Two-Drug Combination Antiretroviral Therapy for HIV-1: Case Series and Literature Review.

Background: Doravirine (DOR) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) approved for use in combination antiretroviral therapy (cART) for treatment of human immunodeficiency virus (HIV) in treatment-naive patients. Doravirine-based regimens are an option for patients with limited alternatives due to drug-drug interactions, toxicities, or resistance. A paucity of data exists for use of two-drug DOR-based regimens in treatment-experienced individuals. Methods: This is a retrospective case series of two treatment-experienced HIV-1 infected patients switched to two-drug doravirine-based regimens. Baseline HIV-RNA and CD4 cell count were measured at the time of switch to the DOR-based regimen. HIV-RNA and CD4 cell count were measured again more than a month after initiating therapy to determine efficacy of the DOR-based regimens. Results: Patient 1 was transitioned to once daily DOR and darunavir with cobicistat (DRV/c). The baseline HIV-RNA was 370,070 copies/mL and CD4 cell count was 196 cells/mm³. After 2 years of treatment, the viral load was less than 30 copies/mL and the CD4 cell count was 239 cells/mm³. Patient 2 was transitioned to once daily DOR and dolutegravir (DTG). The baseline HIV-RNA was <30 copies/mL and CD4 cell count was 229 cells/mm³. After 11 months of therapy, the patient's HIV viral load remained <30 copies/mL and the CD4 cell count was stable at 236 cells/mm³. Conclusions: Two-drug cART including DOR appears to be an acceptable option for patients who may be limited to alternative ART regimens due to drug-drug interactions, resistance mutations, or toxicities. Additional evidence from case reports or clinical trials are needed to further evaluate the long-term efficacy and safety of DOR as part of a two-drug cART regimen.