Frank J. Palella, Jr discusses cabotegravir, a recently approved injectable PrEP medication, that was test in the HTPN 083 and -084 trials.
Frank J. Palella Jr, MD: To go back to HPTN 083 and 084, which I think are among the most pivotal studies ever undertaken for HIV prevention using PrEP, -083 looked at over 3,000 MSM, or transgender women, and and randomized them in a double-blind fashion to receive either the every-other-month injectable cabotegravir, Apretude, vs daily TDFFTC, or generic Truvada, and demonstrated a benefit of 69% lower new infection rate among the Apretude recipients compared with the TDFFTC. As I mentioned, with -084, it was pivotal not only because it was the first to focus on cisgender women, but the superiority in that population of the injectable therapy was unequivocal, in that there was a 90% lower incidence of HIV—keeping in mind, all the other social issues and social determinants and situational issues that may have impeded optimal adherence to daily pill-taking for those randomized to the daily oral therapy. These studies not only established the viability and workability of such an approach of injectable therapy, but the preferability and preventive superiority in terms of making sure that people get protected, have the medication on board, remain protected, and are existing in a health care system that is supportive; they should have a health care system that is able to monitor that patients are receiving the medication they should be getting, so we don't have to worry about daily oral pill-taking and all of the diverse factors that can impact daily oral-pill taking and potentially impede the effectiveness of daily oral PrEP for prevention of HIV.
In the HPTN 083 and -084 studies, not surprisingly, the most common adverse event was injection site reactions. They occurred in a substantial number of people. What was really important is that they were almost never treatment limiting. They almost never resulted in interruption or cessation of therapy, and patients, in general, expressed their comfort with such therapy. Over time, because we do have longitudinal data, those injection site reactions became less severe and of shorter duration, meaning that the level of discomfort associated with them, as well as the derate number of days after injection that they persisted diminished steadily over time. This was consistent with data looking at cabotegravir for treatment in registrational trials for patients already with HIV, so there were no surprises in terms of the acceptability of therapy, let alone the effectiveness and lack of other signature toxicities other than the injection site reactions.
Transcript edited for clarity.