Biotech Values

[DewDiligence]

Re: VRX Taribavirin data

VRX’s share price rose modestly yesterday when these
data were reported, but I think Taribavirin (a.k.a.
Viramidine) is an inconsequential player in the market
for better HCV treatments. Taribavirin is a prodrug of
ribavirin and, based on the VISER2 trial completed in
2006, it may be less efficacious (#msg-13246012).

Taribavirin does not warrant a mention in the “HCV:
Most Likely to Succeed” post (#msg-33808317) because
it is not likely to succeed, IMO. Note the use of the
dreaded word, “encouraging” in the header of this PR.

http://biz.yahoo.com/bw/081124/20081124005471.html

› Valeant Reports Encouraging End of Treatment Results with Taribavirin at Treatment Week 48 in Phase IIb Study

Monday November 24, 8:00 am ET

ALISO VIEJO, Calif.--(BUSINESS WIRE)--Valeant Pharmaceuticals (NYSE: VRX ) today reported results at end of treatment, week 48 analysis point in the Phase IIb clinical trial for its antiviral compound, taribavirin, a prodrug of ribavirin in development for the treatment of chronic hepatitis C in conjunction with a pegylated interferon. Similar to the treatment week 12 results reported earlier this year, the 48-week viral response (EOT) data continue to show comparable reductions in viral load for weight-based doses of taribavirin and ribavirin. The anemia rate was statistically significantly lower for patients receiving taribavirin in the 20mg/kg and 25mg/kg arms versus the ribavirin control arm.

In the Phase IIb study, 278 treatment naïve, genotype 1 patients were randomized with the following patient demographics: mean age 48.8 yr, 61.1% male, 30% African-American or Latino, 80.7% viral load ≥400,000 IU/mL and 82.1 kg mean weight. Treatment week (TW) 48 efficacy and safety results for the intention-to-treat (ITT) population are shown in the table below.

“The results of this phase II study are encouraging, and suggest that comparable efficacy on therapy can be achieved when compared to ribavirin,” stated Fred Poordad, M.D., Chief of Hepatology at the Center for Liver Disease and Transplantation, Cedars-Sinai Medical Center, Los Angeles, CA. “If the sustained response rates are also similar with less anemia, this will be a significant step forward in the development of taribavirin.”

“We are pleased that the 48-week data continues to demonstrate sustained comparable efficacy between taribavirin and ribavirin given that the genotype 1 group is a difficult to treat population and a third of the patients in this study were either African-American or Latino,” said J. Michael Pearson, chairman and chief executive officer. “We believe that taribavirin will be a promising alternative to ribavirin in the treatment of chronic hepatitis C and, with Valeant’s strategic shift away from the infectious disease market, we plan to out-license this compound in order to maximize its potential for these patients.”

Key Efficacy and Safety Data Table at Treatment Week 48 (ITT Population)

Phase IIb
TBV

20 mg/kg

n=67
TBV

25 mg/kg

n=70
TBV

30 mg/kg

n=68
RBV

800-1400mg

n=70
TW4 Undetectable1 11 (16.4%) 10 (14.3%) 11 (16.2%) 8 (11.4%)
TW12 Undetectable1 28 (41.8%) 29 (41.4%) 17 (25.0%) 22 (31.4%)
TW24 Undetectable1 35 (52.2%) 29 (41.4%) 27 (39.7%) 28 (40.0%)
TW48 Undetectable1 29 (43.4%) 23 (32.9%)3 20 (29.4%) 23 (32.9%)
Anemia rate TW 482 9 (13.4%)* 11 (15.7%)** 19 (27.9%) 23 (32.9%)


1 HCV RNA < 39 IU/mL

2 Anemia rate defined as percentage of patients with Hgb level <10g/dL.

3 Includes data on two patients who were virus undetectable at TW36 and FW52, but missed TW48 assessment
*p=0.009
**p=0.03

The most common adverse events were fatigue, nausea, flu-like symptoms, headache and diarrhea. The incidence rates among treatment arms were generally comparable except with respect to diarrhea, where diarrhea was approximately twice as common in taribavirin patients as ribavirin patients. However, the diarrhea was generally mild and not treatment limiting for taribavirin or ribavirin patients.

The Phase IIb trial is a U.S. multi-center, randomized, parallel, open-label study in 278 treatment-naïve, genotype 1 patients evaluating taribavirin at 20 mg/kg, 25 mg/kg, and 30 mg/kg per day in combination with pegylated interferon alfa-2b. The control group is being administered weight-based dose ribavirin (800/1000/1200/1400mg daily) and pegylated interferon alfa-2b. Overall treatment duration is 48 weeks with a post-treatment follow-up period of 24 weeks.

About Valeant

Valeant Pharmaceuticals International (NYSE: VRX - News) is a multinational specialty pharmaceutical company that develops, manufactures and markets a broad range of pharmaceutical products primarily in the areas of neurology and dermatology. More information about Valeant can be found at www.valeant.com.‹