Budget impact analysis of introducing the new single‐tablet regimen rilpivirine/emtricitabine/tenofovir for the treatment of HIV in Portugal

Abstract

Purpose of the studyRilpivirine/emtricitabine/tenofovir (RPV/FTC/TDF) is a new single‐tablet regimen (STR) approved for the initial treatment of HIV‐1 infection. The aim of this study was to estimate the impact on the State Budget of this new STR introduction in the Portuguese Health System (PHS) using secondary data from official statistics and observational studies.MethodsThe analysis considers a time frame of three years, does not include mortality, assumes a constant flow of new patients, and deals only with antiretroviral therapy (ART) costs. Values are not discounted. The stock and flow data of total HIV‐1 patients comes from official statistics from the National Committee for HIV/AIDS. The model starts with recent historical data on the percentage of different ART drugs used for the treatment of naïve patients. Estimates from an observational study also provide 1) the probability that a patient in a given regimen switches to another therapy and 2) the probability distribution for the new therapy choices given that the patient has switched. The penetration of the new STR is also linked with the prevalence of adverse effects of other ART, in particular teratogenic effects, central nervous systems effects and possible interactions with methadone. The distribution of patients according to ART drug, together with price information, allow us to estimate average costs of treatment per year and per patient for each class of ART. Estimates of patients’ numbers for the second and third years assume the same inflow as in the first year, a given annual percentage of non‐switchers from RPV/FTC/TDF and additional flows from patients switching to non‐nucleoside reverse transcriptase inhibitors from other third‐agent classes.Summary of resultsThe model predicts a flow of 245 new naïve patients on RPV/FTC/TDF per year, with 209 and 194 of these patients staying with RPV/FTC/TDF in the second and third years, respectively. Given that the average cost of treatment is lower in the scenarios with RPV/FTC/TDF (because the percentage of patients on the more expensive PI class are lower), the overall budget impact consists in savings of about €2.3 million.ConclusionsThe introduction of the new STR RPV/FTC/TDF in the PHS will lead to cost savings in the resources spent on the anti‐retroviral therapy of HIV‐1.