The Phase III INAVO120 trial reveals that the addition of inavolisib, a selective PI3Kα inhibitor and degrader, to standard-of-care first-line endocrine therapy plus a CDK4/6 inhibitor significantly improves outcomes for patients with advanced-stage, PIK3CA-mutant, hormone receptor-positive (HR+), HER2-negative (HER2–) breast cancer. This finding offers a promising new approach for a subset of breast cancer known for its poorer prognosis.
The INAVO120 trial enrolled 325 patients with metastatic recurrence of PIK3CA-mutant HR+, HER2– breast cancer, all of whom experienced relapse during or within 12 months of completing adjuvant endocrine-based therapy. Participants were randomized (1:1) to receive palbociclib and fulvestrant plus either inavolisib or a placebo. The study population was characterized by early disease relapse and a high proportion of patients who had received chemotherapy (83%), had visceral metastases (80%), liver metastases (52%), or ≥3 metastases (51%). Only a small fraction (1%) had received a CDK4/6 inhibitor as part of adjuvant therapy. The primary endpoint of the trial was progression-free survival (PFS).
The results suggest that inavolisib could offer a significant benefit in a patient population with limited treatment options after endocrine therapy. The study's focus on patients with early relapse enriches the data for those with a poor prognosis, making the findings particularly relevant for this challenging group.
