March 6 (Bloomberg) -- Gilead Sciences Inc., which paid $10.8 billion to buy Pharmasset Inc. for its hepatitis C pill, said the number of patients who relapsed after they stopped taking the treatment has increased.
Eight of nine patients with the most-common form of the virus in the U.S. had a relapse within four weeks after stopping use of the medicine, GS-7977, and ribavirin, according to research presented today at the Conference on Retroviruses and Opportunistic Infections in Seattle. The patients in the study weren’t helped by prior therapies.
Gilead announced last month that six patients relapsed, sending shares down the most in 11 years. A longer duration or combination with other therapies may help these patients, said researcher Edward Gane, deputy director and hepatologist of the New Zealand Liver Transplant Unit at Auckland City Hospital.
“It’s clear the treatment options for this very difficult to treat group will either be longer duration of 7977 plus ribavirin, or alternatively, the addition of another direct acting antiviral,” Gane said at the meeting.
Last year, Pharmasset reported data on PSI-7977 showing that 40 patients with genotypes 2 and 3 who received the therapy were responsive after 12 weeks. About half the patients had been followed up to 24 weeks, and they were all cured.
Hepatitis C is a viral infection that can lead to swelling of the liver. As many as 170 million people globally carry the virus, which is transmitted through exposure to infected blood, and more than 350,000 die from related illnesses each year, according to the Geneva-based World Health Organization.
Gilead declined 1.4 percent to $45.59 at 11:41 a.m. New York time.
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