A Dose-Finding Study of the Second Mitochondrial Activator of Caspases (SMAC) Mimetic Debio 1143 When Given in Combination With Avelumab to Participants With Advanced Solid Malignancies and to Participants With Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC) After Platinum-Based Therapy

MTD:dose with estimated probability of dose limited toxicity(DLT) below 30%.DLT:any of following adverse events(AEs) during 1st treatment cycle if deemed related to treatment:grade (gr) 3/4 febrile neutropenia/any gr 4 neutropenia of >5 days duration;gr 4 thrombocytopenia[<25000 per cubic millimetre(/mm^3)]/gr 3(<50000/mm^3),associated with medically concerning bleeding;gr ≥3 non-hematologic laboratory value;non-hematologic toxicity of gr 3/4,gr ≥2 uveitis/eye pain that does neither respond to topical therapy nor abate to gr 1within the avelumab re-treatment period/that required systemic treatment;gr ≥2 pneumonitis/interstitial lung disease that not resolve with dose delay and systemic steroids;toxicity related to study drug that requires dosing delay of >2weeks,dose reduction,premature discontinuation of any of two;other drug related AE in the opinion of investigator is of potential clinical significance so that further dose-escalation would expose participants to unacceptable risk.

Objective response is defined as any partial response (PR) or complete response (CR) recorded from the start of study treatment until disease progression/recurrence is documented, a new systemic therapy is started or analysis cut-off, whichever occurs first. It is assessed by using Response Evaluation Criteria in Solid Tumors (RECIST) criteria version 1.1. RECIST v1.1 criteria- CR: disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 millimeter (mm). PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

An AE is any untoward medical occurrence in a clinical investigation participant administered a product or medical device; the event need not necessarily have a causal relationship with the treatment or usage. An SAE is any untoward medical occurrence at any dose that results in death; is life-threatening; requires hospitalization; results in persistent or significant disability or in congenital anomaly/birth defect. Severity will be graded by the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Version 4.03.

Change in tumor size is the maximum reduction or, in case of no reduction, the minimum increase in tumor size from the start of study treatment until disease progression/recurrence, the start of a new systemic therapy or analysis cut-off, whichever occurs first.

Objective response is defined as any PR or CR recorded from the start of study treatment until disease progression/recurrence is documented, a new systemic therapy is started or analysis cut-off, whichever occurs first. It is assessed by using RECIST criteria. CR: disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 mm. PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

Best overall response (BOR) is defined as the best response (CR, PR, stable disease or disease progression) recorded from the start of study treatment until disease progression/recurrence is documented, a new systemic therapy is started or analysis cut-off, whichever occurs first. It is assessed by using RECIST criteria version 1.1. CR: disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 millimeter (mm). PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter. Disease progression: At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study). Stable Disease: Neither sufficient shrinkage to qualify for PR, nor sufficient increase to qualify for disease progression, taking as reference the smallest sum diameter while on study.

Duration of response is the time from documentation of tumor response to disease progression was observed in participants with CR or PR. RECIST v1.1 criteria- CR: disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 millimeter (mm). PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter. Disease progression: At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study).

Disease control is derived as CR, PR or stable disease lasting at least 16 weeks reported during the study. RECIST v1.1 criteria- CR: Disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 mm. PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter.

PFS duration is defined as the time elapsed between treatment initiation and tumor progression or death from any cause, whichever occurs first. RECIST v1.1 criteria- CR: disappearance of all target lesions, any pathological lymph nodes must have reduction in short axis to <10 mm. PR: At least a 30% decrease in the sum of diameters of target lesions taking as reference the baseline sum diameter. Disease progression: At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study).

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