FDA Approves Companion Diagnostic for Inavolisib in HR+/HER2–, PIK3CA-Mutated Breast Cancer

FDA Approves Companion Diagnostic for Inavolisib in HR+/HER2–, PIK3CA-Mutated Breast Cancer

The FDA has approved FoundationOne CDx as a companion diagnostic for inavolisib (Itovebi) in combination with palbociclib and fulvestrant for endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative advanced breast cancer. This approval expands the targeted therapy landscape and underscores the importance of genomic testing in patient selection. For pharma BD teams and investors, the Inavolisib FDA approval locks a diagnostic gatekeeper into Roche's targeted therapy strategy.

Key Takeaways

• The FDA approved FoundationOne CDx (tissue-based) and FoundationOne Liquid CDx (blood-based liquid biopsy) as companion diagnostics for the inavolisib triplet regimen — source.
• The indication covers adults with endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative locally advanced or metastatic breast cancer whose disease recurred on or after adjuvant endocrine therapy — openFDA label.
• The INAVO120 phase III trial provided the efficacy and safety data underpinning the approval — a safety analysis was published in PubMed.
• For BD teams, the Itovebi FDA approval reinforces Roche's vertical integration of CDx and targeted therapy, pressuring competing PI3K inhibitor programs such as gedatolisib, which is being evaluated in the VIKTORIA-1 trial — PubMed.
• Next catalysts include Inavolisib EMA approval and real-world evidence readouts.

What the FDA Approval Covers

The Food and Drug Administration approved inavolisib (Itovebi) in combination with palbociclib (Ibrance) and fulvestrant on October 10, 2024, for adults with endocrine-resistant, PIK3CA-mutated, HR-positive, 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 agency simultaneously approved FoundationOne CDx as a companion diagnostic for the regimen, alongside FoundationOne Liquid CDx as a liquid biopsy option for non-invasive patient selection. Foundation Medicine's tissue test can now be used in addition to its blood-based test to identify more patients for treatment.

Inavolisib is a kinase inhibitor; the openFDA label specifies that Itovebi is indicated as part of the triplet with palbociclib and fulvestrant for the defined population. Palbociclib itself is now also labeled for use in this combination, expanding its approved footprint beyond earlier endocrine-based regimens. The Inavolisib FDA label does not currently include an overall survival claim, so positive OS readouts from ongoing studies would be a meaningful catalyst.

The approval traces to the INAVO120 randomized phase III trial, which compared inavolisib or placebo with palbociclib-fulvestrant in patients harboring PIK3CA mutations. A dedicated safety analysis of the INAVO120 trial was later published, detailing the adverse event profile of the triplet combination — PubMed. Clinicians should be aware of a reported case of inavolisib-induced fulminant-like diabetes and hyperosmolar hyperglycemic state, documented in a separate case report — PubMed.

Competitive Landscape and Implications for Pharma Teams

For BD teams and investors, this approval strengthens Roche's position in the PI3K inhibitor market and highlights the growing importance of companion diagnostics in precision oncology. The combination of inavolisib with palbociclib and fulvestrant offers a new targeted option for a defined patient population, potentially shifting treatment paradigms. Competitors developing PI3K inhibitors may face increased pressure — notably, the VIKTORIA-1 trial evaluating gedatolisib plus fulvestrant with or without palbociclib in HR-positive/HER2-negative advanced breast cancer is ongoing, with an erratum published in 2026 — PubMed.

The approval also underscores the value of liquid biopsy diagnostics, which could expand testing access and drive adoption. FoundationOne Liquid CDx enables non-invasive patient selection, potentially capturing patients who might otherwise go untested due to insufficient tissue samples. Next milestones include EMA review and real-world evidence generation. An Inavolisib EMA approval would open the European market, representing a significant revenue opportunity.

For investors tracking the Inavolisib-based therapy in PIK3CA-mutated advanced breast cancer space, the key open question remains whether overall survival data will ultimately support a label expansion. The Inavolisib phase 3 program is generating additional long-term follow-up data that could solidify the drug's position.

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Related profiles

• inavolisib
• palbociclib
• fulvestrant

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