A Study of Samuraciclib in Combination With Fulvestrant in Metastatic or Locally Advanced Breast Cancer in Adult Participants (SUMIT-BC)

December 24, 2025 updated by: Carrick Therapeutics Limited

An Open-label, Interventional, Multicenter, Randomized, Phase 2 Study of Fulvestrant With or Without Samuraciclib in Participants With Metastatic or Locally Advanced Hormone Receptor (HR) Positive and Human Epidermal Growth Factor Receptor (HER)2-Negative Breast Cancer (BC)

The purpose of this study is to evaluate the safety and efficacy of samuraciclib in combination with fulvestrant versus fulvestrant alone in adult participants with metastatic or locally advanced Hormone Receptor (HR) positive and Human Epidermal Growth Factor Receptor (HER)2-negative breast cancer.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Hungary
      • Budapest, Hungary, 1082
        • Semmelweis Egyetem
    • Komárom-Esztergom
      • Tatabánya, Komárom-Esztergom, Hungary, 2800
        • Szent Borbala Korhaz
    • Nógrád megye
      • Salgótarján, Nógrád megye, Hungary, 3100
        • Nograd Varmegyei Szent Lazar Korhaz
  • Mexico
      • Cuauhtémoc, Mexico, 06100
        • Cryptex Investigación Clínica S.A. de C.V.
      • Oaxaca City, Mexico, 68000
        • Oaxaca Site Management Organization S.C.
      • Oaxaca City, Mexico, 68020
        • Centro de Investigacion Clinica de Oaxaca
    • Jalisco
      • Guadalajara, Jalisco, Mexico, 44280
        • Actualidad Basada en la Investigación del Cáncer
      • Guadalajara, Jalisco, Mexico, 44680
        • Renati Innovation S.A.P.I de C.V
    • Mexico City
      • Mexico City, Mexico City, Mexico, 03650
        • Soltmed Smo
  • Spain
      • Badajoz, Spain, 06080
        • Hospital Infanta Cristina
      • Barcelona, Spain, 08035
        • Hospital Universitari Vall d'Hebron
      • Barcelona, Spain, 08003
        • Parc de Salut Mar - Hospital del Mar
      • Madrid, Spain, 28015
        • MD Anderson Cancer Center
      • Málaga, Spain, 29016
        • Hospital Vithas Malaga
      • Salamanca, Spain, 37007
        • Hospital Universitario de Salamanca - Complejo Asistencial Universitario de Salamanca
      • Valencia, Spain, 46010
        • Hospital Clínico de Valencia
    • Barcelona
      • L'Hospitalet de Llobregat, Barcelona, Spain, 08908
        • Institut Català d'Oncologia - L'Hospitalet
    • Cantabria Comunidad de
      • Santander, Cantabria Comunidad de, Spain, 39002
        • Hospital Universitario Marqués de Valdecilla
    • Madrid, Comunidad de
      • Madrid, Madrid, Comunidad de, Spain, 28040
        • Hospital Clinico San Carlos
  • Turkey (Türkiye)
      • Ankara, Turkey (Türkiye), 06200
        • Dr. Abdurrahman Yurtaslan Ankara Onkoloji Eğitim ve Araştırma Hastanesi
      • Ankara, Turkey (Türkiye), 06230
        • Hacettepe Universite Hastaneleri
      • Ankara, Turkey (Türkiye), 06010
        • Gulhane Egitim ve Arastirma Hastanesi
      • Ankara, Turkey (Türkiye), 06120
        • Gazi University
      • Edirne, Turkey (Türkiye), 22030
        • Trakya University
      • Istanbul, Turkey (Türkiye), 34093
        • Istanbul Universitesi Istanbul Tıp Fakultesi Hastanesi
      • Istanbul, Turkey (Türkiye), 34722
        • TC Saglik Bakanligi Goztepe Prof. Dr. Suleyman Yalcin Sehir Hastanesi
      • Izmir, Turkey (Türkiye), 35575
        • I.E.U. Medical Point Hastanesi
  • United States
    • Florida
      • Ocala, Florida, United States, 34474
        • Ocala Oncology Center PL DBA Florida Cancer Affiliates
    • Maryland
      • Baltimore, Maryland, United States, 21237
        • Mfsmc-Hjwci
    • Missouri
      • Kansas City, Missouri, United States, 64111
        • Saint Luke's Cancer Institute
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19107
        • Sidney Kimmel Cancer Center - Jefferson Health
    • Texas
      • Fort Worth, Texas, United States, 76104
        • The Center for Cancer and Blood Disorders

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Histologically confirmed diagnosis of ER-positive, HER2-negative locally advanced or metastatic breast cancer.
  • Documented objective disease progression while on or within 6 months after the end of the most recent therapy.
  • Received prior AI in combination with a CDK4/6i as the last therapy
  • Known TP53 mutation status.
  • Participants must have measurable disease or bone only disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.
  • Pre/peri-menopausal participants must have commenced treatment with a luteinizing hormone-releasing hormone (LHRH) agonist at least 4 weeks prior to first dose of study intervention.
  • Eastern Cooperative Oncology Group (ECOG) performance status ≤1 with no deterioration over the past 2 weeks.
  • Expected life expectancy of >12 weeks in the judgement of the treating investigator.

Exclusion Criteria:

  • Inflammatory breast cancer.
  • Participants with any other active malignancy within 3 years prior to enrollment, except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ of the cervix.
  • More than 1 line of endocrine treatment for locally advanced or metastatic disease treatment.
  • Inadequate hepatic, renal, and bone marrow function.
  • Clinically significant cardiovascular disease.
  • Any current or prior central nervous system metastases, carcinomatous meningitis, or leptomeningeal disease.
  • Pregnant or breastfeeding women.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm A
Participants will receive 360 mg of samuraciclib on cycles of 28 days (Cycle 1 to 6), 56 days (Cycle 7 to 9) and up to 84 days (Cycles 10 onwards in combination with fulvestrant administered monthly, plus an additional dose at Cycle 1 Day 15.
Drug: Samuraciclib
Samuraciclib tablet by mouth once a day
Drug: Fulvestrant
Injection administered monthly (i.e., every 4 weeks), plus additional dose at Cycle 1 Day 15
Other Names:
  • Faslodex
Experimental: Arm B
Participants will receive 240 mg of samuraciclib on cycles of 28 days (Cycle 1 to 6), 56 days (Cycle 7 to 9) and up to 84 days (Cycles 10 onwards in combination with fulvestrant administered monthly, plus an additional dose at Cycle 1 Day 15.
Drug: Samuraciclib
Samuraciclib tablet by mouth once a day
Drug: Fulvestrant
Injection administered monthly (i.e., every 4 weeks), plus additional dose at Cycle 1 Day 15
Other Names:
  • Faslodex
Experimental: Arm C
Participants will receive fulvestrant administered monthly, plus additional dose at Cycle 1 Day 15.
Drug: Fulvestrant
Injection administered monthly (i.e., every 4 weeks), plus additional dose at Cycle 1 Day 15
Other Names:
  • Faslodex

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical Benefit Response (CBR)
Time Frame: From randomization until Week 24
CBR is defined as the overall complete response (CR), partial response (PR), or stable disease (SD) ≥ 24 weeks according to RECIST version 1.1 recorded from randomization until disease progression, or death due to any cause.
From randomization until Week 24

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Objective Response Rate (ORR)
Time Frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
ORR defined as the proportion of participants who achieved a best overall Response (BOR) of CR or PR per RECIST Version 1.1 from randomization until disease progression, or death due to any cause.
Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
Duration of Response (DOR)
Time Frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
DOR defined as the time from the date of first documentation of objective tumor response (CR or PR) to the earliest documented disease progression per RECIST version 1.1, or death due to any cause.
Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
Progression Free Survival (PFS)
Time Frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
PFS defined as the time from the date of randomization to the earliest documented disease progression per RECIST version 1.1, or death due to any cause.
Time from the date of first dose of study intervention until the first documentation of disease progression, death, withdrawal of consent, or start of new anticancer therapy (assessed up to week 48)
Incidence and severity of adverse events (AEs) as assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) v5.0
Time Frame: From first dose of any study intervention through 28 days after the last dose of any study intervention
Safety will be assessed by monitoring adverse events and clinically relevant changes in vital signs and clinical laboratory results.
From first dose of any study intervention through 28 days after the last dose of any study intervention
Samuraciclib plasma exposure: Cmax
Time Frame: Day 1 of Cycles 2 and 3 (each cycle is 28 days)
Day 1 of Cycles 2 and 3 (each cycle is 28 days)
Samuraciclib plasma exposure: Ctrough
Time Frame: Cycle 1 Days 8 and 15; Day 1 of Cycles 2, 3, 4, 5, and 6; and within 28 days of last dose (each cycle is 28 days)
Cycle 1 Days 8 and 15; Day 1 of Cycles 2, 3, 4, 5, and 6; and within 28 days of last dose (each cycle is 28 days)
Fulvestrant plasma exposure: Ctrough
Time Frame: Cycle 1 Days 8 and 15; Day 1 of Cycles 2, 3, 4, 5 and 6; and within 28 days of last dose (each cycle is 28 days)
Cycle 1 Days 8 and 15; Day 1 of Cycles 2, 3, 4, 5 and 6; and within 28 days of last dose (each cycle is 28 days)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Carrick Therapeutics Limited

Collaborators

Pfizer

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 16, 2023

Primary Completion (Actual)

March 20, 2025

Study Completion (Actual)

August 28, 2025

Study Registration Dates

First Submitted

June 30, 2023

First Submitted That Met QC Criteria

July 19, 2023

First Posted (Actual)

July 27, 2023

Study Record Updates

Last Update Posted (Actual)

December 26, 2025

Last Update Submitted That Met QC Criteria

December 24, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CT7001_002
  • 2023-503903-27-00 (Registry Identifier: CTIS)
  • Z0041001 (Other Identifier: Pfizer)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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