Hepatitis C Drug War Heats Up

AbbVie may have been first to release phase 3 data for an all-oral hepatitis treatment for genotype 1 patients, but Gilead Sciences now has the lead for the most phase 3 data. It might even have the best data. Maybe.

The biotech passed AbbVie in the data count, releasing results from three different phase 3 clinical trials today. The trials combined sofosbuvir, which was recently approved as Sovaldi, and a new drug ledipasvir, with and without a generic called ribavirin.

In one trial, dubbed ION-1, 97.7% of patients who had never been treated before were clear of virus 12 weeks after finishing a 12-week course of the two medications; essentially, they were cured. Adding ribavirin didn't help any -- the cure rate was actually slightly lower at 97.2% -- possibly due to patients dropping out because of unwanted side effects of ribavirin.


In AbbVie's first phase 3 trial, 96% of genotype 1 patients were cured with its five-drug cocktail. While lower than Gilead's 97.7%, it's not clear how comparable the number is. AbbVie released the breakdown of genotype 1a, which is harder to treat, and genotype 1b patients with cure rates of 95% and 98%, respectively. If Gilead enrolled a lot of genotype 1b patients, it's 97.7% cure rate could be artificially inflated.

In a second trial, Gilead enrolled patients whohad failed a previous treatment, producing a 93.6% cure rate for the two-drug combination, and a 96.4% cure rate when ribavirin was added for the 12 weeks. That's close to AbbVie's second phase 3 trial where 96% of treatment-experienced patients were cured, although it's even more dangerous to compare those two.

Not only do we still have the issue of the breakdown for genotype 1a/1b, but how the patients responded to the previous treatment -- null responders versus partial responders -- and this should predict how hard they are to treat. AbbVie said about 49% of the patients in the trial were prior null responders, while Gilead didn't release the breakdown. Complicating matters more, Gilead's patients previously failed the best regimen currently available, which includes a protease inhibitor -- either Vertex Pharmaceuticals' Incivek or Merck's Victrelis -- while AbbVie's trial doesn't mention that the patients had to fail the first-generation oral medications from Vertex or Merck.

Unlike AbbVie, Gilead also tested its drug combo for 24 weeks, which appears to have paid off. A solid 99.1% of treatment-experienced patients were cured regardless of whether ribavirin was added to the treatment. Gilead is also testing the combo for 24 weeks in treatment-naive patients, but the results aren't available yet.

In a third trial, Gilead gambled in the other direction, testing the drug combination for just eight weeks. With cure rates dropping to 93.1% to 94% with and without ribavirin respectively, it doesn't look like the shorter course of treatment will get adopted widely. Of course, we could just be looking at a tough-to-treat population, because the control group that was treated for 12 weeks had a cure rate of 95.4%, lower than the 97.7% seen in the first trial mentioned above.

Based on what we know now, it appears Gilead's combination has better efficacy than AbbVie's, but probably not enough to make that much of a difference in which drug is prescribed. Doctors' choice will likely come down to convenience, pricing, and side effects. With fewer pills required, Gilead appears to have AbbVie beat on convenience, but the latter two are still undecided. What we can say for certain is the all-oral combinations are so much better than Vertex's and Merck's drugs, that their use will disappear during the coming year.

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The article Hepatitis C Drug War Heats Up originally appeared on Fool.com.

Fool contributor Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Gilead Sciences and Vertex Pharmaceuticals. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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