scholarly journals Reversion and non-reversion mechanisms of resistance to PARP inhibitor or platinum chemotherapy in BRCA1/2-mutant metastatic breast cancer

2020 ◽  
Vol 31 (5) ◽  
pp. 590-598 ◽  
Author(s):  
A.G. Waks ◽  
O. Cohen ◽  
B. Kochupurakkal ◽  
D. Kim ◽  
C.E. Dunn ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Parp Inhibitor ◽  
Metastatic Breast ◽  
Mechanisms Of Resistance ◽  
Platinum Chemotherapy

scholarly journals Reversion and non-reversion mechanisms of resistance to PARP inhibitor or platinum chemotherapy in BRCA1/2-mutant metastatic breast cancer

2019 ◽  
Author(s):  
Adrienne G. Waks ◽  
Ofir Cohen ◽  
Bose Kochupurakkal ◽  
Dewey Kim ◽  
Connor E. Dunn ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Homologous Recombination ◽  
Parp Inhibitor ◽  
Metastatic Breast ◽  
Circulating Tumor Dna ◽  
Dna End Resection ◽  
Platinum Chemotherapy ◽  
End Resection ◽  
Tumor Dna

AbstractBackgroundLittle is known about mechanisms of resistance to PARP inhibitors and platinum chemotherapy in patients with metastatic breast cancer and BRCA1/2 mutations. Further investigation of resistance in clinical cohorts may point to strategies to prevent or overcome treatment failure.Patients and MethodsWe obtained tumor biopsies from metastatic breast cancer patients with BRCA1/2 deficiency before and after acquired resistance to PARP inhibitor or platinum chemotherapy. Whole exome sequencing was performed on each tumor, germline DNA, and circulating tumor DNA. Tumors underwent RNA sequencing, and immunohistochemical staining for RAD51 foci on tumor sections was performed for functional assessment of intact homologous recombination.ResultsPre- and post-resistance tumor samples were sequenced from 8 patients (4 with BRCA1 and 4 with BRCA2 mutation; 4 treated with PARP inhibitor and 4 with platinum). Following disease progression on DNA-damaging therapy, four patients (50%) acquired at least one somatic reversion alteration likely to result in functional BRCA1/2 protein detected by tumor or circulating tumor DNA sequencing. Two patients with germline BRCA1 deficiency acquired genomic alterations anticipated to restore homologous recombination through increased DNA end resection: loss of TP53BP1 in one patient and amplification of MRE11A in another. RAD51 foci were acquired post-resistance in all patients with genomic reversion, consistent with reconstitution of homologous recombination. All patients whose tumors demonstrated RAD51 foci post-resistance were intrinsically resistant to subsequent lines of DNA-damaging therapy.ConclusionsGenomic reversion in BRCA1/2 was the most commonly observed mechanism of resistance, occurring in 4 of 8 patients. Novel sequence alterations leading to increased DNA end resection were seen in two patients, and may be targetable for therapeutic benefit. The presence of RAD51 foci by immunohistochemistry was consistent with BRCA1/2 protein functional status from genomic data and predicted response to later DNA-damaging therapy, supporting RAD51 focus formation as a clinically useful biomarker.

A phase II trial of the PARP inhibitor veliparib (ABT888) and temozolomide for metastatic breast cancer.

2010 ◽  
Vol 28 (15_suppl) ◽  
pp. 1019-1019 ◽  
Author(s):  
S. J. Isakoff ◽  
B. Overmoyer ◽  
N. M. Tung ◽  
R. S. Gelman ◽  
V. L. Giranda ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Phase Ii ◽  
Phase Ii Trial ◽  
Parp Inhibitor ◽  
Metastatic Breast

Measurement of gamma-H2AX in circulating tumor cells (CTC) from patients receiving ABT-888 (veliparib) in combination with carboplatin on a phase I dose-escalation study (OSU-10080/NCI8609).

2011 ◽  
Vol 29 (27_suppl) ◽  
pp. 58-58
Author(s):  
A. Garcia-Villa
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Metastatic Breast Cancer ◽  
Phase I ◽  
Parp Inhibitor ◽  
Metastatic Breast ◽  
Parp Inhibitors ◽  
Immunocytochemical Staining ◽  
Dose Escalation Study ◽  
Non Invasive

58 Background: Non-invasive methods to accurately measure DNA damage induced by PARP inhibitors in the tumors are crucial in identifying the optimal biological dose and schedule of these novel agents. With the use of an antibody that targets the histone H2AX, which becomes phosphorylated on serine residue 139 (γ-H2AX), it is possible to measure DNA DSB in the cell. But repeated biopsy in patients with metastatic breast cancer is not feasible. We propose here to quantify γ-H2AX in CTCs as a measurement of DNA damage in the tumor in patients receiving veliparib (ABT-888), an oral PARP inhibitor and carboplatin on a phase I study. Methods: CTCs were isolated in 10 mL of peripheral blood using negative selection with immunomagnetic tagging and removal of CD45 positive cells at 3 time points. Immunocytochemical staining for nucleus (DAPI), pan-cytokeratin CD45, and γ-H2AX was completed on available samples. Double staining for nucleus and cytokeratin with high nucleus to cytoplasm ratio defined a CTC. The γ-H2AX foci present in the nucleus of the CTCs will be counted by immunocytochemistry (ICC) analysis. Results: We negatively enriched blood sample from enrolled patients with metastatic breast cancer (n=6). CTCs were observed in all samples (55CTCs/mL of blood - 2000CTCs/mL of blood). Thus far 3 out of 6 patient samples have been analyzed. The number of CTCs per mL of blood after enrichment at baseline has a mean of 293, a median of 140 and a range of (684-140) At time point 1 the mean is 1071.33, the median is 1151 and the range is (1151-63). ICC analysis on the CTCs demonstrated the presence of γ-H2AX positive cells. Conclusions: Our novel negative depletion method for isolating CTCs allows for separation of a wider range of CTCs, since it does not assume presence of epithelial markers before separation. This leads to improved yield and purity allowing better ICC detection of various markers directly on CTCs. Development and validation of the above methodology to determine γ-H2AX foci in CTCs will help in identifying a novel, non-invasive biomarker that can be used to assess the effect of DNA damaging agents during therapy.

Assessment of γH2AX levels in circulating tumor cells in patients treated with veliparib in combination with doxorubicin and cyclophosphamide in metastatic breast cancer.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 2582-2582
Author(s):  
Antoinette R. Tan ◽  
Deborah Toppmeyer ◽  
Serena Tsan-Lai Wong ◽  
Hongxia Lin ◽  
Murugesan Gounder ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Metastatic Breast Cancer ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Brca Mutation ◽  
Parp Inhibitor ◽  
Metastatic Breast ◽  
Chemotherapeutic Agents ◽  
Response To Treatment

2582 Background: Veliparib (V) is a potent PARP inhibitor that delays repair of DNA damage induced by chemotherapeutic agents. In metastatic breast cancer pts, we evaluated V with doxorubicin (A) and cyclophosphamide (C) given both on day 1 with V at 100 mg po BID for 7 days post-chemotherapy every 21 days, to increase DNA damage. We report use of γH2AX, (phosphorylated histone protein), a marker of DNA double-strand breaks, in circulating tumor cells (CTCs) to assess DNA damage. We evaluated number of CTCs and percentage of γH2AX-positive CTCs pre- and post-treatment. Methods: Eligibility included prior A ≤ 300 mg/m2 and EF ≥ 50%. Further A was omitted after a cumulative dose of 420 mg/m2. Primary objective was to assess DNA damage response to treatment by measuring γH2AX-positive CTCs during cycle 1 on days 1 (pre-treatment), 2, 7, and 14. Cell Search System was used to enumerate CTCs. γH2AX was quantitated using a validated assay. Results: Eleven pts enrolled. Median age was 53 (34 – 73); median ECOG PS 1 (0 – 2); there were 1 ER-negative/HER2+, 4 triple-negative (BRCA2+, n =1), and 6 ER+/PR+/HER2-negative (BRCA2+, n =2) tumors. Most common drug-related toxicities were grade (gr) 4 neutropenia, gr 2 anemia and thrombocytopenia, and gr 1 nausea and vomiting. In BRCA2+ pts, there were 2 PRs and 1 SD. In BRCA wt or unknown status, 5 pts had SD ≥ 3 mo and there were 3 PDs. CTCs (≥ 8) were detected in 10/11 pts on days 1 and 2. Day 7 samples were not obtainable in 2 pts. On day 7, 1/8 pts had 0 CTCs and rest had ≥ 3 CTCs. A decrease in CTCs (p < 0.0001) occurred from day 1 (median: 22, range, 8-1216) to day 7 (median: 5, range 3-37). At baseline, 7 pts had ≥ 10% γH2AX-positive CTCs. Fraction of CTCs positive for γH2AX increased to ≥ 50% by day 7 in 6/7 pts and persisted to day 14 in 5 pts. Conclusions: The toxicity profile of V 100 mg BID days 1-7 with AC (60/600 mg/m2) on day 1 on a 21-day cycle was expected. Objective antitumor activity was seen in BRCA mutation carriers. CTCs decreased and percentage of γH2AX-positive CTCs increased after combination treatment with a PARP inhibitor and chemotherapy. This observation is notable and we plan to extend dosing of V to 14 days. This work is supported by NCI U01-CA132194. Clinical trial information: NCT00740805.

Serial circulating tumor DNA samples from patients with metastatic breast cancer and BRCA1/2 mutations.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1025-1025
Author(s):  
Katharine Collier ◽  
David Tallman ◽  
Zachary Weber ◽  
Marcy Haynam ◽  
Elizabeth J. Adams ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Clonal Evolution ◽  
Metastatic Breast ◽  
Circulating Tumor Dna ◽  
Plasma Samples ◽  
Significant Difference ◽  
Platinum Chemotherapy ◽  
Tumor Dna ◽  
Over Time

1025 Background: Analysis of circulating tumor DNA (ctDNA) over time allows non-invasive evaluation of tumor genomic evolution. We characterize changes in tumor fraction (TFx), somatic copy number alterations (SCNAs), and somatic mutations (muts) over time in patients (pts) with BRCA1/2 muts and metastatic breast cancer (mBC) who received a PARP inhibitor (PARPi) or platinum chemotherapy. Specifically, we seek to identify the frequency of BRCA1/2 reversion muts. Methods: Pts with mBC and germline or somatic BRCA1/2 muts were identified on a banking protocol of prospectively-collected serial samples of blood and plasma. Control pts without a BRCA1/2 mut were matched 2:1 by age and hormone receptor (HR) status. Ultra-low-pass whole genome sequencing (ULPWGS) with 0.1x depth was performed on all plasma samples (n = 103) and the ichorCNA algorithm was used to determine TFx and SCNAs. Targeted panel sequencing (TPS) of 402 cancer-related genes was performed at 10,000x depth on plasma samples, and one blood sample per pt. The panel includes BRCA1/2 and 38 other DNA damage repair (DDR) genes. Somatic muts were identified by joint calling with Mutect2 across plasma timepoints with paired pt normal blood. Germline variant calling from TPS on blood with HaplotypeCaller was used to confirm germline muts in BRCA1/2.Results: We identified 10 pts with mBC with a germline (n = 7) or somatic (n = 3) BRCA1 (n = 2) or BRCA2 (n = 8) mut and banked blood and plasma samples at 3-9 timepoints at a median of 8 weeks apart (range 1-43). The control cohort of 20 pts with mBC and wildtype BRCA1/2 was well matched by age and HR status. All pts with BRCA1/2 muts received a PARPi and/or platinum chemotherapy at some point during sample collection. Half of control pts received platinum chemotherapy. Germline BRCA1/2 muts were confirmed in all 7 pts with known germline muts. Among the BRCA1/2 mut cohort, median TFx was 0.04 (range 0-0.57) with 20% of samples having TFx > 0.10. A median of 1.5 (range 0-39) somatic muts per pt were found in DDR genes. Four pts (40%) had secondary non-reversion muts in BRCA1/2. A reversion mut of a germline BRCA2 mut, restoring the open reading frame of BRCA2, was discovered at the last timepoint from 1 pt while receiving carboplatin. A germline BRCA1/2 reversion mut in this cohort occurred in 2.3% of samples, 14.3% of pts. There was no significant difference in the percent of genome with a SCNA between the first and last time point, nor before and after PARPi/platinum. The somatic mut landscape and clonal evolution of TPS using PyClone will be presented. Conclusions: Evaluation of serial ctDNA samples for TFx, SCNAs, and somatic muts from banked plasma and blood from pts with mBC is feasible. The frequency of reversion muts in BRCA1/2 was low, suggesting that either their incidence is low or ctDNA TPS is not sensitive enough to detect them. Secondary non-reversion muts in BRCA1/2 and other somatic DDR muts were more common. SCNAs were stable over time.

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