In two separate reports, one in Science and one in Nature, researchers at the Paul Erlich Institute in Langen, Germany and at Dr. Robert Gallo's new lab at the University of Maryland announced that they believe they have isolated and identified the mysterious HIV suppressive factor believed to be secreted by human CD8+ blood cells. The German team, working in African green monkeys, identified the substance as interleukin-16, a cytokine involved with the inflammatory response. The Gallo team, from work in immortalized T-cell lines, identified the factor as a combination of three substances (RANTES, MIP-1 alpha and MIP-1 beta) known as chemokines, also involved in the inflammatory response. UCSF's Dr. Jay Levy, who first proposed the existence of a "CD8 cell suppressive factor" nearly a decade ago, commented that neither of the research groups is on the right track.
FDA panel recommends approval for ganciclovir implant. On Friday, December 8, an FDA Advisory Panel voted 6-to-1 to recommend approval of Chiron Corp.'s Vitrasert intravitreal ganciclovir implant for HIV-infected persons with CMV retinitis. A study of 173 patients showed that the implant prevented progression of CMV retinitis about three times as long as intravenous ganciclovir: 220 days versus 72 days. The committee cautioned that CMV retinitis patients should not simply get the implant without additional treatment (i.e., concomitant oral ganciclovir for life).
FDA approval for saquinavir; Lottery for ritonavir. Abbott Labs announced Friday, December 1 that it would be making its experimental protease inhibitor ritonavir (ABT-538) available to 2,000 patients (CD4 counts < 50) worldwide via a lottery mechanism like that of Roche and Merck (deadline 12/30/95). The following week, the FDA announced approval for Roche's protease inhibitor, saquinavir, which arrived at pharmacies in New York the next day--at around $6,000 a year.