Intramuscularly administered antiretroviral therapy (ART) may be as effective for HIV treatment as current oral therapies. This is the main conclusion of a Phase II clinical trial carried out by 50 research centers around the world, including nine in Spain, to which the team of Dr. Daniel Podzamczer of the Bellvitge University hospital (HUB) has contributed. The results of the trial, published in The Lancet, pave the way to the implantation of all-injectable antiretroviral therapies with a lower frequency of administration, which would imply a significant improvement of the quality of life of HIV patients.
In the study, which involved 286 patients with previously suppressed viral loads, researchers tested the effectiveness of the combination of the inegrase inhibitor carbotegravir and rilpivirine, a non-nucleoside reverse transcriptase inhibitor, injected intramuscularly every four or eight weeks. This combination was compared to standard maintenance therapy, which includes three orally administered drugs: carbotegravir, abacavir and lamivudine.
"This is the first time that all-injectable ART has been used in a trial," says Dr. Podzamczer. "In addition, it consists of only two drugs, which supports the paradigm shift of three to two drugs in some virologically suppressed patients." The injected drugs are nanoparticles with a longer half-life of several weeks.
After 96 weeks, researchers found that 87 percent of patients in the group treated every four weeks and 94 percent in the group treated every eight weeks maintained viral load suppression, greater than the standard oral treatment group at 84 percent.
"With HIV, we are at a point of chronification of the disease; in a few years, we have moved from giving 14 pills a day to one or two, but it is still a daily treatment that requires strict compliance. Therefore, spacing drug administration to once every month or every two months will potentially translate into improved adherence rates and improved quality of life for patients," explains Dr. Podzamczer.
At the same time, the levels of satisfaction of the participating patients were also evaluated; at the end of the trial, about 90 percent of patients in the groups treated intramuscularly were very satisfied with the idea of continuing with this type of treatment. Currently, participating centers and research teams are already working on the development of a new Phase III clinical trial that corroborates the results in terms of efficacy, safety and tolerability for both injectable treatments, every four and every eight weeks.
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David A Margolis et al, Long-acting intramuscular cabotegravir and rilpivirine in adults with HIV-1 infection (LATTE-2): 96-week results of a randomised, open-label, phase 2b, non-inferiority trial, The Lancet (2017). DOI: 10.1016/S0140-6736(17)31917-7