Precision medicine phase II study evaluating the efficacy of a double immunotherapy by durvalumab and tremelimumab combined with olaparib in patients with solid cancers and carriers of homologous recombination repair genes mutation in response or stable after olaparib treatment.

BACKGROUND: Tumors with deficient homologous repair are sensitive to PARP inhibitors such as olaparib which is known to have immunogenic properties. Durvalumab (D) is a human monoclonal antibody (mAb) which inhibits binding of programmed cell death ligand 1 (PD-L1) to its receptor. Tremelimumab (T) is a mAb directed against the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). This study is designed to evaluate the efficacy of combination of olaparib, durvalumab and tremelimumab in patients with a solid tumors with a mutation in homologous gene repair.

METHODS: This phase II study will assess the efficacy and safety of olaparib/D/T association in patients (n = 213) with several types of solid cancers (breast cancer, ovarian cancer, pancreatic cancer, endometrial cancer, prostate cancer and others) with at least one mutation in homologous repair genes (BRCA1, BRCA2, PALB2, ATM, FANCA, FANCB, FANCC, FANCE, FANCF, CHEK2, RAD51, BARD1, MRE11, RAD50, NBS1, HDAC2), LKB1/STK11, INPP4B, STAG2, ERG, CHEK1, BLM, LIG4, ATR, ATRX, CDK12). Good performance status patients and corresponding to specific inclusion criteria of each cohort will be eligible. STEP1: Patients will receive olaparib 300 mg BID. In absence of progression after 6 weeks of olaparib, they will follow STEP 2 with olaparib and immunotherapy by durvalumab (1500 mg Q4W) + tremelimumab (75 mg IV Q4W) during 4 months and will further pursue durvalumab alone until disease progression, death, intolerable toxicity, or patient/investigator decision to stop (for a maximum duration of 24 months, and 36 months for ovarian cohort). Primary endpoint is safety and efficacy according to progression-free survival (PFS) of olaparib + immunotherapy (durvalumab + tremelimumab) during 4 months followed by durvalumab alone as maintenance in patients with solid cancers and in response or stable, after prior molecular target therapy by olaparib; secondary endpoints include overall survival (OS), disease control rate (DCR), response rate after 6 weeks of olaparib, safety of olaparib/durvalumab/tremelimumab association. Blood, plasma and tumor tissue will be collected for potential prognostic and predictive biomarkers.

DISCUSSION: This study is the first trial to test the combination of olaparib and double immunotherapy based on molecular screening.

TRIAL REGISTRATION: NCT04169841 , date of registration November 20, 2019.