Integration of molecular cancer classification and next-generation sequencing to identify metastatic patients eligible for PARP inhibitors.

Abstract

e15080 Background: Olaparib, rucaparib, and niraparib are 3 poly-ADP-ribose polymerase inhibitors (PARPi) approved by the FDA for ovarian, breast, pancreatic, prostate, fallopian tube and peritoneal cancers with BRCA mutations. Several ongoing clinical trials aim to determine the efficacy of PARPi in various other cancer types, including specific cancer subtypes, such as clear cell renal cell carcinoma and cholangiocarcinoma either as monotherapy or combination therapy; however, eligibility for PARPi therapy requires the identification of the primary tumor type and confirmation of BRCA mutation. The 92-gene assay (CancerTYPE ID) is a validated gene expression classifier of 50 tumor types and subtypes for metastatic patients with unknown or uncertain diagnoses. Multimodal biomarker testing, including next-generation sequencing (NGS), enables identification of actionable biomarkers to guide targeted therapy selection. In the current study, a database of metastatic cases that integrates tumor type with biomarker analysis was characterized to identify those eligible for PARPi treatment. Methods: MOSAIC (Molecular Synergy to Advance Individualized Cancer Care) is an IRB-approved, de-identified database of cases submitted for CancerTYPE ID testing with tissue-guided multimodal biomarker testing by NGS, including tumor mutational burden (TMB) fluorescent in situ hybridization (FISH), and microsatellite instability (MSI), and immunohistochemistry (IHC) (NeoTYPE profiles, Neogenomics). For the current study, metastatic cancers classified as ovarian, breast, pancreatic, or prostate were identified in the database, followed by NGS analysis to detect mutations in BRCA1 or BRCA2. Results: The current analysis included 2151 CancerTYPE ID cases, from which 71 ovarian, 47 breast, 12 pancreatic and 15 prostate cancer cases were identified. Out of 46 cases of ovarian cancer with molecular biomarker results, NGS identified 7 (15.3%) cases with BRCA1 mutation and 4 (8.7%) cases with BRCA2 mutation. Additionally, 4 (10.5%) cases with BRCA1 mutation and 1 (2.6%) case with BRCA2 mutation out of 38 cases of breast cancer with BRCA results were detected. No cases of prostate cancer or pancreatic cancer with mutations in BRCA1 or BRCA2 were detected. Conclusions: These findings in metastatic patients demonstrate the clinical utility of tumor type identification combined with molecular biomarker profiling, leading to additional options for patients with advanced disease. Specifically, analysis of the MOSAIC database identified a subset of patients with metastatic cancers eligible for PARPi therapy based on tumor type and BRCA mutation status. As new and approved PARPi are evaluated for efficacy in additional tumor types, patients can be identified that may be eligible for these targeted cancer drugs.