Shah, Payal D., Wethington, Stephanie L., Pagan, Cheyenne, Latif, Nawar, Tanyi, Janos, Martin, Lainie P., Morgan, Mark, Burger, Robert A., Haggerty, Ashley, Zarrin, Haley, Rodriguez, Diego, Domchek, Susan, Drapkin, Ronny, Shih, Ie-Ming, Smith, Simon A., Dean, Emma, Gaillard, Stéphanie, Armstrong, Deborah, Torigian, Drew A., and Hwang, Wei-Ting
Platinum-resistant, high-grade serous ovarian cancer (HGSOC) has limited treatment options. Preclinical data suggest that poly(ADP-ribose) polymerase inhibitors (PARPi) and ataxia telangiectasia and Rad3-related kinase inhibitors (ATRi) are synergistic. CAPRI (NCT03462342) is an investigator-initiated study of olaparib plus ceralasertib in recurrent HGSOC. Herein, we present results from the platinum-resistant cohort. A Simon 2-stage design was utilized. Platinum-resistant HGSOC patients received ceralasertib 160 mg orally daily, days 1–7 and olaparib 300 mg orally twice daily, days 1–28 of a 28-day cycle until toxicity or progression. Primary endpoints were toxicity and efficacy including objective response rate (ORR) by RECIST. Secondary endpoint was progression-free survival (PFS). The null hypothesis (≤5% ORR) would be rejected if there were ≥ 1 responses in 12 patients. Fourteen PARPi-naïve patients were evaluable for toxicity; 12 were evaluable for response. Three had BRCA1 mutations (1 germline, 2 somatic). Adverse events possibly related to treatment were primarily grade (G) 1/2. G3 toxicities included nausea (14.3%), fatigue (7.1%), anorexia (7.1%), and anemia (7.1%). No objective responses occurred. Best response was stable disease in 9 patients and progressive disease in three. Five patients had a ≥ 20% to <30% reduction in disease burden, including 3 with BRCA1 mutations. Three of 11 patients (27%; 2 with BRCA1 mutations) evaluable by Gynecologic Cancer Intergroup criteria had >50% CA-125 decline, including 2 with CA-125 normalization. Median PFS was 4.2 months overall (90% CI:3.5–8.2) and 8.2 months (3.6 months–not determined) for patients with BRCA1 mutations. Olaparib plus ceralasertib is well-tolerated. No objective responses occurred, though a signal of activity was seen particularly in disease associated with BRCA1. Further evaluation of this combination should include alternate dosing strategies in genomically-selected populations. • Combination olaparib and ceralasertib is tolerable at the current RP2D. • No RECIST radiological responses occurred and PFS was 4.2 months. • PFS was 8.2 months in 3 subjects with BRCA1 mutations. • CA-125 responses by GCIG criteria were seen in 3 of 11 evaluable subjects. • A signal of activity was seen in DNA repair deficient platinum resistant HGSOC. [ABSTRACT FROM AUTHOR]