Forecasting model for drug utilization and expenditure in support of clinical governance in the Veneto Region. The example of drugs for chronic lymphocytic leukemia

BACKGROUND - New onco-hematology drugs exert a high pressure on the Regional Health System, due to high costs and the possibility to offer additional drug lines to patients. Acalabrutinib and venetoclax+obinutuzumab are the most recent new therapies for chronic lymphocytic leukemia (CLL). Definition of place in therapy of such drugs and assessment of their impact on pharmaceutical expenditure is necessary to plan resource allocation. METHODS - HTA Unit of Azienda Zero supported the Working Group on onco-hematology drugs in critically evaluating new therapies and defining place in therapy in accordance with reimbursement criteria, if already available. A forecasting model was developed assuming that each new drug will be used according to place in therapy criteria. RESULTS. Acalabrutinib is a Bruton Tyrosine Kinase inhibitor (BTKi), as well as ibrutinib, and is reimbursed as monotherapy in first line and relapsed-refractory setting. Venetoclax+obinutuzumab is a new first line therapy (reimbursed criteria not yet available at the time of the analysis). Incremental impact of new therapies was estimated for three years, as follow: (i) first year: low impact (below €1 million), due to acalabrutinib market entry, which, at the time of the analysis, had the same cost as ibrutinib, with a broader reimbursed indication (all ages for acalabrutinib vs reimbursement age restrictions for ibrutinib); (ii) second year: about €1,6 million, due to venetoclax+obinutuzumab market entry and to acalabrutinib (new patients and patients continuing therapy from previous year); (iii) third year: impact below €1 million, due to competition between BTKi and venetoclax+obinutuzumab; the latter is a fixed-duration therapy lasting for a maximum of one year, differently from BTKi, that are chronic therapies given for years until disease progression. The usage of venetoclax+obinutuzumab will decrease the number of patients treated for more than one year. CONCLUSIONS - Place in therapy definition optimizes drug utilization, permits to define target population of new therapies, taking into account their competitors already on the market, and leads to pharmaceutical expenditure forecast supporting resource allocation. Forecasting models need to be updated over the time with new reimbursed drugs and/or new reimbursement criteria of therapies already on the market. Prescrition and expenditure monitoring will permit to verify forecast accuracy. Audit could be organized if anomalies will be detected.