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RecruitingLast updated: 15 July 2026

INAVO123: Seeing whether adding a targeted treatment to standard treatment is safe and effective for people with advanced HR+, HER2- breast cancerA Phase III, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of Inavolisib Plus a CDK4/6 Inhibitor and Letrozole Versus Placebo Plus a CDK4/6 Inhibitor and Letrozole in Patients With Endocrine-Sensitive PIK3CA-Mutated, Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer

Trial purpose

Medical clipboardCancer treatment

Tumor type

Breast Cancers Breast

Age

People18+

Trial acronym

INAVO123

Clinical summary

Summary

This study is looking at how well and how safely a new treatment combination works.

It compares adding inavolisib (a targeted therapy) to standard treatment with a CDK4/6 inhibitor and letrozole, versus standard treatment with a placebo instead of inavolisib.

The treatments are being studied as the first treatment (first-line) for this type of cancer.

Who can participate?
You may be eligible if you:

  • are aged 18 or older
  • have hormone receptor-positive (HR+), HER2-negative breast cancer
  • your cancer is advanced (has spread or cannot be cured with surgery)
  • your cancer is either:
    • newly diagnosed at an advanced stage; or
    • has come back after earlier treatment with hormone therapy
  • your cancer has a PIK3CA mutation (this will be confirmed through testing)

What does the study involve?
Participants are randomly allocated (by chance) to receive either:

  • Inavolisib + a CDK4/6 inhibitor + letrozole
  • Placebo + a CDK4/6 inhibitor + letrozole

 

Conditions

This trial is treating people with advanced breast cancer that is HR+ and HER2-, with a PIK3CA mutation

Eligibility

Inclusion

  • Women or men with histologically or cytologically confirmed carcinoma of the breast
  • Documented ER-positive and/or progesterone receptor-positive tumor according to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines
  • Documented HER2-negative tumor according to ASCO/CAP guidelines
  • De-novo HR+ , HER2- ABC, or, alternatively, relapsed HR+ , HER2- ABC after at least 2 years of standard neoadjuvant/adjuvant endocrine therapy without disease progression during that treatment and disease-free interval of at least 1 year since the completion of that treatment
  • Participants who have bilateral breast cancers which are both HR-positive and HER2-negative
  • Confirmation of biomarker eligibility
  • Consent to provide fresh or archival tumor tissue specimen
  • Measurable disease per Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1)
  • Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
  • Adequate hematologic and organ function within 14 days prior to initiation of study treatment

Exclusion

  • Pregnant or breastfeeding, or intention of becoming pregnant during the study or within the time frame in which contraception is required
  • Metaplastic breast cancer
  • Any prior systemic therapy for locally advanced unresectable or metastatic breast cancer
  • Type 2 diabetes requiring ongoing systemic treatment at the time of study entry; or any history of Type 1 diabetes
  • Any history of leptomeningeal disease or carcinomatous meningitis
  • Known and untreated, or active CNS metastases. Participants with a history of treated CNS metastases are eligible
  • Active inflammatory or infectious conditions in either eye or history of idiopathic or autoimmune-associated uveitis in either eye
  • Symptomatic active lung disease
  • History of or active inflammatory bowel disease
  • Any active bowel inflammation
  • Prior hematopoietic stem cell or bone marrow transplantation
  • Treatment with strong cytochrome P450 (CYP) 3A4 inhibitors or strong CYP3A4 inducers within 4 weeks or 5 drug-elimination half-lives, prior to initiation of study treatment

Inclusion

  • Your cancer has spread to other parts of the body (metastatic) or has grown into nearby parts of the body (locally advanced).
  • Your cancer has not spread to other parts of the body, but it is not possible to perform surgery to remove it (unresectable).
  • You are able to swallow medication by mouth.

Exclusion

  • You have been diagnosed with a prior or secondary type of cancer.
  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.
Message

Clinical trials have complex eligibility criteria, and other criteria may apply for this trial. Ask your doctor about whether this trial could be right for you.

Participating hospitals

Recruiting hospitals

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More information

Trial Identifiers

Information on this page is partially produced from ClinicalTrials.gov, UK’s Clinical Study Registry, EU Clinical Trials Register *. View further details about this trial on the registry via the links below:

Trial sponsor

Hoffmann-La Roche

Scientific Title

A Phase III, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of Inavolisib Plus a CDK4/6 Inhibitor and Letrozole Versus Placebo Plus a CDK4/6 Inhibitor and Letrozole in Patients With Endocrine-Sensitive PIK3CA-Mutated, Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer

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