CAB+RPV LA vs B/FTC/TAF for HIV: Which is better?

In virologically suppressed adults with HIV, the cabotegravir + rilpivirine long-acting (CAB+RPV LA) regimen was on par with bictegravir/emtricitabine/tenofovir alafenamide (B/FTC/TAF) in terms of virologic efficacy, but the former gained the upper hand over the latter in terms of patient satisfaction and preference, the SOLAR* study reports.

“This is the first randomized comparison of CAB+RPV LA Q2M vs continued daily oral B/FTC/TAF,” said Dr Moti Ramgopal from Midway Immunology and Research Center, Fort Pierce, Florida, US, at CROI 2023. “[Our findings showed that] switching to CAB+RPV LA from B/FTC/TAF was efficacious, well-tolerated, improved treatment satisfaction, and was preferred by most participants.”

This phase IIIb study randomized 670 participants (median age 37 years, 18 percent female [sex at birth]) 2:1 to switch to CAB+RPV** LA Q2M (~60 percent had an oral lead-in) or continue with daily oral B/FTC/TAF. [CROI 2023, abstract 191]

Virologic efficacy, safety

“At 12 months, CAB+RPV LA demonstrated noninferior efficacy vs B/FTC/TAF for the proportion of participants with HIV-1 RNA ≥50 copies/mL (virologic nonresponse) and <50 copies/mL (virologic success) in the modified intention-to-treat exposed population,” said Ramgopal.

The overall rate of virologic nonresponse was ≤1 percent. Virologic success rates were 90 percent and 93 percent for the respective CAB+RPV LA and B/FTC/TAF regimens.

There were similar rates of grade ≥3 adverse events (AEs; 9 percent and 11 percent) and serious AEs (5 percent and 7 percent) in the CAB+RPV LA and B/FTC/TAF arms. However, the rate of drug-related AEs was higher with the former vs the latter (20 percent vs <1 percent), as was the rate of withdrawal owing to AEs (4 percent vs <1 percent).

Nearly a quarter of participants reported pain with injections, but most ISRs*** were grade 1/2 and short-lived (median 3 days). “Only a few participants discontinued due to injection-related reasons,” said Ramgopal.

Treatment satisfaction

Mean adjusted HIVTSQs^# scores improved significantly from baseline with CAB+RPV LA at months 6 and 12 (+3.86 and +3.36). With B/FTC/TAF, scores worsened at both timepoints (–0.40 and –1.59). Of note, baseline scores were high (57.88 and 58.38 for CAB+RPV LA and B/FTC/TAF, respectively).

Between-group comparisons yielded adjusted differences of 4.26 (6 months) and 4.95 (12 months) and both were statistically significant (p<0.001). “The increase from month 6 to 12 is also quite impressive,” Ramgopal noted. These translate to greater improvement from baseline in HIV treatment satisfaction with CAB+RPV LA vs B/FTC/TAF.

An option beyond daily pills

Treatment preference rate was higher with CAB+RPV LA vs B/FTC/TAF (90 percent vs 5 percent). About 90 percent of those who preferred CAB+RPV LA noted that the regimen freed them from worrying as much about remembering to take their medication daily.

Convenience was also a driving factor, as the injections were only administered every 2 months and patients were not compelled to bring their meds with them. Apart from ridding them of the thought of having HIV, the infrequent dosing also freed them from worrying about others unintentionally discovering their HIV status.

“[These reasons implied that] the less frequent dosing offered by CAB+RPV LA [helped] address concerns associated with daily oral therapy, including fear of disclosure, stigma, anxiety around medication adherence, and the daily reminder of their HIV status,” said Ramgopal.

“The treatment satisfaction and preference findings … demonstrate an important unmet need to address the burden of daily pills for a significant proportion of people living with HIV,” shared Dr Kimberly Smith, ViiV Healthcare Head of Research & Development, in a press release. “We believe LA is both the present and future of HIV and providing an option beyond daily pills is why we chose to do a head-to-head study with a commonly prescribed, daily, oral medicine.”