Safety and Efficacy of Coformulated Pembrolizumab/Quavonlimab (MK-1308A) in Combination With Lenvatinib (E7080/MK-7902) in Advanced Hepatocellular Carcinoma (MK-1308A-004)

DLTs were defined as follows unless determined to be unrelated to study intervention: any Grade 4 nonhematologic toxicity (not laboratory); any Grade 4 hematologic toxicity lasting >7 days (Grade 4 lymphopenia lasting ≥21 days); Grade 3 platelet count decreased if associated with clinically significant hemorrhage; any Grade 3 nonhematologic toxicity (not laboratory) lasting >3 days despite optimal supportive care; any clinically significant Grade 3 or Grade 4 nonhematologic laboratory abnormality if: medical intervention is required to treat participant, or abnormality leads to hospitalization, or abnormality persists for >1 week (or bilirubin if persists >4 weeks); aspartate aminotransferase (AST)/ alanine aminotransferase (ALT) >10.0 times upper limit of normal (ULN) or >10.0 times baseline if baseline >ULN; any febrile neutropenia Grade 3 or Grade 4; a treatment-related adverse event (AE) causing discontinuation of study intervention during the DLT window; any Grade 5 toxicity.

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants with an AE was reported.

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. An SAE was defined as any untoward medical occurrence that, at any dose: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was another important medical event. The number of participants with an SAE was reported.

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. AEs associated with pembrolizumab/quavonlimab exposure may represent an immune-related response. A list of irAEs was pre-specified for the compound of pembrolizumab/quavonlimab. The number of participants with an irAE was reported.

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. Hepatic events of clinical interest (ECIs) included any of the following events if the event is considered not due to disease progression as judged by the investigator: among participants with Baseline ALT <2 × ULN: ALT ≥5 × ULN; among participants with Baseline ALT ≥2 × ULN: ALT >3 × the Baseline level; ALT >500 U/L regardless of baseline level; total bilirubin >3.0 mg/dL; hepatic decompensation diagnosed clinically (regardless of laboratory values) including new onset clinically detectable ascites requiring intervention for >3 days, hepatic encephalopathy, or gastrointestinal bleeding suggestive of portal hypertension. The number of participants with a hepatic AE was reported.

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants that discontinued study treatment due to an AE was reported.

ORR was defined as the percentage of participants who achieve a confirmed Complete Response (CR: disappearance of all target lesions) or a Partial Response (PR: at least a 30% decrease in the sum of diameters [SOD] of target lesions) per RECIST 1.1 adjusted for this study to allow a maximum of 10 target lesions in total and 5 per organ, and assessed by BICR. The percentage of participants who experienced CR or PR per RECIST 1.1 as assessed BICR was presented.

For participants who demonstrated confirmed CR or PR per RECIST 1.1 assessed by BICR, DOR was defined as the time from the first documented evidence of CR (disappearance of all target lesions) or PR (at least a 30% decrease in the SOD of target lesions) until progressive disease (PD) or death due to any cause, whichever occurred first. Per RECIST 1.1 adjusted for this study to allow a maximum of 10 target lesions and a maximum of 5 target lesions per organ, PD was defined as at least a 20% increase in the SOD 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 was also considered PD. The DOR as assessed using RECIST 1.1 for all participants who experienced a confirmed CR or PR was presented.

DCR was defined as the percentage of participants who have achieved CR (disappearance of all target lesions), PR (at least a 30% decrease in the SOD of target lesions), or stable disease (SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD) after ≥6 weeks (the start of the window for the first scheduled scan) per RECIST 1.1 assessed by BICR. Per RECIST 1.1 adjusted for this study to allow a maximum of 10 target lesions and a maximum of 5 target lesions per organ, PD is defined as at least a 20% increase in the SOD 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. The percentage of participants who achieved CR, PR, or SD after ≥6 weeks per RECIST 1.1 assessed by BICR was presented.

PFS was defined as the time from the first dose of study intervention to the first documented PD per RECIST 1.1 by BICR or death due to any cause, whichever occurs first. Per RECIST 1.1 adjusted for this study to allow a maximum of 10 target lesions and a maximum of 5 target lesions per organ, PD is defined as at least a 20% increase in the SOD 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 was also considered PD. PFS per RECIST 1.1 as assessed by BICR was reported.

TTP was defined as the time from the first dose of study intervention to the first documented PD per RECIST 1.1 assessed by BICR. Per RECIST 1.1 adjusted for this study to allow a maximum of 10 target lesions and a maximum of 5 target lesions per organ, PD is defined as at least a 20% increase in the SOD 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. TTP per RECIST 1.1 as assessed by BICR was presented.

OS was defined as the time from the first dose of study intervention to death due to any cause.

ORR was defined as the percentage of participants who achieve a confirmed CR (disappearance of any intratumoral arterial enhancement in all target lesions) or a PR (at least a 30% decrease in the SOD of viable [contrast enhancement in the arterial phase] target lesions, taking as reference the baseline SOD of target lesions) per mRECIST as assessed by BICR. mRECIST for HCC allows evaluation of treatment effects that are not reflected in simple total size changes of lesions. The percentage of participants who experienced CR or PR per mRECIST as assessed BICR was presented.

For participants who demonstrate confirmed CR or PR per mRECIST assessed by BICR, DOR is defined as the time from the first documented evidence of CR (disappearance of any intratumoral arterial enhancement in all target lesions) or PR (at least a 30% decrease in the SOD of viable [contrast enhancement in the arterial phase] target lesions, taking as reference the baseline SOD of target lesions) until PD or death due to any cause, whichever occurs first. mRECIST for HCC allows evaluation of treatment effects that are not reflected in simple total size changes of lesions. Per mRECIST, PD was defined as an increase of at least 20% in the SODs of viable (enhancing) target lesions, taking as reference the smallest SODs of viable (enhancing) target lesions recorded since the treatment started. The DOR as assessed using mRECIST for all participants who experienced a confirmed CR or PR was presented.

DCR was defined as the percentage of participants who have achieved CR (disappearance of any intratumoral arterial enhancement in all target lesions), PR (at least a 30% decrease in the SOD of viable [contrast enhancement in the arterial phase] target lesions, taking as reference the baseline SOD of target lesions), or SD (any cases that do not qualify for either PR or PD) after ≥6 weeks (the start of the window for the first scheduled scan) per mRECIST assessed by BICR. mRECIST for HCC allows evaluation of treatment effects that are not reflected in simple total size changes of lesions. Per mRECIST, PD was defined as an increase of at least 20% in the SODs of viable (enhancing) target lesions, taking as reference the smallest SODs of viable (enhancing) target lesions recorded since the treatment started. The percentage of participants who achieved CR, PR, or SD after ≥6 weeks per mRECIST assessed by BICR was presented.

PFS was defined as the time from the first dose of study intervention to the first documented PD per mRECIST by BICR or death due to any cause, whichever occurs first. mRECIST for HCC allows evaluation of treatment effects that are not reflected in simple total size changes of lesions. Per mRECIST, PD was defined as an increase of at least 20% in the SODs of viable (enhancing) target lesions, taking as reference the smallest SODs of viable (enhancing) target lesions recorded since the treatment started. PFS per mRECIST as assessed by BICR was reported.

TTP was defined as the time from the first dose of study intervention to the first documented PD per mRECIST assessed by BICR. mRECIST for HCC allows evaluation of treatment effects that are not reflected in simple total size changes of lesions. Per mRECIST, PD was defined as an increase of at least 20% in the SODs of viable (enhancing) target lesions, taking as reference the smallest SODs of viable (enhancing) target lesions recorded since the treatment started. TTP per mRECIST as assessed by BICR was presented.