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Combination treatment for advanced HR+/HER2- breast cancer

Phase 3, Open-Label, Randomized, Study Comparing Gedatolisib Combined With Fulvestrant & With or Without Palbociclib to Standard-of-Care Therapies in Patients With HR-Positive, HER2-Negative Advanced Breast Cancer Previously Treated With a CDK4/6 Inhibitor in Combination w/Non-Steroidal Aromatase Inhibitor Therapy

PHASE3 · Celcuity Inc · NCT05501886

This study is testing a new combination of medications for people with advanced breast cancer to see if it can work better than the usual treatments after they haven't responded to earlier therapies.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment701 (estimated)
Ages18 Years and up
SexAll
SponsorCelcuity Inc (industry)
Drugs / interventionschemotherapy
Locations217 sites (Birmingham, Alabama and 216 other locations)
Trial IDNCT05501886 on ClinicalTrials.gov

What this trial studies

This Phase 3, open-label, randomized clinical trial evaluates the efficacy and safety of gedatolisib combined with fulvestrant, with or without palbociclib, for patients with advanced or metastatic HR+/HER2- breast cancer who have progressed after prior CDK4/6 and aromatase inhibitor therapy. Gedatolisib is a pan-PI3K/mTOR inhibitor administered intravenously, while fulvestrant is a selective estrogen receptor degrader. Patients will be assessed for PIK3CA mutation status and randomized into treatment arms based on this status. The study aims to determine if this combination can improve outcomes compared to standard-of-care treatments.

Who should consider this trial

Good fit: Ideal candidates include adult females and males with confirmed metastatic or locally advanced HR+/HER2- breast cancer who have progressed on prior therapies.

Not a fit: Patients with non-HR+/HER2- breast cancer or those who have not progressed on prior CDK4/6 and aromatase inhibitor therapy may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new effective option for patients with advanced HR+/HER2- breast cancer who have limited treatment choices.

How similar studies have performed: Other studies have shown promising results with similar combination therapies in treating HR+/HER2- breast cancer, indicating potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Histologically or cytologically confirmed diagnosis of metastatic or locally advanced breast cancer Adult females, pre- and/or post-menopausal, and adult males. Pre-menopausal (and peri-menopausal) women can be enrolled if amenable to treatment with an LHRH agonist. Patients are to have commenced concomitant treatment with LHRH agonist prior to or on Cycle 1, Day 1 and must be willing to continue on it for the duration of the study.
2. Negative pregnancy test for women of childbearing potential. Female subjects of childbearing potential must use an effective and/or acceptable contraceptive method from screening until 1 year after the last dose of study treatment
3. Confirmed diagnosis of estrogen receptor positive and/or progesterone receptor positive, as per American Society of Clinical Oncology/College of American Pathologists (ASCO-CAP) guidelines (2020), based on most recent tumor biopsy utilizing an assay consistent with local standards
4. Documented HER2 immunohistochemistry (IHC) negative as per ASCO-CAP 2018 guidance
5. Adequate archival or fresh tumor tissue for the analysis of PIK3CA mutational status
6. Subject must have documentation of radiological disease progression on or after the last prior treatment and also have radiologically evaluable disease (measurable and/or non-measurable) according to RECIST v1.1, per local assessment. Subjects with bone only disease must have lytic or mixed lytic/blastic lesions that can be accurately assessed; bone only blastic lesions with no soft tissue component is not allowed.
7. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1
8. Life expectancy of at least 3 months
9. Progressed during or after CDK4/6 inhibitor combination treatment with non-steroidal aromatase inhibitor (AI)
10. Adequate bone marrow, hepatic, renal and coagulation function

Exclusion Criteria:

1. History of malignancies other than adequately treated non-melanoma skin cancer, curatively treated in situ cancer of the cervix, or other solid tumors curatively treated with no evidence of disease for ≥3 years
2. Prior treatment with a phosphoinositide 3-kinase (PI3K) inhibitor, a protein kinase B (Akt) inhibitor, or a mechanistic target of rapamycin (mTOR) inhibitor
3. Prior treatment with chemotherapy and antibody drug conjugates for advanced disease is not permitted (prior adjuvant or neoadjuvant chemotherapy is permitted)
4. More than 2 lines of prior endocrine therapy treatment
5. Bone only disease that is only blastic with no soft tissue component
6. Subjects with type 1 diabetes or uncontrolled type 2 diabetes
7. Known and untreated, or active, brain or leptomeningeal metastases

   a. Subjects with previously treated central nervous system (CNS) metastases may be enrolled in the study if they meet the following criteria: do not require supportive therapy with steroids; do not have seizures and do not exhibit uncontrolled neurological symptoms; stable disease confirmed by radiographic assessment within at least 4 weeks prior to enrollment
8. Patients with advanced, symptomatic, visceral spread that are at risk of life-threatening complication in the short-term
9. History of clinically significant cardiovascular abnormalities such as: Congestive heart failure (New York Heart Association (NYHA) classification ≥ II within 6 months of study entry

   1. Myocardial infarction within 12 months of study entry
   2. History of any uncontrolled (or untreated) clinically significant cardiac arrhythmias, (e.g., ventricular tachycardia), complete left bundle branch block, high grade AV block (e.g., bifascicular block, Mobitz type II and third degree AV block), supraventricular, nodal arrhythmias, or conduction abnormality in the previous 12 months
   3. Uncontrolled hypertension defined by systolic blood pressure (SBP) ≥160 mmHg and/or diastolic blood pressure (DBP) ≥100 mmHg, with or without antihypertensive medication (initiation or adjustment of antihypertensive medication\[s\] is allowed prior to screening)
   4. Long QT syndrome, family history of idiopathic sudden death or congenital long QT syndrome, or any of the following:

      * i. Risk factors for Torsades de Pointes (TdP) including uncorrected hypokalemia or hypomagnesemia, or history of clinically significant/symptomatic bradycardia
      * ii. On screening, inability to determine the corrected QT interval using Fridericia's formula (QTcF) on the ECG (i.e., unreadable or not interpretable) or QTcF \>480 msec (determined by mean of triplicate ECGs at screening)
10. Known hypersensitivity to the study drugs or their components
11. Pregnant or breast-feeding women
12. Concurrent participation in another interventional clinical trial

    1. Subjects must agree not to participate in another clinical trial (other than observational) at any time during participation in VIKTORIA-1.

Where this trial is running

Birmingham, Alabama and 216 other locations

+167 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 →

Conditions: Breast Cancer, Breast Cancer, Advanced or Metastatic, gedatolisib, HR Positive, ER Positive, HER2 Negative, PIK3CA MT, PI3K

Last reviewed 2026-05-15 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.