Primary Objective :
Phase I- Number of Participants with Adverse Events as a Measure of Safety and Tolerability (Time Frame :2 years plus 30 days)
To characterize the safety profile of silmitasertib in combination with chemotherapy

Phase I- Number of Participants with Dose Limiting Toxicities to determine RP2D (Time Frame :21 days)
To determine the Recommended Phase 2 Dose (RP2D) of silmitasertib in combination with chemotherapy

Phase II- Determine the Overall Response Rate (ORR) of Participants using INSS Response (Time Frame :2 years)
To evaluate the efficacy of silmitasertib in combination with chemotherapy in 2 disease cohorts, based upon Overall response rate (ORR)

Secondary Objective :
Phase I- Determine the Overall Response Rate (ORR) of Participants using INSS Response (Time Frame :2 years)
To evaluate the efficacy of silmitasertib in combination with chemotherapy in 2 disease cohorts based upon Overall response rate (ORR)

Number of participants with progression free survival (PFS) during study(Time Frame :2 years)
To evaluate the efficacy of silmitasertib in combination with chemotherapy in 2 disease cohorts based upon Progression Free Survival (PFS)

Phase II- Length of time that participants experience Overall Survival (OS) (Time Frame :2 years)
To evaluate the efficacy of silmitasertib in combination with chemotherapy in 2 disease cohorts based upon Overall Survival (OS)

Phase II- Number of Participants with Adverse Events as a Measure of Safety and Tolerability(Time Frame :2 years plus 30 days)
To characterize the safety profile of silmitasertib in combination with chemotherapy