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Rebetol Intron A (Ribavirin / Interferon Alfa-2B) - Summary

 



CONTRAINDICATIONS AND WARNINGS

Combination REBETOL/INTRON A therapy is contraindicated in females who are pregnant and in the male partners of females who are pregnant. Extreme care must be taken to avoid pregnancy during therapy and for 6 months after completion of treatment in female patients, and in female partners of male patients who are taking combination REBETOL/INTRON A therapy. Females of childbearing potential and males must use two reliable forms of effective contraception during treatment and during the 6-month posttreatment follow-up period. Significant teratogenic and/or embryocidal effects have been demonstrated for ribavirin in all animal species studied. See CONTRAINDICATIONS and WARNINGS. REBETOL monotherapy is not effective for the treatment of chronic hepatitis C and should not be used for this indication. See WARNINGS.

Alpha interferons, including INTRON® A, cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Patients should be monitored closely with periodic clinical and laboratory evaluations. Patients with persistently severe or worsening signs or symptoms of these conditions should be withdrawn from therapy. In many but not all cases these disorders resolve after stopping INTRON A therapy. See WARNINGS, and ADVERSE REACTIONS.

 

SUMMARY

REBETOL is Schering Corporation's brand name for ribavirin, a nucleoside analog with antiviral activity.

REBETOL (ribavirin, USP) Capsules is indicated in combination with INTRON A (interferon alfa-2b, recombinant) Injection for the treatment of chronic hepatitis C in patients with compensated liver disease previously untreated with alpha interferon or who have relapsed following alpha interferon therapy.

Previously Untreated Patients Adults with compensated chronic hepatitis C and detectable HCV RNA (assessed by a central laboratory using a research-based RT-PCR assay) who were previously untreated with alpha interferon therapy were enrolled into two multicenter, double-blind trials (US and International) and randomized to receive REBETOL Capsules 1200 mg/day (1000 mg/day for patients weighing </=75 kg) plus INTRON A Injection 3 MIU TIW or INTRON A Injection plus placebo for 24 or 48 weeks followed by 24 weeks of off-therapy follow-up. The International study did not contain a 24-week INTRON A plus placebo treatment arm. The US study enrolled 912 patients who, at baseline, were 67% male, 89% caucasian with a mean Knodell HAI score (I+II+III) of 7.5, and 72% genotype 1. The International study, conducted in Europe, Israel, Canada, and Australia, enrolled 799 patients (65% male, 95% caucasian, mean Knodell score 6.8, and 58% genotype 1).

Study results are summarized in TABLE 3.

TABLE 3. Virologic and Histologic Responses: Previously Untreated Patients *
US Study International Study
24 weeks
of treatment
48 weeks
of treatment
24 weeks
of treatment
48 weeks
of treatment
INTRON A
plus
REBETOL
(N=228)
INTRON A
plus
Placebo
(N=231)
INTRON A
plus
REBETOL
(N=228)
INTRON A
plus
Placebo
(N=225)
INTRON A
plus
REBETOL
(N=265)
INTRON A
plus
REBETOL
(N=268)
INTRON A
plus
Placebo
(N=266)
Virologic
Response
-Responder1 65 (29) 13 (6) 85 (37) 27 (12) 86 (32) 113 (42) 46 (17)
-Nonresponder 147 (64) 194 (84) 110 (48) 168 (75) 158 (60) 120 (45) 196 (74)
-Missing data 16 (7) 24 (10) 33 (14) 30 (13) 21 (8) 35 (13) 24 (9)
Histologic
Response
-Improvement2 102 (45) 77 (33) 96 (42) 65 (29) 103 (39) 102 (38) 69 (26)
-No improvement 77 (34) 99 (43) 61 (27) 93 (41) 85 (32) 58 (22) 111 (41)
-Missing data 49 (21) 55 (24) 71 (31) 67 (30) 77 (29) 108 (40) 86 (32)
*Number (%) of patients
1 Defined as HCV RNA below limit of detection using a research-based RT-PCR assay at end of treatment and during follow-up period.
2 Defined as posttreatment (end of follow-up) minus pretreatment liver biopsy Knodell HAI score (I+II+III) improvement of >/=2 points.

Of patients who had not achieved HCV RNA below the limit of detection of the research-based assay by week 24 of REBETOL/INTRON A treatment, less than 5% responded to an additional 24 weeks of combination treatment.

Among patients with HCV genotype 1 treated with REBETOL/INTRON A therapy who achieved HCV RNA below the detection limit of the research-based assay by 24 weeks, those randomized to 48 weeks of treatment had higher virologic responses compared to those in the 24-week treatment group. There was no observed increase in response rates for patients with HCV nongenotype 1 randomized to REBETOL/INTRON A therapy for 48 weeks compared to 24 weeks.

Relapse Patients Patients with compensated chronic hepatitis C and detectable HCV RNA (assessed by a central laboratory using a research-based RT-PCR assay) who had relapsed following one or two courses of interferon therapy (defined as abnormal serum ALT levels) were enrolled into two multicenter, double-blind trials (US and International) and randomized to receive REBETOL 1200 mg/day (1000 mg/day for patients weighing </=75 kg) plus INTRON A 3 MIU TIW or INTRON A plus placebo for 24 weeks followed by 24 weeks of off-therapy follow-up. The US study enrolled 153 patients who, at baseline, were 67% male, 92% caucasian with a mean Knodell HAI score (I+II+III) of 6.8, and 58% genotype 1. The International study, conducted in Europe, Israel, Canada, and Australia, enrolled 192 patients (64% male, 95% caucasian, mean Knodell score 6.6, and 56% genotype 1).

Study results are summarized in TABLE 4.

TABLE 4. Virologic and Histologic Responses: Relapse Patients *
US Study International Study
INTRON A
plus
REBETOL
(N=77)
INTRON A
plus
Placebo
(N=76)
INTRON A
plus
REBETOL
(N=96)
INTRON A
plus
Placebo
(N=96)
Virologic
Response
-Responder1 33 (43) 3 (4) 46 (48) 5 (5)
-Nonresponder 36 (47) 66 (87) 45 (47) 91 (95)
-Missing data 8 (10) 7 (9) 5 (5) 0 (0)
Histologic
Response
-Improvement2 38 (49) 27 (36) 49 (51) 30 (31)
-No improvement 23 (30) 37 (49) 29 (30) 44 (46)
-Missing data 16 (21) 12 (16) 18 (19) 22 (23)
*Number (%) of patients
1 Defined as HCV RNA below limit of detection using a research-based RT-PCR assay at end of treatment and during follow-up period.
2 Defined as posttreatment (end of follow-up) minus pretreatment liver biopsy Knodell HAI score (I+II+III) improvement of >/=2 points.

Virologic and histologic responses were similar among male and female patients in both the previously untreated and relapse studies.


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NEWS HIGHLIGHTS

Media Articles Related to Rebetol Intron A (Ribavirin)

InterMune Announces Modification To On-Going Phase 2b Study Of ITMN-191 In Patients With Chronic HCV Infection
Source: Liver Disease / Hepatitis News From Medical News Today [2009.11.18]
InterMune, Inc. (Nasdaq: ITMN) announced that the on-going Phase 2b study conducted by Roche of ITMN-191 (RG7227) combined with standard of care (SOC) PEGASYS® (peginterferon alfa-2a) and COPEGUS® (ribavirin) in HCV treatment-naive patients has been modified. The Phase 2b study has four dosage cohorts: SOC; 300mg q8h plus SOC; 600mg q12h plus SOC and 900mg q12h plus SOC. To date, approximately 175 patients have been enrolled in the study.

AASLD: Treating Before Transplant Cuts HCV Recurrence (CME/CE)
Source: MedPage Today Gastroenterology [2009.11.06]
BOSTON (MedPage Today) -- In patients with advanced liver disease related to hepatitis C, a course of pegylated interferon and ribavirin (Rebetol) before liver transplant may help them avoid recurrence of infection, a researcher said here.

SCYNEXIS' SCY-635 Demonstrates Positive Antiviral Activity In Combination With Approved And Investigational Anti-HCV Agents
Source: Liver Disease / Hepatitis News From Medical News Today [2009.11.04]
Drug discovery company SCYNEXIS, Inc. presented positive data from an in vitro study evaluating the antiviral activity of SCY-635 in combination with approved and investigational non-nucleoside polymerase inhibitors, nucleoside polymerase inhibitors, protease inhibitors, ribavirin and interferon alpha 2b. SCY-635 exhibited additive to synergistic antiviral activity when combined with each of the six compounds tested and all combinations exhibited greater-than-anticipated antiviral activity.

Bristol-Myers Squibb And ZymoGenetics Present Final Phase 1b Results For PEG-Interferon Lambda In Hepatitis C
Source: Liver Disease / Hepatitis News From Medical News Today [2009.11.03]
Bristol-Myers Squibb Company (NYSE: BMY) and ZymoGenetics, Inc. (NASDAQ: ZGEN) today presented final results from a Phase 1b clinical trial of PEG-Interferon lambda administered with ribavirin in relapsed and treatment-naïve hepatitis C virus (HCV) patients. The poster included data on 56 patients in the study. Antiviral activity was observed at all dose levels tested.

Schering-Plough Reports Potent Antiviral Activity With Narlaprevir (SCH 900518), An Investigational, Once-Daily Protease Inhibitor For Hepatitis C
Source: Liver Disease / Hepatitis News From Medical News Today [2009.11.03]
Schering-Plough Corporation (NYSE: SGP) reported that interim results from an ongoing Phase IIa study of narlaprevir (SCH 900518), its investigational, once-daily protease inhibitor, demonstrated potent antiviral activity in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 1.

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Published Studies Related to Rebetol Intron A (Ribavirin)

A phase III study of the safety and efficacy of viramidine versus ribavirin in treatment-naive patients with chronic hepatitis C: ViSER1 results. [2009.09]
Pegylated interferon (peg-IFN) and ribavirin (RBV) are effective in eradicating the hepatitis C virus in more than half of patients. However, anemia arising from RBV-induced hemolysis can prompt dose reductions and lower sustained virologic response (SVR) rates... These results suggest fixed-dose VRD given 600 mg BID is insufficient to treat patients with chronic hepatitis C; a weight-based dosing trial of viramidine is currently under way.

Peginterferon alfa-2b or alfa-2a with ribavirin for treatment of hepatitis C infection. [2009.08.06]
BACKGROUND: Treatment guidelines recommend the use of peginterferon alfa-2b or peginterferon alfa-2a in combination with ribavirin for chronic hepatitis C virus (HCV) infection. However, these regimens have not been adequately compared... CONCLUSIONS: In patients infected with HCV genotype 1, the rates of sustained virologic response and tolerability did not differ significantly between the two available peginterferon-ribavirin regimens or between the two doses of peginterferon alfa-2b. (ClinicalTrials.gov number, NCT00081770.) 2009 Massachusetts Medical Society

Predictability of sustained virological response to pegylated interferon alpha-2b Plus ribavirin therapy by week-8 viral response in HIV-positive patients with chronic hepatitis C virus infection. [2009.07]
Chronic hepatitis C is frequent and aggressive in HIV-positive patients. Identification of early predictors of response to anti-HCV therapy is needed for a lower rate of response and higher discontinuations, compared to HCV mono-infected subjects...

Retreating chronic hepatitis C with daily interferon alfacon-1/ribavirin after nonresponse to pegylated interferon/ribavirin: DIRECT results. [2009.06]
CONCLUSION: Retreatment of PEG-IFN and RBV nonresponders with CIFN and RBV is safe and efficacious and can be considered a retreatment strategy for patients failing previous therapy with PEG-IFN/RBV, especially in interferon-sensitive patients with lower baseline fibrosis scores.

Randomized trial of high-dose interferon-alpha-2b combined with ribavirin in patients with chronic hepatitis C: Correlation between amino acid substitutions in the core/NS5A region and virological response to interferon therapy. [2009.04]
The aim of this study was to compare the efficacy of high-dose interferon (IFN)-alpha-2b with standard dose of IFN-alpha-2b in combination with ribavirin (RBV) for patients with chronic hepatitis C virus (HCV) infection, and to investigate the predictive factors associated with virological response...

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Clinical Trials Related to Rebetol Intron A (Ribavirin)

Peg-Ifn Dose Evaluations for Previously Untreated Subjects With Chronic Hepatitis C Infected With Genotype 1 (Study P03471AM1)(COMPLETED) [Completed]
The objective is to compare the safety and efficacy of the following three treatment regimens in previously untreated adult subjects with chronic hepatitis C infected with Genotype 1: (1) PEG-Intron 1. 5 µg/kg/wk in combination with weight based REBETOL (800-1400 mg/day); (2) PEG-Intron 1µg/kg/wk in combination with weight based REBETOL (800-1400 mg/day); and (3) PEGASYS 180 µg/wk plus COPEGUS 1000-1200 mg/day.

Extended Treatment With PEG-Intron and Rebetol in Patients With Genotype 1 Chronic Hepatitis C and Slow Virologic Response (Study P03685AM3) [Active, not recruiting]
This is a controlled, randomized, parallel-groups, open-label, multinational study designed to evaluate the efficacy and safety of PEG-Intron plus Rebetol in subjects with chronic hepatitis C. It is designed to evaluate whether 72 weeks of treatment with PEG-Intron plus Rebetol is more effective than 48 weeks of treatment in subjects with Genotype 1 chronic hepatitis C who exhibit a slow response to treatment.

Peg-Intron and Rebetol Therapy in Treatment of Naive Hepatitis C Patients: A Comparison of Race and Genotype on Treatment Outcome (Study P04212)(COMPLETED) [Completed]
This is a multicenter clinical trial designed to compare the efficacy of 48 weeks of therapy with pegylated (PEG)-Interferon/ribavirin in Southeastern Asian patients with genotype 1 chronic hepatitis C with 48 weeks of therapy with PEG-Interferon/ribavirin in Caucasian patients with genotype 1 chronic hepatitis C. This study is also designed to provide a randomized comparison of 24 weeks versus 48 weeks of therapy with PEG-Interferon/ribavirin in Southeastern Asian patients with genotypes 6-9. The primary endpoint is sustained virologic response, as defined by negative hepatitis C virus (HCV) ribonucleic acid (RNA) in serum at 24 weeks after therapy completion.

PEG-Interferon a-2b + Ribavirin for Treatment of Patients With Chronic Hepatitis C Who Have Previously Failed to Achieve a Sustained Virologic Response Following Interferon Alfa or Interferon a-2b + Ribavirin Therapy [Completed]
HRN-003 STUDY SYNOPSIS

OBJECTIVE: To compare the Sustained Virologic Response (SVR) of PEGIntron plus ribavirin among patients receiving a fixed dose of PEGIntron versus weighted-adjusted dosing.

OVERVIEW OF STUDY DESIGN: This is a multi-center, randomized, open-label clinical trial using PEGIntron weight-adjusted dose by subcutaneous injection weekly + ribavirin by mouth twice daily for 48 weeks OR PEGIntron fixed dose by subcutaneous injection weekly + ribavirin by mouth twice daily for 48 weeks.

STUDY POPULATION: 600 Adult patients with chronic hepatitis C virus infection who have previously failed to achieve a sustained virologic response following interferon alfa or interferon alfa-2b plus ribavirin therapy.

DOSAGE AND ADMINISTRATION: Eligible participants will be randomized to receive PEGIntron weight-adjusted dose (1. 5 mg/kg) by subcutaneous injection weekly + ribavirin 400 mg by mouth twice daily for 48 weeks OR PEGIntron fixed dose (150 mg if weight > than 80 kg or 100 mg if weight < 80 KG) by subcutaneous injection weekly + ribavirin 400 mg by mouth twice daily for 48 weeks.

EFFICACY EVALUATIONS: Laboratory analysis, quality of life assessments, and change in study medication doses will be obtained.

SAFETY EVALUATIONS: Assessment of laboratory evaluations, vital signs, incidence and severity of adverse experiences and progression of disease, as measured by HCV viral load.

STUDY DESIGN

This is a treatment protocol to evaluate the antiviral efficacy, safety and tolerability polyethylene glycol (PEG) conjugated interferon alfa-2b (PEGIntron) for the treatment of chronic hepatitis C virus infection in patients who have previously failed to achieve a sustained virologic response following interferon alfa or interferon alfa-2b plus ribavirin therapy. Patients will be stratified according to their response to the previous course of therapy (i. e. non-reponse or relapse virologic pattern

This is a multi-center, randomized, open-label clinical trial that will involve approximately 25 sites with an anticipated enrollment of 600 patients over a six-month period.

Eligible participants will be randomized to receive PEGIntron weight-adjusted dose (1. 5 mg/kg) by subcutaneous injection weekly + ribavirin 400 mg by mouth twice daily for 48 weeks OR PEGIntron fixed dose (150 mg if weight > than 80 kg or 100 mg if weight < 80 KG) by subcutaneous injection weekly + ribavirin 400 mg by mouth twice daily for 48 weeks.

- Group A: PEGIntron weight -adjusted dose (1. 5 mg/kg) by subcutaneous injection weekly

+ ribavirin 400 mg by mouth twice daily for 48 weeks (Total therapy x 48weeks).

- Group B: PEGIntron fixed dose (150 mg if weight > than 80 kg or 100 mg if weight < 80

KG) by subcutaneous injection weekly + ribavirin 400 mg by mouth twice daily for an additional 48 weeks (Total therapy x 48 weeks).

REPEAT Study - A Study of PEGASYS (Peginterferon Alfa-2a (40KD)) Therapy in Combination With COPEGUS (Ribavirin) in Patients With Chronic Hepatitis C (CHC) Who Did Not Respond to Previous PegIntron (Peginterferon Alfa-2b (12KD))/Ribavirin Combination Therapy [Completed]
This 4 arm study is designed for patients with CHC who have not responded to peginterferon alfa-2b (12KD)/ribavirin combination therapy. In these patients, the effects of lengthening the duration of treatment, as well as including an initial 12-week period of high-dose PEGASYS (360 micrograms sc), are compared with the standard combination therapy of PEGASYS (180 micrograms sc) and ribavirin (1000-1200mg po). The anticipated time on study treatment is 1-2 years and the target sample size is 500+ individuals.

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Page last updated: 2009-11-18

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