Investors, looking at data from preliminary and mid-stage clinical trials, have already pumped up the market value of Vertex past $7.5 billion largely in anticipation that its drug, telaprevir, will transform the lives of patients with the chronic liver-damaging condition. But the operative word there is preliminary. Vertex, which is based in Cambridge, MA, and has significant operations in San Diego, is still waiting for its first proof from Phase III clinical trials, the final step of testing required by the FDA before a drug can go on sale in the U.S.
These pivotal trials began two years ago, and enrolled more than 2,000 patients combined in three studies. The results are completely blinded to doctors, patients, investors, and people at Vertex. To say all parties are in suspense for these results would be an understatement. They can't wait to get their hands on the new data and start digging through it.
"This is a year of defining moments," says Bob Kauffman, Vertex's chief medical officer.
Vertex has generated the excitement around what could be a first-in-class protease inhibitor drug for hepatitis C. It has excited researchers because it has been able to double the cure rate while enabling patients to cut their standard course of treatment time in half. That means that many more of the 3 million Americans and 170 million people worldwide with chronic hepatitis C liver infections will be likely to seek out treatment, and be able to stand up to the side effects of standard therapy that causes flu-like symptoms. If Vertex can prove this idea once and for all in the three pivotal trials, Vertex could seek FDA approval later this year and bring telaprevir to the market in 2011. U.S. sales alone could amount to more than $2 billion after a couple years, analysts say.
To help our readers get ready for this data, I spoke to Kauffman for a refresher on what the three big Vertex trials were designed to ask and answer. The key point to watch for in all of these studies is what is called a "sustained viral response," or SVR, which is recorded when researchers can't find any sign of virus in a patient's blood sample for a full 24 weeks after they completed their course of therapy. This is the gold standard measurement for all hepatitis C drugs, and is commonly known as a "clinical cure."
The first study to watch for is called "Advance." This trial, started in March 2008, enrolled 1,050 patients who had never been treated before for hepatitis C -- a so-called "naïve" patient population. This study is essentially designed to confirm earlier trials called Prove 1 and Prove 2, Kauffman says. Patients either got the Vertex drug in combination with standard treatments for 24 weeks, or the standard treatments for the usual 48 weeks. The trial is designed to ask whether patients can stop treatment early with the Vertex drug, so they can avoid having to put up with the flu-like side effects of pegylated interferon alpha and ribavirin, Kauffman says. Results from that study should be available by the end of June, he says.
Not long after that data arrives, Vertex plans to hear results from two other key trials before the end of September. One of them, called "Illuminate," is enrolling patients who have never before been treated for hepatitis C infections, just like the earlier trial. The study, which enrolled 500 patients, is also looking to see how many clinical cures it can generate, and whether there's any benefit in subjecting patients to the standard 48-week course of therapy, or whether they do just as well in half the time, Kauffman says. "It should validate that 24 weeks is enough," Kauffman says.
The third study, called "Realize," is important for strategic and competitive reasons. This trial enrolled 663 patients who had previously been treated for hepatitis C, but weren't cured. Vertex has shown some promising results in this tough-to-treat patient population in the past, which is the sort of data that can really give physicians confidence in the drug's punch. Vertex has taken care to stratify this study into three different kinds of patients -- those who benefitted for a while but relapsed, those who only partially responded to prior therapy, and those who never really benefitted at all. Patients will get telaprevir in addition to the standard treatment, or just the standard stuff, for a total of 48 weeks.
As I described back in September 2008, this study is one of the key ways that Vertex seeks to differentiate itself from a competitors that are following fast -- Merck's boceprevir.
Kauffman declined to speculate on how high the clinical cure rates will need to be for Vertex to declare victory. Last October, Vertex presented results from patients who failed prior therapy, which demonstrated telaprevir could induce cure rates between 55% and 90%. Vertex said back in April 2008, before it invested in the pivotal round of telaprevir trials, that between 61% and 68% of treatment-naïve patients were clinically cured in the smaller trials (Prove 1 and Prove 2).
After the past two years of recruiting patients, supplying the clinical sites with experimental drugs, monitoring the sites to make sure they follow the study protocol, and gathering all the data, you could say the expectations are high for this study. Wall Street, after all, is giving Vertex that $7.5 billion market valuation on anticipation of telaprevir's sales trajectory more than any other factor. If the pivotal studies confirm the smaller trials -- which is never a given in drug development -- you will probably hear the victory whoops skimming all the way across the Charles River from Vertex headquarters in Cambridge.
"Phase III is the ultimate confirmation," Kauffman says. "They are the largest and most definitive studies. It's a very important time for us at the company now."
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