A Phase 1b/2 Study of MEDI4736 With Tremelimumab, MEDI4736 or Tremelimumab Monotherapy in Gastric or GEJ Adenocarcinoma

OR: best overall response (BOR) of confirmed complete response (CR) or partial response (PR) per RECIST v1.1. BOR: best response (CR, PR, stable disease [SD], progressive disease [PD], and not evaluable) among all overall responses recorded from date of randomization of participants or date of first dose of study drug until progression, or last evaluable disease assessment or discontinuation from the study, whichever occurred first. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study; PD: at least 20% increase in SOD of target lesions from smallest sum on study (at least 5mm), appearance of one or more new lesions, substantial worsening in non-target disease, increase in tumor burden leading to discontinuation of therapy.

The DSD was defined as the time from the date of first dose of study treatment for Phase 1b until the first date of documented PD (per RECIST v1.1), or death due to any cause, whichever occurred first. PD is at least a 20% increase in sum of diameters of target lesions from smallest sum on study (at least 5mm), appearance of one or more new lesions, substantial worsening in non-target disease, increase in tumor burden leading to discontinuation of therapy. Kaplan Meier method was used to evaluate DSD.

Best percentage change from baseline of the SLD of target lesions per RECIST v1.1 was derived as the biggest decease or the smallest increase from baseline on the SLD among all post-baseline disease assessment including unscheduled assessments. Best percent change is the maximum reduction from baseline or the minimum increase from baseline in the absence of a reduction.

The disease control rate at 16 weeks was defined as the percentage of participants who achieved a BOR of confirmed CR, confirmed PR, or had SD with duration of SD for a minimum duration of 110 days, following the date of first dose of study drug. The DC was defined as a BOR of confirmed CR, confirmed PR or SD per RECIST v1.1. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study.

The disease control rate at 24 weeks was defined as the percentage of participants who achieved a BOR of confirmed CR, confirmed PR, or had SD with duration of SD for a minimum duration of 166 days, following the date of first dose of study drug. The DC was defined as a BOR of confirmed CR, confirmed PR or SD per RECIST v1.1. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study.

The PFS-6 is the 6-month progression-free survival rate, which was the percentage of participants who were progression free and alive at 6 months. PFS was defined as the time from the date of first dose of study drug for Phase 1b participants to the earlier of the dates of the first objective documentation of radiographic disease progression (per RECIST v1.1) or death due to any cause. PFS was censored at the date of their last evaluable tumor assessment. Kaplan Meier method was used to evaluate PFS.

An adverse event (AE) is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. A serious adverse event (SAE) is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. TEAEs are defined as events present at baseline that worsened in intensity after administration of study drug or events absent at baseline that emerged after administration of study drug.

Number of participants with clinical laboratory abnormalities reported as TEAEs are reported. Clinical laboratory abnormalities are defined as any abnormal findings in analysis of serum chemistry, hematology, and urine.

Number of participants with abnormal vital signs reported as TEAEs are reported. Abnormal vital signs are defined as any abnormal findings in the vital signs parameters (temperature, blood pressure [BP], pulse rate [or pulse oximetry at screening], and respiratory rate). Abnormal physical examinations are defined as any abnormal impact on measurements of height and weight.

Number of participants with abnormal electrocardiograms (ECGs) reported as TEAEs are reported. Abnormal ECGs are defined as any abnormal findings in heart rate, PR, RR, QRS and QT intervals from the primary lead of the digital 12-lead ECG.

The ECOG scale of performance status describes the level of functioning of participants in terms of their ability to care for themselves, daily activity, and physical ability. ECOG Performance Status Scorings are: 0= fully active, able to carry on all pre-disease performance without restriction; 1= restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature (for example, light house work, office work); 2= ambulatory and capable of all self-care but unable to carry out any work activities, up and about more than 50% of waking hours; 3= capable of only limited selfcare, confined to bed or chair more than 50% of waking hours; 4= completely disabled, cannot carry on any self-care, totally confined to bed or chair; 5= dead. The baseline performance status of participants is presented.

The disease control rate at 16 weeks was defined as the percentage of participants who achieved a BOR of confirmed CR, confirmed PR, or had SD with duration of SD for a minimum duration of 110 days, following the date of randomization for Arm A, B, and C participants and the date of first dose of study drug for Arm D and E participants. The DC was defined as a BOR of confirmed CR, confirmed PR or SD per RECIST v1.1. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study.

The disease control rate at 24 weeks was defined as the proportion of participants who achieved a BOR of confirmed CR, confirmed PR, or had SD with duration of SD for a minimum duration of 166 days, following the date of randomization for Arm A, B, and C participants and the date of first dose of study drug for Arm D and E participants. The DC was defined as a BOR of confirmed CR, confirmed PR or SD per RECIST v1.1. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study.

The DoR was defined as the time from the date of first documented response (CR or PR) until the first date of documented progression according to RECIST v1.1 that occurred subsequently after response or death due to any cause, whichever occurred first. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline. Kaplan Meier method was used to evaluate DoR.

TTR: time from date of randomization of participants for Arm A, B, and C or date of first dose of study drug for Arm D and Arm E until first documented OR per RECIST v1.1. OR: BOR of confirmed CR or PR per RECIST v1.1. BOR: best response (CR, PR, SD, PD, and not evaluable) among all overall responses recorded from date of randomization/date of first dose of study drug until progression, or last evaluable disease assessment or discontinuation from the study, whichever occurred first. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in SOD of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD; PD: at least 20% increase in SOD of target lesions from smallest sum (at least 5mm), appearance of one or more new lesions, substantial worsening in non-target disease, increase in tumor burden leading to discontinuation of therapy. Kaplan Meier method used to evaluate TTR.

The DSD was defined as the time from the date of randomization for Arm A, B, and C participants or the date of first dose of study drug for Arm D and Arm E participants until the first date of documented PD (per RECIST v1.1), or death due to any cause, whichever occurred first. PD is at least a 20% increase in sum of diameters of target lesions from smallest sum on study (at least 5 mm), appearance of one or more new lesions, substantial worsening in non-target disease, increase in tumor burden leading to discontinuation of therapy. Kaplan Meier method was used to evaluate DSD.

Best percentage change from baseline of the SLD of target lesions per RECIST v1.1 was derived as the biggest decease or the smallest increase from baseline on the SLD among all post-baseline disease assessment including unscheduled assessments. Best percent change is the maximum reduction from baseline or the minimum increase from baseline in the absence of a reduction.

The PFS was defined as the time from the date of randomization for Arm A, B, and C participants or the date of first dose of study treatment for Arm D and E participants to the earlier of the dates of the first objective documentation of radiographic disease progression (per RECIST v1.1) or death due to any cause. PFS was censored at the date of their last evaluable tumor assessment. Kaplan Meier method was used to evaluate PFS.

The PFS-9 is the 9-month progression-free survival rate, which was the percentage of participants who were progression free and alive at 9 months. PFS was defined as the time from the date of first dose of study drug for Arm A, B, C participants or the date of first dose of study drug for Arm D and E participants to the earlier of the dates of the first objective documentation of radiographic disease progression (per RECIST v1.1) or death due to any cause. PFS was censored at the date of their last evaluable tumor assessment. Kaplan Meier method was used to evaluate PFS.

The OS was defined as the time from date of randomization for Arm A, B, and C participants or the date of first dose of study drug for Arm D and Arm E participants until death due to any cause. OS was censored at last known alive date. Kaplan Meier method was used to evaluate OS. Kaplan Meier method was used to evaluate OS.

The OS was defined as the time from date of randomization for Arm A, B, and C participants or the date of first dose of study drug for Arm D and Arm E participants until 12 months. OS was censored at last known alive date. Kaplan Meier method was used to evaluate OS. Kaplan Meier method was used to evaluate OS and 95% confidence interval.

Percentage of participants with OR with positive IFN-γ gene expression is reported. OR: BOR of confirmed CR or PR per RECIST v1.1. BOR: best response (CR, PR, SD, PD, and not evaluable) among all overall responses recorded from date of randomization for Arm A, B, C participants or date of first dose of study drug for Arms D, E participants until progression, or last evaluable disease assessment or discontinuation from the study, whichever occurred first. CR: disappearance of all target/non-target lesions; PR: at least 30% decrease in sum of diameters (SOD) of target lesions from baseline; SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD from smallest SOD on study; PD: at least 20% increase in SOD of target lesions from smallest sum on study (at least 5mm), appearance of one or more new lesions, substantial worsening in non-target disease, increase in tumor burden leading to discontinuation of therapy.

Percentage of participants with PFS at 6 month with positive IFN-γ gene expression is reported. The PFS-6 is the 6-month progression-free survival rate, which was the percentage of participants who were progression free and alive at 6 months. PFS was defined as the time from the date of first dose of study drug for Arm A, B, and C participants or the date of first dose of study drug for Arm D and Arm E participants to the earlier of the dates of the first objective documentation of radiographic disease progression (per RECIST v1.1) or death due to any cause. PFS was censored at the date of their last evaluable tumor assessment. Kaplan Meier method was used to evaluate PFS-6.

Percentage of participants with objective response in Phase 2 by programmed death-ligand (PD-L1) status is reported. PD-L1 is a protein that may be found on some normal cells and in higher-than-normal amounts on some types of cancer cells. It plays a role in regulating the immune response against some types of cancers and therefore, is the target for some anticancer drugs. PD-L1 status was based on the percentage of tumor cells from baseline tumor tissue samples with PD-L1 membrane staining: PD-L1 high if >= 1% tumor cells (better response), PD-L1 low/neg if < 1% tumor cells (low response).