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REPARE THERAPEUTICS Repare Therapeutics Provides Business Update and Reports Second Quarter 2021 Financial Results August 12 , 2021 Announced dosing of first patient in Phase 1b / 2 ATTACC trial of ATR inhibitor RP - 3500 and PARP inhibitor combinations in patients with molecularly selected cancers Planning disclosure of initial monotherapy data from the Phase 1/2 TRESR RP - 3500 clinical trial early in 4Q21 Announced dosing of first patient in RP - 6306 Phase 1 clinical trial CAMBRIDGE , Mass . & MONTREAL -- ( BUSINESS WIRE ) -- Aug . 12 , 2021-- Repare Therapeutics Inc. ( " Repare " or the " Company " ) ( Nasdaq : RPTX ) , a leading clinical - stage precision oncology company enabled by its proprietary synthetic lethality approach to the discovery and development of novel therapeutics , today reported financial results for the second quarter ended June 30 , 2021 . " We are pleased to have dosed the first patient in our Phase 1b / 2 ATTACC trial of our ATR inhibitor RP - 3500 and additional new PARP inhibitor combinations in patients with molecularly selected cancers . " said Lloyd M. Segal , President and Chief Executive Officer of Repare . " We also look forward to disclosing initial results from the monotherapy arm of the Phase 1/2 clinical trial of our ATR inhibitor RP - 3500 early in the fourth quarter of 2021. " Second Quarter 2021 Review and Operational Updates : • Announced dosing of first patient in Phase 1b / 2 ATTACC clinical trial • In August 2021 , the Company dosed the first patient in its Phase 1b / 2 ATTACC clinical trial ( NCT04972110 ) of RP - 3500 , a potent and selective oral small molecule inhibitor of Ataxia - Telangiectasia and Rad3 - related protein kinase , or ATR , and PARP inhibitor combinations in patients with molecularly selected cancers . o The primary objectives of the Phase 1b portion of the trial include assessment of safety and tolerability and dose finding to establish a recommended Phase 2 dose ( " RP2D " ) of RP - 3500 in combination with ZEJULA ( niraparib ) or LYNPARZA ( olaparib ) in up to 48 patients ( 24 per combination ) with advanced solid tumors harboring specific mutations in DNA damage response . o The Phase 2 portion of the trial is designed to include a dose expansion at the RP2D with a primary objective to determine the antitumor activity of RP - 3500 in combination with niraparib or olaparib . • Initial results to be presented from the monotherapy arm of the Phase 1/2 TRESR clinical trial evaluating RP - 3500 as a monotherapy and in combination with Pfizer's PARP inhibitor , talazoparib , in patients with solid tumors o In July 2020 , the Company began dosing in a Phase 1/2 clinical trial of RP - 3500 . • The Company has activated 12 clinical trial sites across North America and Europe . o The Company plans to disclose initial results from the monotherapy arm early in the fourth quarter of 2021 . • Announced dosing of first patient in RP - 6306 Phase 1 clinical trial o In April 2021 , the Company dosed the first patient in its Phase 1 clinical trial of RP - 6306 . • The trial is expected to enroll approximately 60 patients with recurrent tumors characterized by genomic alterations predicted by the Company's SNIPRX® CRISPR - based platform to be sensitive to RP - 6306 . • The trial objectives include assessment of safety , tolerability , dose , and schedule ( including the establishment of a recommended Phase 2 dose ) . • Progressed towards first druggable target option exercise in our Bristol Myers Squibb collaboration and license agreement o In July and August 2021 , the Company received notification with respect to druggable targets from Bristol Myers Squibb , pursuant to the Bristol Meyers Squib collaboration and license agreement . Based on these notifications , we reclassified $ 6.2 million of non - current deferred revenue to current . Second Quarter 2021 Financial Results : • Cash and cash equivalents , restricted cash and marketable securities : Cash and cash equivalents , restricted cash and marketable securities as of June 30 , 2021 were $ 301.0 million . • Research and development expenses , net of tax credits ( Net R & D ) : Net R & D expenses were $ 20.2 million and $ 36.7 million for the three and six - month periods ended June 30 , 2021 , respectively , as compared to $ 9.0 million and $ 17.6 million for the three and six - month periods ended June 30 , 2020 , respectively . The increase in R & D expenses for the three and nine - month periods were primarily due to increases in development costs related to the Company's RP - 3500 and RP - 6306 programs , as well as increases in personnel related expenses , including stock - based compensation .