September 19, 2019
The US FDA has approved a new indication for Pifeltro™ (doravirine) tablets and Delstrigo™ (doravirine/lamivudine/tenofovir disoproxil fumarate) tablets, both manufactured by Merck. They are now approved for use in combination with other antiretroviral medicines to replace the current antiretroviral regimen in adult patients who are virologically suppressed (less than 50 copies of HIV-1 RNA per mL) on a stable antiretroviral regimen with no history of treatment failure and no known substitutions associated with resistance to the individual components of the drug being used.
First approved in 2018, Pifeltro and Delstrigo were initially indicated only for use in patients who had no prior history of antiretroviral treatment. Approval for the new indication is based on a clinical study in which Pifeltro and Delstrigo demonstrated non-inferior efficacy. Recommended dosing with Pifeltro is one tablet taken once a day, or, if used with rifabutin, one tablet taken twice daily with doses approximately 12 hours apart. Delstrigo has a recommended dosing of one tablet taken once daily. If Delstrigo is taken with rifabutin, the patient should also take one tablet of Pifeltro 12 hours following each daily dose of Delstrigo.
A black box warning cautions that Delstrigo, like other products that contain tenofovir or lamivudine, may contribute to severe, acute exacerbations of hepatitis B (HBV) infection in patients coinfected with HIV-1 and HBV who discontinue treatment with either of these two active pharmaceutical ingredients. Patients should be screened for HBV infection before starting Delstrigo, and may require initiation of anti-HBV therapy.