ViiV stops development of NNRTI lersivirine
On 5 February 2013, in a letter to community organisations, ViiV Healthcare announced that it has stopped the development programme of the investigational NNRTI lersivirine. 
The letter states: “After much deliberation about how to proceed with lersivirine, 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. We remain committed to exploring candidates that will advance HIV treatment and contribute to improving outcomes for people living with HIV”.
It continued: “Individuals currently enrolled in trials to investigate lersivirine will be switched to an alternative HIV treatment regimen upon study discontinuation. However, if there are individuals that are benefiting from lersivirine for whom an appropriate alternative treatment option cannot be prescribed, we will continue to offer lersivirine until such time that they are no longer deriving clinical benefit”.
This coincided with the publication in JAIDS of 48-week results of a phase 2b study comparing lersivirine to efavirenz in treatment naive patients. 
- ViiV Healthcare. Update Status of Lersivirine Development Program. 5 February 2013.
- Vernazza et al. Efficacy and safety of lersivirine (UK-453,061) versus efavirenz in antiretroviral treatment–naive HIV-1–infected patients: week 48 primary analysis results from an ongoing, multicenter, randomized, double-blind, phase IIb trial. JAIDS. 62(2):171-179. Published online ahead of print. February 1, 2013. doi: 10.1097/QAI.0b013e31827a2ba2.