Vertex Unveils More Promising Hep C Drug Data

An experimental hepatitis C drug from Vertex Pharmaceuticals VRTX was effective in treating patients who failed to respond previously to currently prescribed hepatitis C drugs, according to preliminary data presented at a liver disease meeting in Europe Thursday.

The Vertex drug, telaprevir, has already shown in previous studies the ability to cure hepatitis C patients who are newly diagnosed and haven't yet been treated. Vertex and Johnson & Johnson JNJ are co-development/marketing partners with the drug.

The new clinical data, however, shows telaprevir may also be a breakthrough treatment for so-called non-responder or relapsed hepatitis C patients. These are patients considered the hardest to treat because they either did not respond to current drugs like interferon and ribavirin, or their virus returned after treatment.

The new clinical data on telaprevir in treatment-resistant hepatitis C patients, while positive, is still preliminary and will have to be confirmed with longer-term patient follow-up.

But if telaprevir is found to be effective for these hardest-to-treat hepatitis C patients, the commercial potential for Vertex is significant. There are an estimated 350,000 hepatitis C patients in the U.S. who have failed current interferon-ribavirin therapy and are waiting for something new and more effective to be approved so they can be retreated, and hopefully cured.

This is one of the major reasons why the race to develop and market a new hepatitis C drug is so frenzied. Vertex and J&J are facing off with companies like Schering-Plough SGP, InterMune ITMN, Roche and ViroPharma VPHM -- all of which are hoping that their respective hepatitis C drugs are superior or can be approved first to be the go-to drug for treatment-resistant patients.

Researchers presented the new telaprevir data from the Study 107 clinical trial Thursday at the annual meeting of the European Association for the Study of Liver Disease, being held this week in Milan, Italy.

This new study enrolled hepatitis C patients from the control arms of Vertex's phase IIb telaprevir studies, known as PROVE 1, PROVE 2 and PROVE 3. These patients failed to respond or relapsed after interferon-ribavirin therapy but were then offered the chance to roll over to a treatment combining telaprevir plus interferon and ribavirin.

After four weeks with this telaprevir combination therapy, 82% of these hard-to-treat patients (49 of 60 patients) showed a significant reduction in the amount of hepatitis C virus in their body.

When measured with a more sensitive test that can detect a commonly used standard for when the virus falls below undetectable levels, the number of patients responding after four weeks fell to 56%.

Still, that's much higher than is ever seen when these types of patients are retreated with just interferon and ribavirin, suggesting that the addition of telaprevir is making a big difference and could lead to higher cure rates.

Based on previous studies, roughly 10% of treatment-resistant hepatitis C patients who are then retreated with interferon and ribavirin are successfully cured of their disease.

So far, 16 of the patients in Vertex's Study 107 have continued telaprevir treatment through 12 weeks and the antiviral response remains strong, according to data presented Thursday. All patients will continue treatment with the telaprevir combination through 12 weeks, then be switched to interferon and ribavirin alone for another 12 or 36 weeks.

The number of patients cured of their hepatitis C won't be known until six months after their treatment ends. Under current treatment guidelines, a patient must be cleared of the hepatitis C virus six months after treatment in order to be deemed cured.

That's why Thursday's telaprevir data are promising and exciting, but not conclusive.