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Safety and Efficacy of Pembrolizumab (MK-3475) in Combination With TS-1+Cisplatin or TS-1+Oxaliplatin as First Line Chemotherapy in Gastric Cancer (MK-3475-659/KEYNOTE-659)

A Phase IIb, Clinical Trial to Study the Safety and Efficacy of Pembrolizumab (MK-3475) in Combination With TS-1+Cisplatin or TS-1+Oxaliplatin as a First Line Chemotherapy in Participants With Advanced or Recurrent Gastric Cancer (KEYNOTE-659)

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03382600
Enrollment
100
Registered
2017-12-26
Start date
2018-03-26
Completion date
2021-05-30
Last updated
2024-06-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Gastric Cancer

Brief summary

The purpose of this study is to estimate objective response rates (ORRs) of pembrolizumab + oxaliplatin + TS-1 and pembrolizumab + cisplatin + TS-1, as first-line treatment for gastric cancer in programmed death-ligand 1 (PD-L1) positive, human epidermal growth factor receptor 2 (HER2/neu)-negative participants with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma.

Detailed description

Approximately 45 participants will be assigned to pembrolizumab + oxaliplatin + TS-1 combination therapy (Cohort 1) first, and then 45 participants will be assigned to pembrolizumab + cisplatin + TS-1 combination therapy (Cohort 2).

Interventions

BIOLOGICALPembrolizumab

200 mg Q3W on Day 1 by IV infusion

DRUGOxaliplatin

130 mg/m\^2 Q3W on Day 1 by IV infusion

DRUGTS-1

40 to 60 mg orally according to Body Surface Area (BSA) BID Q3W on Days 1-14

DRUGCisplatin

60 mg/m\^2 Q3W on Day 1 by IV infusion

Sponsors

Merck Sharp & Dohme LLC
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No

Inclusion criteria

* Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Has histologically- or cytologically-confirmed diagnosis of locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma * Has a PD-L1 positive tumor as determined by immunohistochemistry (IHC) at a central laboratory * Has measurable disease as defined by RECIST 1.1 as determined by investigator assessment. Tumor lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions * Women of childbearing potential (WOCBP) must have a negative urine or serum pregnancy test at the timing of enrollment * Participants of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 120 days after the last dose of study medication * Has adequate organ function

Exclusion criteria

* Has squamous cell or undifferentiated gastric cancer * HER2-positive status * Has had previous therapy for locally advanced, unresectable or metastatic gastric/GEJ cancer * A WOCBP who has a positive urine pregnancy test within 72 hours prior to allocation * Has received prior therapy with a platinum-based anti-cancer drug * Has had major surgery, open biopsy or significant traumatic injury within 28 days prior to enrollment, or anticipation of the need for major surgery during the course of study treatment * Has had radiotherapy within 14 days of enrollment * Has a known additional malignancy that is progressing or has required active treatment within the past 5 years * Has clinically active central nervous system (CNS) metastases and/or carcinomatous meningitis * Has an active autoimmune disease that has required systemic treatment in the past 2 years with use of disease modifying agents, corticosteroids, or immunosuppressive drugs * Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment * Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis * Has any active infection requiring systemic therapy * Will be on flucytosine at the time of enrollment * Has grade ≥ 2 peripheral sensory neuropathy * Has poorly controlled diarrhea (e.g., watery stool, uncontrollable bowel movement with drugs, grade ≥ 2 and number of defecations, ≥ 5/day) * Has accumulation of pleural, ascitic, or pericardial fluid requiring drainage within 2 weeks prior to enrollment * Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with participation for the full duration of the trial, or is not in the best interest of the participant, in the opinion of the treating investigator * Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial * Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 120 days after the last dose of study treatment * Has received prior therapy with an anti-programmed death (PD)-1, anti-PD-L1, or anti PD L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor * Has known history of human immunodeficiency virus (HIV) \[HIV1/2 antibodies\] * Has a known history of Hepatitis B * Has received live vaccine within 30 days of the planned start of study therapy * Is currently participating in and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks prior to the first dose of trial treatment

Design outcomes

Primary

MeasureTime frameDescription
Objective Response Rate (ORR) According to Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR)Up to ~36 monthsFor the primary efficacy analysis, ORR was defined as the percentage of participants who have a best response of complete response (CR, disappearance of all target lesions) or partial response (PR, at least a 30% decrease in the sum of diameters \[SOD\] of target lesions, taking as reference the baseline SOD) per RECIST 1.1 as assessed by BICR.

Secondary

MeasureTime frameDescription
Duration of Response (DOR) According to RECIST 1.1 Assessed by BICRUp to ~36 monthsFor participants who demonstrated complete response (CR, disappearance of all target lesions) or partial response (PR, ≥30% decrease in the SOD of target lesions) according to RECIST 1.1 as assessed by BICR, DOR was defined as the time from the earliest date of qualifying response (CR or PR) until earliest date of progressive disease (PD, ≥20% increase in the SOD of target lesions) or death from any cause, whichever came first. DOR was censored at the last tumor assessment date if a responder did not have PD or death.
DOR According to iRECIST Assessed by BICRUp to ~36 monthsFor participants who demonstrated complete response (CR, disappearance of all target lesions) or partial response (PR, ≥30% decrease in the SOD of target lesions) according to iRECIST as assessed by BICR, DOR was defined as the time from the earliest date of qualifying response (CR or PR) until earliest date of progressive disease (PD, ≥20% increase in the SOD of target lesions) or death from any cause, whichever came first. DOR was censored at the last tumor assessment date if a responder did not have PD or death. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.
Disease Control Rate (DCR) According to RECIST 1.1 Assessed by BICRUp to ~36 monthsDCR was defined as the percentage of participants in the analysis population who have complete response (CR, disappearance of all target lesions), partial response (PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD), or stable disease (SD, neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD, ≥20% increase in the SOD of target lesions\]). Responses are according to RECIST 1.1 as assessed by BICR.
DCR According to iRECIST 1.1 Assessed by BICRUp to ~36 monthsDCR was defined as the percentage of participants in the analysis population who have CR (disappearance of all target lesions), PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD), or stable disease (SD, neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD \[≥20% increase in the SOD of target lesions\]). Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.
Time to Response (TTR) According to RECIST 1.1 Assessed by BICRUp to ~36 monthsTTR was defined as the time from the date of enrollment day to the first date of confirmed CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD). Responses are according to RECIST 1.1 as assessed by BICR.
ORR According to Immune-related Response Evaluation Criteria In Solid Tumors (iRECIST) Assessed by BICRUp to ~36 monthsFor the secondary efficacy analysis, ORR was defined as the percentage of participants whose best response based on imaging is CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to iRECIST as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.
Progression-free Survival (PFS) According to RECIST 1.1 Assessed by BICRUp to ~36 monthsPFS was defined as the time from the date of enrollment day to the first documented PD (defined as ≥20% increase in the SOD of target lesions) or death due to any cause, whichever occurred first. Responses are according to RECIST 1.1 as assessed by BICR.
PFS According to iRECIST 1.1 Assessed by BICRUp to ~36 monthsPFS was defined as the time from the date of enrollment day to the first documented PD (defined as ≥20% increase in the SOD of target lesions) or death due to any cause, whichever occurred first. Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.
Overall Survival (OS)Up to ~36 monthsOS was defined as the time from the date of enrollment day to death due to any cause. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. For these participants, date of last follow up was last visit date instead of death date.
Number of Participants With ≥1 Adverse Event (AE)Up to ~36 monthsAn AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment
Number of Participants Discontinuing From Study Treatment Due to AE(s)Up to ~36 monthsAn AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment.
TTR According to iRECIST 1.1 Assessed by BICRUp to ~36 monthsTTR was defined as the time from the date of enrollment day to the first date of confirmed CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD). Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Countries

Japan

Participant flow

Recruitment details

Programmed cell death ligand 1 (PD-L1) positive, human epidermal growth factor receptor 2 (HER2)/neu negative participants 18 to 75 years of age with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma were recruited at 25 study sites in Japan.

Participants by arm

ArmCount
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)
Participants received pembrolizumab 200 mg Q3W plus oxaliplatin 130 mg/m\^2 Q3W by IV infusion plus TS-1 BID by continuous oral administration for 14 days, followed by a recovery period of 7 days. Study treatment started on Day 1 of each 3-week course, and continued for up to \ 3 years.
54
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)
Participants received pembrolizumab 200 mg Q3W plus cisplatin 60 mg/m\^2 Q3W by IV infusion plus TS-1 BID by continuous oral administration for 14 days, followed by a recovery period of 7 days. Study treatment started on Day 1 of each 3-week course, and continued for up to \ 3 years.
46
Total100

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyAdverse Event33
Overall StudyClinical Disease Progression24
Overall StudyOther97
Overall StudyRadiological Progression4031
Overall StudyWithdrawal by Subject01

Baseline characteristics

CharacteristicPembrolizumab + Cisplatin +TS-1 (Cohort 2)TotalPembrolizumab + Oxaliplatin +TS-1 (Cohort 1)
Age, Continuous62.9 years
STANDARD_DEVIATION 10.2
62.1 years
STANDARD_DEVIATION 10.9
61.5 years
STANDARD_DEVIATION 11.6
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Asian
46 Participants100 Participants54 Participants
Race (NIH/OMB)
Black or African American
0 Participants0 Participants0 Participants
Race (NIH/OMB)
More than one race
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race (NIH/OMB)
White
0 Participants0 Participants0 Participants
Sex: Female, Male
Female
18 Participants29 Participants11 Participants
Sex: Female, Male
Male
28 Participants71 Participants43 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
3 / 540 / 46
other
Total, other adverse events
54 / 5446 / 46
serious
Total, serious adverse events
27 / 5422 / 46

Outcome results

Primary

Objective Response Rate (ORR) According to Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR)

For the primary efficacy analysis, ORR was defined as the percentage of participants who have a best response of complete response (CR, disappearance of all target lesions) or partial response (PR, at least a 30% decrease in the sum of diameters \[SOD\] of target lesions, taking as reference the baseline SOD) per RECIST 1.1 as assessed by BICR.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study treatment are included.

ArmMeasureValue (NUMBER)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Objective Response Rate (ORR) According to Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR)72.2 Percentage of participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Objective Response Rate (ORR) According to Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR)80.4 Percentage of participants
Secondary

DCR According to iRECIST 1.1 Assessed by BICR

DCR was defined as the percentage of participants in the analysis population who have CR (disappearance of all target lesions), PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD), or stable disease (SD, neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD \[≥20% increase in the SOD of target lesions\]). Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (NUMBER)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)DCR According to iRECIST 1.1 Assessed by BICR96.3 Percentage of participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)DCR According to iRECIST 1.1 Assessed by BICR97.8 Percentage of participants
Secondary

Disease Control Rate (DCR) According to RECIST 1.1 Assessed by BICR

DCR was defined as the percentage of participants in the analysis population who have complete response (CR, disappearance of all target lesions), partial response (PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD), or stable disease (SD, neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD, ≥20% increase in the SOD of target lesions\]). Responses are according to RECIST 1.1 as assessed by BICR.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (NUMBER)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Disease Control Rate (DCR) According to RECIST 1.1 Assessed by BICR96.3 Percentage of participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Disease Control Rate (DCR) According to RECIST 1.1 Assessed by BICR97.8 Percentage of participants
Secondary

DOR According to iRECIST Assessed by BICR

For participants who demonstrated complete response (CR, disappearance of all target lesions) or partial response (PR, ≥30% decrease in the SOD of target lesions) according to iRECIST as assessed by BICR, DOR was defined as the time from the earliest date of qualifying response (CR or PR) until earliest date of progressive disease (PD, ≥20% increase in the SOD of target lesions) or death from any cause, whichever came first. DOR was censored at the last tumor assessment date if a responder did not have PD or death. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug and had a confirmed response of CR or PR are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)DOR According to iRECIST Assessed by BICR10.6 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)DOR According to iRECIST Assessed by BICR9.5 months
Secondary

Duration of Response (DOR) According to RECIST 1.1 Assessed by BICR

For participants who demonstrated complete response (CR, disappearance of all target lesions) or partial response (PR, ≥30% decrease in the SOD of target lesions) according to RECIST 1.1 as assessed by BICR, DOR was defined as the time from the earliest date of qualifying response (CR or PR) until earliest date of progressive disease (PD, ≥20% increase in the SOD of target lesions) or death from any cause, whichever came first. DOR was censored at the last tumor assessment date if a responder did not have PD or death.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug and had a confirmed response of CR or PR are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Duration of Response (DOR) According to RECIST 1.1 Assessed by BICR10.6 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Duration of Response (DOR) According to RECIST 1.1 Assessed by BICR9.5 months
Secondary

Number of Participants Discontinuing From Study Treatment Due to AE(s)

An AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Number of Participants Discontinuing From Study Treatment Due to AE(s)3 Participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Number of Participants Discontinuing From Study Treatment Due to AE(s)3 Participants
Secondary

Number of Participants With ≥1 Adverse Event (AE)

An AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Number of Participants With ≥1 Adverse Event (AE)54 Participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Number of Participants With ≥1 Adverse Event (AE)46 Participants
Secondary

ORR According to Immune-related Response Evaluation Criteria In Solid Tumors (iRECIST) Assessed by BICR

For the secondary efficacy analysis, ORR was defined as the percentage of participants whose best response based on imaging is CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to iRECIST as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (NUMBER)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)ORR According to Immune-related Response Evaluation Criteria In Solid Tumors (iRECIST) Assessed by BICR72.2 Percentage of participants
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)ORR According to Immune-related Response Evaluation Criteria In Solid Tumors (iRECIST) Assessed by BICR80.4 Percentage of participants
Secondary

Overall Survival (OS)

OS was defined as the time from the date of enrollment day to death due to any cause. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. For these participants, date of last follow up was last visit date instead of death date.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Overall Survival (OS)16.9 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Overall Survival (OS)17.1 months
Secondary

PFS According to iRECIST 1.1 Assessed by BICR

PFS was defined as the time from the date of enrollment day to the first documented PD (defined as ≥20% increase in the SOD of target lesions) or death due to any cause, whichever occurred first. Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)PFS According to iRECIST 1.1 Assessed by BICR9.4 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)PFS According to iRECIST 1.1 Assessed by BICR10.9 months
Secondary

Progression-free Survival (PFS) According to RECIST 1.1 Assessed by BICR

PFS was defined as the time from the date of enrollment day to the first documented PD (defined as ≥20% increase in the SOD of target lesions) or death due to any cause, whichever occurred first. Responses are according to RECIST 1.1 as assessed by BICR.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Progression-free Survival (PFS) According to RECIST 1.1 Assessed by BICR9.4 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Progression-free Survival (PFS) According to RECIST 1.1 Assessed by BICR8.3 months
Secondary

Time to Response (TTR) According to RECIST 1.1 Assessed by BICR

TTR was defined as the time from the date of enrollment day to the first date of confirmed CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD). Responses are according to RECIST 1.1 as assessed by BICR.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)Time to Response (TTR) According to RECIST 1.1 Assessed by BICR1.5 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)Time to Response (TTR) According to RECIST 1.1 Assessed by BICR1.5 months
Secondary

TTR According to iRECIST 1.1 Assessed by BICR

TTR was defined as the time from the date of enrollment day to the first date of confirmed CR (disappearance of all target lesions) or PR (≥30% decrease in the SOD of target lesions, taking as reference the baseline SOD). Responses are according to iRECIST 1.1 as assessed by BICR. iRECIST is a modification to RECIST that takes into account unique patterns of atypical response in immunotherapy and enables treatment beyond initial radiographic progression.

Time frame: Up to ~36 months

Population: All participants who received ≥1 dose of study drug are included.

ArmMeasureValue (MEDIAN)
Pembrolizumab + Oxaliplatin +TS-1 (Cohort 1)TTR According to iRECIST 1.1 Assessed by BICR1.5 months
Pembrolizumab + Cisplatin +TS-1 (Cohort 2)TTR According to iRECIST 1.1 Assessed by BICR1.5 months

Source: ClinicalTrials.gov · Data processed: Feb 19, 2026