Theratechnologies’ antibody treatment Trogarzo (ibalizumab-uiyk), approved in 2018 for those with multidrug-resistant HIV who are on a failing antiretroviral (ARV) regimen, is safe and effective over the long term. Approval was based on 48-week data from a Phase III trial; 27 of its participants continued for a second year of treatment. Throughout, they received biweekly Trogarzo infusions plus an optimized background regimen of daily oral ARVs. At the study’s outset, these participants had a median viral load of 21,700 and a median CD4 count of 102. The median viral load declined by 316-fold by week 25 and by 631-fold by week 96. At week 96 of treatment, 56% of the participants had a fully suppressed viral load, and the median CD4 count increased by 45. Trogarzo remained well tolerated at week 96, by which point no new safety concerns had arisen.