Study Indicates Antiretroviral Potency Increasing, ‘Bodes Well’ for the Future, Opinion Piece Says
A study published in today's issue of the New England Journal of Medicine indicates that "improvements are being made in the potency of antiretroviral drugs," which "bodes well" for the future of antiretroviral research, as antiretroviral potency is "key" to a drug's initial success, Dr. Scott Hammer of Columbia Presbyterian Medical Center in New York City writes in an opinion piece accompanying the study (Hammer, NEJM, 6/27). The study, conducted by Dr. Sharon Walmsley of Toronto General Hospital and colleagues, examined 653 HIV-positive patients who were randomly assigned to take a combination of the newly developed "potent" antiretroviral lopinavir, which is boosted by low-dose ritonavir, or nelfinavir. All of the patients also took stavudine and lamivudine. After 48 weeks, 67% of those in the lopinavir-ritonavir group had fewer than 50 copies per milliliter of HIV RNA, compared to 52% of those in the nelfinavir group (Walmsley et al., NEJM, 6/27).
Drug Development 'Dynamic'
While Walmsley's study "highlights the progress" of existing antiretroviral drugs, it also indicates that HIV drug development is still "dynamic." Although it is an "important finding" that one drug has virologic superiority over another, the results of such studies "may not ultimately translate into the desired clinical outcome many years, and potentially several regimens, later," he says. Walmsley's study also indicates that "differences in antiviral potency" within each of the most common antiretroviral drug regimens is "becoming increasingly discernable." While antiretroviral drug advances are not without "cost[s]," such as drug resistance and side effects, "link[ing] potency with the other desirable aspects of a therapeutic regimen" -- such as low pill burden, "excellent" tolerability and the absence of major drug reactions, long-term toxic effects and cross-resistance -- is "key," according to Hammer. He concludes, "Future progress in antiretroviral therapy will bring more choices for physicians and patients and will make an already complex field both more challenging and more rewarding" (Hammer, NEJM, 6/27).