Vertex hep C drug superior to standard care-study

NEW YORK, April 25 (Reuters) - Vertex Pharmaceuticals Inc's (VRTX.O) experimental hepatitis C drug, telaprevir, proved significantly better than standard therapy in knocking out the virus in patients for whom prior treatments failed, according to results of a clinical study.

The notoriously difficult to treat patients fared far better when telaprevir was added to their therapy for both those who received the Vertex drug for 12 weeks and those in a 24-week treatment group, researchers said.

The sustained viral response (SVR) rate was 51 percent in the 12-week telaprevir group and 52 percent on the 24-week telaprevir regimen, compared with a 14 percent SVR rate in patients who received a 48-week course of ribavirin and pegylated-interferon -- the current standard of care.

Analysts have said SVR rates above 35 percent in treatment failure patients is an excellent result, with 50 percent or better representing a major advance. One telaprevir sub-group in the study achieved a 76 percent SVR rate.

Hepatitis C is a blood-borne liver disease that can lead to chronic liver disease, liver cancer, cirrhosis and death. The virus affects an estimated 3.4 million people in the United States and some 170 million worldwide.

Vertex released interim data from the 453-patient mid-stage study called Prove 3 in November. Researchers presented the final results, which for the first time included 48-week data on patients who did not get telaprevir, at a major liver disease meeting in Copenhagen, Denmark on Saturday.

"The control arm rates put it all into perspective," said Bob Kauffman, Vertex's senior vice president for clinical development, said in a telephone interview from Copenhagen.

The percentage of patients in whom the virus is undetectable 24 weeks after stopping treatment yields the critical measure known as sustained viral response, which is considered tantamount to a cure.

"Previously treated patients who didn't achieve SVR represent the hardest to treat patient population," Dr. Michael Manns, lead investigator of the Vertex-funded study, said in a statement.

"We observed superior SVR rates across all telaprevir-based treatment arms compared to control in patients who had previously failed treatment for hepatitis C, including patients with cirrhosis. This represents an exciting potential medical advance for patients who currently have very few options," Manns said.

Patients in the study included those who failed to respond to prior treatments with pegylated-interferon and ribavirin, those who relapsed following treatment, and those who reached undetectable levels of the virus during treatment but in whom the virus returned before treatment concluded -- known as breakthroughs.

Patients got either the triple combination for 12 weeks and another 12 weeks of the two standard drugs or 24 weeks on the three-drug combination plus 24 weeks on the standard therapy. The control group received 48 weeks of standard therapy.

The most impressive SVR results were seen in telaprevir patients among the relapsers -- 69 percent with the 12-week regimen and 76 percent in the 24-week group compared with 20 percent in the control group.

Among non-responders telaprevir SVR rates were 39 percent and 38 percent compared with just 9 percent on standard care.

In the much smaller group of breakthroughs, telaprevir SVR rates were 57 percent and 52 percent for the 12- and 24-week regimens versus 40 percent in the control group.

Incidents of skin rash, which has been of some concern in previous telaprevir trials, led to discontinuation in 17 patients, or 5 percent. The rash was reversible upon cessation of treatment, researchers said.

Red blood cell boosting anemia drugs were used in only two of 339 telaprevir patients, a far lower percentage than seen with an experimental Schering-Plough Corp SGP.N drug, boceprevir, that is expected to compete with the Vertex drug. (Reporting by Bill Berkrot; Editing by Richard Chang)