Merck hepatitis C drugs work in HIV co-infected patients -study

March 5 (Reuters) - A combination of oral drugs for hepatitis C developed by Merck & Co appeared to be well tolerated and highly effective in treating the liver disease in patients also infected with HIV, according to data from a midstage clinical trial presented on Wednesday.

The Merck drugs, MK-5172 and MK-8742, which belong to promising new classes of anti-viral medicines, were tested over a 12-week course of treatment both with and without the older hepatitis C drug ribavirin in co-infected patients.

After 12 weeks of treatment, all 29 patients who received the two Merck drugs and ribavirin had undetectable levels of the hepatitis C virus. Among those who got just the experimental Merck drugs, 26 of 29, or 90 percent, appeared to have the hepatitis C virus eliminated from their blood.

If the virus remains undetectable 12 weeks after completion of treatment, those patients are considered cured.

The available data from the ongoing study was presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in Boston. More detailed results of the study dubbed C-Worthy are expected to be presented at a European medical meeting in April, Merck said.

No co-infected patients discontinued treatment due to either an adverse side effect or study medication intolerance, Merck said. The most common side effects of fatigue and headache were no more prevalent in patients with hepatitis C and HIV infection than what had been observed in patients with hepatitis C alone.

A new era in treatment for the serious liver disease has begun with several companies, including Gilead Sciences Inc , AbbVie and Bristol-Myers Squibb Co, developing all oral treatment regimens that have demonstrated cure rates well in excess of 90 percent with treatment durations of just 12 weeks or shorter.

Current standard treatments take 24 to 48 weeks and include the injected drug interferon that causes miserable flu-like symptoms and cure about 75 percent of patients.

Those also living with the virus that causes AIDS are an important patient population.

About seven million people worldwide are co-infected with HIV and hepatitis C (HCV). Co-infected patients have a three times higher rate of progression to cirrhosis and a six times higher risk of liver decompression than those with HCV alone.