GlaxoSmithKline Issues Letter Saying Not To Use Lamivudine, Abacavir, Tenofovir Combination as First-Line Therapy

Drug maker GlaxoSmithKline yesterday sent a letter to health care providers telling them not to use the once-daily, three-drug combination therapy including the company's antiretroviral drugs Epivir, Ziagen and Gilead Sciences' Viread as first-line therapy, after the results of a study showed poor efficacy of the combination, according to the letter (GSK letter, 7/31). The GSK-led study examined the effectiveness of Viread, also known as tenofovir, used in combination with Ziagen, known generically as abacavir, and Epivir, also known as lamivudine, compared with a combination of Bristol-Myers Squibb's Sustiva, or efavirenz, in combination with abacavir and lamivudine, Reuters Health reports. GSK found a high rate of early virologic non-response in patients who had never received HIV treatment and who took the tenofovir combination. After eight weeks, 49% of the 102 patients taking the tenofovir combination had failed to respond to the drugs, and after 12 weeks, 48% of 63 patients met the definition for non-response, according to Reuters Health. Only 5% of patients taking the efavirenz combination had failed to respond at eight and 12 weeks. GSK has yet to determine the reasons why patients failed to respond to the drug combination, Reuters Health reports. The tenofovir combination arm of the study has been stopped. The European Medicines Evaluation Agency also issued a warning to European health care providers telling them not to use the tenofovir combination following the study results. The agency said that patients taking the combination should be "frequently monitored with a sensitive viral load test and considered for modification of therapy at the first sign of viral load increase." The EMEA also said that patients taking the combination should talk with their health care providers "immediately," Reuters Health reports (Woodman, Reuters Health, 7/31).