Risk of Tumor Onset in HIV+ Patients on Two-Drug Regimens: A Cohort Study in an Italian Hospital

Currently approved 2-drug therapies are as effective as 3-drug regimens but could potentially lead to increased cancer risk due to less efficient immune recovery. We conducted a longitudinal cohort study in a tertiary Italian hospital to investigate HIV+ patients starting a triple therapy (TT) (2 NRTIs +3rd agent) or a dual therapy (DT) (3TC/FTC+boosted-PI, boosted-DRV+RAL, and 3TC/FTC or RPV+DTG) regimen between 2009 and 2018. The effect of DT (vs. TT) on tumor onset was evaluated by the multivariable Cox regression and the marginal structural Cox model, after estimating the inverse probability of treatment weights (IPTW). One thousand one hundred and seven patients who had a median follow-up of 4.2 person-years (py) were evaluated; 69.2% were males, with a median age of 43 years. Overall 2,513 treatments were started during the study period (479 DT, 2,034 TT). Eight tumors occurred over 965 py with DT and 35 over 3,817 py during TT (p = .797). In the Cox regression, DT did not predict an increased risk of tumor compared with TT (HR 1.14; p = .757) after adjusting for potential confounders. A marginal structural model using IPTW (HR 0.68; p = .328) and stabilized IPTW (HR 0.69; p = .361) confirmed this result. Preliminary findings from our cohort do not suggest an increased risk of tumors with DT compared to TT.