Drug & Device Development

Telaprevir achieves SVR in toughest hepatitis C patients

Last Updated: 2010-09-08 13:15:21 -0400 (Reuters Health)

By Bill Berkrot

NEW YORK (Reuters) - The experimental hepatitis C drug telaprevir produced a sustained viral response (SVR) in 65% of patients who had previously failed standard therapy, according to data from the phase III REALIZE trial.

Patients in the control group, treated only with pegylated interferon and ribavirin, had an SVR rate of 17%.

There was a 31% telaprevir cure rate among null responders, or those who had almost no response to prior treatment, considered to be the most difficult to treat patient population of all. The standard drugs cured only 5% of those patients in the study.

The results released on Tuesday were from the third phase III study of telaprevir and complete the pivotal data that Vertex Pharmaceuticals will submit to health regulators by year end as it seeks approval of the closely watched medicine, which is expected to be on the market next year. The company announced the data in a press release; as of yet there's been no peer review of the findings.

Telaprevir, an oral inhibitor of HCV protease, is widely expected to become a game changer in the treatment of the serious liver disease. The lofty expectations are based on telaprevir's ability to cure a far higher percentage of patients than the notoriously tough to tolerate standard drugs, and its potential to cut the current 48-week treatment duration in half when used in combination with interferon and ribavirin.

Industry analysts and physicians believe many hepatitis C patients have been delaying treatment until new drugs like telaprevir are approved due to the disappointing cure rate of current treatment as well as debilitating flu-like symptoms that lead many patients to discontinue taking their medication.

The first Phase III study of telaprevir in previously untreated hepatitis C patients led to a 75% cure rate compared with 44% for patients who received interferon and ribavirin. (See Reuters Health story of May 25, 2010.)

A second Phase III trial showed that the overwhelming majority of previously untreated patients who respond early to telaprevir in the treatment regimen can be cured in half the time of current therapy. (See Reuters Health story of Aug 10, 2010.)

The latest trial tackled a much tougher patient population -- those who already failed to be cured by prior treatment -- and was considered the biggest challenge yet for telaprevir.

"The REALIZE data represent a major milestone in the development of new treatments for hepatitis C, as patients who received telaprevir-based therapy had a viral cure rate almost four times greater than the cure rate in those treated with available medicines," Dr. Stefan Zeuzem, the study's lead researcher, said in a statement. Dr. Zeuzem is with JW Goethe University Hospital, Frankfurt, Germany.

In addition to null responders, subjects in the study included patients who had relapsed after prior treatment and those who achieved a partial response to current medicines.

Among relapsers, the telaprevir-based regimen led to an 86% SVR rate compared with 24% from standard drugs. There was a 57% telaprevir SVR rate among the partial responders versus 15% in the control group.

In an analysis of the data, with the null responders excluded, telaprevir had a cure rate of 78% versus 21% for standard medicines, the company said.

Telaprevir is expected to compete with a similar medicine being developed by Merck & Co called boceprevir. But analysts have been virtually unanimous in their belief that telaprevir is the superior medicine.

In Merck's study of treatment failure patients that did not include null responders, boceprevir led to a 66% SVR rate. Boceprevir also produced an SVR rate of 66% in previously untreated patients in a separate Merck trial.

Safety and tolerability in the latest telaprevir study was consistent with what had been observed in previous studies, with the most common side effects mild to moderate incidence of skin rash, fatigue, nausea and anemia, the company said.

Adverse events that led to discontinuation from the study occurred in 4% of telaprevir patients and 3% in the control arm.