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Evaluating Inavolisib with Phesgo for Advanced Breast Cancer

A Phase III, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of Inavolisib in Combination With Phesgo Versus Placebo in Combination With Phesgo As Maintenance Therapy After First Line Induction Therapy in Participants With PIK3CA-Mutated HER2-Positive Locally Advanced or Metastatic Breast Cancer

Phase 3 Interventional Hoffmann-La Roche · NCT05894239

This study is testing if a new combination of inavolisib and Phesgo can help people with advanced breast cancer caused by specific genetic changes feel better after their initial treatment.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment230 (estimated)
Ages18 Years and up
SexAll
SponsorHoffmann-La Roche Industry-sponsored
Drugs / interventionspertuzumab, trastuzumab
Locations192 sites (Gilbert, Arizona and 191 other locations)
Trial IDNCT05894239 on ClinicalTrials.gov

What this trial studies

This study evaluates the effectiveness and safety of inavolisib combined with Phesgo compared to a placebo with Phesgo in patients with PIK3CA-mutated HER2-positive locally advanced or metastatic breast cancer. Participants will receive this combination as maintenance therapy following initial treatment. The study aims to determine if this combination can improve outcomes for patients who have not previously received treatment for their advanced breast cancer.

Who should consider this trial

Good fit: Ideal candidates are adults with HER2-positive, PIK3CA-mutated locally advanced or metastatic breast cancer who have not received prior treatment in this setting.

Not a fit: Patients with breast cancer that is not HER2-positive or does not have a PIK3CA mutation may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new effective option for patients with a specific genetic mutation in their breast cancer.

How similar studies have performed: Other studies have shown promising results with similar combinations targeting HER2-positive breast cancer, suggesting potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1
* Histologically or cytologically confirmed and documented adenocarcinoma of the breast with metastatic or locally advanced disease not amenable to curative resection
* Confirmation of HER2 biomarker eligibility based on valid results from central testing of tumor tissue documenting HER2-positivity
* Confirmation of PIK3CA-mutation biomarker eligibility based on valid results from central testing of tumor tissue documenting PIK3CA-mutated tumor status
* Disease-free interval from completion of adjuvant or neoadjuvant systemic non-hormonal treatment to recurrence of \>= 6 months
* LVEF (left ventricular ejection fraction) of at least 50% measured by echocardiogram (ECHO) or multiple-gated acquisition scan (MUGA)
* Adequate hematologic and organ function prior to initiation of study treatment

Exclusion Criteria:

* Prior treatment in the locally advanced or metastatic setting with any PI3K, AKT, or mTOR inhibitor or any agent whose mechanism of action is to inhibit the PI3K-AKT-mTOR pathway
* Any prior systemic non-hormonal anti-cancer therapy for locally advanced or metastatic HER2-positive breast cancer prior to initiation of induction therapy
* History or active inflammatory bowel disease
* Disease progression within 6 months of receiving any HER2-targeted therapy
* Type 2 diabetes requiring ongoing systemic treatment at the time of study entry; or any history of Type 1 diabetes
* Participants with active HBV infection
* Clinically significant and active liver disease, including severe liver impairment, viral or other hepatitis, current alcohol abuse, or cirrhosis
* Symptomatic active lung disease, including pneumonitis or interstitial lung disease
* Any history of leptomeningeal disease or carcinomatous meningitis
* Serious infection requiring IV antibiotics within 7 days prior to Day 1 of Cycle 1
* Any concurrent ocular or intraocular condition that, in the opinion of the investigator, would require medical or surgical intervention during the study period to prevent or treat vision loss that might result from that condition
* Active inflammatory or infectious conditions in either eye or history of idiopathic or autoimmune-associated uveitis in either eye

Where this trial is running

Gilbert, Arizona and 191 other locations

+142 more sites — see ClinicalTrials.gov for the full list.

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.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Metastatic 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.