Study to Investigate Petosemtamab in Adults With Metastatic Non-Small Cell Lung Cancer

August 12, 2026 updated by: Merus B.V.

A Phase 2 Study to Investigate the Safety and Efficacy of Petosemtamab in Adults With Metastatic Non-Small Cell Lung Cancer in Combination With Pembrolizumab as First-Line Treatment

The study will test the efficacy and safety of petosemtamab in combination with Pembrolizumab in first line patients with squamous non-small cell lung cancer and non-squamous non-small cell lung cancer.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

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

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Australia
    • South Australia
      • Bedford Park, South Australia, Australia, 5042
        • Flinders Medical Centre
    • Victoria
      • Frankston, Victoria, Australia, 3199
        • Australia Site 1
  • France
      • Brest, France, 29609
        • CHU Brest Hopital La Cavale Blanche
      • Créteil, France, 94000
        • Centre Hospitalier Intercommunal de Creteil (CHIC)
      • Montpellier, France, 34298
        • ICM - Montpellier Cancer Institute
      • Nantes, France, 44093
        • Hôpital Nord Laennec
  • Italy
      • Florence, Italy, 50134
        • Universita degli Studi di Firenze - Azienda Ospedaliero-Universitaria Careggi
  • Netherlands
      • Leiden, Netherlands, 2333
        • Leiden University Medical Center
  • South Korea
      • Cheongju-si, South Korea, 28645
        • Chungbuk National University Hospital
      • Daegu, South Korea, 41404
        • Kyungpook National University Chilgok Hospital
      • Seoul, South Korea, 3722
        • Severance Hospital - Yonsei University Health System
      • Suwon, South Korea, 16247
        • The Catholic University of Korea, St. Vincents Hospital
  • Spain
      • Logroño, Spain, 26006
        • START - Rioja
      • Marbella, Spain, 29660
        • HC Hospitales SL
      • Málaga, Spain, 29004
        • Hospital Quirónsalud Málaga
      • Pamplona, Spain, 31008
        • Clinica Universidad de Navarra - Pamplona
      • Pamplona, Spain, 31008
        • Hospital Universitario de Navarra
      • Vigo, Spain, 36312
        • Hospital Alvaro Cunqueiro
  • United States
    • Florida
      • St. Petersburg, Florida, United States, 33701-4553
        • Florida Cancer Specialists - North
    • New York
      • Long Island City, New York, United States, 11101
        • Memorial Sloan Kettering Cancer Center
    • Tennessee
      • Chattanooga, Tennessee, United States, 37403
        • Tennessee Site 2
      • Nashville, Tennessee, United States, 37209
        • Tennessee Site 1
    • Virginia
      • Blacksburg, Virginia, United States, 24060
        • Virginia Site 2
      • Fairfax, Virginia, United States, 22031
        • Virginia Site 1

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Able to provide written informed consent and is willing and able to comply with all study procedures and contraception requirements
  • Age ≥ 18 years at the signing of ICF
  • At least 1 measurable lesion as defined by RECIST 1.1
  • ECOG performance status of 0 or 1
  • Life expectancy ≥ 12 weeks, in the opinion of the Investigator
  • Adequate hematologic function
  • Creatinine clearance ≥ 60 mL/min calculated according to the Cockroft and Gault formula
  • Adequate liver function
  • Serum albumin ≥ 3 g/dL
  • Serum magnesium and corrected calcium, Grade ≤ 1 alteration
  • Participants of childbearing potential must agree to use highly effective contraception methods for the duration of study participation
  • Histologically confirmed metastatic (Stage IV) sqNSCLC with PD-L1 TPS ≥ 50%
  • No prior systemic treatment for metastatic disease
  • Testing is required per local SOC and availability of testing to document absence of actionable genomic tumor aberrations
  • Histologically confirmed metastatic (Stage IV) non-squamous NSCLC with PD-L1 TPS ≥ 50%

Exclusion Criteria:

  • Has untreated CNS metastases and/or carcinomatous meningitis
  • Participation in an interventional clinical study with any investigational drug within 4 weeks prior to the first dose of study treatment OR participation in any clinical study with petosemtamab at any time prior to the first dose of study treatment, regardless of whether petosemtamab was received
  • Participants who received prior treatment with a PD-(L)1 inhibitor
  • Participants who have received prior systemic chemotherapy, targeted or biological antineoplastic therapy for metastatic NSCLC
  • Any systemic anticancer therapy within 4 weeks prior to the first dose of study treatment
  • Major surgery or radiotherapy within 3 weeks prior to the first dose of study treatment. Participants who received prior radiotherapy to ≥ 25% of bone marrow are not eligible, regardless of when it was received.
  • Persistent Grade > 1 clinically significant toxicities related to prior antineoplastic therapies using NCI-CTCAE v5.0
  • History of hypersensitivity reaction to any of the excipients of petosemtamab or pembrolizumab
  • Unstable angina; history of congestive heart failure of Class II-IV New York Heart Association criteria or serious cardiac arrhythmia requiring treatment (except atrial fibrillation, paroxysmal supraventricular tachycardia); or history of myocardial infarction within 6 months prior to the first dose of study treatment
  • History of prior malignancies within the last 5 years, with the exception of excised local cancer
  • Current dyspnea at rest of any origin or other diseases requiring continuous oxygen therapy, including participants with a history of ILD (eg, pneumonitis or pulmonary fibrosis) or evidence of ILD on baseline chest CT scan
  • Current serious illness or medical condition, including but not limited to uncontrolled active infection and clinically significant pulmonary, metabolic, or psychiatric disorders
  • Known infectious disease
  • Participants who are pregnant or breastfeeding.

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: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: First line squamous non-small cell lung cancer patients
Combination product: Petosemtamab + Pembrolizumab
Petosemtamab + Pembrolizumab
Experimental: First line non-squamous non-small cell lung cancer patients
Combination product: Petosemtamab + Pembrolizumab
Petosemtamab + Pembrolizumab

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Objective response rate per investigator assessment
Time Frame: Up to 4.5 years
ORR was defined as the proportion of participants who had a complete response (CR) or partial response (PR) per RECIST v1.1.
Up to 4.5 years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Duration of response per Investigator assessment
Time Frame: Up to 4.5 years
For participants with a confirmed CR or PR per RECIST v1.1, DOR was defined as the time from the date of first documented response of CR or PR per RECIST v1.1 to the date of first documented progression or death due to underlying cancer.
Up to 4.5 years
Disease control rate as per investigator assessment
Time Frame: Up to 4.5 years
DCR is defined as the proportion of participants with CR or PR or stable disease (SD) per RECIST 1.1.
Up to 4.5 years
Clinical Benefit Rate as per investigator assessment
Time Frame: Up to 4.5 years
CBR was defined as the proportion of participants with a CR or PR, or SD lasting ≥24 weeks per RECIST v1.1
Up to 4.5 years
Progression free survival as per investigator assessment
Time Frame: Up to 4.5 years
PFS was defined as the time from first dose to the first documented disease progression per RECIST v1.1 or death due to any cause.
Up to 4.5 years
Overall survival
Time Frame: Up to 4.5 years
OS was defined as the time from first dose to death due to any cause.
Up to 4.5 years
Number of participants who experienced on treatment adverse events
Time Frame: Up to 4.5 years
An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/ biological agent under study. Severity of AEs will be graded according to the NCI CTCAE version 5.0. Severity scale ranges from Grade 1 (Mild) to Grade 5 (Death). Grade 1: mild, Grade 2: moderate, Grade 3: severe, Grade 4: life-threatening and Grade 5: death related to adverse event.
Up to 4.5 years
Concentrations of petosemtamab predose and at end of infusion
Time Frame: Up to 6-12 months
Predose and end of infusion plasma concentrations as measured from all individual plasma concentrations.
Up to 6-12 months
Incidence and serum titers of anti-drug antibodies (ADAs) against petosemtamab
Time Frame: Up to 6-12 months
The frequency and proportion of participants developing anti-drug antibodies.
Up to 6-12 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Merus B.V.

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 27, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 27, 2031

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 21, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • MCLA-158-CL04

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

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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