Trends in use of poly (ADP-ribose) polymerase inhibitor (PARPi) in ovarian cancer.

PARP inhibitor and chemotherapy combination trials for the treatment of advanced malignancies: does a development pathway forward exist?

e17568 Background: The objective of this study was to evaluate changes in medical and pharmacy costs among ovarian cancer (OC) patients since poly (ADP-ribose) polymerase inhibitors (PARPis) were first approved for OC in December 2014. Methods: Optum’s de-identified Clinformatics Data Mart Database was used to identify patients with incident OC between 2013 and 2021 who received platinum-based chemotherapy. Medical, outpatient, inpatient, computed tomography scan (CT), and pharmacy costs were analyzed by time since diagnosis when the costs were incurred, with four stratifications: the first 0-5, 6-11, 12-23, and 24-35 months past diagnosis. Median monthly standard costs were estimated, and inflation-adjusted out-of-pocket (OOP) costs were calculated. Median (interquartile range, IQR) costs per outpatient visit, CT, and month supply of PARPi were assessed. Results: There were 6,680 patients diagnosed with OC, with 5,888, 4,733, 2,801, and 1,696 enrolled for 0-5, 6-11, 12-23, and 24-35 months past diagnosis. From quarter 1, 2015 to quarter 3, 2020, median monthly medical, outpatient, and CT costs increased in all time periods, and pharmacy costs increased 6-35 months past diagnosis. For patients 0-5 months past diagnosis, median monthly inpatient standard costs increased from $6,032 to $6,615 and inpatient OOP costs decreased from $149 to $69. Median monthly inpatient standard and OOP costs 6-35 months past diagnosis were $0. Median (IQR) cost per outpatient visit increased from $40 (8-143) to $42 (8-165), per CT increased from $172 (136-557) to $175 (143-600), and per month supply of PARPi increased from $9,744 (9,744-9,744) to $14,449 (14,449-14,518). Median OOP cost per outpatient visit and CT was $0 and per month supply of PARPi decreased from $71 to $0. Conclusions: In the years of expanding PARPi use in OC, OC patients 6 or more months past diagnosis had increasing pharmacy costs. However, OC patients also incurred increasing medical, particularly outpatient and CT, costs despite minimal increases in the cost per visit or per CT, perhaps reflecting an increase in frequency of visits or CTs per patient or increased utilization of costlier diagnostics. OOP costs did not demonstrate the same increases as standard costs, but do not capture other costs to patients such as increasing premiums or time toxicity. Median monthly standard and out-of-pocket (OOP) medical, outpatient, CT, and pharmacy costs among ovarian cancer patients, quarter 1, 2015 and quarter 3, 2020, by months past diagnosis. Cost ($) Months past diagnosis Medical Medical Outpatient Outpatient CT CT Pharmacy Pharmacy 2015 2020 2015 2020 2015 2020 2015 2020 Standard 0-5 15,316 17,764 8,408 9,968 275 376 128 103 6-11 3,299 3,743 2,620 2,890 251 299 34 110 12-23 2,215 2,514 1,541 1,748 156 199 37 93 24-35 1,119 1,968 819 1,468 79 161 30 79 OOP 0-5 621 625 303 392 0 9 35 32 6-11 114 86 98 76 0 0 15 21 12-23 157 102 135 86 3 4 22 25 24-35 126 87 107 75 0 1 22 21

Background: In vivo synergy with concurrent PI3-Kinase inhibition and PARP inhibition has been observed in BRCA-deficient and BRCA-proficient preclinical models of triple negative breast cancer (TNBC) and ovarian cancer (OC). A phase I trial of the oral pan-class I PI3-Kinase inhibitor BKM120 and the PARP inhibitor olaparib demonstrated anti-cancer activity in TNBC and OC, both in patients with and without germline BRCA1 and BRCA2 (BRCA) mutations. However, CNS toxicity (depression) and liver function test abnormalities limited dose escalation of BKM120 prompting evaluation of the alpha specific PI3-Kinase inhibitor BYL719 (which has no CNS toxicity) in combination with olaparib. Methods: Olaparib was administered twice daily (tablet formulation) and BYL719 daily on a 28-day cycle, both orally. A 3 + 3 dose-escalation design was employed with primary objectives of defining the maximum tolerated dose (MTD) and recommended phase 2 dose of the combination of BYL719 and olaparib, and secondary objectives of defining toxicity, activity, and pharmacokinetic profiles of both agents. Eligibility included recurrent TNBC or high grade serous (HGS) OC, or any histology OC or breast cancer (BC) with presence of a known germline BRCA mutation, performance status of 0-1 and measurable/evaluable cancer. Patients with platinum sensitive or resistant or refractory OC were eligible and prior PARP inhibitor use was allowed. Dose-expansion cohorts at the MTD were enrolled for both BC and OC. Results: 46 patients (16 BC and 30 OC) have been enrolled in the study; 28 patients participated in the dose escalation portion of the study (4 BC and 24 OC). Two patients with OC did not receive study drugs because of ineligibility. MTD was defined as BYL719 200mg once daily and olaparib 200mg twice daily. Dose limiting toxicities included hyperglycemia, rash and fever with decreased neutrophil count. Four patients (3 OC and 1 BC) discontinued protocol therapy because of toxicity (2 for hyperglycemia, 1 for nausea and 1 for allergic reaction). Most common toxicities included nausea, hyperglycemia, fatigue, diarrhea and vomiting. At the MTD, 6 patients with OC and 12 patients with BC were enrolled into a dose expansion cohort. The OC expansion cohort has completed enrollment, while the BC cohort is still enrolling. Among patients with OC who received study drugs (28 patients, 26 (93%) with platinum resistant disease), objective response rate (ORR) by RECIST 1.1 was 36% (10/28 patients, all partial responses (PRs)). Median duration of response was 167 days (range 16-398 days); 5 of 10 patients with PR remain on treatment. ORR was 33% for patients with germline BRCA mutations and 31% for patients without germline BRCA mutations. Among patients without germline BRCA mutations with platinum resistant OC, ORR was 29%. Conclusions: Combined BYL719 and olaparib is feasible, and similar clinical benefit was observed in patients with and without germline BRCA mutations. The activity of this combination in OC patients without germline BRCA mutations and with platinum resistant disease was higher than expected from olaparib monotherapy and warrants further investigation. This work was funded in part by the Stand Up To Cancer Ovarian Dream Team. Clinical trial: NCT01623349. Citation Format: Panagiotis A. Konstantinopoulos, William T. Barry, Michael Birrer, Shannon N. Westin, Sarah Farooq, Karen Cadoo, Christin Whalen, Weixiu Luo, Hui Liu, Carol Aghajanian, David B. Solit, Gordon B. Mills, Barry S. Taylor, Helen Won, Michael F. Berger, Sangeetha Palakurthi, Joyce F. Liu, Lew Cantley, Scott H. Kaufmann, Elizabeth M. Swisher, Alan D. D'Andrea, Eric Winer, Gerburg M. Wulf, Ursula A. Matulonis. Phase I study of the alpha specific PI3-Kinase inhibitor BYL719 and the poly (ADP-Ribose) polymerase (PARP) inhibitor olaparib in recurrent ovarian and breast cancer: Analysis of the dose escalation and ovarian cancer expansion cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT008. doi:10.1158/1538-7445.AM2017-CT008

Purpose: Poly ADP ribose polymerase (PARP) inhibitors can effectively kill cancer cells by restraining the activity of DNA repair enzymes and utilizing the characteristics of BRCA mutations. This article evaluates the efficacy and safety of PARP inhibitors (PARPis) in the maintenance treatment of ovarian cancer.Method: We searched for clinical trials in electronic databases. PARPis efficacy were evaluated by the hazard ratios (HR) and its 95% confidence intervals (95% CI) of overall survival (OS) and progression-free survival (PFS) between the PARPis groups and placebo groups, while the PARPis’ safety was assessed by relative risk (RR) values of adverse events (AEs) between the two arms.Results: The immature OS data manifested that patients with BRCA mutation receiving PARPis therapy versus placebo therapy appeared to have longer OS (HR = 0.78, 95%CI = 0.61–1.01; P = 0.06). Compared with placebo group, PARP group had a significant advantage in PFS in ovarian cancer patients with BRCA wild-type (BRCAwt), BRCA mutation (BRCAm), BRCA status unclassified, BRCA1 mutation subgroup and the BRCA2 mutation subgroup (BRCAwt: HR = 0.53, 95%CI = 0.42–0.68, P < 0.00001; BRCAm: HR = 0.30, 95%CI = 0.26–0.34, P < 0.00001; BRCA status unclassified: HR = 0.52, 95%CI = 0.41–0.66, P < 0.00001; BRCA1m: HR = 0.38, 95%CI = 0.29–0.48, P < 0.00001; BRCA2m: HR = 0.23, 95%CI = 0.10–0.57, P = 0.001). Our analysis revealed the incidence rates for AEs of grade ≥3 (grades 3 to 4) and serious AEs in PARPis group were 55.19% and 26.29%, respectively.Conclusion: Our meta-analysis demonstrates that PARPis therapy can significantly improve PFS in ovarian cancer patients, but it has no benefit in OS. However, the therapy is associated with a significant increase in the risk of AEs of grade ≥ 3 and serious AEs.

Loss of claudin-4 reduces DNA damage repair and increases sensitivity to PARP inhibitors (228)

Understanding the needs and perspectives of ovarian cancer patients when considering PARP inhibitor maintenance therapy: Findings from two online community events

BACKGROUND: A key clinical challenge in ovarian cancer is identifying new strategies to treat patients who do not respond to poly ADP-ribose polymerase (PARP) inhibitor (PARPi) therapy. We previously linked the nuclear orphan receptor NR4A1/TR3 to pro-growth and pro-survival effects in ovarian cancer cells. However, it is unknown whether inhibiting NR4A1 function has therapeutic effects alone or in combination with PARPi in vitro. Moreover, the prognostic value of NR4A1 expression in patient tumors remains ill-defined, as two prior reports had contradictory findings for associations with ovarian cancer survival. OBJECTIVE: We undertook this study to test the therapeutic potential of inhibiting NR4A1 in ovarian cancer cells, and to clarify the prognostic value of NR4A1 expression in patient tumors. METHODS: In a panel of established ovarian cancer cell lines (OVCAR-3, OVCAR-4, SKOV-3), we inhibited NR4A1 using the chemical antagonist, 1,1-Bis(3'-indolyl)-1-(p-hydroxyphenyl) methane (C-DIM) and siRNA targeting NR4A1 (siNR4A1). Effects of C-DIM on cell growth, alone and in combination with the PARPi, olaparib and rucaparib, were assessed in sulforhodamine B (SRB) in vitro assays. Markers of apoptosis (cleaved PARP, cleaved caspase-3) and proliferation (Ki67, PCNA, p21) were measured by western blot or immunohistochemistry (IHC). In ovarian tumors, NR4A1 was measured by IHC in 203 clinically annotated formalin-fixed paraffin-embedded (FFPE) tissue samples from the Vanderbilt University Medical Center (VUMC) Tissue Repository for Ovarian Cancer (TROC). Staining intensity (1: weak; 2: moderate; 3: strong) and percent of positive nuclei (0-100) were multiplied to yield an H score for NR4A1 expression. Associations with progression-free survival (PFS) and overall survival (OS) were quantified by Hazards Ratios (HR) and 95% Confidence Intervals (CI) from proportional hazards regression. RESULTS: In ovarian cancer cell lines, C-DIM induced concentration-dependent decreases in cell growth and markers of proliferation, and stimulated apoptosis. These effects were mimicked in cells transfected with siNR4A1 compared to a non-targeting siRNA-transfected control. In combination with PARPi, C-DIM induced synergistic growth inhibition and apoptosis in vitro. In tumors, NR4A1 expression lower than the median (H score &amp;lt;153.6) was more common among later stage, higher grade, serous tumors with suboptimal cytoreduction or platinum resistant disease. Higher NR4A1 expression was associated with better OS (HR: 0.52, 95% CI: 0.37–0.74) in unadjusted analyses. However, after adjustment for important prognostic covariates, including age, stage, grade, and histologic subtype, higher NR4A1 was associated with significantly shorter PFS (HR: 2.35, 95% CI: 1.29–4.28). CONCLUSIONS: Our current results reconcile the discrepancy between prior NR4A1 reports, as associations differed due to confounding by clinical covariates. Shorter survival among cases with higher NR4A1 expression is supported by experimental evidence showing reduced ovarian cancer cell growth and increased apoptosis following NR4A1 inhibition, both alone and when combined with a PARPi. Together, our findings support further development of NR4A1 inhibition as a novel therapeutic approach that could improve response to PARPi therapy among ovarian cancer patients with chemoresistant disease. Citation Format: Alicia Beeghly-Fadiel, Johnathan Cooks, Dajah Chase, Marta Crispens, Dineo Khabele, and Andrew J Wilson. PROGNOSTIC SIGNIFICANCE OF NR4A1/TR3 EXPRESSION IN OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-088.

e17555 Background: Over the last few years, targeted therapy has become the mainstay maintenance treatment of patients with ovarian cancer including patients with BRCA1 or BRCA2 mutations. Poly ADP ribose polymerase (PARP) inhibitors are effective in the treatment of patients who are in complete or partial remission. PARP inhibitors are known to cause hematological adverse events (AEs), but have not been compared directly to each other. Methods: We conducted a single institution, IRB approved, retrospective study on patients who were treated with PARP inhibitors from December 2016 to October 2020. Patients were stratified according to which PARP inhibitor they received. Our primary objective was to assess the incidence of hematological and non-hematological adverse events associated with the use of PARP inhibitor therapy used in patients with ovarian cancer. Data from absolute neutrophil count, hemoglobin and platelet count during the first 2 cycles were graded for hematologic toxicity according to CTCAE v 5.0. Results: A total of 126 patients received a PARP inhibitor during the study time frame. 34 were excluded and 92 patients were included for analysis. Median age of patients were 64.3 (range, 33.8 to 92.3) years, 66 (71.7%) white, and 84 (91.3%) had an ECOG PS of 0/1. Thirty-one (33.7%) of patients received niraparib and 61 (66.3%) of patients received olaparib. Patients in the niraparib group experienced more hematologic AEs, with 11 (35.5%) (95% CI 19.2-54.6), 20 (64.5%) (95% CI 45.4-80.8), and 18 (58.1%) (95% CI 39.1-75.5) experiencing neutropenia, anemia, thrombocytopenia, respectively. Eight (13.1%) (95% CI 5.8-24.2), 24 (39.3%) (95% CI 27.1-52.7), 16 (26.2%) (95% CI 15.8-39.1) patients in the olaparib group experienced neutropenia, anemia, thrombocytopenia, respectively. Conclusions: This single institution retrospective study outlines the hematological toxicities observed between two PARP inhibitors. Although there are four PARP inhibitors approved by FDA, our data compared only two of the four (as they were the most commonly prescribed PARP inhibitors in our institution). Our results suggested that niraparib tended to be associated with a higher risk for hematologic toxicities than olaparib. Our data showed anemia as the most common hematologic toxicity which was consistent with what has been widely documented in the literature.

Background The economic impact of adverse events (AEs) for poly (ADP-ribose) polymerase inhibitors (PARPis) in ovarian or breast cancer has not been widely evaluated. Objective Compare PARPi-related AE management costs from a US payer perspective. Methods The frequency of treatment-related grade 3–4 AEs was obtained from published clinical trials of PARPis for the treatment of advanced ovarian cancer (AOC), platinum-sensitive recurrent ovarian cancer (PSROC), and metastatic breast cancer (MBC). AE management costs per patient (2020 USD) per treatment course were calculated by multiplying the AE unit costs by the frequency of AEs for each arm of each trial. Sensitivity analyses were conducted according to the lower and upper limits of the 95% confidence interval for AE rates and unit costs, respectively. Scenarios were also performed to explore the uncertainty of outcomes. Results Total AE management costs in AOC were: $3,904, olaparib; $5,595, olaparib plus bevacizumab; and $12,215, niraparib. In PSROC, total costs were: $3,894, olaparib; $6,001, rucaparib; and $11,492, niraparib, and in MBC: $3,574, olaparib; and $9,489, talazoparib. Hematological toxicities were the key drivers of AE management costs for PARPis. Conclusions The main AEs among PARPis were hematological. Olaparib was associated with lower AE costs compared to other PARPis.

The MSH3 gene is one of the DNA mismatch repair (MMR) genes that has undergone somatic mutation frequently in MMR-deficient cancers. MSH3, together with MSH2, forms the MutSβ heteroduplex, which interacts with interstrand cross-links (ICLs) induced by drugs such as cisplatin and psoralen. However, the precise role of MSH3 in mediating the cytotoxic effects of ICL-inducing agents remains poorly understood. In this study, we first examined the effects of MSH3 deficiency on cytotoxicity caused by cisplatin and oxaliplatin, another ICL-inducing platinum drug. Using isogenic HCT116-derived clones in which MSH3 expression is controlled by shRNA expression in a Tet-off system, we discovered that MSH3 deficiency sensitized cells to both cisplatin and oxaliplatin at clinically relevant doses. Interestingly, siRNA-induced down-regulation of the MLH1 protein did not affect MSH3-dependent toxicity of these drugs, indicating that this process does not require participation of the canonical MMR pathway. Furthermore, MSH3-deficient cells maintained higher levels of phosphorylated histone H2AX and 53BP1 after oxaliplatin treatment in comparison with MSH3-proficient cells, suggesting that MSH3 plays an important role in repairing DNA double strand breaks (DSBs). This role of MSH3 was further supported by our findings that MSH3-deficient cells were sensitive to olaparib, a poly(ADP-ribose) polymerase inhibitor. Moreover, the combination of oxaliplatin and olaparib exhibited a synergistic effect compared with either treatment individually. Collectively, our results provide novel evidence that MSH3 deficiency contributes to the cytotoxicity of platinum drugs through deficient DSB repair. These data lay the foundation for the development of effective prediction and treatments for cancers with MSH3 deficiency.

This review will provide an update of recently presented clinical data as well as discuss ongoing trials focused on the incorporation of poly (ADP-ribose) polymerase inhibitors (PARPi) into the treatment paradigm for ovarian cancer. As of this publication, PARPi have indications in many parts of the globe as maintenance therapy following response to platinum-based chemotherapy in the setting of platinum-sensitive recurrence. In addition, in the United States, two PARPi have indications as monotherapy treatment for recurrent ovarian cancer in patients with a BRCA mutation and at least two prior lines of therapy. Exciting data was published in October 2018, demonstrating an unprecedented benefit to utilization of olaparib following response to front-line platinum-based chemotherapy among patients with a BRCA mutation and this data is expected to expand the indication for olaparib globally. Ongoing studies will seek to expand the benefit of PARPi beyond the BRCA population in front-line therapy as well as to overcome inherent and acquired resistance to PARPi with studies of novel combinations with antiangiogenesis agents, immune-oncology agents and chemotherapy. These efforts may identify more settings and populations in which PARPi provide clinical benefit.

Duration of treatment, treatment adherence, and treatment discontinuations associated with second-line PARP inhibitor or bevacizumab maintenance regimens for recurrent ovarian cancer (338)

Real-world clinical outcomes with poly (adenosine diphosphate [ADP]-ribose) polymerase inhibitors as second-line maintenance therapy in patients with recurrent ovarian cancer in the United States (353)

Therapy Related Myeloid Neoplasm Post PARP Inhibitors: Potential Clonal Selection.

55IN - Targeting DNA Repair Deficiency in Ovarian and Endometrial Cancers