Weight gain stopping/switch rules for antiretroviral clinical trials.

Obesity develops in a substantial number of people initiating and maintaining modern antiretroviral therapy. The comorbidities associated with obesity make significant weight gain and metabolic changes a major consideration in clinical trials studying different regimens' potency and safety. It is as yet unclear what role individual antiretrovirals or classes play in weight gain but the issue is a complex one for clinical trial design, especially when deciding when "too much" weight has been gained, in a context where we do not yet know if switching to alternative regimens will slow, halt or reverse weight gain or metabolic changes.