In a major setback in the development of HIV fusion inhibitors, Roche and Trimeris announced Monday that they have halted development of their experimental drug T-1249, a highly touted second-generation version of their already approved medication Fuzeon. Clinical development of the compound was put on indefinite hold due to challenges in manufacturing the complex medication, according to company officials. The current batch of T-1249 available is not suitable for use in advanced clinical trials, they added. However, basic research into a formulation of T-1249 that is easier to mass produce will continue at the pharmaceutical companies.
AIDS experts had viewed T-1249 as the leading fusion inhibitor candidate in development based on previous reports that the compound was more effective than Fuzeon, the only approved fusion inhibitor, in preventing HIV from attaching to and infecting immune system cells. Company officials say the compound is effective but just too difficult to manufacture. "T-1249's safety, efficacy, and tolerability profile as determined to date in Phase I trials were not the reasons for this decision," Miklos Salgo, director of Roche Virology, Clinical Science, wrote to T-1249 and Fuzeon investigators. "The challenges we have encountered with T-1249 are not shared by Fuzeon. Thus, this action has no impact whatsoever on Fuzeon or on the continued use of Fuzeon by patients."
Company officials say that despite halting development of the drug, Roche and Trimeris will manufacture enough of the medication to provide it free to all patients currently enrolled in a human trial of the medication through the study's 96-week endpoint. The companies also plan to continue to develop other fusion inhibitor candidates and announced the signing of a three-year extension of a research agreement to "work together to discover new HIV fusion inhibitors and to pursue improved formulations and delivery technologies which may be applicable to Fuzeon, T-1249, and future peptide fusion inhibitors."