1587. SOLAR 12-Month North American Results: Randomized Switch Trial of CAB+RPV LA vs. Oral BIC/FTC/TAF
Authors: McKellar Mehri , Teichner Paula , Bettacchi Christopher , Angel Jonathan , Gordon Lori A , Sutton Kenneth , Sutherland-Phillips Denise , Talarico Christine L , Urbaityte Rimgaile , Solingen-Ristea Rodica Van , Baugh Bryan , D’Amico Ronald , van Wyk Jean A 
Published: November 2023

Abstract

Background
Cabotegravir + rilpivirine (CAB+RPV) administered monthly or every 2 months (Q2M) is the only complete long-acting (LA) regimen for maintaining HIV-1 suppression and may address challenges associated with daily oral therapy. In the Phase 3b SOLAR study, switching to CAB+RPV LA Q2M was noninferior to continuing daily oral bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). We present results for North American (NA; United States and Canada) participants.

Methods
SOLAR (NCT04542070) is the first randomized (2:1), open-label, multicenter, noninferiority study assessing switching virologically suppressed adults to CAB+RPV LA Q2M (with oral lead-in or starting with injections) vs. continuing BIC/FTC/TAF. The primary analysis was based on the prespecified modified intention-to-treat exposed (mITT-E) population (n=11 from 1 study site excluded from the ITT-E population for protocol deviation) at Month (M) 12. The primary endpoint was the proportion with plasma HIV-1 RNA ≥50 c/mL. Other endpoints were the proportion with plasma HIV-1 RNA &lt; 50 c/mL, incidence of confirmed virologic failure (CVF; 2 consecutive HIV-1 RNA ≥200 c/mL), safety and tolerability (ITT-E), and treatment satisfaction (HIV Treatment Satisfaction Questionnaire status version [HIVTSQs]).

Results
Of 670 participants (mITT-E), 325 were from North America; 66% (n=216/325) switched to LA and 34% (n=109/325) continued BIC/FTC/TAF. Baseline (BL) characteristics were similar between arms (Table 1). At M12, 1 participant in each arm had HIV-1 RNA ≥50 c/mL (Table 2). No NA participant had CVF in the mITT-E population; 1 (0.3%) NA participant excluded from the mITT-E population due to protocol violation had CVF (LA arm). Adverse events (AEs), excluding injection site reactions (ISRs), were similar between the LA (74% [n=164/223]) and BIC/FTC/TAF arms (73% [n=83/113]). More participants in the LA vs. BIC/FTC/TAF arm withdrew due to AEs (8% [n=17/223] vs. &lt; 1% [n=1/113]). Mean adjusted HIVTSQs scores improved significantly (p&lt; 0.001) from BL to M12 for LA (+3.40) vs. BIC/FTC/TAF (–1.07) participants.

Conclusion
Consistent with the overall SOLAR study population, switching to CAB+RPV LA from BIC/FTC/TAF was efficacious and well tolerated, with improved treatment satisfaction, in NA participants.

Disclosures
Mehri McKellar, MD, Gilead Sciences, Inc: Grant/Research Support Paula Teichner, PharmD, GlaxoSmithKline: Stocks/Bonds|ViiV Healthcare: Employment Jonathan Angel, MD, Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Gilead: Honoraria|Merck: Grant/Research Support|ViiV Canada: Advisor/Consultant|ViiV Canada: Grant/Research Support|ViiV Canada: Honoraria Lori A. Gordon, PharmD, ViiV Healthcare: Stocks/Bonds Kenneth Sutton, MA, ViiV Healthcare: Employment|ViiV Healthcare: Stocks/Bonds Denise Sutherland-Phillips, MD, ViiV Healthcare: Employment|ViiV Healthcare: Stocks/Bonds Christine L. Talarico, M.S., ViiV Healthcare: Stocks/Bonds Rimgaile Urbaityte, MSc, GSK: Employment|GSK: Stocks/Bonds Rodica Van Solingen-Ristea, MD, Janssen R&D: Employee Bryan Baugh, MD, Johnson & Johnson: Stocks/Bonds Ronald D'Amico, DO, MSc, ViiV Healthcare Ltd: Stocks/Bonds Jean A. van Wyk, MBChB, MFPM, ViiV Healthcare Ltd: Stocks/Bonds