Clinical trial · Interventional
G1T48, an Oral SERD, Alone and in Combination With Palbociclib in ER-Positive, HER2-Negative Advanced Breast Cancer
A Phase 1, Open-Label, Multicenter Study to Assess the Safety, Tolerability, Pharmacokinetics, and Preliminary Antitumor Activity of Ascending Doses of G1T48 Alone and in Combination With Palbociclib in Women With Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 26, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260926-000001
Summary
Brief summary (as posted)
This is a study to investigate the potential clinical benefit of G1T48 as an oral selective estrogen receptor degrader (SERD) alone and in combination with palbociclib, a cyclin dependent kinase 4/6 (CDK 4/6) inhibitor, in patients with estrogen receptor-positive, HER2-negative metastatic breast cancer. The study is an open-label design, consisting of 3 parts: dose-finding portion including food effect (Part 1), G1T48 monotherapy expansion portion (Part 2), and G1T48 in combination with palbociclib expansion portion (Part 3). All parts include 3 study phases: Screening Phase, Treatment Phase, and Survival Follow-up Phase. The Treatment Phase begins on the day of first dose with study treatment and completes at the Post-Treatment Visit. Approximately, 184 patients may be enrolled in the study.
Conditions
Conditions (7)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Advanced Breast Cancer | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
| Breast Cancer Female | — | UNRESOLVED | — |
| Breast Neoplasm | Breast Neoplasm | ONTOLOGY_EXACT | 0.98 |
| Carcinoma, Ductal, Breast | Breast Ductal Carcinoma | ALIAS | 0.90 |
| Metastatic Breast Cancer | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
| Stage IV Breast Cancer | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
Interventions
Interventions (2)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| G1T48 | Drug | — | UNRESOLVED |
| Palbociclib | Drug | Palbociclib | ALIAS |
Design
Arms and outcomes
Arms (4)
- type
- EXPERIMENTAL
- label
- Part 1: Dose Escalation (G1T48)
- description
- Patients in Part 1 will receive a single oral dose of G1T48 on Cycle 1 Day -3 and will begin once-daily dosing on Cycle 1 Day 1. The initial dose cohort shall receive an identified starting dose and subsequent cohorts shall receive higher doses based on the safety and PK (pharmacokinetic(s)) data obtained from the previous dose levels.
- interventionNames
- Drug: G1T48
- type
- EXPERIMENTAL
- label
- Part 1: Food Effect Cohort (G1T48)
- description
- In Part 1, additional G1T48 cohort(s) of 8 patients may be enrolled to assess the effect of different fat content meals (eg, high fat, moderate fat, or low-fat) on the rate and extent of the absorption of G1T48. Patients will receive a single oral dose of G1T48 on Cycle 1 Day -10 and on Cycle 1 Day -3. Patients will begin G1T48 once-daily dosing on Cycle 1 Day 1.
- interventionNames
- Drug: G1T48
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion Criteria: * For Part 1, postmenopausal women only * For Parts 2 and 3, any menopausal status * Confirmed diagnosis of ER-positive, HER2-negative advanced breast cancer, not amenable to curative therapy * For Part 1, prior treatment with less than 4 prior lines of chemotherapy * For Part 2, prior treatment with less than 2 prior line of chemotherapy * For Part 3, prior treatment with no more than 1 prior line of chemotherapy * For Parts 1 and 2, prior treatment with less than 4 prior endocrine therapies for metastatic breast cancer * For Part 3, prior treatment with no more than 1 prior line of endocrine therapies for metastatic breast cancer * For Parts 1 and 2, patients must satisfy 1 of the following criteria for prior therapy: * Progressed during treatment or within 12 months of completion of adjuvant therapy with an aromatase inhibitor * Progressed after the end of prior aromatase inhibitor therapy for advanced/metastatic breast cancer * For Part 3, patients must satisfy 1 of the following criteria for prior therapy: * Received ≥ 24 months of endocrine therapy in the adjuvant setting prior to recurrence or progression * Received ≥ 6 months of endocrine therapy in the advanced/metastatic setting prior to progression * For Part 1, evaluable or measurable disease * For Parts 2 and 3, evaluable (approximately 25%) or measurable disease (approximately 75%) as defined by RECIST, Version 1.1 including bone-only disease * ECOG performance status 0 to 1 * Adequate organ function Exclusion Criteria: * For Part 3, prior treatment with CDK4/6 inhibitor, investigational oral SERDs or SERCAs in any setting * Active uncontrolled/symptomatic CNS metastases, carcinomatous meningitis, or leptomeningeal disease * Anticancer therapy within 14 days of first G1T48 dose or within 28 days for antibody-based therapy * Concurrent radiotherapy, radiotherapy within 14 days of first G1T48 dose, previous radiotherapy to the target lesion sites, or prior radiotherapy to \> 25% of bone marrow * Prior hematopoietic stem cell or bone marrow transplantation
References
Publications (0)
Data not yet available