Antiretroviral therapy (ART) intramuscularly administered may have the same effectiveness as current oral treatments. This is the main conclusion of the Phase II clinical trial carried out by 50 centers around the world -- 9 in Spain -- to which the team of Dr. Daniel Podzamczer, principal investigator of the Bellvitge Biomedical Research Institute (IDIBELL) and Chief of the HIV and STD Unit of the Infectious Diseases Service of Bellvitge University hospital (HUB) has contributed. The results of the trial, published by the journal 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, the effectiveness of the combination of carbotegravir -- a new inegrase inhibitor -- and rilpivirine -- a no nucleoside -- injected intramuscularly every 4 or 8 weeks was tested in comparison to standard maintenance therapy, which includes three orally-administered drugs: carbotegravir and abacavir -- lamivudine.

"This is the first time that all-injectable ART has been used in a trial; In addition, it consists of only 2 drugs, something that is not new but that supports the paradigm shift of 3 to 2 drugs in some virologically suppressed patients," says Dr. Podzamczer. The injected drugs are nanoparticles, which allows them to have a longer half-life of several weeks.

After 96 weeks, researchers found that 87% of patients in the group treated every 4 weeks and 94% in the one treated every 8 weeks maintained viral load suppression, a better figure than the one achieved in the standard oral treatment group, a 84%.

"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% of patients in the groups treated intramuscularly were very satisfied with the idea of continuing with this type of treatment.

At the moment, 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 4 and every 8 weeks.

Materials provided by IDIBELL-Bellvitge Biomedical Research Institute. Note: Content may be edited for style and length.

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References:

David A Margolis, Juan Gonzalez-Garcia, Hans-Jürgen Stellbrink, Joseph J Eron, Yazdan Yazdanpanah, Daniel Podzamczer, Thomas Lutz, Jonathan B Angel, Gary J Richmond, Bonaventura Clotet, Felix Gutierrez, Louis Sloan, Marty St Clair, Miranda Murray, Susan L Ford, Joseph Mrus, Parul Patel, Herta Crauwels, Sandy K Griffith, Kenneth C Sutton, David Dorey, Kimberly Y Smith, Peter E Williams, William R Spreen. (2017). 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. DOI: 10.1016/S0140-6736(17)31917-7