MedPath

G1T48, an Oral SERD, Alone and in Combination With Palbociclib in ER-Positive, HER2-Negative Advanced Breast Cancer

Phase 1
Completed
Conditions
Carcinoma, Ductal, Breast
Metastatic Breast Cancer
Stage IV Breast Cancer
Breast Cancer Female
Breast Neoplasm
Breast Cancer
Advanced Breast Cancer
Interventions
Registration Number
NCT03455270
Lead Sponsor
G1 Therapeutics, Inc.
Brief Summary

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.

Detailed Description

Not available

Recruitment & Eligibility

Status
COMPLETED
Sex
Female
Target Recruitment
107
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

Study & Design

Study Type
INTERVENTIONAL
Study Design
SEQUENTIAL
Arm && Interventions
GroupInterventionDescription
Part 2: Monotherapy Dose Expansion (G1T48)G1T48Patients in Part 2 will receive G1T48 once-daily at the dose determined in Part 1.
Part 1: Dose Escalation (G1T48)G1T48Patients 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 data obtained from the previous dose levels.
Part 1: Food Effect Cohort (G1T48)G1T48In 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.
Part 3: Combination Dose Expansion (G1T48+palbociclib)G1T48Patients in Part 3 will receive G1T48 once-daily at the dose determined in Part 2 in combination with palbociclib once-daily on Days 1 to 21 of each 28-day cycle.
Part 3: Combination Dose Expansion (G1T48+palbociclib)PalbociclibPatients in Part 3 will receive G1T48 once-daily at the dose determined in Part 2 in combination with palbociclib once-daily on Days 1 to 21 of each 28-day cycle.
Primary Outcome Measures
NameTimeMethod
Dose Limiting ToxicityCycle 1 Day -3 to Cycle 1 Day 28
Number of Treatment Related Adverse Event, including Abnormal Laboratory Events21 months

All AEs, including clinical laboratory, vitals signs, physical examinations and ECGs will be analyzed in all patients receiving study drug(s) from the signing of the informed consent until 30 days after the last dose of study medication(s).

Recommended Phase 2 dose12 months

G1T48 alone and in combination with palbociclib; progression-free survival (PFS)

Secondary Outcome Measures
NameTimeMethod
Pharmacokinetics of G1T48 and metabolites: Maximum Plasma Concentration (Cmax)Part 1, Cycle 1 Day -3 to Cycle 2 Day 1. Part 2, Cycle 2 Day 1 to Cycle 3 Day 1. Part 3, Cycle 2 Day 1 to Cycle 3 Day 1.
Tumor response based on RECIST, Version 1.121 months

G1T48 alone and in combination with palbociclib;

Effect of food on bioavailability of G1T48Part 1, Cycle 1 Day -10 to Cycle 1 Day 1.
Pharmacokinetics of G1T48 and metabolites: Area under Curve - plasma concentration (AUC)Part 1, Cycle 1 Day -3 to Cycle 2 Day 1. Part 2, Cycle 2 Day 1 to Cycle 3 Day 1. Part 3, Cycle 2 Day 1 to Cycle 3 Day 1.
Pharmacokinetics of palbociclib: Plasma - Trough concentrationPart 3, Cycle 2 Day 1 to Cycle 3 Day 1.
Pharmacokinetics of G1T48 and metabolites: Plasma: terminal half life (T1/2)Part 1, Cycle 1 Day -3 to Cycle 2 Day 1. Part 2, Cycle 2 Day 1 to Cycle 3 Day 1. Part 3, Cycle 2 Day 1 to Cycle 3 Day 1.
Pharmacokinetics of G1T48 and metabolites: Plasma - Volume of distributionPart 1, Cycle 1 Day -3 to Cycle 2 Day 1. Part 2, Cycle 2 Day 1 to Cycle 3 Day 1. Part 3, Cycle 2 Day 1 to Cycle 3 Day 1.

Trial Locations

Locations (15)

Spizhenko Clinic

🇺🇦

Kiev, Ukraine

Institut Jules Bordet

🇧🇪

Brussels, Belgium

UZ Leuven

🇧🇪

Leuven, Belgium

Stanford Women Cancer Center

🇺🇸

Stanford, California, United States

Stephenson Cancer Center

🇺🇸

Oklahoma City, Oklahoma, United States

Sarah Cannon Research Institute at Tennessee Oncology

🇺🇸

Nashville, Tennessee, United States

MHAT for Womens Health - Nadezhda OOD

🇧🇬

Sofia, Bulgaria

ARENSIA Exploratory Medicine Phase I Unit, The Institute of Oncology

🇲🇩

Chisinau, Moldova, Republic of

University Medical Center Groningen

🇳🇱

Groningen, Netherlands

VU University Medical Center

🇳🇱

Amsterdam, Netherlands

Erasmus Medical Center

🇳🇱

Rotterdam, Netherlands

Northwestern University - Feinberg School of Medicine

🇺🇸

Chicago, Illinois, United States

University of North Carolina at Chapel Hill

🇺🇸

Chapel Hill, North Carolina, United States

Beverly Hills Cancer Center

🇺🇸

Beverly Hills, California, United States

ARENSIA Exploratory Medicine LLC

🇬🇪

Tbilisi, Georgia

© Copyright 2025. All Rights Reserved by MedPath