In a statement issued February 5, 2013, ViiV Healthcare announced they were halting the development of their new NNRTI lersivirine. This comes on the heals of promising 48-week results released from a phase IIb study that compared lersivirine to efavirenz (Sustiva).
That study showed lersivirine controlled HIV as well as efavirenz. A total of 193 people who were new to treatment enrolled in one of three groups: 500mg or 750mg of lersivirine+Truvada or 600mg efavirenz+Truvada.
Lersivirine suppressed HIV to an undetectable level in 78.5% in each group while 85.7% were suppressed on efavirenz, with no statistical difference among the groups. Despite the promising results and the somewhat more tolerable rate of side effects from lersivirine, ViiV determined “that the compound would not provide an improvement over existing medicines in the NNRTI class.”
“Newer HIV meds that are coming to market from existing classes of drugs have to show clear benefits over what current treatments offer patients today,” stated Alan McCord, Director of Education. “This generally means a new drug or combination pill that shows excellent control in many more people, such as 95% or more, or shows far fewer or even no side effects for most people. Recent drug development has set a very high bar for new compounds to have an honest shot in the marketplace.”