Cost and cost-effectiveness of an HIV pre-exposure prophylaxis (PrEP) programme for high-risk men who have sex with men in England: results of a static decision analytical model

Abstract

BackgroundThe efficacy and effectiveness of pre-exposure prophylaxis (PrEP) for preventing HIV infection acquisition by high-risk men who have sex with men (MSM) is established. We estimated the cost and cost-effectiveness of a proposed daily oral PrEP programme covering 10 000 high-risk MSM attending genitourinary medicine clinics in England. MethodsFrom the perspective of public providers, a static decision analytical model was used to investigate lifetime HIV infections, treatment costs, and quality-adjusted-life-year (QALY) losses associated with daily PrEP given for 1 year, beginning in 2016, compared with no intervention. A cohort of MSM who were not known to be HIV positive at their first attendance in 2012 and had tested HIV negative between 42 and 365 days previously was identified. These men were followed up from the date of their earliest negative HIV test in 2012 for up to 1 year either until they seroconverted or until their last attendance. HIV incidence was calculated as the number of seroconversions (new HIV diagnoses) per 100 person-years. Data sources including genitourinary medicine clinic activity data were used to estimate HIV incidence in year 1 and thereafter. Costs were updated to 2013–14 values and both future costs and QALYs were discounted at 3·5%. Budgetary impact was undiscounted. FindingsAt 86% effectiveness, delivery of PrEP to 10 000 high-risk MSM in the first year (target population with an HIV incidence of 2·4 per 100 person-years in year 1) resulted in 178 fewer lifetime HIV infections, 28 delayed infections, and an incremental cost-effectiveness ratio (ICER) of £26 300, compared with no PrEP. More conservative assumptions of 64% PrEP effectiveness gave an ICER of £54 500, compared with no PrEP. ICER was highly sensitive to year 1 HIV incidence (eg, with HIV incidence of 3·3 per 100 person-years and at 86% PrEP effectiveness, ICER was £4170), PrEP effectiveness, PrEP drug costs, and potential changes in antiretroviral treatment cost upon patent expiry. An investment of £54 million in year 1 breaks even anywhere from year 42 (86% PrEP effectiveness) to beyond year 61 (64% PrEP effectiveness). InterpretationThe model shows that the estimated cost-effectiveness of PrEP is very sensitive to key variables (eg, year 1 HIV incidence and patient adherence), about which there is much uncertainty, especially if programme scale-up occurs. A substantial reduction in the price of antiretroviral drugs, when used for PrEP, is needed to give the necessary assurance of cost-effectiveness, and for an affordable public health programme of sufficient size. FundingNone.