Homologous recombination deficiency (HRD) scoring in pancreatic ductal adenocarcinoma (PDAC) and response to chemotherapy.

2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 741-741
Author(s):  
Grainne M. O'Kane ◽  
Rob Denroche ◽  
Sarah Louise Picardo ◽  
Amy Zhang ◽  
Spring Holter ◽  
...  

741 Background: Whole genome sequencing (WGS) can reveal patterns of substitution base signatures and structural variation consistent with tumours deficient in homologous recombination repair. We evaluated the published HRDetect score and a novel HRD hallmark score (HS) in patients receiving combination chemotherapy (cCT) on the COMPASS trial for advanced PDAC. Methods: The HRD-HS incorporates 10 genomic characteristics of HRD-PDAC with a score ≥ 4 defining HRD. HRD-HS and an HRDetect score ≥0.7 were applied to WGS data and overall survival (OS) and response (ORR) evaluated. Sensitivity and specificity were ascertained. Results: As of 05/19, 205 eligible patients (pts) were enrolled and 186 received cCT including modified FOLFIRINOX n = 108 (58%) or cisplatin/gemcitabine n = 2 (1%) and gemcitabine/nab-paclitaxel n = 76 (41%). HRD-HS had a sensitivity of 87.5% and specificity of 100% in detecting HRD-PDAC. In contrast, HRDetect (≥0.7) had sensitivity of 51.9% and specificity of 100%; sensitivity increased to 73.7% when using a cutoff score of ≥0.99. 23/186 (12%) pts were classified as HRdetecthi and median OS was 15.3months (mo) vs 8.7mo in HRDetectlo pts (HR 0.44 95% CI 0.27-.70, p = 0.009). In platinum treated pts, median OS was 18.1mo (HRDetecthi) vs 9.3mo (HRDetectlo) (HR 0.38 95%CI 0.21-0.69, p = 0.02). HRD-HS predicted the longest median OS for platinum of 21.0mths. ORR in HRDetecthi was not different to HRDetectlo pts treated with cCT, however in those receiving platinum the ORR was 50% vs 19% respectively (p < 0.001). Of the false positives by HRDetect, 46% had a non-BRCA1 tandem duplicator phenotype (TDP). The TDP group comprised 8% of all patients enrolled. HRD-PDAC was caused by inactivation of BRCA1/2, PALB2, RAD51C and XRCC2; all germline variants were pathogenic. Pathogenic ATM and CHEK2 germline variants were present in 3 pts with evidence of a second somatic hit or LOH, none of these identified as HRD by either classifier nor considered a TDP. Conclusions: HRD-HS most correctly identified HRD-PDAC however the HRDetect score classifies additional patients sensitive to cCT, especially platinum. The TDP cohort may be responsive to DNA damaging agents warranting further evaluation. Clinical trial information: NCT02750657.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e16234-e16234
Author(s):  
Nengwen Ke ◽  
Maolin Yan ◽  
Xu Che ◽  
Yu Cheng ◽  
Zheng Wang ◽  
...  

e16234 Background: Pancreatic cancer (PC) is a highly malignant tumor with poor prognosis. Among them, pancreatic ductal adenocarcinoma (PDAC) accounts for 80-90% of pancreatic cancer. While, the treatment of PDAC has always been a clinical challenge. PDAC with mutations in homologous recombination repair (HRR) genes such as BRCA are particularly sensitive to platinum agents. The POLO study has shown that Olaparib was efficient and well-tolerated as maintenance therapy in patients with germline BRCA1/2 mutation and a metastatic PDAC controlled after a platinum-based induction chemotherapy. However, investigation of prevalence of HRR gene mutations in Chinese PDAC patients need to be well defined. Methods: Formalin-fixed, paraffin-embedded (FFPE) tumor tissues and matching blood samples from PDAC patients were collected and sequenced using next-generation sequencing (NGS) targeting 450 cancer genes. Genomic alterations and tumor mutational burden (TMB) values were assessed. The association of HRR gene mutations with TMB was assessed. The testing was carried out by OrigiMed (Shanghai, China) witch a College of American Pathologists accredited and Clinical Laboratory Improvement Amendments certified laboratory. Using targeted capture genomic sequencing, we assessed 98 PDAC patients for germline and somatic loss-of-function mutations in 14 genes, including BRCA1, BRCA2, and 12 other genes in the HR pathway. Results: In total, 98 PDAC patients were recruited including 48 females and 50 males with a median age of 58 (range 35-84). The most frequently mutated genes were KRAS (94%), TP53 (74%), CDKN2A (36%), SMAD4 (27%), GATA6 (9%) and ATM (5%). Mutation rates varied in pancreatic cancer signaling pathway: WNT (35.71%), PI3K (11.22%), HRR (11.22%), NOTCH (3.06%), FGF (2.04%). 2.04% (2/98) patients had high TMB (defined as ≥10 muts/Mb) with a median of 2.2 muts/Mb (0-47 mus/Mb). 34.69% (34/98) of the patients had one or more actionable genetic mutations. We identified that 11.2% (11/98) patients had at least one mutation in HRR genes. The most frequently mutated HRR genes were ATM (50%), BRCA1 (16.7%), BRCA2 (25%) and PALB2 (8.3%). The most common mutation type in HRR-related gene was truncation (75%, 9/12). HRR-related germline mutations in BRCA (71.43%, 5/7), ATM (28.57%, 2/7) were detected in seven patients, six of them with cancer related family history. We confirmed that patients with HRR mutations were younger than wild type HRR (52.6 years vs. 59.3 years, p < 0. 05). We demonstrated that patients with HRR mutations had a significantly higher TMB than patients with wild type HRR (median TMB: 3.4 vs. 1.8 muts/Mb, p < 0. 05). Conclusions: HRR gene alterations occurred in 11.2% of Chinese PDAC patients HRR pathway alterations are relatively frequent in PDAC patients and consideration for biomarker-enriched clinical trials with PARP, immune checkpoint inhibitors, and novel combinations are warranted.


2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Birgitte Bertelsen ◽  
Ida Viller Tuxen ◽  
Christina Westmose Yde ◽  
Migle Gabrielaite ◽  
Mathias Husted Torp ◽  
...  

2021 ◽  
Vol 11 (4) ◽  
pp. 245
Author(s):  
Laura Cortesi ◽  
Claudia Piombino ◽  
Angela Toss

The homologous recombination repair (HRR) pathway repairs double-strand DNA breaks, mostly by BRCA1 and BRCA2, although other proteins such as ATM, CHEK2, and PALB2 are also involved. BRCA1/2 germline mutations are targeted by PARP inhibitors. The aim of this commentary is to explore whether germline mutations in HRR-related genes other than BRCA1/2 have to be considered as prognostic factors or predictive to therapies by discussing the results of two articles published in December 2020. The TBCRC 048 trial published by Tung et al. showed an impressive objective response rate to olaparib in metastatic breast cancer patients with germline PALB2 mutation compared to germline ATM and CHEK2 mutation carriers. Additionally, Yadav et al. observed a significantly longer overall survival in pancreatic adenocarcinoma patients with germline HRR mutations compared to non-carriers. In our opinion, assuming that PALB2 is a high-penetrant gene with a key role in the HRR system, PALB2 mutations are predictive factors for response to treatment. Moreover, germline mutations in the ATM gene provide a better outcome in pancreatic adenocarcinoma, being more often associated to wild-type KRAS. In conclusion, sequencing of HRR-related genes other than BRCA1/2 should be routinely offered as part of a biological characterization of pancreatic and breast cancers.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Thibaut S. Matis ◽  
Nadia Zayed ◽  
Bouchra Labraki ◽  
Manon de Ladurantaye ◽  
Théophane A. Matis ◽  
...  

AbstractIt was hypothesized that variants in underexplored homologous recombination repair (HR) genes could explain unsolved multiple-case breast cancer (BC) families. We investigated HR deficiency (HRD)-associated mutational signatures and second hits in tumor DNA from familial BC cases. No candidates genes were associated with HRD in 38 probands previously tested negative with gene panels. We conclude it is unlikely that unknown HRD-associated genes explain a large fraction of unsolved familial BC.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A344-A344
Author(s):  
Timothy A Yap ◽  
Mallika Dhawan ◽  
Andrew E Hendifar ◽  
Michele Maio ◽  
Taofeek K Owonikoko ◽  
...  

BackgroundTreatment with the anti–PD-1 antibody pembrolizumab has improved clinical outcomes in multiple previously treated advanced solid tumors. The poly (ADP-ribose) polymerase (PARP) inhibitor olaparib has shown antitumor activity as monotherapy in patients with previously treated advanced ovarian, breast, pancreatic, and prostate cancers with BRCA1/BRCA2 mutations (BRCAm). Activity was also seen in patients with previously treated advanced solid tumors with other homologous recombination repair mutation (HRRm) and in those with ovarian cancer with homologous recombination repair deficiency (HRD) phenotype. PARP inhibitors have been found to increase interferon signaling and tumor infiltrating lymphocytes, enhancing tumor susceptibility to immune checkpoint blockade. Antitumor activity of PD-(L)1 plus PARP inhibition was found to be higher than expected with either agent alone in patients with recurrent ovarian cancer regardless of BRCAm or HRD status and in patients with BRCAm breast cancer. KEYLYNK-007 (NCT04123366) evaluates the antitumor activity and safety of olaparib in combination with pembrolizumab in patients with previously treated advanced solid tumors with HRRm and/or HRD.MethodsThis phase 2, nonrandomized, multicenter, open-label study will enroll approximately 300 patients aged ≥18 years with histologically/cytologically confirmed, previously treated, advanced solid tumors with HRRm and/or HRD per Lynparza HRR-HRD assay (Foundation Medicine, Inc., Cambridge, MA, USA), with an ECOG PS of 0-1. Patients will be grouped by biomarker status: subgroup 1: BRCAm; subgroup 2: HRRm without BRCAm; and subgroup 3: HRD positive without HRRm (loss of heterozygosity score ≥16 per Lynparza HRR-HRD assay). Patients will receive olaparib 300 mg twice daily + pembrolizumab 200 mg intravenously Q3W (35 cycles) until PD, unacceptable AEs, intercurrent illness, investigator decision, withdrawal of consent, or pregnancy. Tumor imaging assessment by blinded independent central review (BICR) per RECIST v1.1 or Prostate Cancer Working Group (PCWG)–modified RECIST v1.1 for prostate cancer will occur Q9W for 12 months, then Q12W until PD, start of new anticancer treatment, withdrawal of consent, pregnancy, or death. AEs will be monitored throughout the study and for 30 days after final dose (90 days for serious AEs). The primary endpoint is ORR (RECIST v1.1 or PCWG–modified RECIST version 1.1 by BICR). Secondary endpoints include duration of response (DOR) and PFS (RECIST v1.1 or PCWG–modified RECIST v1.1 by BICR), OS, and safety. Point estimate and exact Clopper-Pearson CI for ORR, and Kaplan-Meier estimates for DOR, PFS, and OS will be calculated. A total of 89 sites are currently enrolling in 20 countries.ResultsN/AConclusionsN/ATrial RegistrationClinicalTrials. gov identifier, NCT04123366Ethics ApprovalAn independent institutional review board or ethics committee approved the protocol at each study site, and the trial is being conducted in compliance with Good Clinical Practice guidelines and the Declaration of Helsinki.


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