Long-acting injectable PrEP may improve adherence and acceptability compared to daily oral dosing. However acceptability may be limited by anxiety about injections and concerns about injection site reactions (ISR), especially pain. We interviewed a subset of participants of a Phase 2 trial of cabotegravir long-acting injection (CAB LA).
ÉCLAIR is a double-blind, randomized, multi-center study in 127 HIV-negative men at risk of HIV infection during which IM injections of 800mg CAB LA or PBO (saline) q12 weeks X 3 cycles were given. This substudy approached 48 participants who self-reported as MSM or male-to-female transgender women at 4 out of 10 sites and offered 30 randomly-selected individuals the opportunity to be interviewed. 2/28 who received placebo are excluded from results presented here. Interviewees included 27 MSM and one MTFT.
23/28 (82.1%) reported ISR with a mean pain score of 2.8 out of 5. Of those 23 subjects, 13 (56.5%) reported that pain lasted more than three days. In a subset of men who were asked more details about the timing of pain, 37.5% (6/16) reported no pain during injections and 31.3% (5/16) reported no pain following injection. 75% (21/28) stated the first injection hurt less than expected. Anxiety before the first injection was felt by 20/28 (64.3%), however this decreased to just 8/28 (28.6%) by subsequent injections. There was no correlation between anxiety and pain. Despite discomfort and anxiety cited by a large proportion, interest in the product remained high: out of the subset of participants queried, 93.8% (15/16) reported that if proven effective, they would definitely or very likely use CAB-LA. In addition, 62.5% (10/16) reported that they would prefer to use CAB-LA every twelve weeks to daily oral PrEP.
CAB-LA injections are acceptable in subset of ÉCLAIR participants who experienced two to three injections. The pain profile is less focused on the injection itself and more on the post-injection period. While there was significant anxiety around injections, this decreased as participants gained experience with injections. These findings suggest that patient education about CAB-LA should focus on informing patients about the true nature of pain associated with injections, and managing both expectations and anxiety. More research is required to validate these findings on a broader scale.