A Study Evaluating the Safety of Inavolisib and Fulvestrant With or Without Palbociclib in Participants With Advanced Breast Cancer (ABC) and Type 2 Diabetes

The film gives the main points. The full list below is copied from the registry; the study team makes the final decision.

• Age18 Years to no maximum
• SexAll
• Healthy volunteersNo

You may be able to join if

• Type 2 diabetes with laboratory fasting blood glucose < 185 milligrams per deciliter (mg/dL) and HbA1c <= 8% on any stable anti-hyperglycemic regimen excluding insulin short-term insulin dosing
• Eligible for triplet of inavolisib, fulvestrant and palbociclib: no prior systemic therapy for locally advanced unresectable or metastatic disease
• Confirmed diagnosis of HR+/HER2- breast cancer
• Confirmation of biomarker eligibility (detection of specified mutation(s) of PIK3CA via specified test)
• Measurable disease per Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1)
• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1
• Adequate hematologic and organ function within 14 days prior to initiation of study treatment

You cannot join if

• 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 history of Type 1 diabetes
• Severe hyper- or hypoglycemia event within 6 months of initiation of study treatment
• Any history of leptomeningeal disease or carcinomatous meningitis
• Known and untreated, or active central nervous system (CNS) metastases Participants with a history of treated CNS metastases are eligible
• Active inflammatory or conditions in either eye or history of idiopathic or autoimmune-associated uveitis in either eye
• Symptomatic active lung disease
• History of active bowel inflammation or active inflammatory bowel disease

This is how the treatment is meant to work. Whether it helps, and how safe it is, is what this trial is testing.

inavolisib. An orally available inhibitor of phosphatidylinositol 3-kinase (PI3K), with potential antineoplastic activity. Upon administration, inavolisib binds to and inhibits various members of the PI3K family, including activating mutations in the catalytic alpha isoform PIK3CA. PI3K inhibition prevents the activation of the PI3K-mediated signaling pathway and results in the inhibition of growth and survival of PI3K-overexpressing tumor cells. Dysregulation of the PI3K signaling pathway is frequently associated with tumorigenesis and tumor resistance to a variety of antineoplastic agents and radiotherapy. PIK3CA, which encodes the p110-alpha catalytic subunit of the class I PI3K, is frequently mutated in a variety of cancer cell types and plays a key role in cancer cell growth and invasion. NCI Drug Dictionary

fulvestrant. A synthetic estrogen receptor antagonist. Unlike tamoxifen (which has partial agonist effects) and the aromatase inhibitors (which reduce the estrogen available to tumor cells), fulvestrant binds competitively to estrogen receptors in breast cancer cells, resulting in estrogen receptor deformation and decreased estrogen binding. In vitro studies indicate that fulvestrant reversibly inhibits the growth of tamoxifen-resistant, estrogen-sensitive, human breast cancer cell lines. NCI Drug Dictionary

letrozole/palbociclib regimen. A regimen consisting of letrozole and palbociclib that can be used in the treatment of breast cancer. NCI Drug Dictionary

Treatments listed in the registry

• Inavolisib (Drug): Participants will receive oral inavolisib on Days 2-28 of each 28-day cycle.
• Fulvestrant (Drug): Participants will receive intramuscular (IM) fulvestrant on Days 1 and 15 of Cycle 1, and then on Day 1 of each subsequent 28-day cycle.
• Palbociclib (Drug): Some participants will receive oral palbociclib on Days 1-21 of each 28-day cycle.

Na · Single Group · masking: None

Main goals

• Percentage of Participants With Grade 4 Hyperglycemia Adverse Events (AEs) After Cycle 1 (Up to approximately 21 months)
• Percentage of Participants Hospitalized for Hyperglycemia or its Complications After Cycle 1 (Up to approximately 21 months)
• Percentage of Participants with AEs After Cycle 1 (Up to approximately 21 months)

Other goals

• Percentage of Particiants With Inavolisib-related Hyperglycemia AEs After Cycle 1
• Percentage of Participants With Inavolisib Discontinuations due to Hyperglycemia and its Complications
• Percentage of Participants With Inavolisib Dose Reduction due to Hyperglycemia
• Percentage of Participants With Return of Hemoglobin A1c or Glycated Hemoglobin (HbA1c) to Within 10% of Baseline Within 90 Days After Inavolisib Discontinuation
• Number of Participants Reporting Presence,Frequency,Severity,&/or Degree of Interference with Daily Function of Selected Symptomatic Treatment Toxicities Assessed by NCI Patient-Reported Outcomes Common Terminology Criteria for AEs (PRO-CTCAE)
• Percentage of Participants Reporting Each Response Option at Each Time Point for the Treatment Side-Effect Bother Item (GP5) From the Functional Assessment of Cancer Therapy - General (FACT-G) Questionnaire
• Change from Baseline in Symptomatic Treatment-Related Toxicities as Assessed Through use of the PRO-CTCAE
• Change from Baseline in Treatment Side-Effect Bother as Assessed Through use of the FACT-G General Population, Question 5 (GP5) Item
• Objective Response Rate (ORR)
• Best Overall Response Rate (BOR)
• Duration of Response (DOR)
• Progression-Free Survival (PFS)
• Overall Survival (OS)
• Mean and Mean Change From Baseline in Physical Function Score as Assessed by European Organisation for Research and Treatment of Cancer Item Library 17 (EORTC-IL17)
• Mean and Mean Change From Baseline in Role Function Score as Assessed by EORTC-IL17
• Mean and Mean Change From Baseline in Health-Related Quality of Life (HRQoL) Score as Assessed by EORTC-IL17

Planned enrollment: 40 (estimated).

• MedStar Washington Hosp Center, Washington D.C., District of Columbia
• Grady Memorial Hospital, Atlanta, Georgia
• Emory University Hospital Midtown, Atlanta, Georgia
• Emory University Hospital, Atlanta, Georgia
• Nebraska Cancer Specialists St Francis - Grand Island, Grand Island, Nebraska
• Nebraska Cancer Specialists, Omaha, Nebraska
• NYU Langone Hospital Long Island Clinical Research, Mineola, New York
• NYU Langone?s Perlmutter Cancer Center - 160 E 34th St, New York, New York
• West Virginia University, Morgantown, West Virginia

1 recruiting sites outside the US. Site status as of Oct 30, 2026. Check the live record before contacting a site.

• ClinicalTrials.gov NCT07748208
• NCI Drug Dictionary: C132166
• NCI Drug Dictionary: C1379
• NCI Drug Dictionary: C49176

Registry record reviewed as fetched Oct 30, 2026, last updated by the sponsor Oct 19, 2026. Public record; not medical advice.