Cost-effectiveness of inavolisib plus palbociclib/fulvestrant versus palbociclib/fulvestrant for PIK3CA-mutated advanced breast cancer in China

Background Based on the positive findings of the INAVO120 study, inavolisib is the only phosphatidylinositol 3-kinase alpha (PI3Kα) inhibitor approved for breast cancer treatment in China and has been included in the National Reimbursement Drug List following national medical insurance price negotiations. Methods A partitioned survival model with a 30-year time horizon was constructed to assess the cost-effectiveness of inavolisib plus palbociclib/fulvestrant versus palbociclib/fulvestrant alone in patients with phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA)-mutated, hormone receptor (HR)+, human epidermal growth factor receptor 2 (HER2)-, locally advanced or metastatic breast cancer (a/m BC). Clinical data were extracted from the Asian cohort of the INAVO120 trial. Drug prices were sourced from the government procurement platform, while additional cost and utility parameters were derived from the published literature. The primary model outcome was the incremental cost-effectiveness ratio (ICER). To assess the robustness of the results, scenario and sensitivity analyses were performed. Additionally, a price simulation analysis was conducted for inavolisib. Results The ICER was determined to be $36,932.91/quality-adjusted life-year (QALY), which exceeded the willingness-to-pay (WTP) threshold of $27,906/QALY. To attain cost-effectiveness, a further price reduction of 27.02% for inavolisib would be necessary. Scenario and sensitivity analyses confirmed the robustness of the results. Conclusion The addition of inavolisib to palbociclib plus fulvestrant for PIK3CA-mutated HR+/HER2-a/m BC is not a cost-effective treatment strategy at the national level in China. However, this triple therapy may achieve cost-effectiveness in economically affluent regions with higher local WTP thresholds.