scholarly journals Overcoming Platinum and PARP-Inhibitor Resistance in Ovarian Cancer

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1607
Author(s):  
Michelle McMullen ◽  
Katherine Karakasis ◽  
Ainhoa Madariaga ◽  
Amit M. Oza

Platinum chemotherapy remains the cornerstone of treatment for epithelial ovarian cancer (OC) and Poly (ADP-ribose) polymerase inhibitors (PARPi) now have an established role as maintenance therapy. The mechanisms of action of these agents is, in many ways, complementary, and crucially reliant on the intracellular DNA Damage Repair (DDR) response. Here, we review mechanisms of primary and acquired resistance to treatment with platinum and PARPi, examining the interplay between both classes of agents. A key resistance mechanism appears to be the restoration of the Homologous Recombination (HR) repair pathway, through BRCA reversion mutations and epigenetic upregulation of BRCA1. Alterations in non-homologous end-joint (NHEJ) repair, replication fork protection, upregulation of cellular drug efflux pumps, reduction in PARP1 activity and alterations to the tumour microenvironment have also been described. These resistance mechanisms reveal molecular vulnerabilities, which may be targeted to re-sensitise OC to platinum or PARPi treatment. Promising therapeutic strategies include ATR inhibition, epigenetic re-sensitisation through DNMT inhibition, cell cycle checkpoint inhibition, combination with anti-angiogenic therapy, BET inhibition and G-quadruplex stabilisation. Translational studies to elucidate mechanisms of treatment resistance should be incorporated into future clinical trials, as understanding these biologic mechanisms is crucial to developing new and effective therapeutic approaches in advanced OC.

PLoS ONE ◽  
2014 ◽  
Vol 9 (9) ◽  
pp. e107142 ◽  
Author(s):  
Erhong Meng ◽  
Aparna Mitra ◽  
Kaushlendra Tripathi ◽  
Michael A. Finan ◽  
Jennifer Scalici ◽  
...  

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 107-117
Author(s):  
H B Lieberman

Abstract Schizosaccharomyces pombe cells that contain a mutation within rad9 are sensitive to ionizing radiation, UV light and hydroxyurea, relative to wild-type strains. In addition, the mutants are moderately hypomutable by UV and unable to delay initiation of mitosis after treatment with radiation or hydroxyurea. Three radioresistant derivatives of rad9::ura4 cells were isolated, and each contained a single unique extragenic suppressor responsible for the acquired resistance. The suppressor loci also conferred radioresistance upon cells containing rad9-192, which differs from rad9+ by a single base pair change. The suppressors additionally enhanced the radioresistance of cells containing rad3-136, a mutation that leads to phenotypes similar to those mediated by rad9::ura4. None of the derivatives of rad9::ura4 cells recovered the ability to delay cycling in G2 after exposure to ionizing radiation or UV light. All three suppressor derivatives, relative to the parental rad9::ura4 strain, also exhibited a moderate increase in resistance to the DNA replication inhibitor hydroxyurea without gaining the ability to stop progression into mitosis despite the inhibition of DNA synthesis. Results are discussed in terms of models to explain the putative role of rad9 and the suppressor genes in promoting radioresistance and mediating checkpoint controls responsive to DNA damage or incomplete DNA replication.


2014 ◽  
Vol 32 (18_suppl) ◽  
pp. LBA5500-LBA5500 ◽  
Author(s):  
Joyce Liu ◽  
William Thomas Barry ◽  
Michael J. Birrer ◽  
Jung-min Lee ◽  
Ronald J. Buckanovich ◽  
...  

LBA5500 Background: PARP inhibitors and anti-angiogenics are clinically active in recurrent ovarian cancer (OvCa). Preclinical studies suggest these agents can synergize, and a phase 1 study showed that the combination of cediranib (ced) and olaparib (olap) is well-tolerated. We therefore compared the activity of olap alone (Olap) to combined ced and olap (Ced/Olap) in treatment of recurrent platinum-sensitive (plat-sens) high-grade serous (HGS) or BRCA-related OvCa (NCT 01116648). Methods: Patients (pts) across 9 centers were randomized 1:1 in this Ph 2 open label study to Olap (olap 400 mg capsules BID) or Ced/Olap (olap 200 mg capsules BID; ced 30 mg daily), stratified by BRCA status and prior anti-angiogenic therapy. Eligibility included pts with recurrent plat-sens HGS or BRCA-related OvCa. Pts had measurable disease by RECIST 1.1, PS 0 or 1, and the ability to take POs. No prior anti-angiogenics in the recurrent setting or prior PARP inhibitor was allowed. Progression-free survival (PFS) was defined as time from randomization to radiographic progression or death. With a target N=90 pts, the study was powered to detect a hazard ratio (HR) of 1.75 (median PFS 6 vs 10.5 mo). Results: Pts were enrolled from Oct 2011 to Jun 2013: 46 to Olap, 44 to Ced/Olap. 48 pts were known BRCA carriers (25 Olap; 23 Ced/Olap). At a planned interim analysis the DSMB recommended release of data. As of Jan 7, 2014, 41 pts had a PFS event. Median PFS was 9.0 mos for Olap and 17.7 mos for Ced/Olap (HR 2.9, 95% CI 1.5-5.6, p = 0.001). There were 2 complete responses (CR) and 21 partial responses (PR) in pts on Olap (56% objective response rate, ORR) and 3 CRs and 33 PRs in pts on Ced/Olap (84% ORR, p = 0.008). The overall rate of Gr3/4 toxicity was higher for pts on Ced/Olap (70%) than on Olap (7%). Differentially occurring toxicities included fatigue (27% Ced/Olap vs 7% Olap), diarrhea (23% vs 0%), and hypertension (39% vs 0%). Updated efficacy and exploratory subgroup analyses will be presented. Conclusions: Combined Ced/Olap significantly extended PFS and ORR compared to Olap in plat-sens OvCa. Further studies of this oral combination in plat-sens OvCa are warranted. Clinical trial information: NCT01116648.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 5505-5505
Author(s):  
Shannon Neville Westin ◽  
Robert L. Coleman ◽  
Bryan M. Fellman ◽  
Ying Yuan ◽  
Anil K. Sood ◽  
...  

5505 Background: Wee1 phosphorylates and inhibits cyclin-dependent kinases 1 and 2 and is involved in regulation of the intra-S and G2/M cell cycle checkpoint arrest for premitotic DNA repair. The Wee1 inhibitor, adavosertib, has demonstrated activity alone and in combination with olaparib in PARP inhibitor (PARPi)-resistant preclinical models. We sought to evaluate efficacy of adavosertib (A) with or without olaparib (O) in a phase II noncomparative study of recurrent PARPi-resistant ovarian cancer. Methods: Women with recurrent ovarian, fallopian tube or primary peritoneal cancer with documented progressive disease on a PARPi were eligible. All patients (pts) had measurable disease and adequate end organ function. On the A arm, pts received A 300mg PO daily on days 1-5 and 8-12 of a 21-day cycle. On the A/O arm, pts received A 150mg PO BID on days 1-3 and 8-10 and O 200mg PO BID on days 1-21 of a 21-day cycle. Primary endpoint was objective response per RECIST 1.1 and was assessed every 2 cycles. Clinical benefit rate (CBR) was defined as proportion of pts with objective response or stable disease > 16 weeks. Progression free survival (PFS) was assessed using the Kaplan Meier method and calculated from date of treatment initiation to earliest date of progression, death, or last visit. Results: 116 pts were screened with 80 pts enrolled and randomized (A: n=39, A/O: n=41). Median age was 60 years (range 36-76) and the majority of pts had platinum resistant disease (64%) and high grade serous histology (98%). Pts received a median of 4 prior therapies (range 1-11) and 48% had germline or somatic BRCA mutations. There were 35 pts evaluable for response in each arm. Table demonstrates efficacy data. On the A arm, Grade 3/4 toxicities occurred in 51% of pts, most commonly neutropenia (13%), thrombocytopenia (10%), and diarrhea (8%). 28 (72%) pts required at least one dose interruption and 20 (51%) required dose reduction. On the A/O arm, Grade 3/4 toxicities occurred in 76% of pts, most commonly thrombocytopenia (20%), neutropenia (15%), diarrhea (12%), fatigue (12%), and anemia (10%). 36 (88%) of pts required at least one dose interruption, 29 (71%) required dose reduction, and 4 (10%) did not restart due to toxicity. Conclusions: A given alone and in combination with O demonstrated efficacy in pts with PARPi-resistant ovarian cancer. Although grade 3 and 4 toxicities were observed on both arms, these were generally manageable with supportive care, dose interruptions and dose reductions as needed. Additional translational analyses are ongoing to clarify which pts received clinical benefit. Clinical trial information: NCT03579316. [Table: see text]


2021 ◽  
Author(s):  
Tzu-Ting Huang ◽  
Jayakumar R. Nair ◽  
Nitasha Gupta ◽  
Tomomi M. Yamamoto ◽  
Benjamin G. Bitler ◽  
...  

2019 ◽  
Vol 122 (4) ◽  
pp. 483-490 ◽  
Author(s):  
Corran Roberts ◽  
Victoria Y. Strauss ◽  
Sylwia Kopijasz ◽  
Charlie Gourley ◽  
Marcia Hall ◽  
...  

Abstract Background Tumour cells with BRCA1/2 gene mutations demonstrate increased sensitivity to platinum and poly (ADP-ribose) polymerase (PARP) inhibitors. 6-mercaptopurine (6MP) was found to selectively kill BRCA-defective cells in a xenograft model as effectively as the PARP inhibitor AG014699, even after these cells acquired resistance to a PARP inhibitor or cisplatin. Methods This phase II single-arm trial investigated the activity of 6MP 55–75 mg/m2 per day, and methotrexate 15–20 mg/m2 per week in advanced breast or platinum-resistant ovarian cancer patients with a BRCA1/2 germline mutation, who had progressed after ≥1 previous line of chemotherapy. The primary outcome was objective response including stable disease (SD) as an assessment of clinical benefit rate (CBR), at 8 weeks, by RECIST v1.1. Secondary outcomes included overall survival (OS) and progression-free survival (PFS). Results In total, 67 evaluable patients were recruited; 55 ovarian and 11 breast cancer patients. In total, 21 patients had SD (31%), one had a partial response (1.5%); CBR was 33% at 8 weeks. In total, 12/67 patients (18%) had SD at 16 weeks. In total, five ovarian cancer patients had SD for over 200 days. Median OS was 10.3 months (95% CI 6.9–14.5), median PFS 1.9 months (1.7–2.8). Conclusions The overall activity of 6MP and methotrexate in these patients was low; however, there was a small group of patients who appeared to derive longer-term clinical benefit. Trial registration NCT01432145 http://www.ClinicalTrials.gov.


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