Abstract Background Long‐acting injectable cabotegravir/rilpivirine (LA‐CAB/RPV) is an effective maintenance strategy for virologically suppressed people with HIV, though virologic failure with resistance remains uncommon and incompletely understood. Methods We describe a case of virologic failure in an HIV‐infected patient receiving LA‐CAB/RPV who developed intensive daily intravenous (IV) chemsex. Clinical history, virologic data, resistance testing, and potential contributing factors were reviewed. Results The patient had sustained viral suppression on prior oral antiretroviral therapy and remained on time with all LA‐CAB/RPV injections. Despite this, viral rebound occurred with emergence of the Y181C mutation, conferring high‐level resistance to RPV, leading to treatment discontinuation. No clinically relevant drug–drug interactions were identified. Plasma concentrations of CAB and RPV were not available. Severe behavioural dysregulation associated with intensive IV stimulant use may have contributed, although causality cannot be established and alternative explanations cannot be excluded. Conclusions This case highlights that unexpected resistance can emerge during adequately administered LA‐CAB/RPV therapy. Careful clinical evaluation is warranted when virologic failure occurs, particularly in the presence of extreme behavioural or physiological stressors.
Asensi et al. (Fri,) studied this question.