Evaluating the cost-effectiveness of a pre-exposure prophylaxis program for HIV prevention for men who have sex with men in Japan

Background: Men who have sex with men (MSM) have been disproportionally affected by the HIV epidemic in many countries, including Japan. Although pre-exposure prophylaxis (PrEP) is a strong prevention tool, it is not yet approved in Japan. Cost-effectiveness analysis can help to determine whether PrEP should be introduced to the MSM population in Japan, where the incidence and prevalence of HIV are relatively low compared with other developed countries. Methods: A Markov model was developed to describe HIV infection and disease progression in an MSM cohort (N=1,000) in Japan under a PrEP program. The model was used to evaluate the cost-effectiveness of a PrEP program with HIV/AIDS treatment, screening, hospitalization due to AIDS, and PrEP considered as costs and gained quality-adjusted life-years (QALYs) as utilities. Cost-effectiveness was assessed by comparing the incremental cost-effectiveness ratio (ICER) over a 10-year period against a cost-effective threshold. A one-way sensitivity analysis and a probabilistic sensitivity analysis were performed. Findings: With 50% PrEP coverage, the cost-effectiveness of the PrEP program was 3·9 million JPY per QALY gained. A one-way sensitivity analysis revealed that cost-effectiveness exceeded the cost-effectiveness threshold with high PrEP cost or low infection rate in the realistic range. Thus, preparing inexpensive PrEP is the key to making the program cost-effective. The probability that the PrEP program would become cost-effective 10 years after program initiation was 70·4%, which supports the idea of approving PrEP for MSM in Japan. Interpretation: Introduction of PrEP to an MSM cohort in Japan would be cost-effective over a 10-year time horizon. Funding: Ministry of Health, Labour, and Welfare of Japan. Declaration of Interests: All other authors declare no competing interest.