A Study of XMT-2056 in Advanced/Recurrent Solid Tumors That Express HER2

NCT05514717 | Recruiting Phase 1 FDA Drug

• 1 other identifier: MER-XMT-2056-1
• Study Type: interventional
• Target: 162
• Locations: 1 country
• Sites: 14

Brief Summary

A Study of XMT-2056 in advanced/recurrent solid tumors that express HER2.

Conditions

HER2-positive Breast Cancer; HER2-positive Gastric Cancer; HER2-positive Non-Small Cell Lung Cancer; HER2-positive Colorectal Cancer; HER2-positive Tumors; HER2 Low Breast Cancer

Outcome Measures

Primary Outcomes (3)

• Frequency of dose-limiting toxicities (DLTs) associated with XMT-2056 during the first cycle of treatment (Dose Escalation)

  Determine the maximum tolerated dose (MTD) of XMT-2056

  15 months

• Incidence of adverse events (Dose Escalation and Dose Expansion)

  Assess the safety and tolerability of XMT-2056 by determining the number of patients with adverse events from date of first dose to 30 days post last dose.

  3 years

• Objective Response Rate (ORR) (Dose Expansion)

  The percentage of patients with a best overall response of confirmed complete or partial response as assessed by the investigator per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1

  3 years

Secondary Outcomes (11)

• Objective Response Rate (ORR) (Dose Escalation)

  3 years

• Duration of response (DOR) (Dose Escalation and Dose Expansion)

  3 years

• Disease control rate (DCR) (Dose Escalation and Dose Expansion)

  3 years

• Time of maximum observed plasma concentration of XMT-2056 (Tmax) (Dose Escalation and Dose Expansion)

  3 years

• Maximum observed plasma concentration of XMT-2056 (Cmax) (Dose Escalation and Dose Expansion)

  3 years

Study Arms (1)

XMT-2056

EXPERIMENTAL

XMT-2056 alone (monotherapy)

Drug: XMT-2056

Interventions

XMT-2056 DRUG

XMT-2056 will be administered through a vein in your arm or port catheter (intravenously)

XMT-2056

Eligibility Criteria

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

You may qualify if:

• Participant has recurrent or metastatic solid tumors with HER2 expression and has disease progression after treatment, is intolerant to treatment, or is contraindicated with available anti-cancer therapies known to confer benefit, based on investigator's judgement. Note: Participants must have HER2 positivity per the results of their most recent tumor tissue testing, defined as IHC 3+ or IHC 2+ in combination with in situ hybridization (ISH)+. Participants with ERBB2-activating mutations or ERBB2 gene amplification in the absence of HER2 positivity are considered ineligible.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.
• Participant must have measurable disease as defined by RECIST version 1.1.
• Participant has fresh tumor biopsy tissue available for submission to central laboratory. If obtaining fresh tumor tissue is medically contraindicated, archival tumor tissue can be submitted following written approval of the request by the study Medical Monitor. Samples must be obtained after the participant's most recent HER2-targeting therapy unless determined to be medically contraindicated after discussion with the medical monitor.

You may not qualify if:

• Participant is receiving immunosuppressive doses of systemic medications, (doses \>10 mg/day prednisone or equivalent) that cannot be discontinued for at least 2 weeks before the first dose and during study drug treatment administration. Note: physiologic hormone replacement therapy is an exception.
• Participant has received prior treatment targeting STING pathway.
• Diagnosis of additional malignancy that required active treatment (including surgery, systemic therapy, and radiation) within the last 2 years, expect for adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the breast or the cervix. Participants with an additional malignancy that has a low risk for recurrence may be eligible after discussion with the study Medical Monitor.
• Participants have untreated CNS metastases (including new and progressive brain metastases), history of leptomeningeal metastasis, or carcinomatous meningitis.
• Participants are eligible if CNS metastases are adequately treated and participants are neurologically stable for at least 2 weeks prior to enrollment.
• In addition, participants must be either off corticosteroids, or on a stable/decreasing dose of ≤ 10 mg prednisone daily (or equivalent).

Sponsors & Collaborators

• Mersana Therapeutics: lead

Study Sites (14)

University of South California

Los Angeles, California, 90033, United States

RECRUITING

University of California Los Angeles

Los Angeles, California, 90095, United States

RECRUITING

Stanford University Medical Center

Stanford, California, 94305, United States

RECRUITING

AdventHealth Celebration

Celebration, Florida, 34747, United States

RECRUITING

Emory Healthcare, Emory Clinic

Atlanta, Georgia, 30322, United States

RECRUITING

Massachusetts General Hospital

Boston, Massachusetts, 02114, United States

RECRUITING

Karmanos Cancer Institute

Detroit, Michigan, 48201, United States

RECRUITING

Hackensack University Medical Center

Hackensack, New Jersey, 07601, United States

RECRUITING

New York University Medical Oncology Associates

New York, New York, 10016, United States

RECRUITING

Icahn School of Medicine at Mount Sinai

New York, New York, 10029, United States

RECRUITING

Memorial Sloan Kettering Cancer Center

New York, New York, 10065, United States

RECRUITING

The Ohio State University Comprehensive Cancer Center

Columbus, Ohio, 43212, United States

RECRUITING

Tennessee Oncology, PLLC

Nashville, Tennessee, 37203, United States

RECRUITING

The University of Texas MD Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

Study Officials

• Brad Sumrow, MD

  Mersana Therapeutics

  STUDY DIRECTOR

Central Study Contacts

June Buchanan

CONTACT

617-844-8613; medicalinformation@mersana.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 8, 2022
• First Posted: August 24, 2022
• Study Start: January 24, 2023
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027
• Last Updated: July 11, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (14)