301. Risk of Virologic Failure with Antiretroviral Switches in HIV/HCV Co-infections

BACKGROUND: Direct-acting antivirals (DAA) and antiretroviral (ARV) medications pose treatment challenges in HIV/HCV co-infection. Management of contraindicated combinations varies across practices. ARV switches may increase the risk of HIV virologic and treatment failure, and has been reported to increase the risk of DAA treatment failure. This analysis assesses how switches in ARV regimen impacts treatment outcomes in HIV/HCV co-infection. METHODS: This retrospective cohort study includes patients 18 years and older with stable HIV/HCV co-infection (HIV RNA<50 for ≥6 months) who received DAA HCV therapy. Data were obtained using the Centers for AIDS Research Network of Integrated Clinical Systems. The “ARV switch” cohort is defined as patients undergoing a switch in ARV regimen within 6 months prior to DAA treatment. The “no ARV switch” cohort was defined as patients without a change in ARV during the same time period. The primary outcome is HIV treatment failure which is a composite endpoint including HIV virologic failure (defined as confirmed loss of HIV viral suppression), discontinuation/change of ARV regimen, progression to AIDS, or death. We compared baseline characteristics, the proportion of patients free of HIV treatment failure, free of HIV virologic failure, and that achieved sustained viral response (SVR) at 12 and 24 weeks after DAA treatment among ARV switch and no ARV switch groups. RESULTS: Of the 256 patients, 63/256 (25%) underwent an ARV switch (Table 1). At baseline, the most common regimen in the ARV switch group was protease inhibitor (PI)-based while for the no ARV switch group, it was an integrase strand transfer inhibitor (INSTI)-based regimen. HIV/HCV transmission risk factors, HCV genotype, and AST/ALT were similar among the two groups (Table 1). The proportion with HIV treatment and virologic failure, and the proportion achieving SVR12/24 were similar among the ARV switch and no ARV switch groups. CONCLUSION: HIV treatment and virologic failure, and SVR12/24 were not different among patients who did or did not undergo a switch in their ARV regimen prior to DAA treatment. This suggests that switches in the ARV regimen for DAA treatment of HCV do not negatively impact HIV or HCV outcomes among patients with HIV/HCV Coinfection. [Image: see text] DISCLOSURES: All authors: No reported disclosures.