First-line HIV treatment: evaluation of backbone choice and its budget impact

OBJECTIVE: The gradual increase of persons living with HIV, mainly due to the reduced mortality achieved with effective antiretroviral therapies, calls for increased rationality and awareness in health resources consumption also during the early illness phases. Aim of this work is the estimation of the budget impact related to the variation in backbone prescribing trends in naïve patients.METHODS: Target population is the number of patients starting antiretroviral therapy each year, according to the Italian HIV surveillance registry, excluding patients receiving non-authorized or non-recommended regimens. We modeled 3-year mortality and durability rates on a dynamic cohort, basing on international literature. A prevalent patients analysis has also been conducted, for which the model is fed by a closed cohort consisting of all the patients without experience of virologic failure. The aim of this collateral analysis is to estimate the difference in current annual expenditures if the past prescription trends for patients starting therapy would have led to the evaluated hypothetical scenarios. Current Italian market shares of triple regimens containing first-choice or alternative backbones (tenofovir/emtricitabine, abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine) are compared to three hypothetical scenarios (base-case, minimum and maximum) in which increasing shares of patients eligible to abacavir/lamivudine start first line treatment with this backbone. Annual cost for each regimen comprises drugs acquisition under hospital pricing rules, monitoring exams and preventive tests, valued basing on regional reimbursement tariffs.RESULTS: According to current prescribing trends, in the next three years about 13,000 patients starting HIV therapy will receive tenofovir/emtricitabine (83% of the target population), and minor portions other regimens (9% abacavir/lamivudine, 8% zidovudine/lamivudine). Patients that would be eligible to abacavir/lamivudine are 1.5, 4.5 and 6 thousand more than those presently treated according to the three hypothetical scenarios, leading to a cumulative saving of 850 thousand, 2.4 million and 3.3 million euro, respectively. If in the past the same modification of first line prescription trend was adopted, the annual current cost saving would vary from 922 thousands to 7.3 million euro. Most of this amount is due to reduced acquisition costs and, secondarily, to lower monitoring needs.CONCLUSION: Where patient features don’t force the choice of the backbone, abacavir/lamivudine prescription may induce substantial savings, allowing the release of resources needed to manage more complicated/advanced cases.