Targeting CCNE1 amplified ovarian and endometrial cancers by combined inhibition of PKMYT1 and ATR.

Ovarian cancers (OVCAs) and endometrial cancers (EMCAs) with CCNE1-amplification are often resistant to standard of care treatment and represent an unmet clinical need. Previously, synthetic-lethal screening identified loss of the CDK1 regulator, PKMYT1, as synthetically lethal with CCNE1-amplification. We hypothesized that CCNE1-amplification associated replication stress will be more effectively targeted by combining the PKMYT1 inhibitor, lunresertib (RP-6306), with the ATR inhibitor, camonsertib (RP-3500/RG6526). Low dose combination RP-6306 with RP-3500 synergistically increased cytotoxicity more in CCNE1 amplified compared to non-amplified cells. Combination treatment produced durable antitumor activity and increased survival in CCNE1 amplified patient-derived and cell line-derived xenografts. Mechanistically, low doses of RP-6306 with RP-3500 increase CDK1 activation more so than monotherapy, triggering rapid and robust induction of premature mitosis, DNA damage and apoptosis in a CCNE1-dependent manner. These findings suggest that targeting CDK1 activity by combining RP-6306 with RP-3500 is a novel therapeutic approach to treat CCNE1-amplifed OVCAs and EMCAs.

Molecular landscape of ERBB2/HER2 gene amplification among patients with gynecologic malignancies; clinical implications and future directions.

OBJECTIVE: Investigate the prevalence of ERBB2/HER2 gene amplification among patients with gynecologic malignancies. METHODS: The American Association of Cancer Research (AACR) Genomics Evidence of Neoplasia Information Exchange (GENIE) (version 13.1) database was accessed and patients with endometrial, ovarian, and cervical cancer were identified. Patients with available data on the presence of copy-number gene alterations were selected for further analysis. Incidence of ERBB2 amplification following stratification by tumor site and histology was evaluated. Data from the OncoKB database, as provided by cBioPortal, was utilized to determine presence of pathogenic genomic alterations. RESULTS: A total of 6961 patients who met the inclusion criteria were identified: 49.1% with ovarian cancer, 45.2% with endometrial cancer and 5.7% with cervical cancer respectively. Overall incidence of ERBB2 amplification was 3.8%. Highest incidence of ERBB2 amplification was observed among patients with mucinous ovarian (14.4%), uterine serous (13.2%), uterine clear cell (9.4%), and uterine carcinosarcoma (7.9%). ERBB2 amplification was rare among patients with TP53 wild-type endometrioid endometrial cancer (0.4%). High incidence of mutations in genes of the PI3K pathway was observed among patients with ERBB2 amplified tumors. CONCLUSION: ERBB2 amplification is frequently encountered among patients with uterine serous carcinoma, and mucinous ovarian carcinoma. In addition, a high incidence was also observed among those with uterine clear cell carcinoma, and uterine carcinosarcoma. For patients with endometrioid endometrial carcinoma, incidence of ERBB2 amplification is low, especially in the absence of TP53 mutations.

A B7-H4-Targeting Antibody-Drug Conjugate Shows Antitumor Activity in PARPi and Platinum-Resistant Cancers with B7-H4 Expression.

PURPOSE: Platinum and PARP inhibitors (PARPi) demonstrate activity in breast and ovarian cancers, but drug resistance ultimately emerges. Here, we examine B7-H4 expression in primary and recurrent high-grade serous ovarian carcinoma (HGSOC) and the activity of a B7-H4-directed antibody-drug conjugate (B7-H4-ADC), using a pyrrolobenzodiazepine-dimer payload, in PARPi- and platinum-resistant HGSOC patient-derived xenograft (PDX) models. EXPERIMENTAL DESIGN: B7-H4 expression was quantified by flow cytometry and IHC. B7-H4-ADC efficacy was tested against multiple cell lines in vitro and PDX in vivo. The effect of B7-H4-ADC on cell cycle, DNA damage, and apoptosis was measured using flow cytometry. RESULTS: B7-H4 is overexpressed in 92% of HGSOC tumors at diagnosis (n = 12), persisted in recurrent matched samples after platinum treatment, and was expressed at similar levels across metastatic sites after acquired multi-drug resistance (n = 4). Treatment with B7-H4-ADC resulted in target-specific growth inhibition of multiple ovarian and breast cancer cell lines. In platinum- or PARPi-resistant ovarian cancer cells, B7-H4-ADC significantly decreased viability and colony formation while increasing cell-cycle arrest and DNA damage, ultimately leading to apoptosis. Single-dose B7-H4-ADC led to tumor regression in 65.5% of breast and ovarian PDX models (n = 29), with reduced activity in B7-H4 low or negative models. In PARPi and platinum-resistant HGSOC PDX models, scheduled B7-H4-ADC dosing led to sustained tumor regression and increased survival. CONCLUSIONS: These data support B7-H4 as an attractive ADC target for treatment of drug-resistant HGSOC and provide evidence for activity of an ADC with a DNA-damaging payload in this population. See related commentary by Veneziani et al., p. 1434.

Combination DNA Damage Response (DDR) Inhibitors to Overcome Drug Resistance in Ovarian Cancer.

The DNA damage response (DDR) results in activation of a series of key target kinases that respond to different DNA damage insults. DDR inhibitors such as PARP inhibitors lead to the accumulation of DNA damage in tumor cells and ultimately apoptosis. However, responses to DDRi monotherapy in the clinic are not durable and resistance ultimately develops. DDRi-DDRi combinations such as PARPi-ATRi, PAPRi-WEE1i and PARPi-AsiDNA can overcome multiple resistance mechanisms to PARP inhibition. In addition, DDRi-DDRi combinations can provide viable treatment options for patients with platinum-resistant disease. In the present chapter we discuss rationale of DDRi-DDRi strategies that capitalize on genomic alterations found in ovarian cancer and other solid tumors and may provide in the near future new treatment options for these patients.

Dual blockade of BRD4 and ATR/WEE1 pathways exploits ARID1A loss in clear cell ovarian cancer.

ARID1A, an epigenetic tumor suppressor, is the most common gene mutation in clear-cell ovarian cancers (CCOCs). CCOCs are often resistant to standard chemotherapy and lack effective therapies. We hypothesized that ARID1A loss would increase CCOC cell dependency on chromatin remodeling and DNA repair pathways for survival. We demonstrate that combining BRD4 inhibitor (BRD4i) with DNA damage response inhibitors (ATR or WEE1 inhibitors; e.g. BRD4i-ATRi) was synergistic at low doses leading to decreased survival, and colony formation in CCOC in an ARID1A dependent manner. BRD4i-ATRi caused significant tumor regression and increased overall survival in ARID1AMUT but not ARID1AWT patient-derived xenografts. Combination BRD4i-ATRi significantly increased γH2AX, and decreased RAD51 foci and BRCA1 expression, suggesting decreased ability to repair DNA double-strand-breaks (DSBs) by homologous-recombination in ARID1AMUT cells, and these effects were greater than monotherapies. These studies demonstrate BRD4i-ATRi is an effective treatment strategy that capitalizes on synthetic lethality with ARID1A loss in CCOC.

Impact of adjuvant chemotherapy on the overall survival of patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery.

OBJECTIVE: To investigate the use and outcomes of adjuvant chemotherapy for patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery. METHODS: Patients diagnosed between 2010 and 2015 with International Federation of Gynecology and Obstetrics stage II-IV low-grade serous ovarian carcinoma who underwent primary debulking surgery with known residual disease status and had at least 1 month of follow-up were identified in the National Cancer Database. Adjuvant chemotherapy was defined as receipt of chemotherapy within 6 months of surgery. Overall survival was evaluated using the Kaplan-Meier method and compared with the log-rank test. A Cox model was constructed to control for a priori-selected confounders. A systematic review of the literature was also performed. RESULTS: In total, 618 patients with stage II-IV low-grade serous ovarian carcinoma who underwent primary cytoreductive surgery were identified; 501 (81.1%) patients received adjuvant chemotherapy, while 117 (18.9%) patients did not. The median follow-up of the present cohort was 47.97 months. There was no difference in overall survival between patients who did and did not receive adjuvant chemotherapy (p=0.78; 4-year overall survival rates were 77.5% and 76.1%, respectively). After controlling for patient age, medical co-morbidities, disease stage, and residual disease status, administration of adjuvant chemotherapy was not associated with better overall survival (HR=0.87, 95% CI 0.55 to 1.38). Based on data from three retrospective studies, omission of adjuvant chemotherapy following cytoreductive surgery was not associated with worse progression-free survival benefit (HR=1.25, 95% CI 0.80 to 1.95) for patients with stage III-V low-grade serous ovarian carcinoma. CONCLUSIONS: Adjuvant chemotherapy may not be associated with an overall survival benefit for patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery.

Telehealth utilization in gynecologic oncology clinical trials.

OBJECTIVE: Prior to the COVID-19 pandemic, telehealth visits and remote clinical trial operations (such as local collection of laboratory tests or imaging studies) were underutilized in gynecologic oncology clinical trials. Current literature on these operational changes provides anecdotal experience and expert opinion with few studies describing patient-level safety data. We aimed to evaluate the safety and feasibility of telehealth and remote clinical trial operations during the COVID-19 Pandemic. METHODS: Gynecologic oncology patients enrolled and actively receiving treatment on a clinical trial at a single, academic institution during the designated pre-Telehealth and Telehealth periods were identified. Patients with at least 1 provider or research coordinator telehealth visit were included. Patient demographics, health system encounters, adverse events, and protocol deviations were collected. Pairwise comparisons were performed between the pre-Telehealth and Telehealth period with each patient serving as their own control. RESULTS: Thirty-one patients met inclusion criteria. Virtual provider visits and off-site laboratory testing increased during the Telehealth period. Delays in provider visits, imaging, and laboratory testing did not differ between time periods. Total and minor protocol deviations increased in incidence during the Telehealth period and were due to documentation of telehealth and deferment of non-therapeutic testing. Major protocol deviations, emergency department visits, admissions, and severe adverse events were of low incidence and did not differ between time periods. CONCLUSIONS: Telehealth and remote clinical trial operations appeared safe and did not compromise clinical trial protocols in a small, single institutional study. Larger scale evaluations of such trial adaptations should be performed to determine continued utility following the Pandemic.

The spectrum of MAPK-ERK pathway genomic alterations in gynecologic malignancies: Opportunities for novel therapeutic approaches.

OBJECTIVE: To investigate the incidence of MAPK/ERK pathway genomic alterations among patients with gynecologic malignancies. METHODS: We accessed the American Association of Cancer Research Genomics Evidence of Neoplasia Information Exchange publicly available dataset (v13.0). Patients with malignant tumors of the ovary, uterus, and cervix were identified. Following stratification by tumor site and histology, we examined the prevalence of MAPK/ERK pathway gene alterations (somatic mutation, and/or structural chromosome alterations). We included the following RAS-MAPK pathway genes known to be implicated in the dysregulation of the pathway; KRAS, NRAS, BRAF, HRAS, MAP2K1, RAF1, PTPN11, NF1, and ARAF. Data from the OncoKB database, as provided by cBioPortal, were utilized to determine pathogenic gene alterations. RESULTS: We identified a total of 10,233 patients with gynecologic malignancies; 48.2% (n = 4937) with ovarian, 45.2% (n = 4621) with uterine and 6.6% (n = 675) with cervical cancer respectively. The overall incidence of MAPK pathway gene alterations was 21%; the most commonly altered gene was KRAS (13%), followed by NF1 (7%), NRAS (1.3%), and BRAF (1.2%). The highest incidence was observed among patients with mucinous ovarian (71%), low-grade serous ovarian (48%), endometrioid ovarian (37%), and endometrioid endometrial carcinoma (34%). CONCLUSIONS: Approximately 1 in 5 patients with a gynecologic tumor harbor a MAPK/ERK pathway genomic alteration. Novel treatment strategies capitalizing on these alterations are warranted.

Next generation sequencing reveals a high prevalence of pathogenic mutations in homologous recombination DNA damage repair genes among patients with uterine sarcoma.

OBJECTIVE: Investigate the incidence of homologous recombination DNA damage response (HR-DDR) genomic alterations among patients with uterine sarcoma. METHODS: The American Association for Cancer Research GENIE v13.0 database was accessed and patients with uterine leiomyosarcoma, adenosarcoma, undifferentiated uterine sarcoma, high-grade endometrial stromal sarcoma, low-grade endometrial stromal sarcoma, and endometrial stromal sarcoma not otherwise specified were identified. We determined the incidence of pathogenic alterations in the following genes involved in HR-DDR: ATM, ARID1A, ATRX, BAP1, BARD1, BLM, BRCA2, BRCA1, BRIP1, CHEK2, CHEK1, FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL, MRE11, NBN, PALB2, RAD50, RAD51, RAD51B, RAD51C, RAD51D, WRN. Data from the OncoKB database, as provided by cBioPortal, was utilized to determine the presence of pathogenic genomic alterations. RESULTS: A total of 509 patients contributing with 525 samples were identified. Median patient age at sample collection was 56 years while the majority were White (80.7%). The most common histologic subtype was leiomyosarcoma (63.8%) followed by adenosarcoma (12.3%). The overall incidence of HR-DDR genomic alterations was 28.2%. The most commonly altered genes were ATRX (18.2%), BRCA2 (4%), and RAD51B (2.6%). The highest incidence of HR-DDR genomic alterations was observed among patients with leiomyosarcoma (35.4%), adenosarcoma (27%) and undifferentiated uterine sarcoma (30%), while those with low-grade endometrial stromal sarcoma had the lowest (2.9%) incidence. CONCLUSIONS: Approximately 1 in 3 patients with uterine sarcoma harbor a pathogenic alteration in HR-DDR genes. Incidence is high among patients with uterine leiomyosarcoma and adenosarcoma.

A Phase Ib Study Assessing the Safety, Tolerability, and Efficacy of the First-in-Class Wee1 Inhibitor Adavosertib (AZD1775) as Monotherapy in Patients with Advanced Solid Tumors.

BACKGROUND: Adavosertib (AZD1775) is a first-in-class, selective, small-molecule inhibitor of Wee1. OBJECTIVE: The safety, tolerability, pharmacokinetics, and efficacy of adavosertib monotherapy were evaluated in patients with various solid-tumor types and molecular profiles. PATIENTS AND METHODS: Eligible patients had the following: confirmed diagnosis of ovarian cancer (OC), triple-negative breast cancer (TNBC), or small-cell lung cancer (SCLC); previous treatment for metastatic/recurrent disease; and measurable disease. Patients were grouped into six matched cohorts based on tumor type and presence/absence of biomarkers and received oral adavosertib 175 mg twice a day on days 1-3 and 8-10 of a 21-day treatment cycle. RESULTS: Eighty patients received treatment in the expansion phase; median total treatment duration was 2.4 months. The most common treatment-related adverse events (AEs) were diarrhea (56.3%), nausea (42.5%), fatigue (36.3%), vomiting (18.8%), and decreased appetite (12.5%). Treatment-related grade ≥ 3 AEs and serious AEs were reported in 32.5% and 10.0% of patients, respectively. AEs led to dose interruptions in 22.5%, reductions in 11.3%, and discontinuations in 16.3% of patients. One patient died following serious AEs of deep vein thrombosis (treatment related) and respiratory failure (not treatment related). Objective response rate, disease control rate, and progression-free survival were as follows: 6.3%, 68.8%, 4.5 months (OC BRCA wild type); 3.3%, 76.7%, 3.9 months (OC BRCA mutation); 0%, 69.2%, 3.1 months (TNBC biomarker [CCNE1/MYC/MYCL1/MYCN] non-amplified [NA]); 0%, 50%, 2 months (TNBC biomarker amplified); 8.3%, 33.3%, 1.3 months (SCLC biomarker NA); and 0%, 33.3%, 1.2 months (SCLC biomarker amplified). CONCLUSION: Adavosertib monotherapy was tolerated and demonstrated some antitumor activity in patients with advanced solid tumors. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02482311; registered June 2015.

Disparities in clinical trial participation in ovarian cancer: A real-world analysis.

BACKGROUND: Significant disparities exist in clinical trial participation in non-gynecologic cancers, but little is known about disparities in ovarian cancer trial participation. Our objective was to examine patient, sociodemographic (race/ethnicity, insurance), cancer, and health system factors associated with clinical trial participation in ovarian cancer. METHODS: We conducted a retrospective cohort study of patients with epithelial ovarian cancer diagnosed from 2011 to 2021, using a real-world electronic health record derived database, representing around 800 sites of care in US academic and community practices. We used multivariable Poisson regression modeling to analyze the association of ever participating in an ovarian cancer clinical drug trial with patient, sociodemographic, health system, and cancer factors. RESULTS: Of the 7540 patients with ovarian cancer, 5.0% (95% CI 4.5-5.5) ever participated in a clinical drug trial. Patients of Hispanic or Latino ethnicity were 71% less likely to participate in clinical trials (RR 0.29, 95% CI 0.13-0.61) than non-Hispanic patients, and patients whose race was unknown or other than Black or White were 40% less likely to participate in clinical trials (RR 0.68, 95% CI 0.52-0.89). Patients who had Medicaid insurance were 51% less likely (RR 0.49, 95% CI 0.28-0.87) and those with Medicare were 32% (RR 0.48-0.97) less likely to participate in clinical trials than privately-insured patients. CONCLUSION: In this national cohort study, only 5% of patients with ovarian cancer participated in clinical drug trials. Interventions are needed to decrease race, ethnicity, and insurance disparities in clinical trial participation.

Combination ATR (ceralasertib) and PARP (olaparib) Inhibitor (CAPRI) Trial in Acquired PARP Inhibitor-Resistant Homologous Recombination-Deficient Ovarian Cancer.

PURPOSE: Addition of ataxia telangiectasia and Rad3-related kinase inhibitors (ATRi) to PARP inhibitors (PARPi) overcomes PARPi resistance in high-grade serous ovarian cancer (HGSOC) cell and mouse models. We present the results of an investigator-initiated study of combination PARPi (olaparib) and ATRi (ceralasertib) in patients with acquired PARPi-resistant HGSOC. PATIENTS AND METHODS: Eligible patients had recurrent, platinum-sensitive BRCA1/2 mutated or homologous recombination (HR)-deficient (HRD) HGSOC and clinically benefited from PARPi (response by imaging/CA-125 or duration of maintenance therapy; > 12 months first-line or > 6 months ≥ second-line) before progression. No intervening chemotherapy was permitted. Patients received olaparib 300 mg twice daily and ceralasertib 160 mg daily on days 1 to 7 of a 28-day cycle. Primary objectives were safety and objective response rate (ORR). RESULTS: Thirteen patients enrolled were evaluable for safety and 12 for efficacy; 62% (n = 8) had germline BRCA1/2 mutations, 23% (n = 3) somatic BRCA1/2 mutations, and 15% (n = 2) tumors with positive HRD assay. Prior PARPi indication was treatment for recurrence (54%, n = 7), second-line maintenance (38%, n = 5) and first-line treatment with carboplatin/paclitaxel (8%, n = 1). There were 6 partial responses yielding an ORR of 50% (95% confidence interval, 0.15-0.72). Median treatment duration was 8 cycles (range 4-23+). Grade (G) 3/4 toxicities were 38% (n = 5); 15% (n = 2) G3 anemia, 23% (n = 3) G3 thrombocytopenia, 8% (n = 1) G4 neutropenia. Four patients required dose reductions. No patient discontinued treatment due to toxicity. CONCLUSIONS: Combination olaparib and ceralasertib is tolerable and shows activity in HR-deficient platinum-sensitive recurrent HGSOC that benefited and then progressed with PARPi as the penultimate regimen. These data suggest that ceralasertib resensitizes PARPi-resistant HGSOCs to olaparib, warranting further investigation.

[18F]FluorThanatrace ([18F]FTT) PET Imaging of PARP-Inhibitor Drug-Target Engagement as a Biomarker of Response in Ovarian Cancer, a Pilot Study.

PURPOSE: PARP inhibitors have become the standard-of-care treatment for homologous recombination deficient (HRD) high-grade serous ovarian cancer (HGSOC). However, not all HRD tumors respond to PARPi. Biomarkers to predict response are needed. [18F]FluorThanatrace ([18F]FTT) is a PARPi-analog PET radiotracer that noninvasively measures PARP-1 expression. Herein, we evaluate [18F]FTT as a biomarker to predict response to PARPi in patient-derived xenograft (PDX) models and subjects with HRD HGSOC. EXPERIMENTAL DESIGN: In PDX models, [18F]FTT-PET was performed before and after PARPi (olaparib), ataxia-telangiectasia inhibitor (ATRi), or both (PARPi-ATRi). Changes in [18F]FTT were correlated with tumor volume changes. Subjects were imaged with [18F]FTT-PET at baseline and after ∼1 week of PARPi. Changes in [18F]FTT-PET uptake were compared with changes in tumor size (RECISTv1.1), CA-125, and progression-free survival (PFS). RESULTS: A decrease in [18F]FTT tumor uptake after PARPi correlated with response to PARPi, or PARPi-ATRi treatment in PARPi-resistant PDX models (r = 0.77-0.81). In subjects (n = 11), percent difference in [18F]FTT-PET after ∼7 days of PARPi compared with baseline correlated with best RECIST response (P = 0.01), best CA-125 response (P = 0.033), and PFS (P = 0.027). All subjects with >50% reduction in [18F]FTT uptake had >6-month PFS and >50% reduction in CA-125. Utilizing only baseline [18F]FTT uptake did not predict such responses. CONCLUSIONS: The decline in [18F]FTT uptake shortly after PARPi initiation provides a measure of drug-target engagement and shows promise as a biomarker to guide PARPi therapies in this pilot study. These results support additional preclinical mechanistic and clinical studies in subjects receiving PARPi ± combination therapy. See related commentary by Liu and Zamarin, p. 1384.

Facility level variation in the utilization of neoadjuvant chemotherapy is associated with higher surgical morbidity for patients with advanced stage epithelial ovarian carcinoma.

OBJECTIVE: Investigate outcomes for advanced stage epithelial ovarian cancer (EOC) patients based on facility-level utilization of neoadjuvant chemotherapy (NACT). METHODS: Stage III-IV EOC patients diagnosed between 2010 and 2016 were identified in the National Cancer Database. Percentage of patients managed with NACT was calculated for facilities, reporting ≥120 patients. Facilities with lowest and highest quartile of NACT rate comprised the low and high-utilizing groups. Clinico-pathological characteristics were collected, and appropriate statistical analysis performed. RESULTS: High- and low-utilizing facilities managed on average 54.1% and 25.4% of patients with NACT respectively. Patients managed at high-utilizing facilities were significantly more likely to be >65 (p = 0.029), have stage IV disease (p < 0.001) and comorbidities (p < 0.001). Patients managed with primary debulking surgery (PDS) at low-utilizing facilities were significantly more likely to be >65, have stage IV disease, and have comorbidities (all, p < 0.001). Patients undergoing PDS at low-utilizing facilities were significantly less likely to achieve complete gross resection (p < 0.001), and were significantly more likely to experience 90-day mortality (p < 0.001), and unplanned 30-day readmission (p < 0.001). After controlling for age, comorbidities, race, insurance status, stage, grade and histology, high-utilizing facilities trended towards better overall survival (OS) (HR: 0.92, 95% CI: 0.85-0.99). Overall, patients undergoing PDS had better OS compared to those who had NACT (median 42 vs 27 months, p < 0.001). CONCLUSIONS: Despite treating an EOC population with more advanced disease and comorbidities, high-utilizing facilities have lower surgical morbidity and mortality with no detrimental impact on long-term survival. Careful patient selection to minimize the morbidity and mortality associated with PDS is pivotal.

Olaparib treatment for platinum-sensitive relapsed ovarian cancer by BRCA mutation and homologous recombination deficiency status: Phase II LIGHT study primary analysis.

OBJECTIVE: Olaparib treatment resulted in significant improvement in objective response rates (ORRs) and progression-free survival (PFS) over non­platinum chemotherapy in patients with BRCA1/BRCA2-mutated (BRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) and ≥2 prior lines of platinum-based chemotherapy in the phase III SOLO3 study. LIGHT (NCT02983799) prospectively evaluated olaparib treatment for patients with PSROC and known BRCAm and homologous recombination deficiency (HRD) status. METHODS: In this phase II open-label multicenter study, patients with PSROC and ≥1 prior line of platinum-based chemotherapy were assigned to cohorts by presence of germline BRCAm (gBRCAm), somatic BRCAm (sBRCAm), HRD-positive tumors without BRCAm, or HRD-negative tumors. The primary endpoint was investigator-assessed ORR. Secondary endpoints included disease control rate (DCR) and PFS. Tumors were analyzed using Myriad BRACAnalysis CDx and myChoice HRD assays; HRD-positive tumors were defined using a genomic instability score of ≥42. RESULTS: Of 272 enrolled patients, 271 received olaparib and 270 were included in efficacy analyses. At data cut-off, ORRs in the gBRCAm, sBRCAm, HRD-positive, and HRD-negative cohorts were 69.3%, 64.0%, 29.4%, and 10.1%, respectively. DCRs were 96.0%, 100.0%, 79.4%, and 75.3% in each cohort, respectively. Median PFS was 11.0, 10.8, 7.2, and 5.4 months, respectively. The most common (≥ 20%) treatment-emergent adverse events included nausea, fatigue/asthenia, vomiting, anemia, constipation, diarrhea, and decreased appetite. CONCLUSIONS: Olaparib treatment demonstrated activity across all cohorts. The greatest efficacy was observed in the BRCAm cohorts, regardless of gBRCAm/sBRCAm. For patients without a BRCAm, greater efficacy was observed in the HRD-positive than the HRD-negative cohorts. The safety profile was consistent with that established in previous olaparib studies.

Kinetic and Static Analysis of Poly-(Adenosine Diphosphate-Ribose) Polymerase-1-Targeted 18F-Fluorthanatrace PET Images of Ovarian Cancer.

The poly-(adenosine diphosphate-ribose) polymerase (PARP) family of proteins participates in numerous functions, most notably the DNA damage response. Cancer vulnerability to DNA damage has led to development of several PARP inhibitors (PARPi). This class of drugs has demonstrated therapeutic efficacy in ovarian, breast, and prostate cancers, but with variable response. Consequently, clinics need to select patients likely to benefit from these targeted therapies. In vivo imaging of 18F-fluorthanatrace uptake has been shown to correspond to PARP-1 expression in tissue. This study characterized the pharmacokinetics of 18F-fluorthanatrace and tested kinetic and static models to guide metric selection in future studies assessing 18F-fluorthanatrace as a biomarker of response to PARPi therapy. Methods: Fourteen prospectively enrolled ovarian cancer patients were injected with 18F-fluorthanatrace and imaged dynamically for 60 min after injection followed by up to 2 whole-body scans, with venous blood activity and metabolite measurements. SUVmax and SUVpeak were extracted from dynamic images and whole-body scans. Kinetic parameter estimates and SUVs were assessed for correlations with tissue PARP-1 immunofluorescence (n = 7). Simulations of population kinetic parameters enabled estimation of measurement bias and precision in parameter estimates. Results:18F-fluorthanatrace blood clearance was variable, but labeled metabolite profiles were similar across patients, supporting use of a population parent fraction curve. The total distribution volume from a reversible 2-tissue-compartment model and Logan reference tissue distribution volume ratio (DVR) from the first hour of PET acquisition correlated with tumor PARP-1 expression by immunofluorescence (r = 0.76 and 0.83, respectively; P < 0.05). DVR bias and precision estimates were 6.4% and 29.1%, respectively. SUVmax and SUVpeak acquired from images with midpoints of 57.5, 110 ± 3, and 199 ± 4 min highly correlated with PARP-1 expression (mean ± SD, r ≥ 0.79; P < 0.05). Conclusion: Tumor SUVmax and SUVpeak at 55-60 min after injection and later and DVR from at least 60 min appear to be robust noninvasive measures of PARP-1 binding. 18F-fluorthanatrace uptake in ovarian cancer was best described by models of reversible binding. However, pharmacokinetic patterns of tracer uptake were somewhat variable, especially at later time points.

Humanized Patient-Derived Xenograft Models of Ovarian Cancer.

In vivo modeling of cancer is a critical step in testing novel therapeutic strategies to advance patient care. Here we describe how to develop a humanized patient-derived xenograft (PDX) model of ovarian cancer that uses orthotopically transplanted patient ovarian tumors with autologous transfer of expanded tumor infiltrating T cells (TILs) as a model that can be utilized to test immunomodulating therapeutics in vivo.

Induction of IL19 expression through JNK and cGAS-STING modulates DNA damage-induced cytokine production.

Cytokine production is a critical component of cell-extrinsic responses to DNA damage and cellular senescence. Here, we demonstrated that expression of the gene encoding interleukin-19 (IL-19) was enhanced by DNA damage through pathways mediated by c-Jun amino-terminal kinase (JNK) and cGAS-STING and that IL19 expression was required for the subsequent production of the cytokines IL-1, IL-6, and IL-8. IL19 expression was stimulated by diverse cellular stresses, including inhibition of the DNA replication checkpoint kinase ATR (ataxia telangiectasia and Rad3-related protein), oncogene expression, replicative exhaustion, oxidative stress, and DNA double-strand breaks. Unlike the production of IL-6 and IL-8, IL19 expression was not affected by abrogation of signaling by the IL-1 receptor (IL-1R) or the mitogen-activated protein kinase p38. Instead, the DNA damage­induced production of IL-1, IL-6, and IL-8 was substantially reduced by suppression of IL19 expression. The signaling pathways required to stimulate IL19 expression selectively depended on the type of DNA-damaging agent. Reactive oxygen species and the ASK1-JNK pathway were critical for responses to ionizing radiation (IR), whereas the cGAS-STING pathway stimulated IL19 expression in response to either IR or ATR inhibition. Whereas induction of IL1, IL6, and IL8 by IR depended on IL19 expression, the cGAS-STING­dependent induction of the immune checkpoint gene PDL1 after IR and ATR inhibition was independent of IL19. Together, these results suggest that IL-19 production by diverse pathways forms a distinct cytokine regulatory arm of the response to DNA damage.

CCNE1 copy number is a biomarker for response to combination WEE1-ATR inhibition in ovarian and endometrial cancer models.

CCNE1-amplified ovarian cancers (OVCAs) and endometrial cancers (EMCAs) are associated with platinum resistance and poor survival, representing a clinically unmet need. We hypothesized that dysregulated cell-cycle progression promoted by CCNE1 overexpression would lead to increased sensitivity to low-dose WEE1 inhibition and ataxia telangiectasia and Rad3-related (ATR) inhibition (WEE1i-ATRi), thereby optimizing efficacy and tolerability. The addition of ATRi to WEE1i is required to block feedback activation of ATR signaling mediated by WEE1i. Low-dose WEE1i-ATRi synergistically decreases viability and colony formation and increases replication fork collapse and double-strand breaks (DSBs) in a CCNE1 copy number (CN)-dependent manner. Only upon CCNE1 induction does WEE1i perturb DNA synthesis at S-phase entry, and addition of ATRi increases DSBs during DNA synthesis. Inherent resistance to WEE1i is overcome with WEE1i-ATRi, with notable durable tumor regressions and improved survival in patient-derived xenograft (PDX) models in a CCNE1-level-dependent manner. These studies demonstrate that CCNE1 CN is a clinically tractable biomarker predicting responsiveness to low-dose WEE1i-ATRi for aggressive subsets of OVCAs/EMCAs.

Combination ATR and PARP Inhibitor (CAPRI): A phase 2 study of ceralasertib plus olaparib in patients with recurrent, platinum-resistant epithelial ovarian cancer.

OBJECTIVE: Platinum-resistant, high-grade serous ovarian cancer (HGSOC) has limited treatment options. Preclinical data suggest that poly(ADP-ribose) polymerase inhibitors (PARPi) and ataxia telangiectasia and Rad3-related kinase inhibitors (ATRi) are synergistic. CAPRI (NCT03462342) is an investigator-initiated study of olaparib plus ceralasertib in recurrent HGSOC. Herein, we present results from the platinum-resistant cohort. METHODS: A Simon 2-stage design was utilized. Platinum-resistant HGSOC patients received ceralasertib 160 mg orally daily, days 1-7 and olaparib 300 mg orally twice daily, days 1-28 of a 28-day cycle until toxicity or progression. Primary endpoints were toxicity and efficacy including objective response rate (ORR) by RECIST. Secondary endpoint was progression-free survival (PFS). The null hypothesis (≤5% ORR) would be rejected if there were ≥ 1 responses in 12 patients. RESULTS: Fourteen PARPi-naïve patients were evaluable for toxicity; 12 were evaluable for response. Three had BRCA1 mutations (1 germline, 2 somatic). Adverse events possibly related to treatment were primarily grade (G) 1/2. G3 toxicities included nausea (14.3%), fatigue (7.1%), anorexia (7.1%), and anemia (7.1%). No objective responses occurred. Best response was stable disease in 9 patients and progressive disease in three. Five patients had a ≥ 20% to <30% reduction in disease burden, including 3 with BRCA1 mutations. Three of 11 patients (27%; 2 with BRCA1 mutations) evaluable by Gynecologic Cancer Intergroup criteria had >50% CA-125 decline, including 2 with CA-125 normalization. Median PFS was 4.2 months overall (90% CI:3.5-8.2) and 8.2 months (3.6 months-not determined) for patients with BRCA1 mutations. CONCLUSIONS: Olaparib plus ceralasertib is well-tolerated. No objective responses occurred, though a signal of activity was seen particularly in disease associated with BRCA1. Further evaluation of this combination should include alternate dosing strategies in genomically-selected populations.