A Phase 1/1B Study of ST-01156, a Small Molecule RBM39 Degrader, in Patients With Advanced Solid Malignancies

NCT07197554 | Recruiting Phase 1 DMC FDA Drug

• 1 other identifier: ST-01156-101
• Study Type: interventional
• Target: 171
• Locations: 1 country
• Sites: 6

Brief Summary

A Phase 1/1B Study of ST-01156 in Patients with Advanced Solid Malignancies

Conditions

Advanced Solid Tumors; Ewing Sarcoma; Hepatocellular Carcinoma (HCC); Biliary Tract Cancer (BTC)

Keywords

cancer; solid tumors; RBM39; RBM39 degrader; metastatic solid malignancies; Ewing sarcoma; Hepatocellular carcinoma; HCC; Biliary tract carcinoma; endometrial carcinoma; Adolescents

Outcome Measures

Primary Outcomes (2)

• Part 1: Dose Escalation

  To characterize the safety, tolerability, and adverse event (AE) profile of escalating doses of ST-01156 administered for 5 consecutive days followed by 2 days without study drug administration every 7 days, with a cycle defined as 28 days (4 weeks).

  First 28 days of treatment

• Part 1: Dose Escalation

  To identify the maximum tolerated dose (MTD) or maximum administered dose (MAD), and to recommend a dose for subsequent studies (recommended Phase 2 dose \[ RP2D\]) of ST-01156 on a daily oral schedule for 5 consecutive days out of every 7 days with a cycle defined as 28 days (4 weeks).

  Duration of treatment period

Secondary Outcomes (2)

• Part 1: Dose Escalation

  First 28 days of treatment

• Part 1: Dose Escalation

  Baseline and every 6 weeks thereafter until disease progression

Other Outcomes (1)

• Part 1: Dose Escalation

  Days 1, 2, 3, 4, 5, 8, 15, and 16 of the first two 28-day cycles of treatment, and days 1 of subsequent cycles, until permanent discontinuation of study treatment.

Study Arms (1)

Dose Escalation

EXPERIMENTAL

ST-01156, administered orally once daily for 5 consecutive days followed by 2 days without study drug administration every 7 days

Drug: ST-01156

Interventions

ST-01156 DRUG

ST-01156 is an orally administered degrader of RBM39, a protein frequently upregulated in cancer

Dose Escalation

Eligibility Criteria

• Age: 16 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years on the day of signing the consent form, except for adolescents with Ewing Sarcoma or other malignancies for which there is a biological rationale to support participation, in which case the participant is ≥ 16 years old.
• Has a metastatic or locally advanced and unresectable solid tumor.
• Has at least 1 measurable lesion or evaluable disease per RECIST v1.1.
• Has an ECOG performance status ≤ 2 at screening.
• Has adequate organ function as defined in the protocol.

You may not qualify if:

• Has received prior radiotherapy within 2 weeks of treatment.
• Has known active CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate, provided they are radiologically stable
• Has received treatment with any local or systemic anticancer therapy or investigational anticancer agent within 14 days or 5 half-lives, whichever is shorter.
• Had major surgery within 28 days before study therapy administration
• Has toxicities from previous anticancer therapies that have not resolved to baseline levels, with the exception of alopecia and peripheral neuropathy.
• Has previously received a RBM39 inhibitor/degrader.

Sponsors & Collaborators

• SEED Therapeutics, Inc.: lead

Study Sites (6)

The City of Hope National Medical Center

Duarte, California, 91010, United States

RECRUITING

Hoag Memorial Hospital

Newport Beach, California, 92263, United States

RECRUITING

Mass General Brigham Cancer Institute

Boston, Massachusetts, 02114, United States

NOT YET RECRUITING

Dana Farber Cancer Institute

Boston, Massachusetts, 02215, United States

RECRUITING

Memorial Sloan Kettering Cancer Center

New York, New York, 10065, United States

RECRUITING

The University of Texas MD Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

MeSH Terms

Conditions

Sarcoma, Ewing; Carcinoma, Hepatocellular; Biliary Tract Neoplasms; Neoplasms; Endometrial Neoplasms

Condition Hierarchy (Ancestors)

Osteosarcoma; Neoplasms, Bone Tissue; Neoplasms, Connective Tissue; Neoplasms, Connective and Soft Tissue; Neoplasms by Histologic Type; Sarcoma; Adenocarcinoma; Carcinoma; Neoplasms, Glandular and Epithelial; Liver Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Digestive System Diseases; Liver Diseases; Biliary Tract Diseases; Uterine Neoplasms; Genital Neoplasms, Female; Urogenital Neoplasms; Uterine Diseases; Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Diseases

Central Study Contacts

Dr. Eric Rowinsky Chief Medical Officer

CONTACT

(908) 883-0647; erowinsky@oncodrugs.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 28, 2025
• First Posted: September 29, 2025
• Study Start: December 1, 2025
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): December 31, 2029
• Last Updated: February 18, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (6)