Study of Epacadostat (INCB024360) Alone and In Combination With Pembrolizumab (MK-3475) With Chemotherapy and Pembrolizumab Without Chemotherapy in Participants With Advanced Solid Tumors (MK-3475-434)

A DLT was defined as the occurrence of any treatment-emergent adverse event occurring up to and including Study Day 7 for Part A Cohort 1 or Day 21 for Part A Cohort 2 and Part B. The following criteria defined DLTs: Grade (G) 4 thrombocytopenia; G4 neutropenia (despite optimal supportive care in Part B) lasting >1 week; febrile neutropenia (only if considered clinically significant in Part B); G4 toxicity; G3 laboratory abnormality lasting >1 week: G3 toxicity excluding nausea or vomiting controlled within 72 hours, rash in the absence of desquamation, no mucosal involvement, does not require systemic steroids, and resolves to G1 by the next scheduled dose of pembrolizumab or 14 days; G2 or higher episcleritis, uveitis, or iritis; unable to receive 75% of epacadostat or 1 dose of pembrolizumab during the DLT observation period because of toxicity, even if the toxicity does not meet DLT criteria; or >2 week delay in initiating Cycle 2 due to toxicity.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An adverse event can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), 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 (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an adverse event. The number of participants who experienced an AE was reported for each arm.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An adverse event can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), 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 (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an adverse event. The number of participants who discontinued due to an AE was reported for each arm.

Cmax was the maximum observed concentration of epacadostat in plasma for epacadostat administered alone (Cohort 1) and epacadostat administered with pembrolizumab (Cohort 2). Per protocol, Cmax for Cohort 1 was measured on Days 1, 5, and 12 and Cmax for Cohort 2 was measured on Day 5 only. Blood samples were collected pre-dose and post-dose at multiple time points up to 12 days during Cycle 1 (28-day cycle). Cmax is presented as a geometric mean with a percent geometric coefficient of variation.

Tmax was the time required to reach the maximum concentration of epacadostat in plasma for epacadostat administered alone (Cohort 1) and epacadostat administered with pembrolizumab (Cohort 2). Per protocol, Tmax for Cohort 1 was measured on Days 1, 5, and 12 and Tmax for Cohort 2 was measured on Day 5 only. Blood samples were collected pre-dose and post-dose at multiple time points up to 12 days during Cycle 1 (28-day cycle). Tmax is presented as a Median with a full range.

AUC0-t was defined as the AUC from zero to the time of the last measurable concentration of epacadostat in plasma for epacadostat administered alone (Cohort 1) and epacadostat administered with pembrolizumab (Cohort 2). Per protocol, AUC0-t for Cohort 1 was measured on Days 1, 5, and 12 and AUC0-t for Cohort 2 was measured on Day 5 only. Blood samples were collected pre-dose and post-dose at multiple time points up to 12 days during Cycle 1 (28-day cycle). AUC0-t is presented as a geometric mean with a percent geometric coefficient of variation.

Ctrough was the lowest concentration of epacadostat in plasma just before the next dose for epacadostat administered alone (Cohort 1) and epacadostat administered with pembrolizumab (Cohort 2). Per protocol, Ctrough for Cohort 1 was measured on Days 1, 5, and 12 and Ctrough for Cohort 2 was measured on Day 5 only. Blood samples were collected pre-dose at multiple time points up to 12 days during Cycle 1 (28-day cycle). Ctrough is presented as a geometric mean with a percent geometric coefficient of variation.

t1/2 was the time required to divide the epacadostat concentration by two after reaching pseudo-equilibrium. Plasma t1/2 was measured for epacadostat administered alone (Cohort 1) and epacadostat administered with pembrolizumab (Cohort 2). Per protocol, t1/2 for Cohort 1 was measured on Days 1, 5, and 12 and t1/2 for Cohort 2 was measured on Day 5 only. Blood samples were collected pre-dose and post-dose at multiple time points up to 12 days during Cycle 1 (28-day cycle). t1/2 is presented as a geometric mean with a percent geometric coefficient of variation.

Cmax was the maximum observed concentration of pembrolizumab in serum for participants that received either dose regimen in Part A for Cohort 1 combined, Cohort 2 combined, and Cohorts 1+2 combined. Per protocol, the analysis for the Cmax of pembrolizumab was performed in Cycle 1 only. Blood samples were collected predose and postdose within 30 minutes post pembrolizumab infusion during Cycle 1 (21-day pembrolizumab treatment cycle starting at Day 8 of Cycle 1). Cmax is presented as a geometric mean with a percent geometric coefficient of variation.

Cmax was the maximum observed concentration of pembrolizumab in serum for participants that received either dose regimen in Part B for Cohort 1, Cohort 2, Cohort 3, and Cohorts 1+2+ 3 combined. Per protocol, the analysis for the Cmax of pembrolizumab was performed in Cycle 1 only. Blood samples were collected predose and postdose within 30 minutes post pembrolizumab infusion during Cycle 1 (21-day pembrolizumab treatment cycle starting at Day 8 of Cycle 1). Cmax is presented as a geometric mean with a percent geometric coefficient of variation.

Ctrough was the lowest concentration of pembrolizumab in serum just before the next dose for participants that received either dose regimen in Part A for Cohort 1 combined, Cohort 2 combined, and Cohorts 1+2 combined. Per protocol, blood sampling for Ctrough was taken at predose prior to the Cycle 1, 2, 4, 6, and 8 infusion. Cycle 1 length was 28 days (21-day pembrolizumab treatment cycle starting at Day 8 of Cycle 1). Cycle 2, 4, 6, and 8 length was 21 days. Ctrough is presented as a geometric mean with a percent geometric coefficient of variation.

Ctrough was the lowest concentration of pembrolizumab in serum just before the next dose for participants that received either dose regimen in Part B for Cohort 1, Cohort 2, Cohort 3, and Cohorts 1+2+3 combined. Per protocol, blood sampling for Ctrough was taken at pre-dose prior to the Cycle 1, 2, 4, 6, and 8 infusion. Cycle 1 length was 28 days (21-day pembrolizumab treatment cycle starting at Day 8 of Cycle 1). Cycle 2, 4, 6, and 8 length was 21 days. Ctrough is presented as a geometric mean with a percent geometric coefficient of variation.