Vertex Hepatitis C Drug Wipes Out Virus For Toughest-to-Treat Patients
Vertex Pharmaceuticals (NASDAQ: VRTX) is vying to set a new standard of care for hepatitis C in some of the toughest patients to treat, and today it is reporting some surprisingly strong evidence that suggests the drug is working like researchers hoped it would over the long haul.
The Cambridge, MA-based biotech company offered an interim peek at results from 117 patients who took its telaprevir compound after they failed to fully respond to standard therapy. Vertex looked at “null responder” patients who didn’t respond at all to prior therapy, and found that 16 out of 28 of them, or 57 percent, achieved a clinical cure after they got telaprevir in combination with another round of standard treatment. The clinical cure, known formally as sustained viral response, is achieved when the hepatitis C virus disappears from the blood for a full 24 weeks after the course of treatment.
Telaprevir had about the same effectiveness rate for patients who partially responded to an earlier round of treatment (55 percent achieved clinical cure), while that rate shot up to 90 percent for patients who initially were helped by standard therapy, but ended up relapsing later. These results were from a study known as ’107. Comparing separate clinical trials can be a dubious exercise because of apples-to-oranges issues, but the clinical cure rates Vertex is reporting today are higher than what it announced in April at a conference of the European Association for the Study of the Liver, in a separate study that also enrolled tough-to-treat patients, called Prove 3.
Side effects from this latest batch of results were consistent with what Vertex has seen in prior studies. Eight of the 117 patients quit taking their medication because of side effects, including four who dropped out because of rash, and one who cited anemia.
For those who are new to the Vertex story, here’s a quick refresher on why this all matters. Telaprevir is aiming to be a first-of-its-kind protease inhibitor against hepatitis C, a chronic liver disease. If it can deliver in the final stage of clinical trials, it will change the standard of treatment for the disease just as an earlier generation of antivirals did for HIV infection. The market is potentially huge, because an estimated 3.2 million people in the U.S. have hepatitis C infections, and about 650,000 have failed to get better after the standard treatment.
Telaprevir must be combined with a pair of standard drugs, pegylated interferon alpha and ribavirin, which have to be taken for almost a year, and cause flu-like symptoms that make patients feel miserable. The Vertex drug is eagerly awaited by physicians and patients because it has shown in earlier trials that it can almost double the cure rate for patients when added to standard therapy, and cut the duration of therapy in half for patients who are new to treatment. If approved, the product could generate $2.6 billion in U.S. sales as soon as 2013, according to the investment firm Cowen & Company.
Vertex is running pivotal clinical trials that it hopes will clear the way for the U.S. market introduction of telaprevir in 2011, which could potentially give it the first-mover advantage against deep-pocketed competitors like Schering-Plough and Roche. But besides being first, Vertex wants to set the highest bar for therapy, by recruiting the most difficult patients to treat—the so-called null responders who didn’t see any improvement on prior therapy. If it can confirm the results from this preliminary study in an ongoing pivotal study of 650 patients, called Realize—that it can truly cure more than half of the null responders—then Vertex could have a significant advantage that it hopes will give physicians great confidence in its drug for all kinds of patients.
“It’s important to keep in mind that this was a small study, there was no control, so it has those weaknesses,” says Robert Kauffman, Vertex’s chief medical officer. “But it really does suggest to us that we are on the right track in our ongoing Phase III trial. If those results are confirmed in the Phase III trial, then this will be a real advance in treatment.”
Still, there are caveats. One of the important things that Vertex learned from this smaller study, known as ’107, is that the tough-to-treat patients need to stay on a full 48-week long combination regimen with the interferon and ribavirin. That’s how long patients need to take the existing drugs now, Kauffman says.
This was a point of a lot of discussion within the company, because one of telaprevir’s big advantages in the so-called “naïve” patient population was that it allows patients to cut their course of therapy down to 24 weeks, meaning they don’t have to endure the flu-like symptoms for nearly as long as with the standard therapy. The pivotal study for naïve patients is still designed to test that supposed advantage, but Vertex has found that tougher-to-treat patients are better off staying on the full 48-week long regimen, and enduring all that goes with it, to achieve the clinical cure rates, Kauffman says.
“The null responders really do respond more slowly. They have to stick with the regimen longer,” he says.
This latest batch of data came out too late to be presented at this weekend’s upcoming meeting of the American Association for the Study of Liver Diseases in Boston, Kauffman says. Vertex has other data that it expects to announce in Boston from telaprevir studies, he says.