Efficacy, Cost of Long-Acting Injectable Cabotegravir vs Tenofovir-Based Regimens for HIV PrEP

Although the efficacy of long-acting injectable cabotegravir (CAB-LA) was found to be increased compared with oral emtricitabine-tenofovir disoproxil fumarate (F/TDF) as HIV pre-exposure prophylaxis (PrEP), the increase did not justify its increased cost for use in HIV PrEP programs. These findings were published in the Annals of Internal Medicine.

In this analysis, researchers used the cost-effectiveness of preventing AIDS complications model to simulate a population of patients on HIV PrEP with risk factors similar to those included in the HIV prevention trials network (HPTN-083) trial. These simulations were used to assess whether the increased efficacy of CAB-LA vs tenofovir-based PrEP justifies its increased cost for use in HIV PrEP programs.

The input data for the simulations used in this study were sourced from a population of men who have sex with men and transgender women at either an increased or significantly increased risk for HIV infection. The mean patient age was 30.1 years, and the incidence of HIV infection without PrEP use among those at significantly increased risk and those at an increased risk was 5.32 and 1.54 per 100 person-years, respectively.

The researchers found that the annual costs of generic F/TDF and branded emtricitabine-tenofovir alafenamide (F/TAF) were $360 and $16,800, respectively, compared with $25,850 for CAB-LA. The assumed cost of PrEP programs were $104 per office visit, with both F/TAF and F/TDF requiring 4 yearly visits vs 6 for programs that used CAB-LA. In regard to HIV care, the annual cost ranged between $3280 and $32,580, and the cost of antiretroviral therapy (ART) ranged between $31,560 and $68,680.

During a 10-year period, the estimated cost of no PrEP program was $33.48 billion. The estimated 10-year cost of PrEP programs that used generic F/TDF, branded F/TAF, and CAB-LA was $30.67 billion, $60.42 billion, and $75.84 billion, respectively. Although the researchers found that the initial costs of PrEP were increased compared with ART, the total cost of PrEP was decreased vs ART by year 10.

Among patients at significantly increased risk for HIV infection, the cost of generic F/TDF was $30.67 billion for 4,626,000 quality-adjusted life-years (QALY). Compared with generic F/TDF, the cost of no PrEP was increased by $2.81 billion with 97,000 QALYs gained; branded F/TAF was increased by $29.75 billion for 99,000 QALYs gained; and CAB-LA was increased by $15.42 billion for 26,000 QALYs gained. Combined, the CAB-LA incremental cost-effectiveness ratio (ICER) was $1,582,000 among patients at significantly increased risk for HIV infection.

Among patients who were at an increased risk for HIV infection, the cost of no PrEP was $39.57 billion for 16,864,000 QALYs. Compared with no PrEP program, the estimated cost of a generic F/TDF program increased by $5.14 billion for 118,000 QALYs gained; branded F/TAF increased costs by $115.37 billion for 9000 QALYs gained; and CAB-LA increased costs by $66.24 billion for 31,000 QALYs gained. The ICER for generic F/TDF and CAB-LA was found to be $43,000 and $4,571,000, respectively, among this patient population.

Assuming a willingness-to-pay threshold of $50,000 per QALY, no model that simulated the use of CAB-LA for use as HIV PrEP fell within the cost-effectiveness threshold.

In a sensitivity analysis, CAB-LA had a maximum cost of $100,000 per QALY compared with $1100 per QALY for generic F/TDF.

This study was limited as it used data from previous studies to estimate the rate of HIV transmission over a 10-year period, thus any fluctuation in the real-world rate of incident HIV infection would deviate from the findings of this study.

According to the researchers, “the superiority of CAB-LA [compared with] generic F/TDF, notwithstanding the presence of highly effective oral PrEP alternatives, limits the additional price that payers should be willing to pay for CAB-LA.”

Disclosure: Multiple authors declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Neilan AM, Landovitz RJ, Le MH, et al. Cost-effectiveness of long-acting injectable HIV preexposure prophylaxis in the United States: A cost-effectiveness analysis. Ann Intern Med. Published online February 1, 2022. doi:10.7326/M21-1548