FDA Approves Merck's Antiretroviral Raltegravir

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Antiretroviral Drug

Merck on Friday announced that FDAhas approved its antiretroviral drug raltegravir for use byHIV-positive people who have not responded to other treatments, the Wall Street Journal reports (Corbett Dooren, Wall Street Journal,10/12). An independent FDA panel of medical experts last monthunanimously recommended accelerated approval of raltegravir, anintegrase inhibitor.

Raltegravir effectively decreases HIVviral loads after 24 weeks of use among HIV-positive people who havenot responded to other treatments, according to a study published inthe April 14 online edition of the journal Lancet.Raltegravir works by blocking an HIV enzyme called integrase. Integraseis one of the three enzymes necessary for HIV to replicate in the body,and integrase inhibitors stop HIV from inserting its genes intouninfected DNA. The other two enzymes necessary for viral replication,reverse transcriptase and protease, already are targeted by a varietyof antiretrovirals.

According to an FDA review of raltegravirreleased ahead of the independent panel's meeting, the drug iseffective at treating HIV-positive people who have shown resistance toavailable treatments. The most common side effects were rash andincreased levels of creatine in the blood, according to the review.Other potential side effects include liver injuries and cancer. Inclinical trials, a higher number of cancers was found among peopletaking raltegravir than among those taking a placebo, but thedifference could be because of a lower rate of cancer among people inthe placebo group, FDA said.

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Merck previously said that the drugwill be used in combination with standard oral antiretrovirals byHIV-positive people who have developed resistance to their currenttreatments. Raltegravir will be sold under the brand name Isentress (Kaiser Daily HIV/AIDS Report, 10/11). According to Amy Rose, a Merck spokesperson, the treatment will cost about $9,850 per patient annually (Wall Street Journal,10/12). People living with HIV who are prescribed the drug will taketwo 400-milligram tablets daily in combination with otherantiretrovirals chosen by their physicians, the San Francisco Chronicle reports. Robert Rode, marketing vice president at Merck, said the new pills should be available in as few as two weeks.

Accordingto Rode, Merck has been providing raltegravir at no cost to 6,000people worldwide -- including 3,400 in the U.S. -- while it waited forFDA marketing approval. He added that the company has a program inplace to "make this product available globally" (Russell, San Francisco Chronicle,10/13). Merck has promised to study the drug for at least five years tomonitor any side effects that might not have appeared in initialclinical trials, Reuters reports (Dixon, Reuters, 10/12).

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"This is fantastic news," Warner Greene, director of the Gladstone Institute of Virology and Immunologyat the University of California-San Francisco, said, adding, "This druglooks more potent than virtually anything we have ever seen." MartinDelaney -- founder of San Francisco-based Project Informwho has participated in price negotiations with Merck on behalf of theFair Pricing Coalition -- said the company is not charging as much ashe had anticipated. The price of the drug "falls in the middle of thehigh end for AIDS drugs," Delaney said, adding, "For us, that is avictory" (San Francisco Chronicle, 10/13).

BenCheng, deputy director of the Forum for Collaborative HIV Research,said that as the "AIDS crisis continues, new drugs like Isentress areneeded, which target the virus in unique ways." He added that the "HIVadvocacy community is really excited and encouraged by this newtreatment" (AP/BusinessWeek, 10/12).

Reprinted with permission from kaisernetwork.org. You can view theentire Kaiser DailyHIV/AIDS Report, search the archives, and sign up for email delivery at kaisernetwork.org/email . TheKaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service ofThe Henry J. Kaiser Family Foundation.

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