OZM-114: Phase Ib expansion study of CX-5461in patients with solid tumors and BRCA2 and/or PALB2 mutation.

TPS5621 Background: Pre-clinical and clinical data demonstrate that CX-5461 selectively kills HR deficient cancer cells through stabilizing G4 structures and inducing replication-dependent DNA damage. Phase 1 studies suggest CX-5461 has clinical activity and warrants further investigation in HR-deficient tumors, including those with pathogenic BRCA2 and PALB2 mutation. The recommended phase 2 dose (RP2D) requires further refinement to establish the chronic tolerable dose for further phase 2 trials, particularly regarding the incidence of ocular toxicity. The doses of 325mg/m2 and 250mg/m2 were selected for this study expansion cohorts because it is well within the efficacy range and below the first occurrence of ocular toxicity in a previous study. Methods: This is an open-label, multi-center, phase 1b study designed to determine a tolerable dose of CX-5461 in patients with ovarian, pancreatic, prostate, and breast cancers for Phase II trials. Eligible patients will be enrolled into two cohorts: A) Main cohort (target accrual: 32 patients) and B) Exploratory cohorts (target accrual: 20 patients), see table-1 below. The primary outcomes include assessment of: 1) Safety and tolerability of CX-5461, in particular to determine late onset ocular toxicity 2) Anti-tumor activity of CX-5461 in patients with solid tumors and germline BRCA2 and/or PALB2 mutation, and 3) Effect of CX-5461 on Quality of Life measures. Secondary outcomes include evaluation of :1) Safety: CTCAE v 5.0, SAEs, dose modifications due to AEs, 2) Activity: best overall response from tumor evaluations performed every 2 cycles, according to RECIST v1.1, and duration of response., and 3) patient-reported outcomes: PRO (PRO-CTCAE v1.0 questionnaires to evaluate cutaneous, gastrointestinal, visual/perceptual, cardio/circulatory, sleep/wake and miscellaneous symptoms. Exploratory Objectives include assessment of: 1) anti-tumor activity of CX-5461 in patients with ovarian cancer and pathogenic/likely-pathogenic BRCA1 mutation and/or other HRD-associated somatic mutation, and 2) molecular profile of tumors and predictive value of mutational signatures in predicting response or resistance to CX-5461. Clinical trial information: NCT04890613. [Table: see text]