Study to Assess Safety and Efficacy of the Second Mitochondrial-derived Activator of Caspases (SMAC) Mimetic Debio 1143

Parts A and B: Number of Participants With Treatment-emergent Adverse Events (TEAEs) Including Laboratory Abnormalities Reported as TEAEs, and Serious Adverse Events (SAEs)

An adverse event (AE) is any untoward medical occurrence in a clinical trial participant administered a medicinal product that does not necessarily have a causal relationship with this treatment. A TEAE is any new, related or non-related, undesirable medical occurrence or change of an existing condition in a participant that occurs during the treatment-emergent period, starting or worsening on or after the first study drug administration and up to 5 months after last nivolumab infusion, or the earliest date of new anticancer therapy - 1 day, whichever occurs first. An SAE is defined as any untoward medical occurrence that at any dose results in death; is life-threatening (i.e., puts the participant at immediate risk of death); requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect, or is otherwise medically significant.

Time frame: From the first study drug administration and up to 5 months after last nivolumab infusion, or the earliest date of new anticancer therapy -1 day, whichever occurs first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: Change From Baseline in Weight

Time frame: From Baseline up to end of treatment (up to approximately 1.53 years in Part A and up to 1 year in Part B)

Parts A and B: Number of Participants With Markedly Abnormal Change From Baseline in Vital Signs

Vital sign parameters assessed comprise of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate. Markedly abnormal criteria for vital signs include SBP \[millimeters of mercury (mmHg)\]: ≤ 90 mmHg OR change from baseline ≤ -20 mmHg, ≥ 140 mmHg OR change from baseline ≥ 20 mmHg; DBP (mmHg): ≤ 60 mmHg OR change from baseline ≤ -20 mmHg, ≥ 90 mmHg OR change from baseline ≥ 20 mmHg; Heart rate \[beats per minute (bpm)\]: ≤ 50 bpm OR change from baseline ≤ -20 bpm, ≥ 100 bpm OR change from baseline ≥ 20 bpm.

Time frame: From Baseline up to end of treatment (up to approximately 1.53 years in Part A and up to 1 year in Part B)

Parts A and B: Number of Participants With Change From Baseline in Temperature Reported as TEAEs

Change from baseline in temperature reported as TEAEs included pyrexia. A TEAE is any new, related or non-related, undesirable medical occurrence or change of an existing condition in a participant that occurs during the treatment-emergent period, starting or worsening on or after the first study drug administration and up to 5 months after last nivolumab infusion, or the earliest date of new anticancer therapy - 1 day, whichever occurs first.

Time frame: From Baseline up to end of treatment (up to approximately 1.53 years in Part A and up to 1 year in Part B)

Parts A and B: Number of Participants With Markedly Abnormal Change From Baseline in Electrocardiogram (ECG) Readings

ECG parameters comprised of PR Interval \[millisecond (msec)\], QRS Interval (msec), QT Interval (msec), QTcB Interval (msec), QTcF Interval (msec), heart rate (HR) (bpm), RR interval (msec), derived HR (msec), calculated as 60000/RR interval \[for data checking only: should be within 5% of HR\]. Marked abnormal criteria for ECG parameters included absolute values QRS interval: \< 50 msec, \> 110 msec; absolute values for QT interval, QTcB interval: \>450 msec, \> 480 msec, \> 500 msec, QTcF: \> 480 msec, \> 500 msec; change from baseline values for QTcB interval, and QTcF: \>30 msec increase from baseline, \>60 msec increase from baseline. Data for highest on-treatment change from baseline as per the markedly abnormal criteria for ECG parameters are reported. On-treatment is the period of time between the first and last administration of any study drug. Participants with at least one markedly abnormal change from baseline value in the above categories are reported.

Time frame: From Baseline up to end of treatment (up to approximately 1.53 years in Part A and up to 1 year in Part B)

Parts A and B: Number of Participants With Shift From Baseline to Worst On-Treatment Value in Eastern Cooperative Oncology Group Performance Status (ECOG-PS)

The ECOG-PS was used to assess the effect of disease progression on participants' daily activities. ECOG-PS is graded as follows: Grade 0 - fully active, able to carry on all pre-disease performance without restriction; Grade 1 - restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature; Grade 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; Grade 3 - capable of only limited self-care, confined to bed or chair for more than 50% of waking hours; Grade 4 - completely disabled, cannot carry on any self-care, totally confined to bed or chair; Grade 5 - dead. Shift values from baseline grade to worst on-treatment grade and missing values were reported.

Time frame: From Baseline up to end of treatment (up to approximately 1.53 years in Part A and up to 1 year in Part B)

Parts A and B: Number of Participants With TEAEs Including Laboratory Abnormalities Leading to Treatment Discontinuations and Dose Modifications

Time frame: From the first study drug administration and up to 5 months after last nivolumab infusion, or the earliest date of new anticancer therapy -1 day, whichever occurs first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Part A: Confirmed Objective Response Rate (ORR)

ORR was determined per RECIST v1.1. ORR was calculated as the percentage of participants with a confirmed objective response. A confirmed objective response is a confirmed best overall response of PR or CR recorded after the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first. CR is defined by the disappearance of all target lesions and reduction of any pathological lymph nodes in short axis to \<10 mm. PR is defined by at least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

Time frame: Part A: From the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first (up to approximately 2.08 years)

Parts A and B: Unconfirmed Objective Response Rate (uORR)

uORR was calculated as the percentage of participants with unconfirmed objective response per RECIST v1.1. Unconfirmed objective response is an unconfirmed best overall response of PR or CR. Objective response was derived as any PR or CR recorded after the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first. CR is defined by the disappearance of all target lesions and reduction of any pathological lymph nodes in short axis to \<10 mm. PR is defined by at least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

Time frame: From the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: Disease Control Rate (DCR)

DCR was calculated as the percentage of participants with disease control. Disease control was derived as any CR, PR, or stable disease reported during the study. CR is defined by the disappearance of all target lesions and reduction of any pathological lymph nodes in short axis to \<10 mm. PR is defined by at least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

Time frame: From the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: Median Duration of Response (DOR)

DOR is defined as the time, in months, between date of the initial response (PR or CR) or date of first reduction of 50% in carbohydrate antigen 125 (CA-125), and date of the first documented disease progression or death due to any cause, whichever occurs first. CR is defined by the disappearance of all target lesions and reduction of any pathological lymph nodes in short axis to \<10 mm. PR is defined by at least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter. Data is reported as Kaplan-Meier product-limit estimates.

Time frame: From the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: Progression Free Survival (PFS)

PFS duration is defined as the time, in months, elapsed between treatment initiation and tumor progression or death from any cause, whichever occurs first.

Time frame: From the start of study treatment until disease progression/recurrence or death from any cause, whichever occurs first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: PFS Rate at Months 6 and 12

PFS is defined as duration elapsed between treatment initiation and tumor progression or death from any cause, whichever occurs first. Data for PFS rate is reported as Kaplan-Meier product-limit estimates and includes Brookmeyer-Crowley confidence intervals.

Time frame: Months 6 and 12

Parts A and B: Overall Survival (OS)

OS is defined as the time elapsed, in months, between treatment initiation and death from any cause.

Time frame: From the start of study treatment until death from any cause, whichever occurs first (up to approximately 2.08 years in Part A and 2.05 years in Part B)

Parts A and B: OS Rate at Months 12 and 18

OS is defined as the time elapsed, in months, between treatment initiation and death from any cause. Data for OS rate is reported as Kaplan-Meier product-limit estimates and includes Brookmeyer-Crowley confidence intervals.

Time frame: Months 12 and 18

Part A: Area Under the Curve From Time 0 to 4 Hours (AUC0-4H) of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose, 0.5, 1.5, 4 hours post-dose on Days 1 and 15, predose, 1.5, 4 hours post-dose on Days 8 and 22; Cycle 3: predose, 0.5, 1.5, 4 hours post-dose on Day 1 and predose, 1.5, 4 hours post-dose on Day 15 (each cycle=28 days)

Part B: AUC0-4H of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose, 1.5, 4 hours post-dose on Days 1 and 22; Cycle 3: predose, 1.5, 4 hours post-dose on Day 1 (each cycle = 28 days)

Part A: Area Under the Curve From Time 0 to 8 Hours (AUC0-8H) of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose, 0.5, 1.5, 4, 8 hours post-dose on Days 1 and 15, and predose, 1.5, 4, 8 hours post-dose on Day 8; Cycle 3: predose, 0.5, 1.5, 4, 8 hours post-dose on Day 1 and predose, 1.5, 4, 8 hours post-dose on Day 15 (each cycle = 28 days)

Part A: Maximum Observed Concentration (Cmax) of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: Predose,0.5,1.5,4,8 hours post-dose (Days 1 and 15), predose,1.5,4,8 hours post-dose (Day 8), predose,1.5,4 hours post-dose (Day 22); Cycle 3: predose,0.5,1.5,4,8 hours post-dose (Day 1), predose,1.5,4,8 hours post-dose (Day 15) (Cycle=28 days)

Part B: Cmax of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose, 1.5, 4 hours post-dose on Days 1 and 22; Cycle 3: predose, 1.5, 4 hours post-dose on Day 1 (each cycle = 28 days)

Part A: Trough Concentration (Cmin) of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose on Days 3, 8, 15, 17 and 22; Cycle 3: predose on Days 1, 3, 15, 17; Cycle 6: predose on Day 1

Part B: Trough Concentration (Cmin) of Debio 1143 and Debio 1143-MET1

Time frame: Cycle 1: predose on Days 8 and 22; Cycle 3: predose on Day 1 (each cycle = 28 days)

Part A: Serum Trough Concentration of Nivolumab

Time frame: Cycle 1: predose, 1.5, 8 hours post-dose on Day 15; Cycle 3: predose, 0.5, 1.5, 8 hours post-dose on Day 1 and predose, 1.5 hours post-dose on Day 15 (each cycle = 28 days)

Part B: Serum Trough Concentration of Nivolumab

Time frame: Cycle 1: predose, 1.5 hours post-dose on Day 15; Cycle 3: predose, 1.5 hours post-dose on Days 1 and Day 15; Cycle 6: predose on Day 1 (each cycle = 28 days)

Parts A and B: Time to Response (TTR)

The average of the time taken in days for PR is reported. PR is defined by at least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

Time frame: From the start of study treatment until disease progression/recurrence was documented, a new systemic anti-cancer therapy was started or analysis cut-off, whichever occurred first (up to approximately 2.08 years in Part A and 2.05 years in Part B)