Inavolisib plus fulvestrant for PIK3CA‑mutated HR‑positive, HER2‑negative advanced breast cancer after CDK4/6 inhibitors

A Phase II, Randomized, Open-Label Study Evaluating Two Inavolisib Dose Levels in Combination With Fulvestrant in Participants With PIK3CA-Mutated, HR-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer

Phase 2 Interventional Hoffmann-La Roche · NCT07368998

This tests whether adding inavolisib to fulvestrant helps people with PIK3CA‑mutated, hormone receptor–positive, HER2‑negative locally advanced or metastatic breast cancer whose disease progressed after CDK4/6 inhibitor therapy.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment80 (estimated)
Ages18 Years and up
SexAll
SponsorHoffmann-La Roche Industry-sponsored
Drugs / interventionschemotherapy
Locations19 sites (Los Angeles, California and 18 other locations)
Trial IDNCT07368998 on ClinicalTrials.gov

What this trial studies

This phase 2 interventional study enrolls participants with ER‑positive, HER2‑negative locally advanced or metastatic breast cancer who have a confirmed PIK3CA mutation and progression after CDK4/6 inhibitor plus endocrine therapy. Eligible participants receive inavolisib in combination with fulvestrant and are followed with tumor assessments per RECIST v1.1 and routine safety monitoring. The trial requires measurable or evaluable disease, life expectancy greater than six months, and collection of patient‑reported outcomes. Key outcomes include anti‑tumor activity, progression‑free intervals, and adverse event profiles.

Who should consider this trial

Good fit: Adults with ER+/HER2‑ locally advanced or metastatic breast cancer who have at least one qualifying PIK3CA mutation, progressed on a CDK4/6 inhibitor, and for whom endocrine‑based therapy is still appropriate are the intended participants.

Not a fit: Patients without a PIK3CA mutation, with HER2‑positive or metaplastic tumors, or those who require immediate cytotoxic chemotherapy are unlikely to benefit from this combination.

Why it matters

Potential benefit: If successful, the combination could delay disease progression and provide a new targeted option for PIK3CA‑mutated, HR‑positive patients after CDK4/6 inhibitor therapy.

How similar studies have performed: Other PI3K‑targeting agents combined with endocrine therapy have shown benefit in PIK3CA‑mutant HR‑positive breast cancer, although safety and patient selection have been key considerations.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Documented ER +/ HER2- tumor according to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines
* Disease progression after or during treatment with a combination of CDK4/6i and endocrine therapy: \<= 1 prior lines of systemic therapy in the locally advanced (recurrent or progressed) or metastatic setting
* Measurable or evaluable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1)
* Participants for whom endocrine-based therapy is recommended and treatment with cytotoxic chemotherapy is not indicated at time of entry into the study, as per national or local treatment guidelines
* Confirmation of biomarker eligibility: presence of \>= 1 study-eligible PIK3CA mutation
* Life expectancy of \> 6 months
* Ability, in the investigator's judgment, and willingness to comply with all study -related procedures, including completion of patient-reported outcomes

Exclusion Criteria:

* Metaplastic breast cancer
* Prior treatment with chemotherapy in the recurrent locally advanced/metastatic setting
* Type 2 diabetes requiring ongoing systemic treatment at the time of study entry; or any history of Type 1 diabetes
* Prior treatment with PI3K/Akt/mTOR inhibitors in the recurrent locally advanced/metastatic setting
* Requirement for daily supplemental oxygen
* Symptomatic active lung disease, including pneumonitis

Where this trial is running

Los Angeles, California and 18 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast Cancer
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.