On Oct. 10, 2024, Genentech announced today that the U.S. Food and Drug Administration (FDA) approved Itovebi^TM (inavolisib), in combination with palbociclib (Ibrance^®) and fulvestrant, for the treatment of adults with endocrine-resistant, PIK3CA-mutated, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, locally advanced or metastatic breast cancer, as detected by an FDA-approved test, following recurrence on or after completing adjuvant endocrine therapy. The PIK3CA mutation is found in approximately 40% of HR-positive metastatic breast cancers.

This approval is based on results of the pivotal Phase III INAVO120 study, which showed that the Itovebi-based regimen reduced the risk of disease worsening or death by 57% compared with palbociclib and fulvestrant alone (15.0 months vs. 7.3 months; hazard ratio [HR]=0.43, 95% CI: 0.32-0.59, p<0.0001) in the first-line setting, demonstrating a statistically significant and clinically meaningful benefit.

Overall survival (OS) data were immature at the time of primary analysis, but a clear positive trend was observed (stratified HR=0.64, 95% CI: 0.43-0.97, p=0.0338 [boundary of 0.0098]). Follow-up for OS is continuing to the next analysis.

HR-positive breast cancer is the most prevalent type of all breast cancers, accounting for approximately 70% of cases. A defining feature of HR-positive breast cancer is that its tumor cells have receptors that attach to one or both hormones – estrogen or progesterone – which can contribute to tumor growth.

People diagnosed with HR-positive metastatic breast cancer often face the risk of disease progression and treatment side effects, creating a need for additional treatment options. The PI3K signaling pathway is commonly dysregulated in HR-positive breast cancer, often due to activating PIK3CA mutations, which have been identified as a potential mechanism of intrinsic resistance to standard of care endocrine therapy in combination with cyclin-dependent kinase 4/6 inhibitors.