cortodoxone, deflazacort, 21-deoxycortisol, deprodone, descinolone,
desonide, desoximethasone, dexamethasone, dexamethasone-21-acetate,
dichlorisone, diflorasone, diflorasone diacetate, diflucortolone,
doxibetasol, fludrocortisone, flumethasone, flumethasone pivalate,
flumoxonide, flunisolide, fluocinonide, fluocinolone acetonide,
9-fluorocortisone, fluorohydroxyandrostenedione, fluorometholone,
fluorometholone acetate, fluoxymesterone, flupredidene,
fluprednisolone, flurandrenolide, formocortal, halcinonide,
halometasone, halopredone, hyrcanoside, hydrocortisone,
hydrocortisone acetate, hydrocortisone butyrate, hydrocortisone
cypionate, hydrocortisone sodium phosphate, hydrocortisone sodium
succinate, hydrocortisone probutate, hydrocortisone valerate,
6-hydroxydexamethasone, isoflupredone, isoflupredone acetate,
isoprednidene, meclorisone, methylprednisolone, methylprednisolone
acetate, methylprednisolone sodium succinate, paramethasone,
paramethasone acetate, prednisolone, prednisolone acetate,
prednisolone metasulphobenzoate, prednisolone sodium phosphate,
prednisolone tebutate, prednisolone-21-hemisuccinate free acid,
prednisolone-21-acetate, prednisolone-21(beta-D-glucuronide),
prednisone, prednylidene, procinonide, tralonide, triamcinolone,
triamcinolone acetonide, triamcinolone acetonide 21-palmitate,
triamcinolone diacetate, and triamcinolone hexacetonide. Desirably,
the corticosteroid is selected from budesonide, cortisone,
dexamethasone, hydrocortisone, methylprenisolone, prednisone,
triamcinolone, and diflorasone.
[0017] Ramoplanin may also be formulated or used with non-steroidal
anti-inflammatory drugs (NSAIDs; e.g., detoprofen, diclofenac,
diflunisal, etodolac, fenoprofen, flurbiprofen, ibuprofen,
indomethacin, ketoprofen, meclofenameate, mefenamic acid,
meloxicam, nabumeone, naproxen sodium, oxaprozin, piroxicam,
sulindac, tolmetin, celecoxib, rofecoxib, aspirin, choline
salicylate, salsalte, and sodium and magnesium salicylate), DMARDs,
i.e., disease modifying antirheumatic drugs (e.g., cyclosporine,
azathioprine, methotrexate, leflunomide, cyclophosphamide,
hydroxychloroquine, sulfasalazine, D-penicillamine, minocycline,
and gold), recombinant proteins (e.g., ENBREL.RTM. (etanercept, a
soluble TNF receptor) and REMICADE.RTM. (infliximab) a chimeric
monoclonal anti-TNF antibody), 5-ASA (mesalamine) drugs (e.g.,
sulfasalazine, olsalazine, balsalazide), azathioprine,
6-mercaptopurine, and methotrexate.
[0018] Ramoplanin and one or more of the foregoing compounds can be
packaged as components of a kit (e.g., as a single pharmaceutical
composition), which optionally also includes instructions for
administering the two agents to a patient diagnosed as having a
disease caused by a bacterial infection of the colon. The two
compounds are desirably administered within 10 days of each other,
within five days of each other, or within twenty-four hours of each
other. In certain embodiments, the two compounds are administered
simultaneously.
[0019] By "antibiotic-associated condition" is meant a condition
resulting when antibiotic therapy disturbs the balance of the
microbial flora of the gut, allowing pathogenic organisms such as
enterotoxin producing strains of C. difficile, S. aureus and C.
perfringens to flourish. These organisms can cause diarrhea,
pseudomembranous colitis, and colitis and are manifested by
diarrhea, urgency, abdominal cramps, tenesmus, fever among other
symptoms. Diarrhea, when severe, causes dehydration and the medical
complications associated with dehydration.
[0020] By "pseudomembranous colitis" or "enteritis" is meant an
inflammation of the mucous membrane of both the small and large
intestine with the formation of pseudomembranous material (i.e.,
material composed of fibrin, mucous, necrotic epithelial cells and
leukocytes).
[0021] By "ramoplanin" is meant A/16686 or a preparation containing
approximately 80% (with respect to the whole antibiotic substance,
by HPLC assay) of A2 of A/16686 with a range of between 50-100%.
The remaining portions consist essentially of small amounts of the
related A and A' factors of A/16686. Preparations of this type are
currently obtained from pilot or semi-industrial fermentation and
recovery operations described in detail in U.S. Pat. No.
4,303,646.
[0022] By "patient" is meant a human in need of medical treatment.
For the purposes of this invention, patients are typically
institutionalized in a primary medical care facility such as a
hospital or nursing home. However, treatment of a disease
associated with the use of antibiotics can occur on an outpatient
basis, upon discharge from a primary care facility, or can be
prescribed by a physician for home-care, not in association with a
primary medical care facility.
[0023] By "corticosteroid" is meant any naturally occurring or
synthetic steroid hormone that can be derived from cholesterol and
is characterized by a hydrogenated cyclopentanoperhydrophenanthrene
ring system. Naturally occurring corticosteriods are generally
produced by the adrenal cortex. Synthetic corticosteriods may be
halogenated. Functional groups required for activity include a
double bond at .DELTA.4, a C3 ketone, and a C20 ketone.
Corticosteroids may have glucocorticoid and/or mineralocorticoid
activity. Examples of exemplary corticosteroids are described
above.
[0024] The treatment of the present invention allows for the
effective treatment of diarrheal diseases associated with
enterotoxigenic strains of C. difficile, S. aureus, and C.
perfringens without compromising systemic antibiotics and without
increasing vancomycin resistant enterococci (VRE) in the gut. The
present invention also reduces the presence of VRE in the gut.
Other features and advantages will be apparent from the
description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a graph showing the effect of ramoplanin or
vancomycin on clindamycin-induced CDAD in Syrian hamsters.
[0026] FIG. 2 is a graph showing the effect of ramoplanin on CDAD
induced in Syrian hamsters by administration of clindamycin and C.
difficile strain 4013.
[0027] FIG. 3 is a graph showing the effect of vancomycin on CDAD
induced in Syrian hamsters by administration of clindamycin and C.
difficile strain 4013.
[0028] FIG. 4 is a graph showing the effect of metronidazole on
CDAD induced in Syrian hamsters by administration of clindamycin
and C. difficile strain 4013.
[0029] FIG. 5 is a graph showing the effect of various durations of
treatment with ramoplanin or vancomycin on CDAD induced in Syrian
hamsters by administration of clindamycin and C. difficile strain
4013.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The present invention relates to the unexpected discovery
that conditions associated with the use of antibiotics, such as
diarrhea associated with C. difficile, S. aureus, or C.
perfringens, can be treated or prevented by the administration of
ramoplanin in patients. The subject antibiotic-associated
conditions include, but are not limited to, antibiotic-associated
diarrhea, colitis, and pseudomembranous colitis. This discovery may
be particularly relevant in patients at risk for enterococcal
infections, including vancomycin resistant enterococci (VRE). The
present invention has also been discovered to be effective at
decreasing the presence of VRE in the gut.
[0031] The present invention includes methods for the treatment and
prevention of conditions associated with the use of antibiotics
without causing or encouraging the growth of vancomycin resistant
enterococci (VRE) in the gut. The antibiotic-associated conditions
include, but are not limited to, antibiotic-associated diarrhea,
colitis, and pseudomembranous colitis.
[0032] As it is common for antibiotic associated conditions to
recur following treatment with standard antibiotics, the present
invention also provides methods for inhibiting relapse of the
subject antibiotic-associated conditions in patients. The methods
include the administration of ramoplanin in an amount sufficient to
inhibit the relapse of antibiotic-associated diarrhea.
[0033] Further, as pseudomembranous colitis is especially
debilitating, the present invention provides methods for treating
pseudomembranous colitis by administering ramoplanin to a patient
in need thereof.
[0034] The present invention includes relatively short dosing
durations for the treatment or prevention of the subject antibiotic
associated conditions.
[0035] The present invention also provides combination therapies
for the treatment and prevention of the subject antibiotic
associated conditions. By adding ramoplanin to the standard courses
of broad-spectrum antibiotics, the treatments of the present
invention prevent the growth of C. difficile and other bacteria
known to cause antibiotic-associated diarrheal diseases.
Antibiotics used in conjunction with ramoplanin in the combination
therapies of the present invention include, but are not limited to,
vancomycin, bacitracin, and metronidazole. The antibiotics of the
combination therapies may be administered sequentially or
simultaneously.
[0036] The present invention also contemplates compositions and
methods for the treatment of symptoms associated with antibiotic
associated conditions, which result when antibiotics allow certain
bacteria such as toxigenic strains of C. difficile, S. aureus, and
C. perfringens to flourish in the gut. For example, the present
invention could include a combination of ramoplanin with an
antidiarrheal preparation including, but not limited to, bismuth,
diphenoxylate, atropine, kaolin, pectin, loperamide, paragoric, and
combinations thereof. In addition, ramoplanin could be combined
with preparations to treat the dehydration resulting from chronic
diarrhea, including, but not limited to, intravenous fluids or
over-the-counter drinks containing electrolytes.
Clostridium difficile
[0037] C. difficile is a Gram-positive anaerobic, spore-forming
bacillus, found in the colon of humans. In the 1970's, epidemics of
pseudomembranous colitis due to widespread usage of antibiotics
were described, and it was discovered that C. difficile causes
antibiotic associated diarrhea/colitis, and almost all cases of
pseudomembranous colitis (Cleary et al., Dis. Colon. Rectum. (1998)
41:1435-1449). These conditions develop as a result of the
production of two large toxins, toxin A and toxin B, by C.
difficile in the colon. Toxin A is a potent enterotoxin and is
believed to cause most of the gastrointestinal symptoms. There is
also some evidence that toxins A and B act synergistically and that
the tissue damage caused by toxin A further potentiates toxin
B.
[0038] Once infection by C. difficile is established, the combined
effects of toxin A and toxin B initiate an inflammatory response in
the colonic mucosa. The early response is erythema of the mucosa,
which resembles other nonspecific colitis syndromes.
Symptomatically, the patient experiences abdominal cramps/pain,
tenesmus, urgency, diarrhea (including bloody diarrhea) and fever
among other symptoms. Progression of the disease results in areas
of full mucosal cell death and the appearance of pseudomembranes,
which may involve the entire length of the colon. Dilatation of
colon, perforation, peritonitis, sepsis, and even death may
result.
[0039] C. difficile is refractory to a number of antimicrobial
agents, and is often endemic in hospitals and nursing homes and
causes epidemics of the subject conditions. It can appear when the
normal bacterial flora in the colon is suppressed, e.g., after
treatment with broad-spectrum antibacterial agents. Prolonged
nasogastric tube insertion and gastrointestinal tract surgery also
increase the risk of developing an infection by C. difficile. The
overuse of antibiotics, especially penicillin, ampicillin,
clindamycin, and cephalosporins alter the normal intestinal flora
and increase the risk of developing C. difficile infections.
[0040] Individuals with C. difficile-associated disease shed spores
in the stool that can be spread from person to person. Those spores
can survive up to 70 days outside a host and can be transported on
the hands of health care personnel who have direct contact with
infected patients, or they may persist on environmental
surfaces.
[0041] The pathophysiology of CDAD is not completely understood. It
is believed that spores of C. difficile are ingested into the upper
digestive tract and survive the hostile gastric environment. If the
normal bacterial flora has been altered by, for example, systemic
antibiotic therapy, the spores can undergo vegetative
transformation in the distal small intestine. The C. difficile
bacteria adhere to the gut mucosal cells, which allows for the
proliferation of the organism and production of cytotoxins.
Bacteria that fail to adhere to the gut pass harmlessly into the
intestinal tract.
[0042] Age appears to be a specific risk factor for C. difficile
enterocolitis, as 80% of the cases appear in patients 65 or older.
Other patients at risk include postoperative patients, patients
undergoing chemotherapy, patients with bone marrow transplants, and
patients suffering from immunological conditions that reduce the
effectiveness of the immune system. These immunological conditions
may include, but are not limited to, cancer, malnutrition,
infection with human immunodeficiency virus, and connective tissue
disorders (e.g., lupus erythematosus, Sjogren's Syndrome).
Furthermore, these patients are also at risk for VRE colonization
and infection (Fry, Pharmanual: Emerging Pathogens and Implications
for the Future (1999) pp. 50-75). Thus, these populations may also
benefit from the methods of treatment and compositions described
herein.
Clostridium perfringens
[0043] C. perfringens is an anaerobic, Gram-positive, spore forming
bacterium. It is widely distributed in the environment and
frequently occurs in the intestines of humans and many domestic and
feral animals. Spores of the organism persist in soil, sediments,
and areas subject to human or animal fecal pollution. C.
perfringens may cause food poisoning characterized by intense
abdominal cramps and diarrhea that begin 8-22 hours after ingestion
of enterotoxigenic strains of C. perfringens. Death may result due
to dehydration and other complications.
[0044] C. perfringens can also case a far more serious condition
known as necrotic enteritis, also known as pig-bel syndrome. This
condition is often fatal. The disease begins as a result of
ingesting large numbers of C. perfringens in contaminated foods.
Deaths from necrotic enteritis are caused by infection and necrosis
of the intestines and from resulting septicemia.
[0045] Institutional feeding (such as school cafeterias, hospitals,
nursing homes and prisons) where large quantities of food are
prepared several hours before serving is the most common
circumstance in which C. perfringens food poisoning occurs. The
young and elderly are the most frequently affected. Elderly persons
are more likely to experience prolonged or severe symptoms.
[0046] C. perfringens may also cause antibiotic-associated diarrhea
similar to that caused by C. difficile.
Staphylococcus aureus
[0047] S. aureus is a Gram-positive coccus. Although it is a
well-known cause of food poisoning, it may also cause
antibiotic-associated diarrhea similar to that caused by C.
difficile. Staphylococcal enterocolitis may involve the terminal
ileum and cecum more frequently than other causes of
antibiotic-associated diarrhea, and has usually occurred in the
setting of tetracycline and chloramphenicol administration.
Ramoplanin
[0048] Ramoplanin (A-16686; MDL 62,198; IB-777), a
glycolipodepsipeptide antibiotic obtained from fermentation of
Actinoplanes strain ATCC 33076, has targeted activity against
Gram-positive aerobic and anaerobic microorganisms. Ramoplanin is
described in U.S. Pat. No. 4,303,646, along with the process of
manufacture.
[0049] Ramoplanin binds to lipid II at a unique site and affects
both extracellular and intracellular peptidoglycan synthesis. It
has been shown to inhibit the synthesis of the bacterial cell wall
by inhibiting the N-acetylglucosaminyl transferase-catalyzed
conversion of lipid intermediate I to lipid intermediate II, thus
interfering with peptidoglycan synthesis at this step. The
mechanism of action of ramoplanin is different from that of
vancomycin, teicoplanin, or other cell wall-synthesis inhibitors.
No evidence of cross-resistance between ramoplanin and other
glycopeptides has been observed.
[0050] Ramoplanin's spectrum of activity includes staphylococci,
streptococci, clostridia, enterococci, including
antibiotic-resistant strains of these species (e.g.,
methicillin-resistant staphylococci and vancomycin- and
gentamicin-resistant enterococci and vancomycin or metronidazole
resistant clostridia). Ramoplanin is bactericidal with minimal
differences between the minimum inhibitory concentration (MIC) and
minimum bactericidal concentration (MBC) for most Gram-positive
species.
[0051] Ramoplanin has the advantage of being orally administered
but not orally absorbed. Thus, a high concentration of orally
administered ramoplanin reaches the full length of the
gastrointestinal tract, including areas where bacteria such as C.
difficile are present. Ramoplanin is bactericidal against
clinically important Gram-positive bacteria including Enterococcus
and Clostridium species. Furthermore, ramoplanin has activity
against clostridium species, including C. difficile and C.
perfringens, two organisms associated with diarrhea. In humans,
ramoplanin is also known to reduce S. aureus colonization in the
gut.
Dosages
[0052] Ramoplanin is administered orally in an amount and for a
duration sufficient to treat CDAD, pseudomembranous colitis, or
other diseases associated with the use of antibiotics. Although the
exact dosage of ramoplanin sufficient to treat a particular patient
may differ, the dosage can be easily determined by a person of
ordinary skill. Typically, the amount of ramoplanin that is
administered is an amount that maintains the stool concentration of
the antibiotic at least equal to the MIC for the target organism.
Preferably, the amount of ramoplanin that is administered maintains
the stool concentration equivalent to two, three, four, or more
times the MIC for the target organism. Thus, the particular
treatment regimen may vary for each patient, dependent upon the
species and resistance pattern of the identified Gram-positive
bacteria, and biological factors unique to each patient including
the comorbidity, disease etiology, patient age (pediatric, adult,
geriatric), and the nutritional and immune status.
[0053] The suggested oral dosage of ramoplanin is at least about
50, 100, 200, 300, 400, or 500 mg/day up to as much as 600, 700,
800, 900, or 1000 mg/day for three to fifteen days. Ramoplanin may
be given daily (e.g., once, twice, three times, or four times
daily) or less frequently (e.g., once every other day, or once or
twice weekly). A particularly suitable dose is between 200 and 400
mg BID (twice daily). The antibiotic may be contained in any
appropriate amount in any suitable carrier substance, and is
generally present in an amount of 1-99% by weight of the total
weight of the composition. The composition is provided in a dosage
form that is suitable for oral administration and delivers a
therapeutically effective amount of the antibiotic to the small and
large intestine, as described below.
[0054] Ramoplanin is available as granules for oral solution,
provided, for example, in packets containing 400 mg free base of
ramoplanin, along with pharmaceutically acceptable excipients
(e.g., mannitol, hydroxypropyl methylcellulose, magnesium
stearate). The contents of the packet can be reconstituted with
approximately 15-30 mL of water, and the resulting solution either
consumed directly, or further diluted with water, cranberry juice,
apple juice, or 7-Up prior to drinking. After consumption, the drug
may be followed with subsequent amounts of these beverages or with
food (e.g., cracker, bread). The 400 mg granulated powder packets
are stable for at least one year at refrigerated or unrefrigerated
conditions. The reconstituted ramoplanin aqueous solution has a
shelf life of 48 hours when stored at refrigerated conditions.
[0055] Alternatively, ramoplanin is also available as capsules
containing pharmaceutically acceptable excipients that are
generally regarded as safe. The capsule formulation may be
available as 100 mg, 200 mg or 400 mg strengths and are stable for
at least one year.
[0056] The dosing regimen required to treat CDAD, pseudomembranous
colitis, or other disease associated with the use of antibiotics
may be altered during the course of the therapy. For example, the
patient can be monitored periodically or at regular intervals to
measure the patient's bacterial load and dosage or frequency of
antibiotic therapy can be adjusted accordingly. Ramoplanin may be
dosed for a duration shorter or similar to that of commonly used
treatments.
Pharmaceutical Formulations
[0057] Pharmaceutical compositions according to the invention may
be formulated to release an antibiotic substantially immediately
upon administration or at any predetermined time or time period
after administration. The latter types of compositions are
generally known as controlled release formulations, which include
formulations that create a substantially constant concentration of
the drug within the intestinal tract over an extended period of
time, and formulations that have modified release characteristics
based on temporal or environmental criteria.
[0058] Any oral biologically-acceptable dosage form, or
combinations thereof, can be employed in the methods of the
invention. Examples of such dosage forms include, without
limitation, chewable tablets, quick dissolve tablets, effervescent
tablets, reconstitutable powders, elixirs, liquids, solutions,
suspensions, emulsions, tablets, multi-layer tablets, bi-layer
tablets, capsules, soft gelatin capsules, hard gelatin capsules,
caplets, lozenges, chewable lozenges, beads, powders, granules,
particles, microparticles, dispersible granules, ingestibles,
infusions, health bars, confections, animal feeds, cereals, cereal
coatings, foods, nutritive foods, functional foods and combinations
thereof. The preparation of any of the above dosage forms is well
known to persons of ordinary skill in the art. Additionally, the
pharmaceutical formulations may be designed to provide either
immediate or controlled release of the antibiotic upon reaching the
target site. The selection of immediate or controlled release
compositions depends upon a variety of factors including the
species and antibiotic susceptibility of Gram-positive bacteria
being treated and the bacteriostatic/bactericidal characteristics
of the therapeutics. Methods well known in the art for making
formulations are found, for example, in Remington: The Science and
Practice of Pharmacy (20th ed.), ed. A. R. Gennaro, 2000,
Lippincott Williams & Wilkins, Philadelphia, or in Encyclopedia
of Pharmaceutical Technology, eds. J. Swarbrick and J. C. Boylan,
1988-1999, Marcel Dekker, New York.
[0059] Immediate release formulations for oral use include tablets
or capsules containing the active ingredient(s) in a mixture with
non-toxic pharmaceutically acceptable excipients. These excipients
may be, for example, inert diluents or fillers (e.g., sucrose,
sorbitol, sugar, mannitol, microcrystalline cellulose, starches
including potato starch, calcium carbonate, sodium chloride,
lactose, calcium phosphate, calcium sulfate, or sodium phosphate);
granulating and disintegrating agents (e.g., cellulose derivatives
including microcrystalline cellulose, starches including potato
starch, croscarmellose sodium, alginates, or alginic acid); binding
agents (e.g., sucrose, glucose, mannitol, sorbitol, acacia, alginic
acid, sodium alginate, gelatin, starch, pregelatinized starch,
microcrystalline cellulose, magnesium aluminum silicate,
carboxymethylcellulose sodium, methylcellulose, hydroxypropyl
methylcellulose, ethylcellulose, polyvinylpyrrolidone, or
polyethylene glycol); and lubricating agents, glidants, and
antiadhesives (e.g., magnesium stearate, zinc stearate, stearic
acid, silicas, hydrogenated vegetable oils, or talc). Other
pharmaceutically acceptable excipients can be colorants, flavoring
agents, plasticizers, humectants, buffering agents, and the
like.
[0060] Dissolution or diffusion controlled release can be achieved
by appropriate coating of a tablet, capsule, pellet, or granulate
formulation of compounds, or by incorporating the compound into an
appropriate matrix. A controlled release coating may include one or
more of the coating substances mentioned above and/or, e.g.,
shellac, beeswax, glycowax, castor wax, carnauba wax, stearyl
alcohol, glyceryl monostearate, glyceryl distearate, glycerol
palmitostearate, ethylcellulose, acrylic resins, dl-polylactic
acid, cellulose acetate butyrate, polyvinyl chloride, polyvinyl
acetate, vinyl pyrrolidone, polyethylene, polymethacrylate,
methylmethacrylate, 2-hydroxymethacrylate, methacrylate hydrogels,
1,3 butylene glycol; ethylene glycol methacrylate, and/or
polyethylene glycols. In a controlled release matrix formulation,
the matrix material may also include, e.g., hydrated
methylcellulose, carnauba wax and stearyl alcohol, carbopol 934,
silicone, glyceryl tristearate, methyl acrylate-methyl
methacrylate, polyvinyl chloride, polyethylene, and/or halogenated
fluorocarbon.
[0061] A controlled release composition may also be in the form of
a buoyant tablet or capsule (i.e., a tablet or capsule that, upon
oral administration, floats on top of the gastric content for a
certain period of time). A buoyant tablet formulation of the
compound(s) can be prepared by granulating a mixture of the
antibiotic with excipients and 20-75% w/w of hydrocolloids, such as
hydroxyethylcellulose, hydroxypropylcellulose, or
hydroxypropylmethylcellulose. The obtained granules can then be
compressed into tablets. On contact with the gastric juice, the
tablet forms a substantially water-impermeable gel barrier around
its surface. This gel barrier takes part in maintaining a density
of less than one, thereby allowing the tablet to remain buoyant in
the gastric juice. Other useful controlled release compositions are
known in the art (see, for example, U.S. Pat. Nos. 4,946,685 and
6,261,601).
[0062] Formulations that target ramoplanin release to particular
regions of the intestinal tract can also be prepared. Ramoplanin
can be encapsulated in an enteric coating that prevents release
degradation and release from occurring in the stomach, but
dissolves readily in the mildly acidic or neutral pH environment of
the small intestine. A formulation targeted for release of
antibiotic to the colon, utilizing technologies such as
time-dependent, pH-dependent, or enzymatic erosion of polymer
matrix or coating can also be used.
[0063] Alternatively, a multilayer formulation having different
release characteristics between the layers can be prepared. These
formulations can result in the antibiotic being released in
different regions of the intestinal tract. A multilayer formulation
of this type may be particularly useful for maintaining a more
constant antibiotic concentration throughout the length of the
intestinal tract.
[0064] The targeted delivery properties of the
ramoplanin-containing formulation may be modified by other means.
For example, the antibiotic may be complexed by inclusion, ionic
association, hydrogen bonding, hydrophobic bonding, or covalent
bonding. In addition polymers or complexes susceptible to enzymatic
or microbial lysis may also be used as a means to deliver drug.
[0065] Microsphere encapsulation of ramoplanin is another useful
pharmaceutical formulation for targeted antibiotic release. The
antibiotic-containing microspheres can be used alone for antibiotic
delivery, or as one component of a two-stage release formulation.
Suitable staged release formulations may consist of acid stable
microspheres, encapsulating ramoplanin to be released later in the
lower intestinal tract admixed with an immediate release
formulation to deliver antibiotic to the stomach and upper
duodenum.
[0066] Microspheres can be made by any appropriate method, or from
any pharmaceutically acceptable material. Particularly useful are
proteinoid microspheres (see, for example, U.S. Pat. No. 5,601,846,
or 5,792,451) and PLGA-containing microspheres (see, for example,
U.S. Pat. No. 6,235,224 or 5,672,659). Other polymers commonly used
in the formation of microspheres include, for example,
poly-.epsilon.-caprolactone,
poly(.epsilon.-caprolactone-Co-DL-lactic acid), poly(DL-lactic
acid), poly(DL-lactic acid-Co-glycolic acid) and
poly(.epsilon.-caprolactone-Co-glycolic acid) (see, for example,
Pitt et al., J. Pharm. Sci., 68:1534, 1979). Microspheres can be
made by procedures well known in the art including spray drying,
coacervation, and emulsification (see for example Davis et al.
Microsphere and Drug Therapy, 1984, Elsevier; Benoit et al.
Biodegradable Microspheres Advances in Production Technologies,
Chapter 3, ed. Benita, S, 1996, Dekker, New York;
Microencapsulation and Related Drug Processes, Ed. Deasy, 1984,
Dekker, New York; U.S. Pat. No. 6,365,187).
[0067] Powders, dispersible powders, or granules suitable for
preparation of aqueous solutions or suspensions of ramoplanin by
addition of water are convenient dosage forms for oral
administration. Formulation as a suspension provides the active
ingredient in a mixture with a dispersing or wetting agent,
suspending agent, and one or more preservatives. Suitable
dispersing or wetting agents are, for example, naturally-occurring
phosphatides (e.g., lecithin or condensation products of ethylene
oxide with a fatty acid, a long chain aliphatic alcohol, or a
partial ester derived from fatty acids) and a hexitol or a hexitol
anhydride (e.g., polyoxyethylene stearate, polyoxyethylene sorbitol
monooleate, polyoxyethylene sorbitan monooleate, and the like).
Suitable suspending agents are, for example, sodium
carboxymethylcellulose, methylcellulose, sodium alginate, and the
like.
Example 1
Efficacy of Ramoplanin in the Hamster Model of C. difficile
Associated Colitis
[0068] To evaluate the in vivo efficacy of ramoplanin in the
treatment of C. difficile-associated colitis, ramoplanin was tested
in a hamster model of clindamycin (CL)-induced colitis in
comparison with both vancomycin and metronidazole. Animals were
treated with a single subcutaneous (s.c.) injection of 100 mg/kg
clindamycin, and after 24 hours received oral ramoplanin or
vancomycin at 50 mg/kg/day for 5 days. Animals were observed daily
for the presence or absence of diarrhea. Necropsies were performed
on some animals that died during the experiment, and cecal contents
were assayed for C. difficile toxin A. Hamsters were monitored for
20 days, and the cumulative mortality during this period was
recorded (FIG. 1). Clindamycin alone rapidly induced a fatal
enterocolitis with 100% mortality within 4 days. Autopsy revealed
hemorrhagic ceca and watery stools. C. difficile toxin A was always
detected in these animals. Oral administration of either vancomycin
or ramoplanin was highly effective in prolonging survival and
protecting animals from death (FIG. 1). Ramoplanin was
significantly more effective than vancomycin, with an 80% survival
rate compared to 20% for vancomycin-treated animals (P<0.05).
All hamsters that died had gross pathologic evidence of
enterocolitis and cecal contents were positive for Toxin A.
[0069] In a second study, animals were challenged orally with a
bacterial suspension of C. difficile and then administered a single
s.c. injection of 100 mg/kg clindamycin. Oral treatment with
ramoplanin or vancomycin at 25-50-100 mg/kg or metronidazole at
100-200-400 mg/kg started 24 hours after clindamycin administration
and lasted for five days. Hamsters were weighed and observed every
24 hours for evidence of diarrhea or moribund conditions, and the
cecal contents were analyzed for C. difficile toxin A (ELISA). The
challenge with C. difficile to clindamycin-treated animals also
induced a rapidly fatal enterocolitis (FIGS. 2-4). Both vancomycin
and ramoplanin were more effective in prolonging survival than was
metronidazole (13-17 days and 9 days respectively). Time of death
in ramoplanin-treated animals was delayed compared to that of
vancomycin-treated animals, and 20% survival was recorded at the
end of observation period in the group treated with 100 mg/kg
ramoplanin (FIG. 2). No animals treated with vancomycin or
metronidazole survived the study (FIGS. 3 and 4).
[0070] The effect of different durations of treatment with
ramoplanin or vancomycin is shown in FIG. 5. Hamsters were
inoculated with C. difficile on day 0 and then administered 100
mg/kg clindamycin s.c. on day 1. Hamsters received daily oral doses
of 50 mg/kg ramoplanin or vancomycin for 3 or 5 days starting on
day 2. Ramoplanin administration for 3 days was more effective than
vancomycin administration for 5 days (FIG. 5).
[0071] In another study, animals were administered a single dose of
clindamycin and then treated with either vancomycin or ramoplanin.
C. difficile spores were recovered from some of the animals treated
with vancomycin. No C. difficile spores or vegetative cells were
recovered from any animals treated with ramoplanin.
Example 2
Oral Administration of Ramoplanin to Humans
[0072] As is described in detail below, single oral doses (up to
1000 mg) and multiple oral doses (200, 400, or 800 mg BID for 10
days) of ramoplanin have been administered to healthy male
volunteers. Both bioassay and HPLC-based assays to assess the
absorption, distribution, metabolism, and excretion were utilized
in these studies. Ramoplanin was not detected in serum/plasma or
urine by either method, indicating that very little, if any, is
absorbed. Treatment with oral ramoplanin at all doses was
efficacious in reducing the Gram-positive colony counts in feces to
undetectable levels during the 10-day regimen. Ramoplanin was not
effective against Gram-negative flora.
[0073] Single Dose Study in Healthy Male Volunteers
[0074] The absorption, tolerability, and recovery of ramoplanin
following single dose oral administration were investigated in male
volunteers. Ramoplanin was administered as an aqueous solution at a
dose of 100, 200, 500, or 1000 mg to fasting subjects. Serum
samples were obtained prior to drug administration of ramoplanin
and 0.5, 1, 2, 3, 6, 9, 12, 24, 48, 72, and 96 hours after
treatment. Urine samples were collected prior to administration of
ramoplanin and over the periods 0-3, 3-6, 6-12, 12-24, 24-48,
48-72, and 72-96 hours after dosing. Fecal samples were collected
prior to dosing and over the periods 0-16 (Day 1), 16-40 (Day 2),
40-64 (Day 3), 64-88 (Day 4), and 88-96 (Day 5) hours after dosing.
A microbiological assay employing Bacillis subtilis ATCC 6633 as
the test organism was used to determine ramoplanin concentrations
in serum, urine, and feces. The limits of quantitation for this
assay were 0.02 .mu.g/mL in serum, 0.012 .mu.g/mL in urine, and 3
.mu.g/g in feces. Tolerability was assessed on the basis of
clinical signs and symptoms and the results of blood and urine
laboratory tests.
[0075] Ramoplanin concentrations in feces varied widely due to the
variation in the weight of the fecal samples (6-468 g); detectable
concentrations ranged from 2.9 to 278 .mu.g/g in the 100 mg group,
7.7 to 454 .mu.g/g in the 200 mg group, 6.6 to 3316 .mu.g/g in the
500 mg group, and 16.0 to 3154 .mu.g/g in the 1000 mg group.
Maximum ramoplanin concentrations in feces, as well as maximum
percentage recoveries, generally occurred the day after
administration (Day 2). The time of occurrence of maximum
ramoplanin concentrations in feces was not dose dependent. In
contrast, the maximum ramoplanin fecal concentrations were
dose-dependent. Mean maximum concentrations were 214 .mu.g/g (range
148-278 .mu.g/g), 287 .mu.g/g (range 164-454 .mu.g/g), 1655 .mu.g/g
(range 737-3316 .mu.g/g), and 1835 .mu.g/g (range 1336-3154
.mu.g/g) for the 100, 200, 500, and 1000 mg groups, respectively.
Mean cumulative recovery of ramoplanin in feces for the 100, 200,
500, and 1000 mg groups were 67.7% (range 55.7-84%), 48.5% (range
39.3-56.5%), 52.8% (range 41.3-79.6%), and 46.4% (range 39.9-58.4%)
of the administered dose, respectively. On the fourth day of study,
ramoplanin was still detectable in feces obtained from 17 of 24
subjects.
[0076] Multiple Dose Study in Healthy Male Volunteers
[0077] Healthy male volunteers were administered 200, 400, or 800
mg ramoplanin twice-a-day, for ten consecutive days. The
predetermined dose was reconstituted in 5 mL water per vial, mixed
with 50 mL of sweetened, aromatized solution, and immediately
administered orally to the subjects.
[0078] No absorption from the human gastrointestinal tract was
observed. On Days 1, 5, and 10, no serum levels of ramoplanin were
detected at hour 0.5, 1, 2, 3, 6, 9, and 12 after the morning dose.
No levels were found in urine at Day 1 and 5, or in the pooled
urine samples of the periods 0-12, 12-24, 24-36, 48-72, and 72-96
after the last dose.
[0079] The fecal concentrations of ramoplanin were dose related on
both Day 3 (average concentration 827, 1742, 1901 .mu.g/g in the
200, 400, and 800 mg group, respectively) and Day 10 (949, 1417,
2647 .mu.g/g, respectively). The concentrations declined on the
first day post-treatment, but remained detectable in some subjects
four days post-treatment. The cumulative recovery up to Day 4
post-treatment was 25% of the administered dose.
[0080] The antibacterial activity of ramoplanin on the stool
microflora was assessed in a subset of the subjects. Microbial
concentrations (i.e., the number of organisms per gram of fecal
matter) were determined at the following time points: Day -4
(pre-treatment), Days 4 and 10 (treatment), and Days 7 and 24
(follow-up). Tolerability and absorption were also
investigated.
[0081] As expected, no effect was seen in Gram-negative bacteria
(enteric bacteria and Bacteroides spp.) or yeast. A marked effect
was seen on Gram-positive bacteria by the first measurement on Day
4. In all subjects, the concentrations of staphylococci,
streptococci, and enterococci were below the level of detection by
Day 10. In 10 of 12 subjects, the concentration of ramoplanin and
vancomycin-resistant Clostridium spp. was reduced below detectable
levels. In the other two subjects who carried ramoplanin- and
vancomycin-resistant Clostridium spp. (C. rectum and C.
beijerinckii) before treatment, no variation in the clostridial
load was observed. No ramoplanin- or vancomycin-resistant strain of
C. difficile was detected, either pre- or post-treatment.
[0082] After therapy, the intestinal tracts of the volunteers were
re-colonized by normal Gram-positive bacteria, with a tendency for
enterococci and clostridia to transiently achieve concentrations
higher than the basal level. To evaluate if the predominant species
that colonized the intestinal tract after therapy was that isolated
before treatment, all enterococci isolated before and after
ramoplanin therapy were speciated using the API system. DNA-typing
was also performed when identification at the strain level was
necessary. In most cases, the predominant strain appeared to be
different before and after treatment, suggesting a lack of
persistence of the initial isolate.
[0083] The in vitro interaction of ramoplanin with human intestinal
contents was studied. Ramoplanin was found to be microbiologically
active in feces and to bind reversibly to solid components of
feces. The binding and the subsequent release of ramoplanin from
feces would likely result in long-lasting concentrations in the
intestinal tract.
[0084] Multiple Dose Study in Asymptomatic Carriers of Intestinal
VRE
[0085] Patients identified as asymptomatic carriers of VRE were
administered placebo or one of two dosages (100 mg, 400 mg) of
ramoplanin BID (twice daily) for seven days. Patients were assessed
by rectal swab on Days 7, 14, and 21 to determine the presence or
absence of VRE. On Days 45 and 90, stool samples were analyzed for
long-term effects of ramoplanin on the recurrence of, or
reinfection with, VRE. All VRE isolates were tested for
susceptibility to ramoplanin.
[0086] Analysis of the primary efficacy variable showed that
ramoplanin effectively suppressed intestinal VRE (i.e., ramoplanin
substantially decolonized the intestinal tract of VRE). None of the
placebo-treated patients were VRE-free after seven days of
treatment. In contrast, 17 of 21 patients (81.0%; p<0.01) who
received 100 mg ramoplanin BID and 18 of 20 patients (90.0%;
p<0.01) who received 400 mg ramoplanin BID were had no
detectable VRE at Day 7. Seven days after cessation of treatment
(Day 14), 6 of 21 patients (28.6%) who received 100 mg ramoplanin
BID and 7 of 17 patients (41.2%) who received 400 mg ramoplanin BID
remained VRE free. At Day 21, the number of VRE-free patients was
comparable among all treatment groups.
Other Embodiments
[0087] All references discussed above are herein incorporated by
reference in their entirety for all purposes. While this invention
has been particularly shown and described with references to
preferred embodiments thereof, it will be understood by those
skilled in the art that various changes in form and details may be
made therein without departing from the spirit and scope of the
invention as defined by the appended claims.
* * * * *