Boceprevir Hepatitis C Patients Continue to Fare Well, Data Show

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European Association for the Study of the Liver (EASL) 45th Annual Meeting

This coverage is not sanctioned by, nor a part of, the European Association for

the Study of the Liver.

From Medscape Medical News

Boceprevir Hepatitis C Patients Continue to Fare Well, Data Show

R.

April 19, 2010 (Vienna, Austria) - Additional encouraging results for

boceprevir, an investigational oral protease inhibitor for the treatment of

hepatitis C virus (HCV), were unveiled here at the European Association for the

Study of the Liver (EASL) 45th Annual Meeting. New data showed that patients

with sustained virologic response (SVR) rates continued to have SVR after 2

years of follow-up.

Also, no serious adverse events (SAEs) have emerged since the initial 24-week

study period of the Serine Protease Inhibitor Therapy 1 (SPRINT-1) study,

according to data reported at the EASL meeting.

New results, however, showed that some mutations were slow in reverting to

wild-type virus.

The drug - developed by Schering-Plough, which merged with Merck in November

2009 - is now in a fully enrolled phase 3 trial. Merck officials expect to file

the Food and Drug Administration application later this year, and they hope for

approval in 2011.

Merck officials hope the new results only bolster their case.

" They did give some signals a few years ago that they would look favorably upon

fast-tracking this, " said Vierling, MD, chief of hepatology at the Baylor

College of Medicine, Houston, Texas, who worked on the study.

" Is the SVR still defined the same; is it durable? Here it's durable, " Dr.

Vierling said. " Was there any latent SAE? The answer to that was no....These are

new drugs. And we know the on-treatment responses and we know information about

SVR, but making sure there's not a latent capacity of these to have done any

harm I think is an important safety aspect. "

Results of the SPRINT-1 study unveiled last year at the EASL meeting included

the best SVR rates ever reported for HCV genotype 1 patients.

Those taking peginterferon alfa-2b (1.5 ìg/kg once weekly) and ribavirin (800 -

1400 mg/daily, dosed by weight) followed by boceprevir (800 mg 3 times a day)

achieved an SVR rate of 75%, almost double the nonboceprevir control group's

rate.

In the new study, researchers followed up those who did and did not achieve SVR

in the SPRINT-1 study and followed up nonresponders from 2 other, smaller

studies.

They found that none of the patients who had achieved SVR after 24 weeks in the

SPRINT-1 study had relapsed compared with 21 patients from another study.

One of the 290 SPRINT-1 study patients was reinfected because of a new mutation

that emerged. Researchers did not consider this a relapse.

Dr. Vierling's team also tracked the reversion to wild-type virus for those who

had had mutations. They found 91% of those with the V36M mutation reverted,

compared with lower reversion rates for types R155K and T54, which reverted to

wild type at rates of 71% and 62%, respectively.

Mark Thursz, MD, at Imperial College London in England and vice secretary of

EASL, said the SVR data and SAE data were not unexpected, going by previous

findings on boceprevir.

" It's not the most exciting [data], but it's still interesting, " he said.

He said the slow-to-revert nature of the mutations was troubling.

" What was worrying with that was how slowly they go back to the wild type and

the fact that a few months after you've withdrawn the therapy you can still

detect mutations which confer resistance, " Dr. Thursz said. " The implication of

this is we should not be using these protease inhibitors inappropriately.

" We have to be really sure that once you start that therapy you're going to

clear the virus so you give the patient the best chance that they're going to

clear the virus. Otherwise, you're inducing mutations by inappropriate use,

which may compromise future therapies with protease-targeting drugs, " Dr. Thursz

cautioned.

The study received commercial support from Merck & Co. Dr. Vierling was an

investigator on the study. Dr. Thursz has disclosed no relevant financial

relationships.

The European Association for the Study of the Liver (EASL) 45th Annual Meeting.

Presented April 15-17, 2010.