Stopping long-acting cabotegravir/rilpivirine: 1 in 5 trial participants didn’t restart oral ART within eight weeks

Simon Collins, HIV i-Base

With long-acting cabotegravir/rilpivirine injections are now approved in the US and EU, and by NHS Scotland (with NHS England about to decide), other aspects from these formulations are also important to follow.

Results were presented at EACS on 150/1651 participants (9%) in the phase 2/3 studies (FLAIR, ATLAS and ATLAS-2M) who discontinued long-acting injections. Of these 92/150 completed 12 months follow-up, 4 had withdrawn and 54 were still being followed. [1]

Median duration on CAB-LA/RPV-LA was 36 weeks (range: 1 to 144), with about one-third lasting more than a year. Most (76%) were on monthly rather than two-monthly injections.

The most common reasons for discontinuations were side effects (40%), participant choice (23%) or lack of efficacy (18%). Although most people (82%) switched to oral ART within 8 weeks (median 4 weeks; IQR: 4 to 6), reasons were not given for the 18% that did not restart HIV treatment..

Of those that restarted oral ART, 60% used INSTI-based ART, with roughly 20% using PI-based and 20% using NNRTI-based treatment. Tolerability of oral ART was reported as good with no further discontinuations due to side effects.

Virologic outcomes for the 92/150 people who completed 12 month follow-up, 84/92 (91%) achieved viral suppression on oral ART, although this included several people with missing data. No results were presented by dosing regimen (4- or 8-week) or time taken to restart.

comment

Although it is good that most participants achieved undetectable viral load on subsequent oral ART, it is concerning that this dataset did not include information on why almost one in five trial participants who consented to follow-up, hadn’t restarted oral ART.

The detailed prescribing information for these long-acting treatments state: “it is essential to adopt an alternative, fully suppressive antiretroviral regimen no later than two months after the last two-monthly injection”.[2, 3]

CAB-LA/RPV-LA was approved by NHS Scotland on 11 October and by NHS England on 18 November 2021.

Reference

1. Teichner P et al. Outcomes for participants during long-term follow-up after discontinuation of cabotegravir + rilpivirine long-acting in the phase III/IIIb clinical trials. EACS 2021, oral abstract session, 28 October 2021, 3-4 pm. Oral abstract OS1/2.
   https://eacs2021.abstractserver.com/program/#/details/presentations/255 (abstract)
2. EMA. Cabotegravir-LA, Summary of Product Characteristics (SPC).
   https://www.ema.europa.eu/en/documents/product-information/vocabria-epar-product-information_en.pdf (PDF)
3. EMA. Rilpivirine-LA, Summary of Product Characteristics (SPC).
   https://www.ema.europa.eu/en/documents/product-information/rekambys-epar-product-information_en.pdf (PDF)

This report was first published on 14 November 2021.