A phase II study of olaparib (AZD2281) in patients (Pts) with metastatic/advanced urothelial carcinoma and other genitourinary (GU) tumors with DNA-repair defects.
Authors: Chandran Elias , Simon Nicholas I. , Niglio Scot Anthony , Ley Lisa , Cordes Lisa M. , Banday Rouf , Kesserwan Chimene , Mouw Kent William , Kydd Andre Rashad , Boudjadi Salah , Prokunina-Olsson Ludmila , Parikh Mamta , Flaig Thomas W. , McKay Rana R. , Rezazadeh Arash , Ivy S. Percy , Iannantuono Giovanni Maria , Atiq Saad Omar , Steinberg Seth M. , Apolo Andrea B. 
Published: June 2023

TPS4607 Background: Olaparib is a poly-ADP-ribose polymerase (PARP) inhibitor that induces synthetic lethality in tumor cells with dysfunctional DNA damage repair (DDR) from loss of function of BRCA or other DDR genes. It improves survival in advanced ovarian, pancreatic, prostate and breast carcinoma with DDR gene alterations and is FDA approved for these indications. PARP inhibitors still have an undefined role in non-prostate GU tumors. We hypothesize that PARP inhibitors will have activity in DDR deficient tumors, regardless of histology. We are conducting a phase 2 trial of olaparib in non-prostate GU cancers with DDR gene defects. Methods: Eligible pts must have metastatic/advanced urothelial carcinoma or other non-prostate GU cancers and have measurable disease by RECIST 1.1. Pts in Cohorts 1 and 2 must harbor tumor or liquid pathologic DDR alterations identified by FoundationOne CDx (F1CDx) panel and reviewed by a molecular genetics review panel: Cohort 1 includes BRCA1, BRCA2, ATM, BAP1, MSH2, PALB2, and BRIP1 alterations, and pts with high tumor mutational burden (TMB) (>15 mutations/megabase); Cohort 2 (exploratory cohort) includes ABL1, ATR, ATRX, BARD1, BRD4, CCND1, CHEK1, CHEK2, DOTIL, FANCC, FANCE, FANCG, FANCL, IKBKE, MEN1, MLH1, MSH2, MSH6, MUTYH, NPM1, PMS2, POLD1, POLE, RAD51, SMARCB1, STEK11, and TP53 alterations. Cohort 3 (natural history) will include pts without pathologic alterations in any Cohort 1 or 2 genes. Pts with eligible gene alterations (Cohorts 1 and 2) will be given olaparib 300mg twice daily until progressive disease, unacceptable adverse events, withdrawal of consent or death. They will have circulating tumor cells (CTCs) collected at baseline and every 4 weeks, and CT restaging every 8 weeks. Pts in Cohort 3 will receive standard of care treatment and have baseline CTC collection and be followed for survival. The primary objective is to evaluate the objective response rates (ORR) in Cohorts 1 and 2. Secondary objectives include progression-free survival (PFS), overall survival (OS) and safety. In these cohorts, the trial will have a Simon optimal two-stage design. In Cohort 1, 25 evaluable pts will be required to provide 90% power with alpha = 0.1 to differentiate between a promising ORR of 30% versus an unacceptably low ORR of 10%. In Cohort 2, 35 evaluable pts will be required to provide 90% power with alpha = 0.05 to differentiate between a promising ORR of 30% versus an unacceptably low ORR of 10%. Exploratory objectives include estimating the distribution of DDR alterations in non-prostate GU malignancies, assessing the effectiveness of NGS in detecting DDR alterations in circulating tumor DNA (ctDNA), assessing levels of baseline CTCs and changes in CTC level with olaparib, and correlating with clinical outcomes. This is an ECTCN network clinical trial and is open to enrollment. Clinical trial information: NCT03375307 .