Cost-effectiveness of inavolisib plus palbociclib-fulvestrant versus palbociclib plus fulvestrant as first-line treatment in HR+/HER2-advanced breast cancer.

This study aims to evaluate the cost-effectiveness of inavolisib plus palbociclib-fulvestrant versus palbociclib-fulvestrant for treating advanced HR+/HER2-breast cancer patients with PIK3CA mutations from both United States (U.S.) and Chinese healthcare system perspectives. A partitioned survival model was used, with survival data from the INAVO120 clinical trials. Primary outcomes assessed were costs, life-years, quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER). Sensitivity analysis was performed to explore the uncertainty of model inputs. Changes in treatment efficacy were modeled to assess their impact on cost-effectiveness. Subgroup analysis was also conducted to refine the findings. In the base-case analysis, the inavolisib triple regimen showed an ICER of $249,487.22/QALY in the U.S. and $43,812.01/QALY in China, both exceeding their respective willingness-to-pay thresholds. Price simulation indicated that the inavolisib-based combination would be preferred in China if the price were reduced to $133.19/9 mg, while a price of $421.13/9 mg would be required to achieve cost-effectiveness in the U.S. Sensitivity analysis demonstrated robust results from the U.S. perspective, while for China, variations in the price of inavolisib and utility of progression-free-survival influenced the conclusions. Subgroup analyses suggested certain patient subgroups could be cost-effective in the Chinese context. Compared with palbociclib-fulvestrant, the inavolisib triple regimen is not cost-effective at its current price. A substantial price reduction or careful selection of the target patient may be required for the regimen to be economically viable.