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

A Multicenter Study With an Open-label Phase Ib Part Followed by a Randomized, Placebo-controlled, Double-blind, Phase II Part to Evaluate Efficacy, Safety, Tolerability, and Pharmacokinetics of the DNA-PK Inhibitor Peposertib (M3814) in Combination With Capecitabine and RT in Participants With Locally Advanced Rectal Cancer

The main purpose of the study was to define maximum tolerated dose (MTD), recommended Phase II dose (RP2D) safety and tolerability of Peposertib in combination with capecitabine and radiotherapy (RT).

Inclusion Criteria:

• Participants who have an Eastern Cooperative Oncology Group Performance Status less than or equals to (<=) 1
• Participants who have histologically confirmed and localized resectable rectal cancer (Stage 3)
• Participants who received induction chemotherapy are allowed to be enrolled to this study except this induction is resulting in clinical complete response (cCR) or tumor progression
• Participants who have lower edge of the tumor located in rectum
• Adequate hematological, hepatic and renal function as defined in the protocol
• Male participants if they agree to the following during the study intervention period and for at least 12 weeks after the last dose of study intervention
• Female participants are eligible if not pregnant or breastfeeding
• Other protocol defined inclusion criteria could apply

Exclusion Criteria:

• Participants with history of any other significant medical disease or psychiatric conditions that might in the assessment of the Investigator preclude safe participation in the study
• Participants with history of difficulty swallowing, malabsorption, or other chronic gastrointestinal disease or conditions that may hamper compliance and/or absorption of the study intervention
• Unstable cardiovascular function within 6 months prior to enrollment
• Hypertension uncontrolled by medication (ie, systolic blood pressure >= 150 millimeter of mercury (mmHg) and diastolic blood pressure >= 90 mmHg)
• Participants with history of other malignant disease within the past 5 years, other than successfully treated basal carcinoma of the skin or carcinoma in situ of the cervix
• Participants with known human immunodeficiency virus positivity, known active hepatitis (for example, hepatitis B virus or hepatitis C virus), current alcohol abuse, or cirrhosis
• Participants with ongoing active infection or treatment with a live attenuated vaccine within 4 weeks of dosing
• Participants with concomitant use of H2-blocker or proton pump inhibitors (PPIs) (or unable to stop at least 5 days prior to the first treatment). Note that calcium carbonate is acceptable
• Participation in any interventional clinical study within 28 days prior to Screening or during participation in this study
• Other protocol defined exclusion criteria could apply.