Can INSTI-associated Weight Gain be Halted or Reversed With a Switch to Doravirine/Lamivudine/Tenofovir DF?

Weight gain with the integrase inhibitors and tenofovir alafenamide has been observed in observational cohorts and randomized controlled clinical trials. Although some risk factors have been identified, the cause is unknown and it remains to be determined if the changes are reversible. The weight gain is of concern to persons living with HIV. This pilot intervention study is designed to provide preliminary data on whether switching patients with weight gain on an INSTI-based regimen to a combination of doravirine/tenofovir disoproxil fumarate/lamivudine (DOR/3TC/TDF, an NNRTI-based regimen) for one year can slow down or even reverse weight gain. These data will then be used to inform the design and sample size of a larger switch study.

Background and Importance: Lifelong antiretroviral treatment (ART) is recommended for all people living with HIV (PLWH) primarily with integrase strand inhibitor (INSTI)-based regimens. While weight gain following ART initiation was previously considered "return to health", recent studies have raised concerns of weight gain and increasing obesity in PLWH, most notably with INSTIs and possibly with tenofovir alafenamide (TAF), a preferred nucleoside backbone agent. The weight gain may be progressive and may increase cardiovascular risk. A critical unanswered question is whether weight gain and metabolic effects are permanent or reversible. This data is crucial to optimize ART therapy and health of PLWH. Goal/Research Aims: No therapeutic alternatives are substantiated for ART-associated weight gain. Doravirine/lamivudine/tenofovir DF (DOR/3TC/TDF) is an attractive option to explore as it does not include an INSTI or TAF, is a well tolerated once daily single tablet, minimal drug interactions and has not been associated with significant weight gain to date. The investigators hypothesize that switching from an INSTI regimen to DOR/3TC/TDF will slow or reverse weight gain while maintaining viral suppression. Before embarking on a large randomized controlled study (RCT), the investigators propose this pilot study to determine the feasibility and acceptability and to obtain estimate measures of weight change to inform its design and sample size. Methods: Open-label, exploratory pilot switch study. Patients who are virally suppressed on an INSTI regimen for \>1 year, without ART resistance, and have experienced significant weight gain will be approached to switch to DOR/3TC/TDF for 48 weeks. Weight, adherence, viral load, CD4, and other relevant labs will be measured every 3 months. A DXA body scan and body image questionnaires will be completed at baseline and 12 months. The anticipated sample size is 25 with an aim to recruit 50% male, 50% female. The primary objective is to determine what proportion of clinic patients meet eligibility criteria, agree to participate, and complete the study. The secondary objective is to estimate the distribution of various weight-related outcomes while on DOR/3TC/TDF compared to previous INSTI regimens. Exploratory outcomes will address metabolic changes and body image impact.