Phase 1 Study of MST-168 in Participants With Advanced Solid Malignant Tumors

June 8, 2026 updated by: Mabsoft Therapeutics (Shanghai) Co., Ltd.

A Phase 1, Multiregional, Open-label Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Efficacy of MST-168, in Participants With Advanced Solid Malignant Tumors

A Phase 1, multiregional, open-label study of MST-168 in participants with target-driven advanced solid tumors.

The goal of this clinical trial is to evaluate the safety, tolerability, pharmacokinetics, immunogenicity, pharmacodynamic effects, and preliminary efficacy of MST-168 in participants with target-driven advanced solid tumors. MST-168 is an investigational ADC.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

420

Phase

  • Phase 1

Contacts and Locations

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

Study Contact

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:

  • Participants are eligible to be included in the study only if all of the following criteria apply:

I1. Is capable of giving signed informed consent, including compliance with the requirements and restrictions listed in the ICF and in this protocol.

I2. Is at least 18 years of age at the time of signing the ICF.

I3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

I4. Life expectancy ≥ 12 weeks.

I5. Has adequate organ function.

I6. Pregnancy and Contraception: Female participants agree not to be pregnant or lactating from beginning of the study screening until 6 months after receiving the last treatment. Male participants with partners of childbearing potential and female participants of childbearing potential are willing and able to employ a highly effective method of birth control/contraception to prevent pregnancy from beginning of the study screening until 6 months after receiving the last treatment of MST-168.

I7. Has a pathologically documented advanced/unresectable or metastatic solid tumor that is refractory to or intolerable with standard treatment, or for which no standard treatment is available.

Exclusion Criteria:

  • Participants are excluded from the study if any of the following criteria apply:

E1. Has untreated brain or CNS metastases or brain/CNS metastases that have progressed [e.g., evidence of new or enlarging brain metastasis or new neurologic symptoms attributable to brain/CNS metastases]. Participants with previously unstable brain or CNS metastases.

E2. Has a malignancy (except disease under study) that has progressed or required active treatment within the past 24 months except for basal cell or squamous cell carcinomas of the skin or in-situ carcinomas [e.g., breast, cervix, bladder] that have been resected with no evidence of metastatic disease.

E3. Has any history of prior allogenic or autologous bone marrow transplant or other solid organ transplant.

E4. Has known sensitivity to study intervention components or excipients.

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: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: MST-168 initial dose level treatment Cohort
MST-168 initial dose level
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.
Experimental: MST-168 dose level 2 treatment Cohort
MST-168 dose level 2
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.
Experimental: MST-168 dose level 3 treatment Cohort
MST-168 dose level 3
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.
Experimental: MST-168 dose level 4 treatment Cohort
MST-168 dose level 4
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.
Experimental: MST-168 dose level 5 treatment Cohort
MST-168 dose level 5
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.
Experimental: MST-168 dose level 6 treatment Cohort
MST-168 dose level 6, if needed
Biological: MST-168
MST-168 is a proprietary antibody-drug conjugate (ADC) developed by Mabsoft Therapeutics.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of dose-limiting toxicities (DLT)
Time Frame: Day 1 - Day 28
Day 1 - Day 28
Incidence and severity of AEs, clinically significant changes from Baseline (pre-dose on D1) through to the EOT in vital signs, laboratory tests, physical examinations, 12-lead ECG, and ECHO/MUGA.
Time Frame: Through study completion, up to 25 months
Through study completion, up to 25 months

Secondary Outcome Measures

Outcome Measure
Time Frame
PK parameters for MST-168, total anti-drug antibody and free payload: Tmax
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: Cmax
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: AUC0-t
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: AUC0-∞
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: t1/2
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: CL
Time Frame: Day 1 to Day 8
Day 1 to Day 8
PK parameters for MST-168, total anti-drug antibody and free payload: Vss
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
PK parameters for MST-168, total anti-drug antibody and free payload: AUCss
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
PK parameters for MST-168, total anti-drug antibody and free payload: Css,max
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
PK parameters for MST-168, total anti-drug antibody and free payload: Css,min
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Frequencies of ADAs and neutralizing antibodies specific to MST-168.
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Biomarkers: cytokines/chemokines and immune cell phenotypes
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Objective response rate (ORR) based on RECIST v1.1.
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Duration of response (DoR) based on RECIST v1.1.
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Progression-free survival (PFS) based on RECIST v1.1.
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months
Disease control rate (DCR) based on RECIST v1.1.
Time Frame: Through study completion, up to 24 months
Through study completion, up to 24 months

Collaborators and Investigators

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

Sponsor

Mabsoft Therapeutics (Shanghai) Co., Ltd.

Collaborators

Mabsoft Therapeutics (Australia) Pty. Ltd.
Mabsoft Therapeutics (Guangdong Hengqin) Co., Ltd.

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 (Estimated)

June 15, 2026

Primary Completion (Estimated)

June 30, 2028

Study Completion (Estimated)

June 30, 2030

Study Registration Dates

First Submitted

May 31, 2026

First Submitted That Met QC Criteria

June 8, 2026

First Posted (Actual)

June 12, 2026

Study Record Updates

Last Update Posted (Actual)

June 12, 2026

Last Update Submitted That Met QC Criteria

June 8, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • MST-168-101

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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