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What's on the Horizon? New PrEP Options Presented at CROI 2016

February 25, 2016

"Overwhelming" Preference for an Injectable PrEP Over Oral PrEP Despite Pain

Injectable Long-Acting Cabotegravir: ÉCLAIR

Cabotegravir LA vial and syringe (Photo courtesy of David Margolis)

Cabotegravir LA vial and syringe (Photo courtesy of David Margolis)

Long-acting cabotegravir as PrEP is generating quite a lot of buzz among researchers and other conference attendees. It's exciting not just because it's a new drug, but because the long-acting formulation could provide freedom from a daily pill regimen. Cabotegravir is an integrase inhibitor similar to dolutegravir, and it has been formulated as a nanosuspension that can be injected intramuscularly. The ÉCLAIR study, presented by Martin Markowitz, M.D., from the Aaron Diamond AIDS Research Center, assessed safety and tolerability of a long-acting cabotegravir injection.

The study lasted for 81 weeks, and included an oral run-in phase (to test for adverse reactions to cabotegravir before the injection was given); an injection phase where three injections were given 12 weeks apart; and a follow-up phase. A total of 106 participants received cabotegravir and 21 received placebo.

Ouch! Study Injections Were Painful

Pain from the injection (which was administered in the gluteal region) was the most frequently reported adverse effect in the study -- in both the placebo and cabotegravir groups.

"As far as safety goes, it was relatively well tolerated both orally and as an injectable," said Markowitz during a press conference. All of the adverse events revolved around injection site pain. 92% of the injections of cabotegravir were associated with pain that lasted about 5 days on average. Half of the participants experienced mild pain, 40% moderate, and 10% described it as severe."

Number of Doses Needed Will Likely Increase From Four to Six Times a Year

Martin Markowitz, M.D.

Martin Markowitz, M.D.

The drug was absorbed faster than anticipated -- leading to higher drug "peak" concentrations and lower drug "trough" concentrations.

"Approximately 70% of subjects had trough levels below the predicted 4 x PA-IC90 [a measure of drug concentration] during the injection phase. And 15% to 31% of the cabotegravir subjects had trough concentrations less than 1x PA-IC90, a concentration that will not afford protection, based on previous studies," said Markowitz.

Because of this faster drug absorption rate, Markowitz reported that the team is evaluating the possibility of changing the dosing schedule to once every 8 weeks, instead of once every 12 weeks.

This excerpt was cross-posted with the permission of Read the full article.

This article was provided by BETA. It is a part of the publication The 23rd Conference on Retroviruses and Opportunistic Infections. Visit their website at

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