Cost-effectiveness Analysis of Pertuzumab With Trastuzumab in Patients With Metastatic Breast Cancer.

IMPORTANCE: The initial assessment of pertuzumab use for treatment of metastatic breast cancer by health technology assessment agencies suggested that pertuzumab was not cost-effective. In Ontario, Canada, pertuzumab became funded in November 2013 based on the substantial clinical benefit. To date, there is a paucity of analysis of pertuzumab using real-world data for cost-effectiveness. OBJECTIVE: To assess the cost-effectiveness of pertuzumab, trastuzumab, and chemotherapy vs trastuzumab and chemotherapy for patients with metastatic breast cancer. DESIGN, SETTING, AND PARTICIPANTS: A population-based retrospective economic evaluation was conducted in Ontario, Canada. Patients who received first-line treatments for metastatic breast cancer from January 1, 2008, to March 31, 2018, were identified. Patients were followed up from the start of treatment up to 5 years, with maximum follow-up to March 31, 2019. Patients were identified from the Ontario Cancer Registry and linked to the New Drug Funding Program database to identify receipt of first-line treatment (N = 1158). INTERVENTIONS: Treatment with pertuzumab, trastuzumab, and chemotherapy after public funding (November 25, 2013) compared with treatment with trastuzumab and chemotherapy before funding. MAIN OUTCOMES AND MEASURES: Cost-effectiveness, from a public payer perspective, was estimated from administrative data with a 5-year time horizon, adjusted for censoring, and discounted (1.5%). Incremental cost-effectiveness ratios for life-years gained and quality-adjusted life year (QALY) with bootstrapped 95% CIs were calculated. Sensitivity analysis with price reduction of pertuzumab alone or in combination with trastuzumab was conducted. RESULTS: A total of 579 pairs of matched patients receiving pertuzumab and controls were included. The mean (SD) age of the matched study cohort was 58 (12.97) years; 1151 were women (99.4%). Pertuzumab resulted in 0.61 life-years gained and 0.44 QALYs gained at an incremental cost of $192 139 (all costs measured in Canadian dollar values, CAD) with an incremental cost-effectiveness ratio of $316 203 per life-year gained and $436 679 per QALY. The main factors associated with cost included the cost of pertuzumab (60%), outpatient cancer treatment delivery (24%), and trastuzumab (15%). With 100% price reduction of pertuzumab, the incremental cost-effectiveness ratio was $174 027 per QALY. When the price of pertuzumab and trastuzumab were both reduced by more than 71%, the incremental cost-effectiveness ratio decreased below $100 000 per QALY. CONCLUSIONS AND RELEVANCE: The findings of this population-based study suggest that pertuzumab may increase survival for patients with metastatic breast cancer but would not be considered cost-effective, even after 100% price reduction, under conventional thresholds.