2.5. Cost Data

The model was developed from a public healthcare perspective. For this reason, only direct medical costs were considered, including the costs of drug acquisition, follow-up/monitoring and AEs. Drug costs were calculated based on treatment regimens recommended dosages obtained from product monographs and Cancer Care Ontario (CCO), using a body surface area of 1.89 and an average weight of 76 kg. Unit drug costs were obtained from the Ontario Drug Benefit Formulary and the list of the Association Québécoise des Pharmaciens Propriétaires. For OTT, drug costs were accumulated until treatment discontinuation, due to relapse or other clinical reasons. The probability of discontinuation for each 4-week cycle was estimated at 0.70% and 1.40%, for first-line and relapse patients, respectively [¹³].

Monitoring cost included the cost of laboratory testing per treatment. The unit costs were obtained from the Schedule of Benefits for Laboratory Services from the Ontario Ministry of Health and Long-Term Care, and the testing frequency was obtained from CCO and validated by KOLs. Administration costs included the cost of chemotherapy infusion as well as professional fee costs, which comprised the hematologist, nurse and pharmacist costs. These costs were calculated based on the Schedule of Benefits of Physician Services in Ontario, the average hourly wage of a nurse and pharmacist obtained from Statistics Canada and the frequency of administration per cycle, as determined by CCO.

Adverse events were extracted from clinical trials and product monographs for each treatment regimen. Four main AEs were considered for all therapies: neutropenia, thrombocytopenia, anemia and infection. For ibrutinib, arterial fibrillation was included due to specific concerns regarding this treatment. Only grades 3 and 4 AEs were considered in this economic evaluation. The management cost for each type of AE was derived from the Ontario Care Costing Initiative (OCCI), based on the inpatient related data [¹⁷].