Cost-effectiveness of inavolisib-based therapy in PIK3CA-mutated advanced breast cancer in the USA.

Inavolisib plus palbociclib and fulvestrant has been approved for treating PIK3CA-mutated, hormone receptor-positive human epidermal growth factor receptor 2-negative (HR + HER2-), advanced breast cancer in the USA. This study evaluated the cost-effectiveness of inavolisib plus palbociclib and fulvestrant compared with palbociclib plus fulvestrant from the US payer perspective. We developed a partitioned survival model at a 28-day cycle length over 15-year time horizons to predict total costs, life-years, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratio (ICER), and incremental cost-utility ratio (ICUR) at willingness-to-pay (WTP) threshold of $150,000 per QALY. Survival data were extracted from the INAVO120 clinical trial, costs and utilities were obtained from the department of Veterans Affairs, published literature and quality-of-life studies using the EQ-5D-5L scale. Uncertainty was addressed via scenario, one-way and probabilistic sensitivity analyses. In the base-case, inavolisib plus palbociclib and fulvestrant resulted in 1.99 life-years and 1.43 QALYs at an incremental cost of $211,639.64 with an ICER of $106,595.61 per life-year and an ICUR of $148,417.37 per QALY. The utility value of progression-free survival was the most influential parameter on the base-case results. Alterations in each model parameter did not significantly impact on the conclusions. The probability of inavolisib plus palbociclib and fulvestrant was cost-effective at the WTP threshold of $150,000 was 54.59%. Inavolisib plus palbociclib and fulvestrant may be a high-value treatment option for patients with PIK3CA-mutated, HR + HER2-, advanced breast cancer in the USA.