A Phase 1/2 interventional study of Gocatamig and Atezolizumab in Small-Cell Lung Cancer and Neuroendocrine Carcinoma, sponsored by Harpoon Therapeutics, Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA). Active, not recruiting at 11 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-24.
Sponsored by Harpoon Therapeutics, Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA) · Phase 1/2, Interventional, and Treatment
This study will investigate the maximum tolerated dose, the recommended dose for expansion (RDE), safety, efficacy, and pharmacokinetics of gocatamig alone, gocatamig with Atezolizumab and gocatamig with I-DXd in participants with advanced cancers associated with expression of Delta-like Canonical Notch Ligand 3 (DLL3).
1,203 studies on the registry are indexed under Small Cell Lung Carcinoma; 342 are open to participants now.
This study's planned enrollment of 232 is above the median of 56 across 1,031 interventional studies indexed under Small Cell Lung Carcinoma.
Browse Small Cell Lung Carcinoma studies →Harpoon Therapeutics, Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA) is the lead sponsor of 4 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
The main inclusion criteria include but are not limited to the following:
Has high-grade neuroendocrine tumor types other than SCLC and NEPC, with at least one of the following:
Exclusion Criteria:
The main exclusion criteria include but are not limited to the following:
Participants will receive gocatamig once weekly (Q1W) via intravenous (IV) infusion during each 21-day cycle. Dose escalation may continue until one or more RDEs are identified, participant discontinuation or the Sponsor decides to stop enrollment.
Biological: Gocatamig
Participants will receive gocatamig via IV infusion once every 2 weeks (Q2W) of a 28-day cycle. Dose escalation may continue until one or more RDEs are identified, participant discontinuation, or the Sponsor decides to stop enrollment.
Biological: Gocatamig
Participants will receive gocatamig via IV infusion once every 3 weeks (Q3W) of a 21-day cycle. Dose escalation may continue until one or more RDEs are identified, participant discontinuation, or the Sponsor decides to stop enrollment.
Biological: Gocatamig
Small cell lung cancer (SCLC) participants will receive gocatamig via IV infusion Q2W during each 28-day cycle and Atezolizumab via IV infusion every 4 weeks (Q4W) on Day 1 of each 28-day cycle. Dose escalation may continue until one or more RDEs are identified, participant discontinuation, or the Sponsor decides to stop enrollment.
Biological: Gocatamig · Biological: Atezolizumab
SCLC participants will receive gocatamig via IV infusion Q2W during each 42-day cycle and I-DXd via IV infusion Q3W on Day 1 and Day 22 of each 42-day cycle. Dose escalation may continue until one or more RDEs are identified, participant discontinuation, or the Sponsor decides to stop enrollment.
Biological: Gocatamig · Biological: Ifinatamab Deruxtecan (I-DXd)
IV infusion
Also known as: HPN328, MK-6070
IV infusion
IV infusion
Also known as: DS-7300a, MK-2400
Percentage of participants who experience an adverse event
An AE is any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE. AEs will be graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTACAE) version 5.0 (American Society for Transplant and Cellular Therapy (ASTCT) grading criteria for cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS)). The percentage of participants who experience an AE in the study will be presented.
Time frame: Up to ~4 years
Percentage of participants who discontinue due to an adverse event
An AE is any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE. AEs will be graded according to NCI CTACAE version 5.0 (ASTCT grading criteria for CRS and ICANS). The percentage of participants who discontinue due to an AE in the study will be presented.
Time frame: Up to ~4 years
Number of participants with dose limiting toxicity (DLT) following treatment with HPN328 as monotherapy or in combination with atezolizumab or I-DXd
A DLT is defined as an AE that represents a clinically significant shift from baseline and must be considered related or suspected to be related to study drug (gocatamig and/or atezolizumab or I-DXd) by the Investigator or Sponsor. AEs will be graded according to NCI CTACAE version 5.0 (ASTCT grading criteria for CRS and ICANS). The number of participants with a DLT will be presented.
Time frame: Up to ~4 years
Maximum concentration (Cmax) of Gocatamig
Cmax is the maximum concentration of the drug observed in serum. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Cmax of gocatamig.
Time frame: At designated time points up to ~4 years
Cmax of Atezolizumab
Cmax is the maximum concentration of the drug observed in serum. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Cmax of Atezolizumab.
Time frame: At designated time points up to ~4 years
Cmax of I-DXd
Cmax is the maximum concentration of the drug observed in plasma. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Cmax of I-DXd.
Time frame: At designated time points up to ~4 years
Time to maximum concentration (Tmax) of Gocatamig
Tmax is the amount of time that a drug is present at the maximum concentration observed in serum. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax of gocatamig.
Time frame: At designated time points up to ~4 years
Tmax of atezolizumab
Tmax is the amount of time that a drug is present at the maximum concentration observed in serum. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax of atezolizumab.
Time frame: At designated time points up to ~4 years
Tmax of I-DXd
Tmax is the amount of time that a drug is present at the maximum concentration observed in plasma. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax of I-DXd.
Time frame: At designated time points up to ~4 years
Area under the concentration-time curve over the dosing interval t (AUCt) of Gocatamig
AUC is a measure of serum drug concentration and time and is estimated as the area under the plot of serum concentration against time after drug administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine t (AUCt) of gocatamig.
Time frame: At designated time points up to ~4 years
AUCt of atezolizumab
AUC is a measure of serum drug concentration and time and is estimated as the area under the plot of serum concentration against time after drug administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine t (AUCt) of atezolizumab.
Time frame: At designated time points up to ~4 years
AUCt of I-DXd
AUC is a measure of plasma drug concentration and time and is estimated as the area under the plot of plasma concentration against time after drug administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine t (AUCt) of I-DXd.
Time frame: At designated time points up to ~4 years
Area under the concentration-time curve extrapolated to infinity (AUCinf) of Gocatamig
AUCinf is a measure of serum drug concentration and time to infinity and is estimated as the area under the plot of serum concentration against time to infinity after drug administration. Blood samples collected at multiple timepoints post-dose will be used to determine the AUCinf of gocatamig.
Time frame: At designated time points up to ~4 years
AUCinf of atezolizumab
AUCinf is a measure of serum drug concentration and time to infinity and is estimated as the area under the plot of serum concentration against time to infinity after drug administration. Blood samples collected at multiple timepoints post-dose will be used to determine the AUCinf of atezolizumab.
Time frame: At designated time points up to ~4 years
AUCinf of I-DXd
AUCinf is a measure of plasma drug concentration and time to infinity and is estimated as the area under the plot of plasma concentration against time to infinity after drug administration. Blood samples collected at multiple timepoints post-dose will be used to determine the AUCinf of I-DXd.
Time frame: At designated time points up to ~4 years
Terminal half-life (t1/2) of Gocatamig
t1/2 is a measure of how long it takes to clear 50% of the drug from serum after reaching Cmax. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2 of gocatamig.
Time frame: At designated time points up to ~4 years
t1/2 of atezolizumab
t1/2 is a measure of how long it takes to clear 50% of the drug from serum after reaching Cmax. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2 of atezolizumab.
Time frame: At designated time points up to ~4 years
t1/2 of I-DXd
t1/2 is a measure of how long it takes to clear 50% of the drug from plasma after reaching Cmax. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2 of I-DXd.
Time frame: At designated time points up to ~4 years
Single dose clearance (CL) of Gocatamig
CL is the apparent total clearance of the drug from serum after oral administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL of gocatamig.
Time frame: At designated time points up to ~4 years
CL of atezolizumab
CL is the apparent total clearance of the drug from serum after oral administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL of atezolizumab.
Time frame: At designated time points up to ~4 years
CL of I-DXd
CL is the apparent total clearance of the drug from plasma after oral administration. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state maximum concentration (Cmax,ss) of Gocatamig
Cmax,ss is the maximum concentration of the drug in serum observed in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Cmax,ss of gocatamig.
Time frame: At designated time points up to ~4 years
Cmax,ss of atezolizumab
Cmax,ss is the maximum concentration of the drug observed in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Css,max of atezolizumab.
Time frame: At designated time points up to ~4 years
Cmax,ss of I-DXd
Cmax,ss is the maximum concentration of the drug observed in plasma under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Cmax,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state Ctrough (Ctrough,ss) of Gocatamig
Ctrough,ss is the lowest concentration reached by a drug in serum under steady state conditions before the next dose is administered. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Ctrough,ss of gocatamig.
Time frame: At designated time points up to ~4 years
Ctrough,ss of atezolizumab
Ctrough,ss is the lowest concentration reached by a drug in serum under steady state conditions before the next dose is administered. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Ctrough,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
Ctrough,ss of I-DXd
Ctrough,ss is the lowest concentration reached by a drug in plasma under steady state conditions before the next dose is administered. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine Ctrough,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state time to maximum concentration (Tmax,ss) of Gocatamig
Tmax,ss is the amount of time that a drug is present at the maximum concentration observed in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax,ss of gocatamig.
Time frame: At designated time points up to ~4 years
Tmax,ss of atezolizumab
Tmax,ss is the amount of time that a drug is present at the maximum concentration observed in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
Tmax,ss of I-DXd
Tmax,ss is the amount of time that a drug is present at the maximum concentration observed in plasma under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the Tmax,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Area under the steady state concentration-time curve over dosing interval t (AUCt,ss) of Gocatamig
AUCt,ss is a measure of serum drug concentration and time and is estimated as the area under the plot of serum concentration against time after drug administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AUCt,ss of gocatamig.
Time frame: At designated time points up to ~4 years
AUCt,ss of atezolizumab
AUCt,ss is a measure of serum drug concentration and time and is estimated as the area under the plot of serum concentration against time after drug administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AUCt,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
AUCt,ss of I-DXd
AUCt,ss is a measure of plasma drug concentration and time and is estimated as the area under the plot of plasma concentration against time after drug administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AUCt,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state t1/2 (t1/2,ss) of Gocatamig
t1/2,ss is a measure of how long it takes to clear 50% of the drug in serum after reaching Cmax under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2,ss of gocatamig.
Time frame: At designated time points up to ~4 years
t1/2,ss of Gocatamig with atezolizumab
t1/2,ss is a measure of how long it takes to clear 50% of the drug after reaching Cmax under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
t1/2,ss of IDXd
t1/2,ss is a measure of how long it takes to clear 50% of the drug in plasma after reaching Cmax under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the t1/2,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state CL (CL,ss) of Gocatamig
CL,ss is the apparent total clearance of the drug from serum after administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL,ss of gocatamig.
Time frame: At designated time points up to ~4 years
CL,ss of Gocatamig with atezolizumab
CL,ss is the apparent total clearance of the drug from serum after administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
CL,ss of I-DXd
CL,ss is the apparent total clearance of the drug from plasma after administration under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine CL,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state volume of distribution (V,ss) of Gocatamig
V,ss is defined as the volume of distribution in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the V,ss of gocatamig.
Time frame: At designated time points up to ~4 years
V,ss of atezolizumab
V,ss is defined as the volume of distribution in serum under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the V,ss of atezolizumab.
Time frame: At designated time points up to ~4 years
V,ss of I-DXd
V,ss is defined as the volume of distribution in plasma under steady state conditions. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine the V,ss of I-DXd.
Time frame: At designated time points up to ~4 years
Steady state accumulation ratio (AC) of Gocatamig
AC is the ratio of accumulation of a drug in serum under steady state conditions after repeated administration as compared to a single dose. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AC of gocatamig.
Time frame: At designated time points up to ~4 years
AC of atezolizumab
AC is the ratio of accumulation of a drug in serum under steady state conditions after repeated administration as compared to a single dose. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AC of atezolizumab.
Time frame: At designated time points up to ~4 years
AC of I-DXd
AC is the ratio of accumulation of a drug in plasma under steady state conditions after repeated administration as compared to a single dose. Blood samples collected pre dose and at multiple timepoints post dose will be used to determine AC of I-DXd.
Time frame: At designated time points up to ~4 years
Objective response rate (ORR) based on Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) (Prostate cancer clinical trials working group 3 (PCWG3) for participants with neuroendocrine prostate cancer (NEPC))
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 RECIST 1.1. Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1. ORR will be presented.
Time frame: Up to ~4 years
Extra-cranial objective response rate (EC-ORR) based on modified RECIST v1.1
EC-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 RECIST 1.1 considering extra-cranial disease (i.e. exclusive of brain metastases). Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1 considering extra-cranial disease. EC-ORR will be presented.
Time frame: Up to ~4 years
Best Overall Response (BOR)
BOR is defined as the participants' best disease response during the study given a hierarchy of objective response results CR: disappearance of all target lesions per RECIST 1.1 \> PR: at least a 30% decrease in the sum of diameters of target lesions per RECIST 1.1 \> stable disease (SD): neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum on study \> progressive disease (PD): at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (nadir), including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. \> not all evaluated/non-PD (NE): persistence of one or more non-target lesions and/or (if applicable) maintenance of tumor marker level above the normal limits. Percentage of participants in each BOR category will be presented.
Time frame: Up to ~4 years
Progression-free survival (PFS)
PFS is defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurs first as assessed by Response Criteria in Solid Tumors Version 1.1 (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. Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1 PFS will be presented.
Time frame: Up to ~4 years
Extra-cranial progression free survival (EC-PFS)
EC-PFS is defined as the time from randomization to the first documented extra-cranial progressive disease (PD) or death due to any cause, whichever occurs first as assessed by Response Criteria in Solid Tumors Version 1.1 (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. Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1. EC-PFS will be presented.
Time frame: Up to ~4 years
Overall survival (OS)
OS is defined as the time from first dose of study drug to death due to any cause (summarized descriptively using Kaplan Meier method). OS will be presented.
Time frame: Up to ~4 years
Duration of response (DOR)
For participants who demonstrate a confirmed 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), DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. 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 at least 5 mm. The appearance of one or more new lesions is also considered PD. Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1. DOR will be presented.
Time frame: Up to ~4 years
Duration of extra-cranial response (EC-DOR)
For participants who demonstrate a confirmed 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), EC-DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per RECIST 1.1 considering only extra-cranial disease (i.e., exclusive of brain metastases), 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 at least 5 mm. The appearance of one or more new lesions is also considered PD. Participants with NEPC will be evaluated using PCWG3-modified RECIST v1.1. EC-DOR as assessed will be presented.
Time frame: Up to ~4 years
Incidence of anti-drug antibodies (ADAs) against Gocatamig
Blood samples collected at designated timepoints will be used to determine the ADA response to gocatamig. The incidence of ADAs for gocatamig will be presented.
Time frame: At designated time points up to ~4 years
Incidence of ADAs against atezolizumab (for combination-treatment patients)
Blood samples collected at designated timepoints will be used to determine the ADA response to atezolizumab. The incidence of ADAs for atezolizumab will be presented.
Time frame: At designated time points up to ~4 years
Incidence of ADAs against I-DXd (for combination-treatment patients)
Blood samples collected at designated timepoints will be used 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 ~4 years
Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
This study is active, not recruiting, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.
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Harpoon Therapeutics, Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)