Study of Peposertib in Combination With Capecitabine and RT in Rectal Cancer

DLT is defined as any of following treatment emergent adverse events (TEAEs) considered possibly related to study treatment by Investigator and/or Sponsor up to completion of assigned chemoradiotherapy treatment. DLT were based on SMC: Adverse drug reaction that, in the opinion of SMC, is of potential clinical significance such that further dose escalation would expose participants to unacceptable risk; Any occurrence of drug-induced liver injury meeting the Hy's law criteria; Any Grade 3 toxicity excluding diarrhea, neutropenia lasting for ≤ 5 days, nausea & vomiting, Grade 3 thrombocytopenia without bleeding; Grade ≥ 4 AEs at least possibly related to study drug, irrespective of duration, excluding: Isolated Grade 4 lymphocytopenia without clinical symptoms; Neutropenia lasting for ≤ 5 days and not associated with fever; Any toxicity related to study drug that causes participant to receive > 80% of planned peposertib, capecitabine or RT dose.

Adverse event (AE) is any untoward medical occurrence in participant administered pharmaceutical product, regardless of causal relationship with this treatment. Therefore, an AE can be any unfavorable & unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with use of a medicinal product, regardless if it is considered related to medicinal product. Serious AE: an AE that resulted in any of the following outcomes: death; life threatening; persistent/significant disability/incapacity; initial or prolonged inpatient hospitalization; congenital anomaly/birth defect or was otherwise considered medically important. TEAE: AE with onset after start of treatment or with onset date before the treatment start date but worsening after treatment start date. TEAEs included both serious and non-serious TEAEs. Treatment-related TEAEs: reasonably related to study intervention. Number of participants with TEAEs and treatment related TEAEs were reported.

The laboratory measurements included hematology and biochemistry values were graded with National Cancer Institute - Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0 toxicity grades (where Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe, Grade 4 = life threatening and Grade 5 = death). Number of participants with abnormalities Grade >= 3 in laboratory test values were reported.

Vital sign assessments included assessments of heart rate, diastolic blood pressure, systolic blood pressure, respiratory rate and temperature. Number of participants with markedly abnormal vital sign measurements were reported.

Electrocardiograms (ECG) was obtained after the participant has been in a semi-supine position for at least 5 min. ECG parameters included heart rate, PQ/PR duration, QRS and QT duration, QT Interval. Clinical significance was determined by the investigator. Number of participants with clinically significant abnormalities in 12-lead ECG were reported.

pCR: It is defined as absence of viable tumor cells in the primary tumor and lymph nodes. Participants considered to have a pCR if they undergo surgery and no residual cancer is found on histological examination of removed specimen. cCR: Participants are considered to have a cCR if: 1) Absence of any residual tumor in primary site and draining lymph nodes on imaging with magnetic resonance imaging; 2) No visible lesion at endoscopy except a flat scar, telangiectasia, and/or whitening of mucosa; 3) Absence of any palpable tumor or irregularity on digital rectal examination (DRE) and endoscopic ultrasonography (EUS); 4) If a biopsy is taken, it must be negative. Participants are considered as responders to composite endpoint pCR/cCR if participant had surgery and had pCR; participant did not undergo surgery but had cCR. Number of participants with composite pathological complete response (pCR)/ clinical complete response (cCR) were reported.

Disease-free Survival time, defined as the time from first treatment day to the date of the first documentation of objective progressive disease or death due to any cause, whichever occurs first. Median disease-free survival time was estimated according to Kaplan-Meier method.

pCR is defined as the absence of viable tumor cells in the primary tumor and lymph nodes. Participants are considered to have a pCR if they undergo surgery and no residual cancer is found on histological examination of the removed specimen.

cCR: It is defined as participants considered to have a cCR if: 1) Absence of any residual tumor in the primary site and draining lymph nodes on imaging with magnetic resonance; 2) No visible lesion at endoscopy except a flat scar, telangiectasia, and/or whitening of the mucosa; 3) Absence of any palpable tumor or irregularity on digital rectal examination (DRE) and endoscopic ultrasonography (EUS); 4) If a biopsy is taken, it must be negative.

Time from surgery to local recurrence defined as time from day of surgery to the date of the first documentation of progression of disease, flagged as local recurrence. Median time from surgery to local recurrence was estimated according to Kaplan-Meier method.

Time from surgery to distant metastasis defined as time from day of surgery to the date of the first documentation of progression of disease, flagged as distant metastasis. Median time from surgery to distant metastasis was estimated according to Kaplan-Meier method.

The NAR formula includes the clinical tumor (cT) stage, pathologic tumor (pT), and node (pN) stage according to the tumor, node, metastasis classification system for colorectal cancers. The NAR formula is as follows:

[5pN- 3 (cT- pT) + 12]2 / 9.61

NAR score ranges from 0 to 100, whereas a score close to 100 is indicative of a poorer prognosis.

Cmax was obtained directly from the concentration versus time curve. One participant was assigned to receive peposertib 100 mg; however, this participant took peposertib 50 mg for FD 1 through FD 10 and then took peposertib 100 mg for remainder of study participation. PK results for this participant was summarized by actual dose received (50 mg) whereas non-PK results are summarized by planned dose (100 mg).

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 (LLQ). AUC0-t was to be calculated according to the mixed log-linear trapezoidal rule.

Time to reach the maximum plasma concentration (Tmax) was obtained directly from the concentration versus time curve.

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.

The apparent volume of distribution during the terminal phase following extravascular administration, based on the fraction of dose absorbed. Vz/f = Dose/(AUC0-inf multiplied by Lambda z) following single dose. Vz/f= Dose/(AUCtau*Lambda z) following multiple dose. One participant was assigned to receive peposertib 100 mg; however, this participant took peposertib 50 mg for FD 1 through FD 10 and then took peposertib 100 mg for remainder of study participation. PK results for this participant was summarized by actual dose received (50 mg) whereas non-PK results are summarized by planned dose (100 mg).

Terminal half-life is the time measured for the concentration to decrease by one half. Terminal half-life calculated by natural log 2 divided by lambda z. One participant was assigned to receive peposertib 100 mg; however, this participant took peposertib 50 mg for FD 1 through FD 10 and then took peposertib 100 mg for remainder of study participation. PK results for this participant was summarized by actual dose received (50 mg) whereas non-PK results are summarized by planned dose (100 mg).