A First-in-Human Study of MEN2312 in Adults With Advanced Breast Cancer

Phase 1

Recruiting

• Conditions: Advanced Breast Cancer
• Interventions: Drug: MEN2312; Drug: Elacestrant

• Registration Number: NCT06638307
• Lead Sponsor: Stemline Therapeutics, Inc.

Brief Summary

This is a first-in-human study of MEN2312, a lysine acetyltransferase 6 (KAT6) inhibitor, in adult participants with advanced breast cancer.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-10-09
• Study First Submitted QC: 2024-10-09
• Study First Posted: 2024-10-15
• Study Start: 2024-10-25
• Status Verified: 2025-09
• Last Update Submitted: 2025-09-24
• Last Update Posted: 2025-09-30
• Primary Completion: 2025-10
• Study Completion: 2026-10-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 240

Inclusion Criteria

• Participant has advanced (locoregionally recurrent or metastatic) breast cancer not amenable to curative therapy.
• Participant must have received at least one prior line of endocrine therapy for advanced/metastatic disease or participant who has radiological evidence of breast cancer recurrence or progression during or within 12 months from the end of or during adjuvant treatment with endocrine therapy, as these participants are considered as first-line relapsed participants. Progression on previous cyclin-dependent kinase 4/6 inhibitor treatment in combination with fulvestrant or aromatase inhibitor is required. No other therapeutic options are considered appropriate by the investigator.
• Up to 6 prior lines of systemic therapy (including up to 2 prior lines consisting of chemotherapy, cytotoxic antibody drug conjugate, or a combination of both regimens) are allowed in the advanced/metastatic setting.
• Presence of genetic alterations in PIK3CA/AKT1/PTEN in participants' tumor tissue.

Key

Exclusion Criteria

• Active or newly diagnosed central nervous system metastases.
• Participants with advanced, symptomatic visceral spread, who are at risk of life-threatening complications in the short term, including massive uncontrolled effusions (peritoneal, pleural, pericardial), pulmonary lymphangitis, or liver involvement >50%.

Note: Other inclusion/exclusion criteria may apply.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
MEN2312: Combination Therapy (Elacestrant)	Elacestrant	Participants will receive MEN2312 in combination with elacestrant.
MEN2312: Combination Therapy (Elacestrant)	MEN2312	Participants will receive MEN2312 in combination with elacestrant.
MEN2312: Monotherapy	MEN2312	Participants will receive MEN2312.

Primary Outcome Measures

Name	Time	Method
Number of Participants Experiencing Dose-limiting Toxicity When Administered MEN2312	Baseline through Day 28
Recommended Phase 2 Dose (RP2D) of MEN2312	Baseline through Month 6

Secondary Outcome Measures

Name	Time	Method
Overall Response Rate (ORR)	Baseline through 28 days after the last treatment administration (up to approximately 7 months)
Duration of Response (DOR)	Baseline through 28 days after the last treatment administration (up to approximately 7 months)
Clinical Benefit Rate (CBR)	Baseline through 28 days after the last treatment administration (up to approximately 7 months)
Progression-free Survival (PFS)	Baseline through 28 days after the last treatment administration (up to approximately 7 months)
Overall Survival (OS)	Baseline through 3 months after the last treatment administration (up to approximately 9 months)
Time to Response (TTR)	Baseline through 28 days after the last treatment administration (up to approximately 7 months)
Area Under the Plasma Concentration-time Curve (AUC) of MEN2312 When Administered as Monotherapy	Up to 6 months post dose
AUC of MEN2312 When Administered as Combination Therapy	Up to 6 months post dose
Amount of MEN2312 Excreted in Urine When Administered as Monotherapy	Up to 2 months post dose
Comparison of Plasma Concentration of MEN2312 Monotherapy With MEN2312 Combination Therapy	Up to 6 months post dose

Trial Locations

Locations (38)

Mayo Clinic Cancer Center; 🇺🇸 Phoenix, Arizona, United States

City of Hope Medical Center; 🇺🇸 San Francisco, California, United States

UCLA Hematology Oncology - Parkside; 🇺🇸 Santa Monica, California, United States

Mayo Clinic Comprehensive Cancer Center; 🇺🇸 Jacksonville, Florida, United States

Sarah Cannon Research Institute at Florida Cancer Specialists; 🇺🇸 Orlando, Florida, United States

Moffitt Cancer Center; 🇺🇸 Tampa, Florida, United States

University of Illinois at Chicago - Hematology/Oncology; 🇺🇸 Chicago, Illinois, United States

University of Iowa Hospital and Clinics; 🇺🇸 Iowa City, Iowa, United States

University of Kansas Medical Center, Richard & Annette Bloch Cancer Care Pavilion - Blood & Marrow Transplantation; 🇺🇸 Westwood, Kansas, United States

NYU Langone Medical Center - Laura and Issac Perlmutter Cancer Center; 🇺🇸 New York, New York, United States

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