A Clinical Study of Gocatamig (MK-6070) and Infinatamab Deruxtecan (MK-2400) in People With Small Cell Lung Cancer (MK-6070-003)

A Phase 1b/2 Open-label Study Evaluating Different MK-6070 and Ifinatamab Deruxtecan (MK-2400)-Based Regimens in First-line Extensive Stage Small Cell Lung Cancer

Researchers are looking for new ways to treat extensive-stage small cell lung cancer (ES-SCLC). ES-SCLC is a type of lung cancer that has spread throughout the lung, to the other lung, or to other parts of the body.

A standard (usual) treatment for ES-SCLC uses both chemotherapy and immunotherapy.

• Chemotherapy is a treatment that works to destroy cancer cells or stop them from growing.
• Immunotherapy is a treatment that helps the immune system fight cancer.

Gocatamig and I-DXd (short for ifinatamab deruxtecan) are study medicines. Researchers want to know if giving gocatamig and I-DXd together can treat ES-SCLC. Researchers will also look at giving the study medicines with standard treatment. Gocatamig is a T-cell engager therapy. I-DXd is an antibody drug conjugate.

• T-cell engager therapy is a certain type of immunotherapy that uses T-cells to find and destroy cancer cells.
• A T-cell is a type of white blood cell, which are cells that help the body fight infection.
• An antibody drug conjugate (ADC) is a treatment that attaches to a protein on cancer cells and delivers treatment to destroy those cells.

The goals of this study are to learn:

• About the safety of combining gocatamig and I-DXd and if people tolerate them together
• If people who receive gocatamig and I-DXd have ES-SCLC respond, which means the cancer gets smaller or goes away

Study Overview

• Status: Recruiting
• Conditions: Small Cell Lung Cancer Extensive Stage
• Intervention / Treatment: Drug: Gocatamig; Drug: I-DXd; Drug: Rescue Medications; Drug: Atezolizumab; Drug: Carboplatin; Drug: Etoposide

Detailed Description

In Part A, participants will be allocated to Arm 1 or Arm 2 per investigator's discretion. In Part B, participants will be allocated to Arm 1 per investigator's discretion and randomized to Arms 2, 3, and 4.

• Study Type: Interventional
• Enrollment (Estimated): 170
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Toll Free Number; Phone Number: 1-888-577-8839; Email: Trialsites@msd.com

Study Locations

• Argentina
  • Buenos Aires
    • Pilar, Buenos Aires, Argentina, B1629AHJ
      • Recruiting
      • Hospital Austral ( Site 1901)
      • Contact: Study Coordinator; Phone Number: +54911 38018573
• Chile
  • Region M. de Santiago
    • Santiago, Region M. de Santiago, Chile, 7500921
      • Recruiting
      • FALP ( Site 0200)
      • Contact: Study Coordinator; Phone Number: 56224205098
    • Santiago, Region M. de Santiago, Chile, 8330032
      • Recruiting
      • Pontificia Universidad Catolica de Chile ( Site 0202)
      • Contact: Study Coordinator; Phone Number: +56934271024
    • Santiago, Region M. de Santiago, Chile, 8420383
      • Recruiting
      • Bradfordhill ( Site 0201)
      • Contact: Study Coordinator; Phone Number: 56229490970
• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100142
      • Recruiting
      • Beijing Cancer Hospital ( Site 1604)
      • Contact: Study Coordinator; Phone Number: 010-88121122
  • Guangdong
    • Guangzhou, Guangdong, China, 510515
      • Recruiting
      • Southern Medical University Nanfang Hospital ( Site 1608)
      • Contact: Study Coordinator; Phone Number: +86 13632102245
    • Jiangmen, Guangdong, China, 529000
      • Recruiting
      • Jiangmen Central Hospital ( Site 1611)
      • Contact: Study Coordinator; Phone Number: +86 13702282382
  • Jiangxi
    • Nanchang, Jiangxi, China, 330209
      • Recruiting
      • The First Affiliated Hospital of Nanchang University ( Site 1610)
      • Contact: Study Coordinator; Phone Number: +86079186319453
  • Shanghai Municipality
    • Shanghai, Shanghai Municipality, China, 200000
      • Recruiting
      • Shanghai East Hospital ( Site 1600)
      • Contact: Study Coordinator; Phone Number: 021-20334534
  • Sichuan
    • Chengdu, Sichuan, China, 610213
      • Recruiting
      • Sichuan Cancer hospital. ( Site 1609)
      • Contact: Study Coordinator; Phone Number: 18180900912
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310003
      • Recruiting
      • The first Affiliated Hospital, Zhejiang University School of Medicine ( Site 1602)
      • Contact: Study Coordinator; Phone Number: +8657187236560
    • Taizhou, Zhejiang, China, 317000
      • Recruiting
      • Taizhou Hospital of Zhejiang Province ( Site 1601)
      • Contact: Study Coordinator; Phone Number: 0576-85199810
• Israel
  • Haifa, Israel, 3109601
    • Recruiting
    • Rambam Health Care Campus ( Site 0602)
    • Contact: Study Coordinator; Phone Number: +97247772688
  • Ramat Gan, Israel, 5265601
    • Recruiting
    • Sheba Medical Center ( Site 0601)
    • Contact: Study Coordinator; Phone Number: +97235303030
• South Korea
  • Seoul, South Korea, 05505
    • Recruiting
    • Asan Medical Center ( Site 1404)
    • Contact: Study Coordinator; Phone Number: +82230103215
  • Seoul, South Korea, 06351
    • Recruiting
    • Samsung Medical Center ( Site 1401)
    • Contact: Study Coordinator; Phone Number: 02-3410-1795
  • Seoul, South Korea, 03080
    • Recruiting
    • Seoul National University Hospital ( Site 1402)
    • Contact: Study Coordinator; Phone Number: 82-2-2072-3559
  • Seoul, South Korea, 03722
    • Recruiting
    • Severance Hospital Yonsei University Health System ( Site 1403)
    • Contact: Study Coordinator; Phone Number: +82215991004
• United States
  • California
    • Santa Rosa, California, United States, 95403
      • Recruiting
      • Providence Medical Foundation ( Site 0124)
      • Contact: Study Coordinator; Phone Number: 707-521-3830
  • Florida
    • Orlando, Florida, United States, 32806
      • Recruiting
      • Orlando Health Cancer Institute ( Site 0108)
      • Contact: Study Coordinator; Phone Number: 321-841-1869
  • Kentucky
    • Edgewood, Kentucky, United States, 41017
      • Recruiting
      • Saint Elizabeth Medical Center Edgewood ( Site 0112)
      • Contact: Study Coordinator; Phone Number: 859-301-4000
  • Missouri
    • St Louis, Missouri, United States, 63110
      • Recruiting
      • Washington University School of Medicine ( Site 0134)
      • Contact: Study Coordinator; Phone Number: 314-747-1171
  • New Jersey
    • Hackensack, New Jersey, United States, 07601
      • Recruiting
      • John Theurer Cancer Center at Hackensack University Medical Center ( Site 0101)
      • Contact: Study Coordinator; Phone Number: 551-996-5955
  • Oregon
    • Portland, Oregon, United States, 97213
      • Recruiting
      • Providence Cancer Institute, Franz Clinic - Eastside ( Site 0107)
      • Contact: Study Coordinator; Phone Number: 503-215-5696
  • South Dakota
    • Sioux Falls, South Dakota, United States, 57105
      • Recruiting
      • Avera Cancer Institute- Research ( Site 0104)
      • Contact: Study Coordinator; Phone Number: 605-322-6900
  • Tennessee
    • Knoxville, Tennessee, United States, 37920
      • Recruiting
      • The University of Tennessee Medical Center ( Site 0120)
      • Contact: Study Coordinator; Phone Number: 865-305-8780
    • Nashville, Tennessee, United States, 37203
      • Recruiting
      • SCRI Oncology Partners ( Site 7000)
      • Contact: Study Coordinator; Phone Number: 844-482-4812
  • Texas
    • Houston, Texas, United States, 77030
      • Recruiting
      • Houston Methodist Hospital - Houston Methodist Neal Cancer Center ( Site 0113)
      • Contact: Study Coordinator; Phone Number: 646-407-2086

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

• Has a histologically or cytologically confirmed diagnosis of extensive-stage small cell lung cancer (ES-SCLC)

• For participants receiving gocatamig + ifinatamab deruxtecan (I-DXd) in maintenance only:

  • Completed 3 to 4 cycles of platinum + etoposide chemotherapy with concurrent approved anti-programmed cell death 1/Ligand 1 (anti PD-1/L1) as first line (1L) treatment of ES-SCLC within 6 weeks prior to enrollment
  • No radiological disease progression per Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST 1.1)
  • No other prior systemic ES-SCLC therapy allowed
  • Rechallenge therapy counts as an additional line and leads to exclusion
• For participants receiving gocatamig + I-DXd in induction and maintenance, or gocatamig + I-DXd in induction followed by gocatamig + atezolizumab in maintenance, or carboplatin + etoposide + atezolizumab in induction followed by atezolizumab in maintenance: No prior systemic ES-SCLC treatment allowed
• Applicable to all participants: prior limited-stage small cell lung cancer (SCLC) is allowed if > 6 months have passed since the end of previous therapy and progression
• Must be able to provide a pretreatment archival tumor tissue sample or newly obtained core, incisional, or excisional biopsy of a tumor lesion not previously irradiated
• Measurable disease by RECIST 1.1 as assessed by the local site investigator/radiology. Lesions situated in a previously irradiated area are considered measurable if growth has been shown in such lesions since the completion of radiation

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

• Has pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures
• Has any history of interstitial lung disease (ILD)/pneumonitis irrespective of steroid use, current ILD, ILD that cannot be ruled out by imaging at screening, or suspected ILD
• Has clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses
• Has history of clinically significant intracranial bleeding or spinal cord bleeding
• Has active neurologic paraneoplastic syndrome
• Has history of coronary/peripheral artery bypass graft and/or any coronary/peripheral angioplasty or clinically significant cardiovascular disease such as myocardial infarction, symptomatic congestive heart failure (CHF), and/or uncontrolled cardiac arrhythmia within 6 months before the first dose of study intervention
• Has other uncontrolled or significant protocol specified cardiovascular disease
• Has history of arterial thrombosis within 6 months before the first dose of study intervention
• Has chronic liver disease
• Has history of allogeneic tissue/solid organ transplant
• Has history of leptomeningeal disease
• Is infected with human immunodeficiency virus (HIV) and has a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease
• Has received prior therapy with an anti-programmed cell death protein 1 (anti-PD-1), anti-programmed cell death ligand 1 (anti-PD-L1), or anti-programmed cell death ligand 2 (anti-PD-L2) agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor
• Has received prior radiotherapy within 2 weeks of start of study intervention, or has radiation-related toxicities, requiring corticosteroids
• Has known additional malignancy that is progressing or has required active treatment within the past 3 years
• Has active autoimmune disease that has required systemic treatment in the past 2 years except replacement therapy
• Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
• Has major surgery within 4 weeks or minor surgery within 2 weeks of allocation/randomization (or first dose), or is anticipated to require a major surgical procedure during the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Arm 4, Part B: Carboplatin + etoposide + atezolizumab → atezolizumab; Participants who did not receive prior systemic treatment for ES-SCLC will receive SOC (carboplatin + etoposide + atezolizumab) in the induction phase, followed by atezolizumab in the maintenance phase, until documented disease progression or meeting other study discontinuation criteria.	Drug: Atezolizumab; IV administration; Drug: Carboplatin; IV administration; Drug: Etoposide; IV administration
Experimental: Arm 1, Parts A and B: Gocataming + I-DXd; Participants who completed standard of care (SOC) induction chemotherapy with concurrent approved anti-programmed cell death 1/ligand 1 protein (anti-PD-1/L1) treatment for ES-SCLC and did not have disease progression per investigator discretion, will receive gocatamig and I-DXd in the maintenance phase, until documented disease progression or meeting other study discontinuation criteria.	Drug: Gocatamig; Intravenous (IV) administration; Other Names: HPN328; MK-6070; DS-3280; Drug: I-DXd; IV administration; Other Names: DS-7300a; MK-2400; Drug: Rescue Medications; Participants will receive rescue medications at the investigator's discretion. Recommended rescue medications include tocilizumab for treatment of cytokine release syndrome (CRS); dexamethasone, acetaminophen, and diphenhydramine for CRS/infusion-related reaction (IRR) prophylaxis; and 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, neurokinin 1 (NK-1) receptor antagonist, and corticosteroid for prevention of nausea and vomiting.
Experimental: Arm 2, Parts A and B: Gocataming + I-DXd; Participants who did not receive prior systemic treatment for ES-SCLC will receive gocatamig and I-DXd during induction and maintenance phases, until documented disease progression or meeting other study discontinuation criteria.	Drug: Gocatamig; Intravenous (IV) administration; Other Names: HPN328; MK-6070; DS-3280; Drug: I-DXd; IV administration; Other Names: DS-7300a; MK-2400; Drug: Rescue Medications; Participants will receive rescue medications at the investigator's discretion. Recommended rescue medications include tocilizumab for treatment of cytokine release syndrome (CRS); dexamethasone, acetaminophen, and diphenhydramine for CRS/infusion-related reaction (IRR) prophylaxis; and 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, neurokinin 1 (NK-1) receptor antagonist, and corticosteroid for prevention of nausea and vomiting.
Experimental: Arm 3, Part B: Gocataming + I-DXd → gocatamig + atezolizumab; Participants who did not receive prior systemic treatment for ES-SCLC will receive gocatamig and I-DXd in the induction phase, followed by gocatamig and atezolizumab in the maintenance phase, until documented disease progression or meeting other study discontinuation criteria.	Drug: Gocatamig; Intravenous (IV) administration; Other Names: HPN328; MK-6070; DS-3280; Drug: I-DXd; IV administration; Other Names: DS-7300a; MK-2400; Drug: Rescue Medications; Participants will receive rescue medications at the investigator's discretion. Recommended rescue medications include tocilizumab for treatment of cytokine release syndrome (CRS); dexamethasone, acetaminophen, and diphenhydramine for CRS/infusion-related reaction (IRR) prophylaxis; and 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, neurokinin 1 (NK-1) receptor antagonist, and corticosteroid for prevention of nausea and vomiting.; Drug: Atezolizumab; IV administration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants Who Experience One or More Dose-Limiting Toxicities (DLTs)	DLT will be defined as any drug-related AE observed during the DLT evaluation period (up to 21 days) that meets the protocol-specified DLT criteria. The number of participants who experience at least one DLT will be presented.	Up to approximately 21 days
Number of Participants Who Experience an Adverse Event (AE)	An AE is defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants who experience an AE will be reported.	Up to approximately 58 months
Number of Participants Who Discontinue Study Intervention Due to an AE	An AE is defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants who discontinue study intervention due to an AE will be reported.	Up to approximately 58 months
Objective Response Rate (ORR)	ORR is defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1). The percentage of participants who experience CR or PR as assessed by Blinded Independent Central Review (BICR) will be presented.	Up to approximately 58 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Disease Control Rate (DCR)	DCR is defined, per RECIST 1.1, as the percentage of participants who have a CR or PR or Stable Disease (SD: Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD: At least a 20% increase in the sum of diameters of target lesions and an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered PD). The DCR as assessed by BICR will be presented.	Up to approximately 58 months
Duration of Response (DOR)	For participants who demonstrate a confirmed CR or PR per RECIST 1.1, DOR is defined as the time from first documented evidence of CR or PR until PD or death due to any cause, whichever occurs first. Per RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. DOR as assessed by BICR will be presented.	Up to approximately 58 months
Progression-Free Survival (PFS)	PFS is defined as the time from randomization (Part B for Arms 2-4) or from the first dose of study treatment (safety run-in Part A and Arm 1 Part B) to the first documented PD or death due to any cause, whichever occurs first as assessed by RECIST 1.1. PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. PFS as assessed by BICR will be presented.	Up to approximately 58 months
Overall Survival (OS)	OS is defined as the time from the first dose of study treatment (Part A and Arm 1 Part B) or randomization (Part B for Arms 2-4) to death due to any cause.	Up to approximately 58 months
Area Under the Concentration-Time Curve Over the Dosing Interval t (AUCt) of Gocatamig	Blood samples will be collected at multiple time points to determine the AUCt of the drug gocatamig.	At designated time points (up to approximately 58 months)
AUCt of I-DXd	Blood samples will be collected at multiple time points to determine the AUCt of the drug I-DXd.	At designated time points (up to approximately 58 months)
AUCt of Deruxtecan (DXd)	DXd is the payload released from the drug I-DXd. Blood samples will be collected at multiple time points to determine the AUCt of the drug payload DXd.	At designated time points (up to approximately 58 months)
AUCt of Anti-B7-H3 Antibody	Blood samples will be collected at multiple time points to determine the AUCt of the anti-B7-H3 antibody.	At designated time points (up to approximately 58 months)
Area Under the Steady-State Concentration-Time Curve Over the Dosing Interval t (AUCt,ss) of Gocatamig	Blood samples will be collected at multiple time points to determine the AUCt,ss of the drug gocatamig.	At designated time points (up to approximately 58 months)
AUCt,ss of I-DXd	Blood samples will be collected at multiple time points to determine the AUCt,ss of the drug I-DXd.	At designated time points (up to approximately 58 months)
AUCt,ss of DXd	DXd is the payload released from the drug I-DXd. Blood samples will be collected at multiple time points to determine the AUCt,ss of the drug payload DXd.	At designated time points (up to approximately 58 months)
AUCt,ss of Anti-B7-H3 Antibody	Blood samples will be collected at multiple time points to determine the AUCt,ss of the anti-B7-H3 antibody.	At designated time points (up to approximately 58 months)
Maximum Concentration (Cmax) of Gocatamig	Blood samples will be collected at multiple time points to determine Cmax of the drug gocatamig.	At designated time points (up to approximately 58 months)
Cmax of I-DXd	Blood samples will be collected at multiple time points to determine Cmax of the drug I-DXd.	At designated time points (up to approximately 58 months)
Cmax of DXd	DXd is the payload released from the drug I-DXd. Blood samples will be collected at multiple time points to determine Cmax of the drug payload DXd.	At designated time points (up to approximately 58 months)
Cmax of Anti-B7-H3 Antibody	Blood samples will be collected at multiple time points to determine Cmax of the anti-B7-H3 antibody.	At designated time points (up to approximately 58 months)
Trough Concentration (Ctrough) of Gocatamig	Blood samples will be collected at multiple time points to determine Ctrough of the drug gocatamig.	At designated time points (up to approximately 58 months)
Ctrough of I-DXd	Blood samples will be collected at multiple time points to determine Ctrough of the drug I-DXd.	At designated time points (up to approximately 58 months)
Ctrough of DXd	DXd is the payload released from the drug I-DXd. Blood samples will be collected at multiple time points to determine Ctrough of the drug payload DXd.	At designated time points (up to approximately 58 months)
Ctrough of Anti-B7-H3 Antibody	Blood samples will be collected at multiple time points to determine Ctrough of the anti-B7-H3 antibody.	At designated time points (up to approximately 58 months)
Incidence of Anti-Drug Antibodies (ADAs) Against Gocatamig	Blood samples will be collected at multiple time points to determine the ADA response to gocatamig. The incidence of ADAs for gocatamig will be presented.	At designated time points (up to approximately 58 months)
Incidence of ADAs Against I-DXd	Blood samples will be collected at multiple time points to determine the ADA response to I-DXd. The incidence of ADAs for I-DXd will be presented.	At designated time points (up to approximately 58 months)

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Collaborators: Daiichi Sankyo
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information
• Plain Language Summary

Study record dates

Study Major Dates

• Study Start (Actual): January 29, 2026
• Primary Completion (Estimated): November 29, 2030
• Study Completion (Estimated): December 30, 2030

Study Registration Dates

• First Submitted: November 10, 2025
• First Submitted That Met QC Criteria: November 10, 2025
• First Posted (Actual): November 12, 2025

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 27, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Carbohydrates; Podophyllotoxin; Tetrahydronaphthalenes; Naphthalenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Polycyclic Compounds; Glucosides; Glycosides; Coordination Complexes; Etoposide; Carboplatin; atezolizumab
• Other Study ID Numbers: 6070-003; MK-6070-003 (Other Identifier: MSD); U1111-1318-5025 (Registry Identifier: UTN); 2025-521032-11-00 (Registry Identifier: EU CT)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No