Triangle Pharmaceuticals has announced that all patients receiving d4T in study FTC-301 will be switched to FTC, after a review by the trial’s Data and Safety Monitoring Board found that participants receiving FTC were significantly more likely to have viral load below 50 copies (81% vs 70%). Participants receiving d4T were also significantly more likely to have stopped treatment (10.5% vs 5.6%).
571 treatment-naïve participants in FTC-301 were randomised to receive either FTC (emtricitabine) once daily or d4T (stavudine) twice daily, with ddI (Videx EC) and efavirenz (Sustiva) (both dosed once daily). FTC-301 was a placebo controlled study, which means that all participants took at least one component of the regimen twice daily. The interim analysis took place after participants had completed at least 24 weeks on treatment; unblinding of the study was mandated if a significant difference in either efficacy or discontinuations due to side effects was apparent at this point.
Full results of the study will be presented at future scientific meetings; the first opportunity to learn more about the factors driving the superior performance of FTC will come at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), due to be held in San Diego in late September.
Triangle also announced that it has bought back full marketing rights to FTC from Abbott Laboratories, and is preparing to file for US marketing approval shortly. A European Union application is likely to follow soon afterwards.
FTC is a similar compound to 3TC. The drugs share the same resistance profile, but analysis of previous studies has shown that the MI84V mutation is significantly less likely to be selected after viral rebound on FTC when compared with 3TC. See FTC in the A to Z of drugs on this website for further details.