An adverse event (AE) was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related, that occurred after a participant provided informed consent. Abnormal laboratory values or test results occurring after informed consent constituted AEs only if they induced clinical signs or symptoms, were considered clinically meaningful, required therapy (e.g., hematologic abnormality that required transfusion), or required changes in the study drug(s). A TEAE was defined as any AE either reported for the first time or the worsening of a pre-existing event after the first dose of study drug.

Full Analysis Set (FAS): all participants enrolled in the study who received at least 1 dose of INCB001158, mFOLFOX6, gemcitabine/cisplatin, or paclitaxel. As pre-defined in the Statistical Analysis Plan, data analysis was conducted based on treatment group and dose level, regardless of study phase, because the safety profile was expected to be generally uniform across tumor types.

A DLT was defined as the occurrence of any protocol-defined toxicity occurring up to and including Day 28, except those with a clear alternative explanation (e.g., disease progression) or transient (≤72 hours) abnormal laboratory values without associated clinically significant signs or symptoms based on investigator determination. All DLTs were assessed by the investigator using Common Terminology Criteria for Adverse Events (CTCAE) v4.03 criteria.

Phase 1 DLT Evaluable Population: all participants enrolled in Phase 1 who had been treated with the assigned dose level of INCB001158 and who had received at least 32 of the 42 doses prescribed for a 21-day cycle regimen or at least 42 of the 56 doses prescribed for a 28-day cycle regimen (both representing ≥ 75% of the dose planned) or who had experienced a DLT

The RP2D of the combination of INCB001158 and chemotherapy in 21-day (for gemcitabine/cisplatin) or 28-day (for mFOLFOX6 or paclitaxel) treatment cycles in participants with advanced or metastatic solid tumors was determined. After the dose escalation was completed, the INCB001158 dose level that was pharmacologically active and tolerable in combination with each chemotherapy regimen (i.e., maximum tolerated dose or lower) was determined to be the RP2D. The RP2D was then further assessed in tumor expansion cohorts in Phase 2.

DLT Evaluable Population

ORR was defined as the percentage of participants with a best overall response of complete response (CR) or partial response (PR), as determined by investigator assessment of radiographic disease as per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 (v1.1). CR: disappearance of all target and non-target lesions and no appearance of any new lesions. Any pathological lymph nodes (whether target or non-target) must have a reduction in the short axis to <10 millimeters (mm). PR: complete disappearance or at least a 30% decrease in the sum of the diameters of target lesions, taking as a reference the baseline sum diameters, no new lesions, and no progression of non-target lesions. Analysis was conducted by cohort (tumor type) in Phase 2 because different tumor types could have different response criteria or different background response rates.

Phase 2 Response Evaluable Population: all participants who had received ≥1 dose of study treatment (INCB001158, mFOLFOX6, gemcitabine/cisplatin, or paclitaxel), completed a Baseline scan, and met ≥1 of the following criteria: (a) had ≥1 post-Baseline scan; (b) was in the study for a minimum of 63 days (8 weeks + 1 week window) of follow-up; (c) discontinued from study treatment

ORR was defined as the percentage of participants with a confirmed best overall response of CR or PR, as determined by investigator assessment of radiographic disease as per RECIST v1.1. CR: disappearance of all target and non-target lesions and no appearance of any new lesions. Any pathological lymph nodes (whether target or non-target) must have a reduction in the short axis to <10 mm. PR: complete disappearance or at least a 30% decrease in the sum of the diameters of target lesions, taking as a reference the Baseline sum diameters, no new lesions, and no progression of non-target lesions.

Phase 1 Response Evaluable Population: all participants who had received ≥1 dose of study treatment (INCB001158, mFOLFOX6, gemcitabine/cisplatin, or paclitaxel), completed a Baseline scan, and met ≥1 of the following criteria: (a) had ≥1 post-Baseline scan; (b) was in the study for a minimum of 63 days (8 weeks + 1 week window) of follow-up; (c) discontinued from study treatment. Analysis was conducted by dose.

DOR was defined as the time from initial objective response (CR or PR) (as determined by investigator assessment of radiographic disease assessment per RECIST v1.1) until the earliest date of disease progression or death due to any cause, if it occurred sooner than disease progression. CR: disappearance of all target and non-target lesions and no appearance of any new lesions. Any pathological lymph nodes (whether target or non-target) must have a reduction in the short axis to <10 mm. PR: complete disappearance or at least a 30% decrease in the sum of the diameters of target lesions, taking as a reference the baseline sum diameters, no new lesions, and no progression of non-target lesions. PD: progression of a target or non-target lesion or presence of a new lesion.

Response Evaluable Population. Analysis was conducted based on study phase. Analysis was conducted by dose in Phase 1 and by cohort (tumor type) in Phase 2 because different tumor types could have different response criteria or different background response rates. Analysis was conducted in cohorts with >5 objective responders; the Kaplan Meier estimation method on a sample size of <5 responders is not valid. The confidence interval was calculated using the method of Brookmeyer and Crowley.

DCR was defined as the percentage of participants with an overall response of CR, PR, or stable disease (SD), as determined by investigator assessment of radiographic disease as per RECIST v1.1, for at least 8 weeks. CR: disappearance of all target and non-target lesions and no appearance of any new lesions. Any pathological lymph nodes (whether target or non-target) must have a reduction in the short axis to <10 mm. PR: complete disappearance or at least a 30% decrease in the sum of the diameters of target lesions, taking as a reference the baseline sum diameters, no new lesions, and no progression of non-target lesions. PD: progression of a target or non-target lesion or presence of a new lesion. SD: no change in target lesions to qualify for CR, PR, or PD.

Response Evaluable Population. Data analysis was conducted based on study phase. Additionally, analysis was conducted by dose in Phase 1 and by cohort (tumor type) in Phase 2 because different tumor types could have different response criteria or different background response rates.

According to RECIST 1.1, PFS was defined as the length of time from the date of the first dose study of drug until the earliest date of disease progression, as determined by investigator assessment of radiographic disease per RECIST v1.1, or death due to any cause, if it occurred sooner than progression.

FAS. Data analysis was conducted based on study phase. Additionally, analysis was conducted by dose in Phase 1 and by cohort (tumor type) in Phase 2 because different tumor types could have different response criteria or different background response rates. Median survival time was estimated using the Kaplan-Meier method. CI for median survival time was calculated using the method of Brookmeyer and Crowley.

Cmin was defined as the minimum observed plasma concentration over the dose interval. Extensive sample collection was used for the first 12 participants enrolled in each chemotherapy regimen. Sparse sample collection was used for the 13th participant enrolled and onward.

Phase 2 Pharmacokinetic (PK) Population. Only participants with available data were analyzed.

Cmax was defined as the maximum observed plasma concentration over the dose interval. Extensive sample collection was used for the first 12 participants enrolled in each chemotherapy regimen. Sparse sample collection was used for the 13th participant enrolled and onward.

Phase 2 PK Population. Only participants with available data were analyzed.

tmax was defined as the time to the maximum concentration. Extensive sample collection was used for the first 12 participants enrolled in each chemotherapy regimen. Sparse sample collection was used for the 13th participant enrolled and onward.

Phase 2 PK Population. Only participants with available data were analyzed.

AUC0-t was defined as the area under the plasma concentration-time curve from time = 0 to the last measurable concentration at time = t. Extensive sample collection was used for the first 12 participants enrolled in each chemotherapy regimen. Sparse sample collection was used for the 13th participant enrolled and onward.

Phase 2 PK Population. Only participants with available data were analyzed.

tlast was defined as the time of the last sample collected from which a concentration was measured. Extensive sample collection was used for the first 12 participants enrolled in each chemotherapy regimen. Sparse sample collection was used for the 13th participant enrolled and onward.

Phase 2 PK Population. Only participants with available data were analyzed.