A panel discussion organized within the virtual edition of the Conference on Retroviruses and Opportunistic Infections (CROI 2021) highlighted the importance of making injectable antiretroviral drugs for HIV practical and affordable.
Professor Diane Havlir said that advances in antiretroviral treatment in the last decade were dominated by the emergence of the powerful family of integrase inhibitors and the development of single-pill treatment regimens, but this next decade promises to be the of long-acting drugs.
Professor François Venter stated that in South Africa there is great enthusiasm among patients for long-acting medicines, while healthcare professionals are more concerned with operational challenges.
South Africa's successful antiretroviral therapy program is the largest in the world and modifying it to accommodate injectable treatment would mean rethinking the workflow in already overloaded clinics. Venter was more receptive to the potential benefits of injectable HIV pre-exposure prophylaxis (PrEP), considering the limited number of people who have been able to access oral PrEP so far.
The first long-acting formulation for PrEP (based on injectable cabotegravir) could begin shipping later this year or early next. However, the cost is still unknown.
On the other hand, an analysis presented at CROI 2021 - carried out by Dr. Anne Neilan, from Massachusetts General Hospital (USA) - concluded that, for such an intervention to be cost-effective in the USA, it would have to cost less than half the list price (the manufacturer's suggested retail price) of the injectable combination of cabotegravir / rilpivirine Cabenuva (licensed for the treatment of HIV).
To be more cost-effective than the generic combination of tenofovir disoproxil fumarate and emtricitabine (TDF / FTC) -which costs 8,300 dollars a year in the United States-, the price of injectable cabotegravir (CAB-LA) should not exceed 11,600 Dollars. At this price, it would cost less than $ 100,000 per additional quality-adjusted life year, which is the upper threshold for what is often considered cost-effective in the US.
In Europe and elsewhere, the generic TDF / FTC combination is available for between $ 300-900 per year. Although Neilan's team did not include it in their analysis, the model implies that the greater preventive efficacy of long-acting cabotegravir could make it remain cost-effective (or long-term cost savings) as PrEP in a European setting, but only if its price is adjusted to about 2,000-3,000 dollars per year.
Findings from another study presented at CROI revealed that injections of cabotegravir (Vocabria) and rilpivirine (Rekambys) given every four to eight weeks as HIV treatment were able to maintain viral load suppression throughout the two-year follow-up of the study.
The European Medicines Agency (EMA) approved the injectable combination in December 2020, endorsing both a monthly and bimonthly administration regimen. However, regulatory agencies in the US and Canada (where the injections are marketed together as Cabenuva) only approved the monthly regimen.
The ATLAS-2M study involved 1,045 people who were randomized to receive injections of 400mg of cabotegravir and 600mg of rilpivirine every four weeks or 600mg of cabotegravir and 900mg of rilpivirine every eight weeks. After two years, 90.2% of the participants in the monthly injection group and 91.0% in the bimonthly administration group maintained undetectable viral load.
Source: Own elaboration (gTt-HIV)
