Merck has posted 96-week data on a HIV prospect it hopes will replace drugs including Bristol-Myers Squibb’s Sustiva in combination regimens. The update linked Merck’s doravirine to a higher rate of viral suppression than a combination of antiretroviral drugs from AbbVie and Johnson & Johnson.
Merck is developing doravirine in the belief that all of the drugs currently added to Gilead’s Truvada and ViiV Healthcare’s Epzicom have shortcomings. Bristol-Myers’ Sustiva is associated with a higher rate of certain side effects than rival non-nucleoside reverse transcriptase inhibitors (NNRTIs), while J&J’s Edurant struggles in patients with very high viral loads. Boehringer Ingelheim’s Viramune and J&J’s Intelence also have limitations that create an opportunity for a new NNRTI.
Doravirine is Merck’s attempt to seize that opportunity. Last year, Merck showed the NNRTI was as effective as a combination of AbbVie’s Norvir and J&J’s Prezista at suppressing the HIV virus after 48 weeks, teeing up a filing for FDA approval that has an Oct. 23 PDUFA date.
Now, Merck has followed up with 96-week data. The update shows the rate of viral suppression in HIV patients taking doravirine on top of Gilead or ViiV’s drugs dipped by 10 percentage points over the second 48 weeks of the trial. But with the rate of viral suppression in the control arm falling by 14 percentage points, doravirine performed better than the Norvir-Prezista combination. The difference between viral suppression in the doravirine and control arms was 7.1%.
Doravirine fared worse in participants who started the trial with high viral loads but again held its own against the control regimen. After 96 weeks, 65.4% of the high viral load subgroup experienced viral suppression, down from 81% at the earlier readout. The 96-week rate of viral suppression in the control arm came in at 65.2%.
Merck emerged from the 96-week update without sounding any safety alarms. Doravirine remains free of the increases in fasting serum blood lipids associated with the Norvir-Prezista combination, and it had a lower rate of adverse event-triggered dropouts than the control regimen.
The update comes three months before Merck is due to learn whether the FDA will approve doravirine, both as a monotherapy and in combination with lamivudine and tenofovir.