Saturday, October 30, 2010

Vertex v. Merck | In Black Hep C Patients, Which Drug Is More Efficacious?

It has been known for decades that people of color bear a disproportionate share of the disease burden from the Hepatitis C virus in humans. [I recall first reading of this, in 1991, in the Wall Street Journal.]

As the race to cure Hep C nears the finish line, Merck is making claims about how effective Boceprevir® is in treating the black population subgrouping in its investigational clinical trial (where the law of small numbers clearly applies -- n: 172 total). Within minutes of Merck's breathless presser this morning, Vertex had answered with one of its own, explaining the Telaprevir® subgrouping performance figures.

How is it that so many people are working press lines on the Saturday of Halloween? Well, the 61st Annual Meeting of the American Association for the Study of Liver Diseases is in full swing, in Boston. It is the most important US conference on the subject, and the spin machines (from both companies) are (fittingly) working at near election-day fervor.

Here, though (near as I can tell), is what sorts out from what is actually known -- on the actual data-sets: Vertex's Telaprevir holds a clear lead on overall cure-rates, in patients who've previously failed treatment -- across all ethnic and racial groups. The two are closer, in "new" patients, people who've never been treated for Hep C -- close enough that it wouldn't be fair to call a clear win for Vertex, though on paper it is ahead, statistically.

Similarly, though both drugs clearly blow away the current 25 percent cure rate for African Americans (on standard therapy), Vertex is again ahead, curing about 60 to 62 percent of this subgroup overall (Merck comes in at 58 percent). Either way, this is a momentus day for the advancement of science: it is fair to say that -- between these two candidates -- some time in the coming decade, we will be calling this conference the moment when "the cure" for Hep C was announced. That's heady stuff.

From the Vertex release, then:

. . . .In ILLUMINATE, 72% of people overall achieved SVR with telaprevir-based therapy. New data from this study showed that 60% of African Americans/Blacks and 63% of people with advanced liver fibrosis or cirrhosis achieved SVR with telaprevir-based therapy in the overall study analysis. Of African Americans/Blacks whose virus was undetectable at weeks 4 and 12, 88% of people achieved SVR in both the 24-week and 48-week randomized treatment arms. There was no control arm of pegylated-interferon and ribavirin alone in ILLUMINATE.

The safety and tolerability profile of telaprevir was consistent in both trials, with low discontinuation rates of all drugs during the telaprevir treatment phase due to adverse events.

"Less than half of people with the most common form of hepatitis C - genotype 1- achieve a viral cure with currently approved medicines, and factors such as race and extent of liver fibrosis can further limit cure rates to less than a third," said Ira Jacobson, M.D., Chief of the Division of Gastroenterology and Hepatology, at New York-Presbyterian Hospital/Weill Cornell Medical Center, and the Vincent Astor Distinguished Professor of Medicine at Weill Cornell Medical College. "After treatment with telaprevir-based combination therapy in the ADVANCE study, 75% of people overall achieved a viral cure. Importantly, 62% of African Americans/Blacks and people with extensive liver disease achieved a viral cure -- nearly twice as many as those who received pegylated-interferon and ribavirin alone. . . ."

Merck's comparable rates are lower, overall, and lower for African-Americans -- at 58 percent, on an "apples to apples" basis.

More on the race to file with FDA, in the next post.

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