Trial Outcomes & Findings for Phase 1 Trial of MSC2490484A, an Inhibitor of a DNA-dependent Protein Kinase, in Combination With Radiotherapy (NCT NCT02516813)

First Participant First Visit (FPFV): 15 September 2015; Last Participant last Visit (LPLV): 19 November 2021

The study was planned to be conducted in 3 parts: Phase Ia (dose escalation), Phase Ib (dose expansion) and Ancillary clinical proof-of-principle (cPoP). Phase Ib part of the study was never initiated due to early discontinuation as per sponsor's decision.

Phase 1 Trial of MSC2490484A, an Inhibitor of a DNA-dependent Protein Kinase, in Combination With Radiotherapy

DLT: any Grade (Gr) greater than or equal to (\>=) 3 nonhematologic adverse event (AE)/any Gr\>=4 hematologic AE that is related to any of study treatments and occurs during the DLT period of 5 weeks (Phase Ia, Arm A) after the first dose of M3814. Following are considered as DLTs: Gr3 thrombocytopenia with medically concerning bleeding; Febrile neutropenia; Any toxicity/study treatment-related adverse event (TEAE) that, in opinion of Safety Monitoring Committee (SMC), is of potential clinical significance such that further dose escalation would expose participants to unacceptable risk; Any toxicity related to study treatments that causes participant to receive less than 80 percent (%) of the planned RT dose; Evidence of study treatment-related hepatocellular injury for \> 3 days.

DLT: any Grade (Gr) greater than or equal to (\>=) 3 nonhematologic AE/any Gr\>=4 hematologic AE that is related to any of study treatments and occurs during the DLT period of 12 weeks (Phase Ia, Arm B) after the first dose of M3814. Following are considered as DLTs: Gr3 thrombocytopenia with medically concerning bleeding; Febrile neutropenia; Any toxicity/study treatment-related adverse event (TEAE) that, in opinion of Safety Monitoring Committee (SMC), is of potential clinical significance such that further dose escalation would expose participants to unacceptable risk; Any toxicity related to study treatments that causes participant to receive less than 80 percent (%) of the planned RT dose; Any toxicity related to study treatments leading to an interruption of RT longer than 1 week in Arm B; Evidence of study treatment-related hepatocellular injury for \> 3 days.

Adverse Event (AE) was defined any untoward medical occurrence in a participant administered with a study drug, which does not necessarily have a causal relationship with this treatment. Serious AE was defined AE that resulted in any of the following outcomes: death; life threatening; persistent/significant disability/incapacity; initial/prolonged inpatient hospitalization; congenital anomaly/birth defect. TEAEs: TEAEs was defined as events with onset date or worsening during the on-treatment period. TEAEs included serious AEs and non-serious AEs. As per NCI-CTCAE v4.03, Grade 1: Mild; Grade 2: Moderate; Grade 3: Severe; Grade 4: Life-threatening; Grade 5: Death. Number of participants with Grade \>=3 TEAEs were reported.

Number of participants with shifts from Baseline values (Grade 0/1/2) to worst post-baseline values (Grade 1/2/3/4) were reported as per NCI-CTCAE, v4.03 graded from Grade 1 to 5. Grade 1: Mild; Grade 2: Moderate; Grade 3: Severe; Grade 4: Life-threatening; Grade 5: Death. Shifts in hematology parameter (hemoglobin low, leukocytes low, lymphocytes low, neutrophil count decreased, and platelet count decreased) were reported.

Number of participants with shifts from Baseline values (Grade 0/1/2) to worst post-baseline values (Grade 1/2/3/4) were reported as per NCI-CTCAE, v4.03 graded from Grade 1 to 5. Grade 1: Mild; Grade 2: Moderate; Grade 3: Severe; Grade 4: Life-threatening; Grade 5: Death. Shifts in biochemistry parameter (phosphate low, potassium low, sodium low, alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood bilirubin increased, glucose high, glucose low, albumin low and creatinine increased) were reported.

Vital sign assessments included assessments of heart rate, blood pressure, body weight and body temperature. Abnormal vital sign measurement was decided by Investigator. Number of participants with markedly abnormal vital sign measurements were reported.

Electrocardiograms (ECG) was obtained after the participant has been in a supine position for at least 5 minutes. ECG parameters included heart rate, atrial ventricular conduction, QR and QT intervals (including QTcF), and possible arrhythmias. Any ECG finding that was judged by the investigator as a abnormal (worsening) compared with a baseline value was considered an adverse event. Number of participants with shifts from normal baseline values to abnormal post-baseline values in ECG were reported.

Confirmed BOR was defined as best response of any of complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) recorded from date of randomization until disease progression. CR: Disappearance of all evidence of target and non-target lesions. PR: At least 30 percent (%) reduction from baseline in the sum of the longest diameter (SLD) of all lesions. SD: Neither sufficient increase to qualify for PD nor sufficient shrinkage to qualify for PR. PD: defined as at least a 20% increase in the SLD, taking as reference the smallest SLD recorded from baseline or the appearance of 1 or more new lesions. CR or PR must be confirmed by a subsequent tumor assessment, at least 4 weeks after initial documentation of CR or PR.

Unconfirmed BOR was defined as unconfirmed best response of any of complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) recorded from date of randomization until disease progression. CR: Disappearance of all evidence of target and non-target lesions. PR: At least 30 percent (%) reduction from baseline in the sum of the longest diameter (SLD) of all lesions. SD: Neither sufficient increase to qualify for PD nor sufficient shrinkage to qualify for PR. PD: defined as at least a 20% increase in the SLD, taking as reference the smallest SLD recorded from baseline or the appearance of 1 or more new lesions.

The tumor size was defined as the sum of the longest diameters for the target lesions. The sum of lesion diameters was calculated using RECIST v1.1 and was assessed by Investigator.

Cmax was taken directly from the observed concentration-time curve.

tmax was obtained directly from the concentration versus time curve.

AUC0-24 of M3814 was defined as the area under the concentration time curve from time 0 to 24 hours post-dose.

The AUC from time zero (dosing time) extrapolated to infinity, based on the predicted value for the concentration at tlast, as estimated using the linear regression from the determination of the terminal first order (elimination) rate constant (lambda z). AUC0-inf = AUC0-t plus Clast pred/lambda z. Lambda z was terminal elimination rate constant determined from the terminal slope of the log-transformed plasma concentration curve using linear regression on terminal data points of the curve.

t1/2 was the time measured for the concentration to decrease by one half. t1/2 was calculated by natural log 2 divided by Lambda z.

The apparent total body clearance of study intervention following extravascular administration on FD1, taking into account the fraction of dose absorbed. CL/f = Dose oral (p.o.)/AUC0-inf. The predicted AUC0-inf should be used.

Apparent volume of distribution during the terminal phase following extravascular administration for M8891 was calculated. Vz/f = Dose/(AUC0-infinity multiply by Lambda z) following single dose. The AUC from time zero (dosing time) extrapolated to infinity, based on the predicted value for the concentration at tlast, as estimated using the linear regression from lambda z determination. AUC(0- inf)=AUC0-t plus Clastpred/lambda z where Clastpred was last predicted concentration. Lambda Z was terminal elimination rate constant determined from the terminal slope of the log-transformed plasma concentration curve using linear regression on terminal data points of the curve.

Cmax was taken directly from the observed concentration-time curve.

tmax was obtained directly from the concentration versus time curve.

AUCtau was defined as area under the plasma concentration-time curve from time zero to the end of the dosing interval (tau). AUCtau was calculated using the mixed log linear trapezoidal rule.

The AUC from time zero (dosing time) extrapolated to infinity, based on the predicted value for the concentration at tlast, as estimated using the linear regression from the determination of the terminal first order (elimination) rate constant (lambda z). AUC0-inf = AUC0-t plus Clast pred/lambda z. Lambda z was terminal elimination rate constant determined from the terminal slope of the log-transformed plasma concentration curve using linear regression on terminal data points of the curve.

t1/2 was the time measured for the concentration to decrease by one half. t1/2 was calculated by natural log 2 divided by Lambda z.

Clearance of a drug was a measure of the rate at which a drug is metabolized or eliminated by normal biological processes.

Volume of distribution was defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug. Vss/f after oral dose was influenced by the fraction absorbed.

Accumulation ratio for AUC was calculated as AUC, after dosing on fraction Day 10 divided by AUC, after dosing on fraction Day 1 of cycle 1.

Accumulation ratio for Cmax was calculated as Cmax, after dosing on fraction Day 10 divided by Cmax, after dosing on fraction Day 1 of cycle 1.

Cmax was taken directly from the observed concentration-time curve.

tmax was obtained directly from the concentration versus time curve.

AUC0-4hr is the area under the plasma concentration-time curve from time 0 to 4 hours post-dose. This is a measure of the average amount of study drug M3814 in the blood plasma over a period of 4 hours after the dose.

Area under the plasma concentration vs time curve from time zero to the last sampling time t at which the concentration was at or above the lower limit of quantification (LLOQ). AUC0-t was to be calculated according to the mixed log-linear trapezoidal rule.

AUC0-t/Dose was defined as AUC from time of dosing to the time of the last measurable concentration divided by dose.

AUC0-4/Dose was defined as AUC from time of dosing to the time zero to 4 hours divided by dose.

Cmax/Dose was calculated as maximum observed plasma concentration obtained directly from the concentration versus time curve divided by dose. Cmax/dose was measured in nanogram per milliliter per milligram (ng/mL/mg).