HIV/AIDS TREATMENT: Merck Identifies New Target

      With currently available HIV treatments beginning to lose their edge, researchers at pharmaceutical maker Merck & Co., have identified a crucial step in the virus' infection cycle, giving scientists a different, "long-elusive target" at which to aim. However, experts cautioned that it will take years to turn the discovery into a viable treatment, the AP/Philadelphia Inquirer reports. Researchers have long known that the enzyme integrase plays a crucial role in HIV infection as it combines the virus' genetic material with the genetic material in patients' cells, allowing the mutated genes to reproduce at high rates. Despite attempts to create "integrase inhibiting" drugs, none have proved effective. That might all change, according to a study published in today's Science, in which lead researcher Daria Hazuda and her Merck colleagues say they have identified the exact spot in the integrase cycle that must be blocked. By screening 250,000 chemical samples, researchers found two compounds known as "diketo acids" that successfully blocked the integrase cycle (Neergaard, AP/Philadelphia Inquirer, 1/28). The compounds were shown to work in the laboratory, proving that such drugs are possible. Dr. Larry Hirsch, vice president for public affairs at Merck Research Laboratories, said, "We want to be very clear and very cautious in this. We do not at this point have plans to test these in animals, but we are actively engaged in working for better leads" (Fox, Reuters, 1/27). Nonetheless, experts hailed the discovery, indicating that they now have a third way to fight the disease. Current treatments like reverse transcriptase inhibitors AZT and ddI target early HIV infection, while protease inhibitors fight HIV at a late stage in the viral reproduction cycle. Senior Scientist for the American Foundation for AIDS Research Dr. Jeffrey Laurence said, "It's opened a third target, a target everyone knew was out there but ... that no one's been able to hit." Dr. Douglas Richmond of the University of California-San Diego, said, "They have now developed methodology, which is a critical step in developing drugs against this target" (AP/Philadelphia Inquirer, 1/28).