Oral HIV preexposure prophylaxis limits willingness to pay for long-acting injectable prophylaxis

1. Compared with generic oral emtricitabine-tenofovir disoproxil fumarate (F/TDF), long-acting injectable cabotegravir (CAB-LA) increased life expectancy by 28,000 QALYs.

2. In PrEP-eligible populations, CAB-LA could achieve incremental cost-effectiveness ratios of at most $100,000 per QALY compared to generic F/TDF.

Evidence Rating Level: 2 (Good)

Study Rundown: The HIV Prevention Trials Network 083 trial demonstrated superior effectiveness for HIV pre-exposure prophylaxis when using CAB-LA compared to daily oral F/TDF for men who have sex with men and transgender women. However, with various pricing models, including generic and branded F/TDF, there is a gap in knowledge as to understanding how much society should be willing to pay for the improved effectiveness of CAB-LA over both branded and generic F/TDF options. This study found that the incremental clinical benefits of CAB-LA would not justify a large price difference compared with F/TDF, especially the generic brand which is substantially less expensive than the branded version. This study was limited by uncertainties of future HIV transmissions and the lack of data to incorporate potential changes in quality of life while receiving oral or long-acting PrEP. Nevertheless, these study’s findings are significant, as they demonstrate that though CAB-LA may offer superior clinical benefits, with the presence of highly effective and affordable oral PrEP alternatives, this limits the additional price that society should be willing to pay for CAB-LA.

Click to read the study in AIM

Relevant Reading: Determining the Most Appropriate Use of Available Regimens for HIV Preexposure Prophylaxis

In-Depth [cost-effectiveness analysis]: This cost-effectiveness analysis utilized the cost-effectiveness of preventing AIDS complications model, a validated state-transition microsimulation model of HIV prevention and treatment. Persons with HIV incidences were included in the study whereas persons who discontinued participation in a PrEP program were excluded from the study. Estimated HIV incidence was as follows: 5.32, 1.33, and 0.26 per 100 person-years for off PrEP, generic F/TDF and branded F/TDF, and CAB-LA, respectively. Annual base-case drug costs were as follows: $360 and $16 800 for generic F/TDF and branded F/TAF. The primary outcome measured was quality-adjusted life-years (QALYs), costs (2020 US dollars), incremental cost-effectiveness ratios (ICERs), and maximum price premium for CAB-LA versus F/TDF. Outcomes in the primary analysis were assessed via sensitivity and scenario analyses. In the case-based analysis, CAB-LA increased life expectancy by 28,000 QALYs compared to generic or branded F/TDF. At ten years, CAB-LA had an ICER of at most $100,000 per QALY compared to generic F/TDF at a maximum price premium of $3700 per year over generic F/TDF (if CAB-LA price <$4100 a year). In the sensitivity analysis, CABA-LA could achieve an ICER of $100 000 per QALY versus generic F/TDF at a maximum price premium of $1100 per year over generic F/TDF. Using simulation models, CAB-LA would only provide good value for money if its annual price was less than $3000 to $6600 higher than generic F/TDF. Therefore, CAB-LA should be priced to compete with generic PrEP, not branded PrEP. Overall, this study demonstrates that though CAB-LA may be clinically superior, the return on investment may not justify a switch from low-priced, well-tolerated, generic, oral alternatives, depending on how CAB-LA is priced.

Image: PD

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