In what circumstances could nondaily preexposure prophylaxis for HIV substantially reduce program costs?

Abstract

Objectives: To review the main factors influencing the costs of nondaily oral preexposure prophylaxis (PrEP) with tenofovir (±emtricitabine). To estimate the cost reductions possible with nondaily PrEP compared with daily PrEP for different populations (MSM and heterosexual populations).

Design: Systematic review and data triangulation.

Methods: We estimated the required number of tablets/person/week for dosing regimens used in the HPTN 067/ADAPT (daily/time-driven/event-driven) and IPERGAY (on-demand) trials for different patterns of sexual intercourse. Using trial data, and behavioural and cost data obtained through systematic literature reviews, we estimated cost savings resulting from tablet reductions for nondaily versus daily oral PrEP, assuming 100% adherence.

Results: Among different populations being prioritized for PrEP, the median reported number of days of sexual activity varied between 0 and 2 days/week (0-1.5 days/week for MSM, 1-2 days/week for heterosexual populations). With 100% adherence and two or fewer sex-days/week, HPTN 067/ADAPT nondaily regimens reduced the number of tablets/week by more than 40% compared with daily PrEP. PrEP program costs were reduced the most in settings with high drug costs, for example, by 66-69% with event-driven PrEP for French/US populations reporting on average one sex-day/week.

Conclusion: Nondaily oral PrEP could lower costs substantially (>50%) compared with daily PrEP, particularly in high-income countries. Adherence and efficacy data are needed to determine cost-effectiveness.

Fig. 1

Tablets required per person in a given week for different number and pattern of sex-days per week assuming 100% regimen adherence and accurate forecasting of sexual behaviour – patterns giving maximum and minimum tablet numbers are shown.

Fig. 2

Forest plot showing median and inter-quartile range (IQR; 25th and 75th percentile) number of days per week sexual activity reported in different populations identified in systematic literature search.

Fig. 3

The proportion of PrEP program costs which are attributable to medication costs plotted against the costs of PrEP medication per person per year, from costing or cost-effectiveness studies published during or after 2010, for low-income, lower middle-income, upper middle-income and high-income countries (World Bank 2017 classifications).