A Phase 1/2 interventional study of Gocatamig and I-DXd in Small Cell Lung Cancer Extensive Stage, sponsored by Merck Sharp & Dohme LLC. Recruiting at 53 sites in 12 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Merck Sharp & Dohme LLC · Phase 1/2, Interventional, and Treatment
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.
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.
The goals of this study are to learn:
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.
The main inclusion criteria include but are not limited to the following:
For participants receiving gocatamig + ifinatamab deruxtecan (I-DXd) in maintenance only:
Exclusion Criteria:
The main exclusion criteria include but are not limited to the following:
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 · Drug: I-DXd · Drug: Rescue Medications
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 · Drug: I-DXd · Drug: Rescue Medications
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 · Drug: I-DXd · Drug: Atezolizumab · Drug: Rescue Medications
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 · Drug: Carboplatin · Drug: Etoposide
Intravenous (IV) administration
Also known as: MK-6070, HPN328, DS-3280
IV administration
Also known as: MK-2400, DS-7300a
IV administration
IV administration
IV administration
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.
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.
Time frame: Up to approximately 58 months
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.
Time frame: Up to approximately 21 days
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.
Time frame: 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.
Time frame: Up to approximately 58 months
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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: At designated time points (up to approximately 58 months)
Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
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Merck Sharp & Dohme LLC