Drug Pipeline Update: Lersivirine Out of the Running
Pharmaceutical company ViiV Healthcare announced the decision to discontinue development of lersivirine, its experimental non-nucleoside reverse transcriptase inhibitor (NNRTI), in an email message sent yesterday to HIV community writers.
After much deliberation, wrote ViiV Director of External Affairs Marc Meachem, “it was determined that the compound would not provide an improvement over existing medicines in the NNRTI class, and that R&D resources for ViiV Healthcare should prioritize efforts to identify compounds that further HIV treatment.”
The message stated the decision was not based on safety concerns. Study results published in the February 1, 2013, issue of Journal of Acquired Immune Deficiency Syndromes highlighted differences in side effects and viral loads following 48 weeks of treatment with the already approved NNRTI efavirenz (brand name Sustiva) vs two different doses of lersivirine (500 mg and 750 mg), all taken along with the Truvada combination pill (tenofovir/emtricitabine).
In this Phase IIb trial, nausea was reported by more people in the two lersivirine groups than in the efavirenz group (23.1% and 41.5% vs 12.7%, respectively), whereas more participants taking efavirenz reported experiencing dizziness (20.6% vs 7.7% and 6.2%, respectively) and abnormal dreams (19.0% vs 7.7% and 7.7%, respectively).
After 48 weeks, slightly more people taking efavirenz than either dose of lersivirine reached a viral load below 50 copies/mL (85.7% vs 78.5% and 78.5%, respectively).
ViiV has two other potential HIV drugs in the pipeline, both of them integrase inhibitors. The company recently applied to the Food and Drug Administration for regulatory approval of dolutegravir. (Learn more about dolutegravir here.) Its other integrase inhibitor, known in studies as S/GSK1265744, is a long-acting injectible drug that many hope will allow for monthly dosing.
Want to know what else is in the HIV drug pipeline? Longtime HIV education and advocacy organization Treatment Action Group has answers: Read their 2012 Pipeline Report online or download a full PDF copy.
Reilly O’Neal is a freelance writer and former editor of BETA.