Phase II trial of pembrolizumab and epacadostat in recurrent clear cell carcinoma of the ovary: An NRG oncology study GY016.

INTRODUCTION: Early reports of PD-1 inhibition in ovarian clear cell carcinomas (OCCC) demonstrate promising response. We evaluated the combination of pembrolizumab and IDO-1 inhibitor epacadostat in patients with recurrent OCCC. METHODS: This single arm, two-stage, phase 2 trial included those with measurable disease and 1-3 prior regimens. Patients received intravenous pembrolizumab 200 mg every 3 weeks and oral epacadostat 100 mg twice a day. Primary endpoint was overall response rate (ORR), secondary endpoints were toxicity, progression-free survival (PFS) and overall survival (OS). The study was powered to detect an absolute 25% increase in response (15% to 40%). RESULTS: Between September 28, 2018 and April 10, 2019, 14 patients enrolled at first stage. Rate of accrual was 2.3 patients per month. Median age was 65 years (44-89), 10 (71.4%) had ≥2 prior regimens. ORR was 21% (95% CI 5-51%) within 7 months of study entry with 3 partial responses, and 4 had stable disease (disease control rate 50%). Median PFS was 4.8 months (95% CI: 1.9-9.6), OS 18.9 months (95% CI: 1.9-NR). Most common grade ≥ 3 adverse events were electrolyte abnormalities and gastrointestinal pain, nausea, vomiting, bowel obstruction. In July 2019, the study reached the pre-specified criteria to re-open to second stage; however, the study closed prematurely in February 2021 due to insufficient drug supply. CONCLUSIONS: Pembrolizumab and epacadostat demonstrated an ORR of 21% in this small cohort of recurrent OCCC. The rapid rate of accrual highlights the enthusiasm and need for therapeutic studies in patients with OCCC.

A phase 2 study of dasatinib in recurrent clear cell carcinoma of the ovary, fallopian tube, peritoneum or endometrium: NRG oncology/gynecologic oncology group study 0283.

OBJECTIVE: Gynecologic cancers are traditionally managed according to their presumed site of origin, without regard to the underlying histologic subtype. Clear cell histology is associated with chemotherapy refractoriness and poor survival. Mutations in SWI/SNF chromatin remodeling complex member ARID1A, which encodes for BAF250a protein, are common in clear cell and endometriosis-associated endometrioid carcinomas. High-throughput cell-based drug screening predicted activity of dasatinib, a tyrosine kinase inhibitor, in ARID1A-mutant clear cell carcinoma. METHODS: We conducted a phase 2 clinical trial of dasatinib 140 mg once daily by mouth in patients with recurrent or persistent ovarian and endometrial clear cell carcinoma. Patients with measurable disease were enrolled and then assigned to biomarker-defined populations based on BAF250a immunohistochemistry. The translational endpoints included broad next-generation sequencing to assess concordance of protein expression and treatment outcomes. RESULTS: Twenty-eight patients, 15 of whom had tumors with retained BAF250a and 13 with loss of BAF250a were evaluable for treatment response and safety. The most common grade 3 adverse events were anemia, fatigue, dyspnea, hyponatremia, pleural effusion, and vomiting. One patient had a partial response, eight (28%) had stable disease, and 15 (53.6%) had disease progression. Twenty-three patients had next-generation sequencing results; 13 had a pathogenic ARID1A alteration. PIK3CA mutations were more prevalent in ARID1A-mutant tumors, while TP53 mutations were more prevalent in ARID1A wild-type tumors. CONCLUSIONS: Dasatinib was not an effective single-agent treatment for recurrent or persistent ovarian and endometrial clear cell carcinoma. Studies are urgently needed for this rare gynecologic subtype.

Incidence of venous thromboembolism in patients with advanced stage ovarian cancer undergoing neoadjuvant chemotherapy: Is it time for thromboprophylaxis?

OBJECTIVES: Our objectives were to determine the incidence, timing, and risk factors for venous thromboembolisms (VTEs) in patients with advanced stage epithelial ovarian cancer (EOC) who received neoadjuvant chemotherapy (NACT). We explored the utilization of direct-acting oral anticoagulants (DOACs) for VTE treatment. METHODS: This retrospective cohort study included patients with advanced stage EOC receiving NACT followed by interval cytoreductive surgery (ICS) at a single institution. Risk factors were compared between patients with versus without VTE between EOC diagnosis and 180 days after ICS. Bleeding complications were compared between patient who received a DOAC versus non-DOAC. RESULTS: VTE cases occurred amongst 33 of the 154 (21.4%) patients with 4 (2.6%) concurrent with EOC diagnosis, 9 (5.8%) between EOC diagnosis and NACT start, 13 (8.4%) between NACT start and ICS, and 7 (4.5%) within 180 days after ICS. There were no statistically significant differences in risk factors assessed (age, body mass index, functional status, histology, Khorana score, and smoking history) between patients with versus without VTE. Eleven patients (33.3%) received a DOAC for VTE treatment. There were no significant differences in number of intraoperative blood transfusions (p = 0.38), blood loss (p = 0.95), or bleeding complications (p = 0.53) between patients treated with a DOAC versus a non-DOAC. CONCLUSION: There is a high incidence of VTE events (21.4%) in patients with advanced stage EOC undergoing NACT. Two-thirds of the VTEs may have been prevented with thromboprophylaxis as they occurred between EOC diagnosis and ICS. These data support consideration of thromboprophylaxis in all patients with advanced stage EOC undergoing NACT.

Carboplatin dosing in the treatment of ovarian cancer: An NRG oncology group study.

OBJECTIVE: To determine the effects of using National Comprehensive Cancer Network (NCCN) guidelines to estimate renal function on carboplatin dosing and explore adverse effects associated with a more accurate estimation of lower creatinine clearance (CrCl). METHODS: Retrospective data were obtained for 3830 of 4312 patients treated on GOG182 (NCT00011986)-a phase III trial of platinum-based chemotherapy for advanced-stage ovarian cancer. Carboplatin dose per patient on GOG182 was determined using the Jelliffe formula. We recalculated CrCl to determine dosing using Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (with/without NCCN recommended modifications) formulas. Associations between baseline CrCl and toxicity were described using the area under the receiver operating characteristic curve (AUC). Sensitivity and positive predictive values described the model's ability to discriminate between subjects with/without the adverse event. RESULTS: AUC statistics (range, 0.52-0.64) showed log(CrClJelliffe) was not a good predictor of grade ≥3 adverse events (anemia, thrombocytopenia, febrile neutropenia, auditory, renal, metabolic, neurologic). Of 3830 patients, 628 (16%) had CrCl <60 mL/min. Positive predictive values for adverse events ranged from 1.8%-15%. Using the Cockcroft-Gault, Cockcroft-Gault with NCCN modifications, and MDRD (instead of Jelliffe) formulas to estimate renal function resulted in a >10% decrease in carboplatin dosing in 16%, 32%, and 5.2% of patients, respectively, and a >10% increase in carboplatin dosing in 41%, 9.6% and 12% of patients, respectively. CONCLUSION: The formula used to estimate CrCl affects carboplatin dosing. Estimated CrCl <60 mL/min (by Jelliffe) did not accurately predict adverse events. Efforts continue to better predict renal function. Endorsing National Cancer Institute initiatives to broaden study eligibility, our data do not support a minimum threshold CrCl <60 mL/min as an exclusion criterion from clinical trials.

The effect of older age on treatment outcomes in women with advanced ovarian cancer receiving chemotherapy: An NRG-Oncology/Gynecologic Oncology Group (GOG-0182-ICON5) ancillary study.

OBJECTIVE: To assess the effect of age on overall survival (OS) in women with ovarian cancer receiving chemotherapy. Secondary objectives were to describe the effect of age on treatment compliance, toxicities, progression free survival (PFS), time from surgery to chemotherapy, and rates of optimal cytoreduction. METHODS: Women enrolled in GOG 0182-ICON5 with stage III or IV epithelial ovarian cancer (EOC) who underwent surgery and chemotherapy between 2001 and 2004 were included. Patients were divided into ages <70 and ≥ 70 years. Baseline characteristics, treatment compliance, toxicities, and clinical outcomes were compared. RESULTS: We included a total of 3686 patients, with 620 patients (16.8%) ≥ 70 years. OS was 37.2 months in older compared to 45.0 months in younger patients (HR 1.21, 95% CI, 1.09-1.34, p < 0.001). Older patients had an increased risk of cancer-specific-death (HR 1.16, 95% CI, 1.04-1.29) as well as non-cancer related deaths (HR 2.78, 95% CI, 2.00-3.87). Median PFS was 15.1 months in older compared to 16.0 months in younger patients (HR 1.10, 95% CI, 1.00-1.20, p = 0.056). In the carboplatin/paclitaxel arm, older patients were just as likely to complete therapy and more likely to develop grade ≥ 2 peripheral neuropathy (35.7 vs 19.7%, p < 0.001). Risk of other toxicities remained equal between groups. CONCLUSIONS: In women with advanced EOC receiving chemotherapy, age ≥ 70 was associated with shorter OS and cancer specific survival. Older patients receiving carboplatin and paclitaxel reported higher rates of grade ≥ 2 neuropathy but were not more likely to suffer from other chemotherapy related toxicities. Clintrials.gov: NCT00011986.

Real-World Implementation of Best-Evidence Cancer Distress Management: Truly Comprehensive Cancer Care.

BACKGROUND: Cancer distress management is an evidence-based component of comprehensive cancer care. Group-delivered cognitive behavioral therapy for cancer distress (CBT-C) is the first distress treatment associated with replicated survival advantages in randomized clinical trials. Despite research supporting patient satisfaction, improved outcomes, and reduced costs, CBT-C has not been tested sufficiently within billable clinical settings, profoundly reducing patient access to best-evidence care. This study aimed to adapt and implement manualized CBT-C as a billable clinical service. PATIENTS AND METHODS: A stakeholder-engaged, mixed-methods, hybrid implementation study design was used, and the study was conducted in 3 phases: (1) stakeholder engagement and adaptation of CBT-C delivery, (2) patient and therapist user testing and adaptation of CBT-C content, and (3) implementation of practice-adapted CBT-C as a billable clinical service focused on evaluation of reach, acceptability, and feasibility across stakeholder perspectives. RESULTS: A total of 40 individuals and 7 interdisciplinary group stakeholders collectively identified 7 primary barriers (eg, number of sessions, workflow concerns, patient geographic distance from center) and 9 facilitators (eg, favorable financial model, emergence of oncology champions). CBT-C adaptations made before implementation included expanding eligibility criteria beyond breast cancer, reducing number of sessions to 5 (10 total hours), eliminating and adding content, and revising language and images. During implementation, 252 patients were eligible; 100 (40%) enrolled in CBT-C (99% covered by insurance). The primary reason for declining enrollment was geographic distance. Of enrollees, 60 (60%) consented to research participation (75% women; 92% white). All research participants completed at least 60% of content (6 of 10 hours), with 98% reporting they would recommend CBT-C to family and friends. CONCLUSIONS: CBT-C implementation as a billable clinical service was acceptable and feasible across cancer care stakeholder measures. Future research is needed to replicate acceptability and feasibility results in more diverse patient groups, test effectiveness in clinical settings, and reduce barriers to access via remote delivery platforms.

Combined PARP and HSP90 inhibition: preclinical and Phase 1 evaluation in patients with advanced solid tumours.

PURPOSE: PARP inhibitor resistance may be overcome by combinatorial strategies with agents that disrupt homologous recombination repair (HRR). Multiple HRR pathway components are HSP90 clients, so that HSP90 inhibition leads to abrogation of HRR and sensitisation to PARP inhibition. We performed in vivo preclinical studies of the HSP90 inhibitor onalespib with olaparib and conducted a Phase 1 combination study. PATIENTS AND METHODS: Tolerability and efficacy studies were performed in patient-derived xenograft(PDX) models of ovarian cancer. Clinical safety, tolerability, steady-state pharmacokinetics and preliminary efficacy of olaparib and onalespib were evaluated using a standard 3 + 3 dose-escalation design. RESULTS: Olaparib/onalespib exhibited anti-tumour activity against BRCA1-mutated PDX models with acquired PARPi resistance and PDX models with RB-pathway alterations(CDKN2A loss and CCNE1 overexpression). Phase 1 evaluation revealed that dose levels up to olaparib 300 mg/onalespib 40 mg and olaparib 200 mg/onalespib 80 mg were safe without dose-limiting toxicities. Coadministration of olaparib and onalespib did not appear to affect the steady-state pharmacokinetics of either agent. There were no objective responses, but disease stabilisation ≥24 weeks was observed in 7/22 (32%) evaluable patients including patients with BRCA-mutated ovarian cancers and acquired PARPi resistance and patients with tumours harbouring RB-pathway alterations. CONCLUSIONS: Combining onalespib and olaparib was feasible and demonstrated preliminary evidence of anti-tumour activity.

Adavosertib plus gemcitabine for platinum-resistant or platinum-refractory recurrent ovarian cancer: a double-blind, randomised, placebo-controlled, phase 2 trial.

BACKGROUND: The Wee1 (WEE1hu) inhibitor adavosertib and gemcitabine have shown preclinical synergy and promising activity in early phase clinical trials. We aimed to determine the efficacy of this combination in patients with ovarian cancer. METHODS: In this double-blind, randomised, placebo-controlled, phase 2 trial, women with measurable recurrent platinum-resistant or platinum-refractory high-grade serous ovarian cancer were recruited from 11 academic centres in the USA and Canada. Women were eligible if they were aged 18 years or older, had an Eastern Cooperative Oncology Group performance status of 0-2, a life expectancy of more than 3 months, and normal organ and marrow function. Women with ovarian cancer of non-high-grade serous histology were eligible for enrolment in a non-randomised exploratory cohort. Eligible participants with high-grade serous ovarian cancer were randomly assigned (2:1), using block randomisation (block size of three and six) and no stratification, to receive intravenous gemcitabine (1000 mg/m2 on days 1, 8, and 15) with either oral adavosertib (175 mg) or identical placebo once daily on days 1, 2, 8, 9, 15, and 16, in 28-day cycles until disease progression or unacceptable toxicity. Patients and the team caring for each patient were masked to treatment assignment. The primary endpoint was progression-free survival. The safety and efficacy analysis population comprised all patients who received at least one dose of treatment. The trial is registered with ClinicalTrials.gov, NCT02151292, and is closed to accrual. FINDINGS: Between Sept 22, 2014, and May 30, 2018, 124 women were enrolled, of whom 99 had high-grade serous ovarian cancer and were randomly assigned to adavosertib plus gemcitabine (65 [66%]) or placebo plus gemcitabine (34 [34%]). 25 women with non-high-grade serous ovarian cancer were enrolled in the exploratory cohort. After randomisation, five patients with high-grade serous ovarian cancer were found to be ineligible (four in the experimental group and one in the control group) and did not receive treatment. Median age for all treated patients (n=119) was 62 years (IQR 54-67). Progression-free survival was longer with adavosertib plus gemcitabine (median 4·6 months [95% CI 3·6-6·4] with adavosertib plus gemcitabine vs 3·0 months [1·8-3·8] with placebo plus gemcitabine; hazard ratio 0·55 [95% CI 0·35-0·90]; log-rank p=0·015). The most frequent grade 3 or worse adverse events were haematological (neutropenia in 38 [62%] of 61 participants in the adavosertib plus gemcitabine group vs ten [30%] of 33 in the placebo plus gemcitabine group; thrombocytopenia in 19 [31%] of 61 in the adavosertib plus gemcitabine group vs two [6%] of 33 in the placebo plus gemcitabine group). There were no treatment-related deaths; two patients (one in each group in the high-grade serous ovarian cancer cohort) died while on study medication (from sepsis in the experimental group and from disease progression in the control group). INTERPRETATION: The observed clinical efficacy of a Wee1 inhibitor combined with gemcitabine supports ongoing assessment of DNA damage response drugs in high-grade serous ovarian cancer, a TP53-mutated tumour type with high replication stress. This therapeutic approach might be applicable to other tumour types with high replication stress; larger confirmatory studies are required. FUNDING: US National Cancer Institute Cancer Therapy Evaluation Program, Ontario Institute for Cancer Research, US Department of Defense, Princess Margaret Cancer Foundation, and AstraZeneca.

Prognostic significance of ethnicity and age in advanced stage epithelial ovarian cancer: An NRG oncology/gynecologic oncology group study.

BACKGROUND: Age and ethnicity are among several factors that influence overall survival (OS) in ovarian cancer. The study objective was to determine whether ethnicity and age were of prognostic significance in women enrolled in a clinical trial evaluating the addition of bevacizumab to front-line therapy. METHODS: Women with advanced stage ovarian, primary peritoneal, or fallopian tube cancer were enrolled in a phase III clinical trial. All women had surgical staging and received adjuvant chemotherapy with one of three regimens. Cox proportional hazards models were used to evaluate the relationship between OS with age and race/ethnicity among the study participants. RESULTS: One-thousand-eight-hundred-seventy-three women were enrolled in the study. There were 280 minority women and 328 women over the age of 70. Women age 70 and older had a 34% increase risk for death when compared to women under 60 (HR = 1.34; 95% CI 1.16-1.54). Non-Hispanic Black women had a 54% decreased risk of death with the addition of maintenance bevacizumab (HR = 0.46, 95% CI:0.26-0.83). Women of Asian descent had more hematologic grade 3 or greater adverse events and a 27% decrease risk of death when compared to non-Hispanic Whites (HR = 0.73; 95% CI: 0.59-0.90). CONCLUSIONS: Non-Hispanic Black women showed a decreased risk of death with the addition of bevacizumab and patients of Asian ancestry had a lower death rate than all other minority groups, but despite these clinically meaningful improvements there was no statistically significant difference in OS among the groups.

Berzosertib plus gemcitabine versus gemcitabine alone in platinum-resistant high-grade serous ovarian cancer: a multicentre, open-label, randomised, phase 2 trial.

BACKGROUND: High-grade serous ovarian cancers show increased replication stress, rendering cells vulnerable to ATR inhibition because of near universal loss of the G1/S checkpoint (through deleterious TP53 mutations), premature S phase entry (due to CCNE1 amplification, RB1 loss, or CDKN2A mRNA downregulation), alterations of homologous recombination repair genes, and expression of oncogenic drivers (through MYC amplification and other mechanisms). We hypothesised that the combination of the selective ATR inhibitor, berzosertib, and gemcitabine could show acceptable toxicity and superior efficacy to gemcitabine alone in high-grade serous ovarian cancer. METHODS: In this multicentre, open-label, randomised, phase 2 study, 11 different centres in the US Experimental Therapeutics Clinical Trials Network enrolled women (aged ≥18 years) with recurrent, platinum-resistant high-grade serous ovarian cancer (determined histologically) and Eastern Cooperative Oncology Group performance status of 0 or 1, who had unlimited previous lines of cytotoxic therapy in the platinum-sensitive setting but no more than one line of cytotoxic therapy in the platinum-resistant setting. Eligible patients were randomly assigned (1:1) to receive intravenous gemcitabine (1000 mg/m2) on day 1 and day 8, or gemcitabine plus intravenous berzosertib (210 mg/m2) on day 2 and day 9 of a 21-day cycle until disease progression or intolerable toxicity. Randomisation was done centrally using the Theradex Interactive Web Response System, stratified by platinum-free interval, and with a permuted block size of six. Following central randomisation, patients and investigators were not masked to treatment assignment. The primary endpoint was investigator-assessed progression-free survival, and analyses included all patients who received at least one dose of the study drugs. The study is registered with ClinicalTrials.gov, NCT02595892, and is active but closed to enrolment. FINDINGS: Between Feb 14, 2017, and Sept 7, 2018, 88 patients were assessed for eligibility, of whom 70 were randomly assigned to treatment with gemcitabine alone (36 patients) or gemcitabine plus berzosertib (34 patients). At the data cutoff date (Feb 21, 2020), the median follow-up was 53·2 weeks (25·6-81·8) in the gemcitabine plus berzosertib group and 43·0 weeks (IQR 23·2-69·1) in the gemcitabine alone group. Median progression-free survival was 22·9 weeks (17·9-72·0) for gemcitabine plus berzosertib and 14·7 weeks (90% CI 9·7-36·7) for gemcitabine alone (hazard ratio 0·57, 90% CI 0·33-0·98; one-sided log-rank test p=0·044). The most common treatment-related grade 3 or 4 adverse events were decreased neutrophil count (14 [39%] of 36 patients in the gemcitabine alone group vs 16 [47%] of 34 patients in the gemcitabine plus berzosertib group) and decreased platelet count (two [6%] vs eight [24%]). Serious adverse events were observed in ten (28%) patients in the gemcitabine alone group and nine (26%) patients in the gemcitabine plus berzosertib group. There was one treatment-related death in the gemcitabine alone group due to sepsis and one treatment-related death in the gemcitabine plus berzosertib group due to pneumonitis. INTERPRETATION: To our knowledge, this is the first randomised study of an ATR inhibitor in any tumour type. This study shows a benefit of adding berzosertib to gemcitabine in platinum-resistant high-grade serous ovarian cancer. This combination warrants further investigation in this setting. FUNDING: US National Cancer Institute.

Niraparib monotherapy for late-line treatment of ovarian cancer (QUADRA): a multicentre, open-label, single-arm, phase 2 trial.

BACKGROUND: Late-line treatment options for patients with ovarian cancer are few, with the proportion of patients achieving an overall response typically less than 10%, and median overall survival after third-line therapy of 5-9 months. In this study (QUADRA), we investigated the activity of niraparib monotherapy as the fourth or later line of therapy. METHODS: QUADRA was a multicentre, open-label, single-arm, phase 2 study that evaluated the safety and activity of niraparib in adult patients (≥18 years) with relapsed, high-grade serous (grade 2 or 3) epithelial ovarian, fallopian tube, or primary peritoneal cancer who had been treated with three or more previous chemotherapy regimens. The study was done in the USA and Canada, and 56 sites screened patients (50 sites treated at least one patient). Patients received oral niraparib 300 mg once daily continuously, beginning on day 1 and every cycle (28 days) thereafter until disease progression. The primary objective was the proportion of patients achieving an investigator-assessed confirmed overall response in patients with homologous recombination deficiency (HRD)-positive tumours (including patients with BRCA and without BRCA mutations) sensitive to their last platinum-based therapy who had received three or four previous anticancer therapy regimens (primary efficacy population). Efficacy analyses were additionally done in all dosed patients with measurable disease at baseline. FINDINGS: Between April 1, 2015 and Nov 1, 2017, we screened 729 patients for eligibility and enrolled 463 patients, who were initiated on niraparib therapy. At the time of database lock (April 11, 2018), enrolment had closed and the study was ongoing, with 21 patients still on treatment. Patients had received a median of four (IQR 3-5) previous lines of therapy, and the median follow-up for overall survival was 12·2 months (IQR 3·7-22·1). 151 (33%) of 463 patients were resistant and 161 (35%) of 463 patients were refractory to the last administered platinum therapy. 13 (28%) of 47 patients in the primary efficacy population achieved an overall response according to RECIST (95% CI 15·6-42·6; one-sided p=0·00053). The most common drug-related grade 3 or worse treatment-emergent adverse events were anaemia (113 [24%] of 463 patients) and thrombocytopenia (95 [21%] of 463 patients). The most common treatment-emergent serious adverse events were small intestinal obstruction (34 [7%] of 463 patients), thrombocytopenia (34 [7%] of 463 patients), and vomiting (27 [6%] of 463 patients). One death due to gastric haemorrhage was considered treatment related. INTERPRETATION: We observed clinically relevant activity of niraparib among women with heavily pretreated ovarian cancer, especially in patients with HRD-positive platinum-sensitive disease, which includes not only patients with a BRCA mutation but also a population with BRCA wild-type disease. We identified no new safety signals. Our data support expansion of the treatment indication for poly(ADP-ribose) polymerase inhibitors to include patients with HRD-positive ovarian cancer beyond those with BRCA mutations. FUNDING: Tesaro.

53BP1 as a potential predictor of response in PARP inhibitor-treated homologous recombination-deficient ovarian cancer.

OBJECTIVE: Poly(ADP-ribose) polymerase (PARP) inhibitors have shown substantial activity in homologous recombination- (HR-) deficient ovarian cancer and are undergoing testing in other HR-deficient tumors. For reasons that are incompletely understood, not all patients with HR-deficient cancers respond to these agents. Preclinical studies have demonstrated that changes in alternative DNA repair pathways affect PARP inhibitor (PARPi) sensitivity in ovarian cancer models. This has not previously been assessed in the clinical setting. METHODS: Clonogenic and plasmid-based HR repair assays were performed to compare BRCA1-mutant COV362 ovarian cancer cells with or without 53BP1 gene deletion. Archival biopsies from ovarian cancer patients in the phase I, open-label clinical trial of PARPi ABT-767 were stained for PARP1, RAD51, 53BP1 and multiple components of the nonhomologous end-joining (NHEJ) DNA repair pathway. Modified histochemistry- (H-) scores were determined for each repair protein in each sample. HRD score was determined from tumor DNA. RESULTS: 53BP1 deletion increased HR in BRCA1-mutant COV362 cells and decreased PARPi sensitivity in vitro. In 36 women with relapsed ovarian cancer, responses to the PARPi ABT-767 were observed exclusively in cancers with HR deficiency. In this subset, 7 of 18 patients (39%) had objective responses. The actual HRD score did not further correlate with change from baseline tumor volume (r = 0.050; p = 0.87). However, in the HR-deficient subset, decreased 53BP1 H-score was associated with decreased antitumor efficacy of ABT-767 (r = -0.69, p = 0.004). CONCLUSION: Differences in complementary repair pathways, particularly 53BP1, correlate with PARPi response of HR-deficient ovarian cancers.

Phase 2 trial of everolimus and letrozole in relapsed estrogen receptor-positive high-grade ovarian cancers.

OBJECTIVES: We report the results of a phase 2 clinical trial of the combination of everolimus and letrozole in patients with relapsed estrogen receptor-positive high-grade ovarian cancer. The trial's primary endpoint was the proportion of patients alive and progression-free after 12weeks of therapy with the combination of everolimus and letrozole. A 12-week PFS of 45% or greater was considered a positive result. The feasibility of generating patient-derived xenograft (PDX) models from biopsy specimens was also evaluated. METHODS: Eligibility criteria included relapsed estrogen receptor-positive ovarian, fallopian tube or primary peritoneal carcinomas with measurable disease, not previously treated with everolimus or AIs. Both platinum-resistant and sensitive tumors were included. Xenografts were created from image-guided tumor biopsies at baseline. Patients received oral everolimus 10mg daily and letrozole 2.5mg daily. RESULTS: Twenty patients were enrolled, 19 were evaluable. Nine out of 19 were alive, progression-free, and still on treatment at the 12week evaluation time-point (12-week PFS of 47%) with a median PFS of 3.9months (95% CI: 2.8-11.0). The median overall survival was 13.0months. Twelve patients (63%) experienced at least one grade 3 or worse adverse events. PDX tumor engraftment was feasible in the majority of patients (9 out of 17, 52.9%). CONCLUSIONS: The combination of everolimus and letrozole is associated with a promising 47% 12-week PFS rate in patients with ER-positive relapsed high-grade ovarian cancer with acceptable toxicity. PDX tumor models can be generated from biopsies of ovarian tumors.

Assessment of published models and prognostic variables in epithelial ovarian cancer at Mayo Clinic.

OBJECTIVES: Epithelial ovarian cancer (EOC) is an aggressive disease in which first line therapy consists of a surgical staging/debulking procedure and platinum based chemotherapy. There is significant interest in clinically applicable, easy to use prognostic tools to estimate risk of recurrence and overall survival. In this study we used a large prospectively collected cohort of women with EOC to validate currently published models and assess prognostic variables. METHODS: Women with invasive ovarian, peritoneal, or fallopian tube cancer diagnosed between 2000 and 2011 and prospectively enrolled into the Mayo Clinic Ovarian Cancer registry were identified. Demographics and known prognostic markers as well as epidemiologic exposure variables were abstracted from the medical record and collected via questionnaire. Six previously published models of overall and recurrence-free survival were assessed for external validity. In addition, predictors of outcome were assessed in our dataset. RESULTS: Previously published models validated with a range of c-statistics (0.587-0.827), though application of models containing variables which are not part of routine practice were somewhat limited by missing data; utilization of all applicable models and comparison of results are suggested. Examination of prognostic variables identified only the presence of ascites and ASA score to be independent predictors of prognosis in our dataset, albeit with marginal gain in prognostic information, after accounting for stage and debulking. CONCLUSIONS: Existing prognostic models for newly diagnosed EOC showed acceptable calibration in our cohort for clinical application. However, modeling of prospective variables in our dataset reiterates that stage and debulking remains the most important predictors of prognosis in this setting.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial.

PURPOSE: To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC). METHODS: Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples. RESULTS: Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)-deficient, and 17.1% were HR repair (HRR)-mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy. CONCLUSION: Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

A Phase I Trial of Nab-Paclitaxel/Bevacizumab (AB160) Nano-Immunoconjugate Therapy for Gynecologic Malignancies.

PURPOSE: AB160 is a 160-nm nano-immunoconjugate consisting of nab-paclitaxel (ABX) nanoparticles noncovalently coated with bevacizumab (BEV) for targeted delivery into tissues expressing high levels of VEGF. Preclinical data showed that AB160 resulted in greater tumor targeting and tumor inhibition compared with sequential treatment with ABX then BEV. Given individual drug activity, we investigated the safety and toxicity of AB160 in patients with gynecologic cancers. PATIENTS AND METHODS: A 3+3 phase I trial was conducted with three potential dose levels in patients with previously treated endometrial, cervical, and platinum-resistant ovarian cancer to ascertain the recommended phase II dose (RP2D). AB160 was administered intravenously on days 1, 8, and 15 of a 28-day cycle (ABX 75-175 mg/m2, BEV 30-70 mg/m2). Pharmacokinetic analyses were performed. RESULTS: No dose-limiting toxicities (DLT) were seen among the three dose levels tested. Grade 3/4 toxicities included neutropenia, thromboembolic events, and leukopenia. DL2 (ABX 150 mg/m2, BEV 60 mg/m2) was chosen as the RP2D. Seven of the 19 patients with measurable disease (36.8%) had confirmed partial responses (95% confidence interval, 16.3%-61.6%). Pharmacokinetic analyses demonstrated that AB160 allowed 50% higher paclitaxel dosing and that paclitaxel clearance mirrored that of therapeutic antibodies. CONCLUSIONS: The safety profile and clinical activity of AB160 supports further clinical testing in patients with gynecologic cancers; the RP2D is DL2 (ABX 150 mg/m2, BEV 60 mg/m2).

Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses.

PURPOSE: The multicenter, open-label, randomized phase 2 NCI-9944 study (NCT02595892) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation). METHODS: We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib. RESULTS: At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06). CONCLUSION: The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.

A phase 1 and pharmacodynamic study of chronically-dosed, single-agent veliparib (ABT-888) in patients with BRCA1- or BRCA2-mutated cancer or platinum-refractory ovarian or triple-negative breast cancer.

PURPOSE: BRCA1 or BRCA2 mutated cancers (BRCAmut) have intrinsic sensitivity to PARP inhibitors due to deficiency in homologous recombination-mediated DNA repair. There are similarities between BRCAmut and BRCAwt ovarian and basal-like breast cancers. This phase I study determined the recommended phase II dose (RP2D) and preliminary efficacy of the PARP inhibitor, veliparib (ABT-888), in these patients. PATIENTS AND METHODS: Patients (n = 98) were dosed with veliparib 50-500 mg twice daily (BID). The BRCAmut cohort (n = 70) contained predominantly ovarian (53%) and breast (23%) cancers; the BRCAwt cohort (n = 28) consisted primarily of breast cancer (86%). The MTD, DLT, adverse events, PK, PD, and clinical response were assessed. RESULTS: DLTs were grade 3 nausea/vomiting at 400 mg BID in a BRCAmut carrier, grade 2 seizure at 400 mg BID in a patient with BRCAwt cancer, and grade 2 seizure at 500 mg BID in a BRCAmut carrier. Common toxicities included nausea (65%), fatigue (45%), and lymphopenia (38%). Grade 3/4 toxicities were rare (highest lymphopenia at 15%). Overall response rate (ORR) was 23% (95% CI 13-35%) in BRCAmut overall, and 37% (95% CI 21-55%) at 400 mg BID and above. In BRCAwt, ORR was 8% (95% CI 1-26%), and clinical benefit rate was 16% (95% CI 4-36%), reflecting prolonged stable disease in some patients. PK was linear with dose and was correlated with response and nausea. CONCLUSIONS: Continuous veliparib is safe and tolerable. The RP2D was 400 mg BID. There is evidence of clinical activity of veliparib in patients with BRCAmut and BRCAwt cancers.