A phase Ia/Ib trial of the DNA-dependent protein kinase inhibitor (DNA-PKi) M3814 in combination with radiotherapy in patients with advanced solid tumors.

Abstract

e14048 Background: DNA-PK, with its protein subunits, Ku70 and Ku80, regulates one of the major pathways responsible for repair of double-strand breaks in DNA that are induced by radiotherapy (RT) and some chemotherapeutic agents (CT). Therefore, the combined strategy of RT with a DNA-PKi is promising. The purpose of this phase I trial is to explore the safety, tolerability, pharmacokinetic (PK) profile, and clinical activity of M3814 administered together with RT and chemo-RT (CRT). Methods: Patients (pts) with tumors or metastasis in the head and neck region or thorax in need of palliative RT (10 x 3 Gy) are eligible for the dose escalation part Ia, with a starting dose of 100 mg once daily. Dose escalation decisions are aided by the Bayesian logistic regression model with overdose control. Dose-limiting toxicity (DLT) is evaluated up to 3 weeks after RT. Rich PK sampling is taken during treatment. Tumor evaluation is performed every 6 weeks up to 6 months and every third month thereafter. Results: As of January 2017, 7 pts had been enrolled into the part Ia dose escalation arm and treated with 100 mg daily. The most frequent adverse events (AEs) were fatigue, constipation, decreased appetite, dry mouth, dysphagia, headache, oral pain, radiation skin injury, and mucositis in more than 1 pt (20%). No pts discontinued due to AE. Two episodes of grade 3 mucositis lasting > 7 days were reported; one of these was classified as a DLT, and both pts recovered without sequelae. Two of 7 pts enrolled had local tumor control at +300 days. PK analysis demonstrated high exposure variability. Conclusions: M3814 at the 100 mg daily dose was tolerable as palliative treatment and dose escalation is currently at 200 mg. In part Ib of the study, two separate dose escalation arms will enroll pts with either head and neck squamous cell carcinoma (SCCHN; US only) or non-small cell lung cancer (EU and US) to receive CRT 2 Gy x 30-35 over 6-7 weeks with curative intent; the SCCHN cohort is now open for enrollment. For these two cohorts, the DLT window will be 12 weeks. Clinical trial information: NCT02516813.

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DNA folds threaten genetic stability and can be leveraged for chemotherapy

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