Following the approval of cabotegravir in 2021, governments and donor agencies in low- and middle-income countries are contemplating replacing oral pre-exposure prophylaxis or augmenting the approach with long-acting treatment.
Although a long-acting injectable for pre-exposure prophylaxis (PrEP) has the potential to change the game of HIV prevention, wide-spread implementation of the treatment in resource-limited countries may be stifled by its price, according to the authors of a new study published in The Lancet.
Following the FDA approval of cabotegravir in 2021, the researchers highlighted the timeliness of their findings as governments and donor agencies in low- and middle-income countries contemplate replacing oral PrEP or augmenting the approach with long-acting treatment.
The modeled economic evaluation and threshold analysis, conducted in South Africa, showed that compared with traditional PrEP taken orally every day, long-acting injectable cabotegravir was estimated to prevent 3 times as many new HIV cases and save 3 times as many life-years over 2 decades under various case scenarios. However, the researchers cautioned that at its current price, national rollout of the new treatment may be unlikely.
“Preference studies have suggested that long-acting injectable cabotegravir could be a preferred prevention option over tenofovir disoproxil fumarate and emtricitabine, including in South Africa; real-world uptake and preference can only be assessed once it is available for use,” the study authors wrote. “However, although long-acting injectable cabotegravir has the potential to change HIV prevention, for large-scale implementation across low-income and middle-income countries, it first needs to be affordable.”
The researchers wrote of the importance of careful consideration for the cost-effectiveness and affordability of new treatments, such as cabotegravir, in countries with limited resources, such as South Africa, which in 2019 had an estimated 7.8 million people living with HIV. Although oral PrEP with tenofovir disoproxil fumarate and emtricitabine has proven effective in preventing HIV, concerns over low adherence have highlighted the promise of a treatment administered every 2 months.
The group incorporated data from 2 cabotegravir trials—HPTN 083 and HPTN 084—into a deterministic model of the HIV epidemic in the country across several patient populations: heterosexual adolescents and young men and women aged between 15 and 24 years, female sex workers, and men who have sex with men. The group’s model determined that cabotegravir would need to be between 1- and 2-fold that of a 2-month supply of tenofovir disoproxil fumarate and emtricitabine in order to be cost-effective.
However, tenofovir disoproxil fumarate and emtricitabine has a monthly cost of $4.70—$56.39 a year—whereas cabotegravir, under patent protection until 2031, costs more than $22,200 per year, 200 times the identified threshold. To be considered cost effective under the group’s model, cabotegravir would need to cost between $9.03 per injection—approximately $63 per year—and $14.47—approximately $101 per year. Notably, the cost threshold would remain similar even if cabotegravir was administered every 3 months, rather than 2, or if the long-acting injectable had similar coverage as the oral PrEP treatment.
“Even given the uncertainty in our analysis, it is clear that unless dramatic price reductions occur, long-acting injectable cabotegravir will not be an option for HIV prevention for those at highest risk of HIV in low-income and middle-income countries,” the study authors wrote. “Options for these price reductions include the recently agreed voluntary licenses through the Medicines Patent Pool, a buy-down similar to that establishing a market for HIV self-testing, or a combination of these factors.”
The researchers highlighted several imitations of their study, including a lack of data on real-world update of cabotegravir, which will continue until the treatment is implemented widely. The group also noted that they used an ingredients-based approach to the cost of facilitating PrEP due to the absence of bottom-up cost data, which could have resulted in an underestimation or overestimation of incremental costs required. However, the researchers noted that the cost of service would likely be similar between the 2 PrEP approaches.
Jameison L, Johnson L, Nichols B, et al. Relative cost-effectiveness of long-acting injectable cabotegravir versus oral pre-exposure prophylaxis in South Africa based on the HPTN 083 and HPTN 084 trials: a modelled economic evaluation and threshold analysis. Lancet HIV. 2022;9(12):857-867.