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

A Phase 1, First-in-Human, Dose Escalation and Expansion, Multicenter Study of XMT-2056 in Participants With Advanced/Recurrent Solid Tumors That Express HER2

Status
Terminated
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05514717
Enrollment
57
Registered
2022-08-24
Start date
2023-01-24
Completion date
2026-05-22
Last updated
2026-06-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

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

Brief summary

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

Detailed description

The first-in-human (FIH) study of XMT-2056 is a Phase 1, open-label study of XMT-2056 in previously treated patients with advanced/recurrent solid tumors expressing HER2. The XMT-2056 monotherapy trial will consist of dose escalation (DES) and expansion (EXP) parts. DES will be the dose-finding portion of the study to assess the safety and tolerability of XMT-2056 and determine the maximum tolerated dose (MTD) and/or Recommended Phase 2 Dose (RP2D). The RP2D will be determined based on the totality of the clinical data, including safety and preliminary anti-tumor effect, PK, and relevant biomarker data.

Interventions

DRUGXMT-2056

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

Sponsors

Day One Biopharmaceuticals, Inc.
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* 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.

Exclusion criteria

* • 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. 1. Participants are eligible if CNS metastases are adequately treated and participants are neurologically stable for at least 2 weeks prior to enrollment. 2. In addition, participants must be either off corticosteroids, or on a stable/decreasing dose of ≤ 10 mg prednisone daily (or equivalent).

Design outcomes

Primary

MeasureTime frameDescription
Frequency of dose-limiting toxicities (DLTs) associated with XMT-2056 during the first cycle of treatment (Dose Escalation)15 monthsDetermine the maximum tolerated dose (MTD) of XMT-2056
Incidence of adverse events (Dose Escalation and Dose Expansion)3 yearsAssess 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.
Objective Response Rate (ORR) (Dose Expansion)3 yearsThe 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

Secondary

MeasureTime frameDescription
Objective Response Rate (ORR) (Dose Escalation)3 yearsThe percentage of patients with a best overall response of confirmed complete or partial response as assessed by the investigator per Resist Evaluation Criteria in Solid Tumors (RECIST) version 1.1
Duration of response (DOR) (Dose Escalation and Dose Expansion)3 yearsThe time from when response criteria are first met until disease progression or death in participants who achieve a confirmed complete or partial response.
Disease control rate (DCR) (Dose Escalation and Dose Expansion)3 yearsThe percentage of patients who achieve a complete response, partial response or stable disease as the result of study treatment
Time of maximum observed plasma concentration of XMT-2056 (Tmax) (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056
Maximum observed plasma concentration of XMT-2056 (Cmax) (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056
Area under the concentration-time curve of XMT-2056 (AUC) (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056
Systemic clearance of XMT-2056 (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XmT-2056 by measuring the rate at which the drug is eliminated from the body
Apparent terminal elimination of half-life of XMT-2056 (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056
Volume of Distribution (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056
Trough concentration of XMT-2056 (Ctrough) (Dose Escalation and Dose Expansion)3 yearsAssess the pharmacokinetics of XMT-2056 by measuring the lowest concentration of drug before dosing
Serum samples for analysis of XMT-2056 antidrug and neutralizing antibodies (ADA/nAb) (Dose Escalation and Dose Expansion)3 yearsAssess the development of antidrug antibodies (ADA) and neutralizing antibodies (nAB) to XMT-2056

Countries

United States

Contacts

STUDY_DIRECTORBrad Sumrow, MD

Mersana Therapeutics

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 19, 2026