Thaker, Premal H.

BACKGROUND Treatment of tubo-ovarian high-grade serous carcinoma (HGSC) includes cytoreductive surgery, platinum-based chemotherapy, and often poly(ADP-ribose) polymerase (PARP) inhibitors. While homologous recombination (HR) deficiency is a well-established predictor of therapy sensitivity, over 50% of HR-proficient HGSCs also exhibit sensitivity. Currently, there are no biomarkers to identify which HR-proficient HGSCs will be sensitive to standard-of-care therapy. Replication stress may serve as a key determinant of response. METHODS We evaluated phospho–RPA2-T21 (p-RPA2) foci via immunofluorescence as a biomarker of replication stress in formalin-fixed, paraffin-embedded HGSC samples collected at diagnosis from patients treated with platinum chemotherapy (discovery cohort, n = 31; validation cohort, n = 244) or PARP inhibitors ( n = 63). Recurrent HGSCs ( n = 38) were also analyzed. p-RPA2 score was calculated using automated imaging analysis. RESULTS Samples were defined as p-RPA2-high if more than 16% of cells had ≥2 p-RPA2 foci on automated analysis. In the discovery cohort, HR-proficient, p-RPA2-high HGSCs demonstrated significantly higher rates of a chemotherapy response score of 3 to platinum chemotherapy than HR-proficient, p-RPA2-low HGSCs. In the validation cohort, patients with HR-proficient, p-RPA2-high HGSCs had significantly longer survival after platinum treatment than those with HR-proficient, p-RPA2-low HGSCs. Additionally, the p-RPA2 assay effectively predicted survival outcomes in patients treated with PARP inhibitors and in recurrent HGSC samples. CONCLUSION Our study underscores the importance of considering replication stress markers, such as p-RPA2, alongside HR status in therapeutic planning. This approach has the potential to increase the number of patients receiving effective therapy while reducing unnecessary toxicity. FUNDING The Reproductive Scientist Development Program, GOG Foundation, Pilot Translational and Clinical Studies function of the Washington University Institute of Clinical and Translational Sciences, the Foundation for Barnes-Jewish Hospital, Washington University School of Medicine Dean’s Scholar Program, The Cancer Biology Pathway Training Grant (5T32CA113275-17), The Lucy, Anarcha, and Betsey (L.A.B.) Award from the Department of Obstetrics and Gynecology at Washington University School of Medicine, and Veterans Affairs Office of Research and Development (I01BX006020).

The NCCN Guidelines for Ovarian Cancer/Fallopian Tube Cancer/Primary Peritoneal Cancer provide multidisciplinary diagnostic workup, staging, and treatment recommendations for this disease. These NCCN Guidelines Insights detail how the evolution of the use of PARP inhibitors as maintenance and single-agent regimens for the treatment of ovarian cancer informed panel recommendations in the guidelines.

PURPOSE Uterine leiomyosarcoma (uLMS) is an aggressive subtype of soft-tissue sarcoma with frequent metastatic relapse after curative surgery. Chemotherapy provides limited benefit for advanced disease. Multiomics profiling studies have identified homologous recombination deficiency in uLMS. In preclinical studies where olaparib and temozolomide provided modest activity, the combination was highly effective for inhibiting uLMS tumor growth. PATIENTS AND METHODS NCI Protocol 10250 is a single-arm, open-label, multicenter, phase II study evaluating olaparib and temozolomide in advanced uLMS. Patients with progression on ≥1 prior line received temozolomide 75 mg/m2 orally once daily with olaparib 200 mg orally twice a day both on days 1-7 in 21-day cycles. The primary end point was the best objective response rate (ORR) within 6 months. A one-stage binomial design was used. If ≥5 of 22 responded, the treatment would be considered promising (93% power; α = .06). All patients underwent paired biopsies that were evaluated with whole-exome sequencing (WES)/RNAseq and a RAD51 foci formation assay. RESULTS Twenty-two patients were evaluable. The median age was 55 years, and 59% had received three or more prior lines. Best ORR within 6 months was 23% (5 of 22). The overall ORR was 27% (6 of 22). The median progression-free survival (mPFS) was 6.9 months (95% CI, 5.4 months to not estimable). Hematologic toxicity was common (grade 3/4 neutropenia: 75%; thrombocytopenia: 32%) but manageable with dose modification. Five of 16 (31%) of tumors contained a deleterious homologous recombination gene alteration by WES, and 9 of 18 (50%) were homologous recombination-deficient by the RAD51 assay. In an exploratory analysis, mPFS was prolonged for patients with homologous recombination-deficient versus homologous recombination-proficient tumors (11.2 v 5.4 months, P = .05) by RAD51. CONCLUSION Olaparib and temozolomide met the prespecified primary end point and provided meaningful clinical benefit in patients with advanced, pretreated uLMS.

307 Background: In the US, more than 12,000 people die from ovarian cancer annually. Although new treatments have recently become available, ovarian cancer care delivery remains suboptimal. The Association of Community Cancer Centers (ACCC) developed a series of initiatives to improve the quality of care for patients with ovarian cancer. In Phase I, ACCC evaluated the needs of cancer programs, conducted 3 quality improvement (QI) workshops, and developed expert-driven Quality of Care recommendations to aid cancer programs in self-assessment and quality improvement. In Phase II, ACCC invited programs to self-assess their level of care using the Quality of Care recommendations. Methods: In 2022, ACCC surveyed 7 ovarian cancer programs across the US. Developed by a multidisciplinary expert steering committee, the 26-question survey assessed the patient populations served, services provided, diagnostic evaluations performed, access to molecular testing, and a self-assessment of quality care delivery and interest in conducting QI projects related to self-identified needs. The survey was administered in Qualtrics and summarized using descriptive statistics. Results: Surveys were completed by 1 community, 2 comprehensive community, 2 hospital-associated, 1 academic comprehensive, and 1 NCI-designated comprehensive cancer programs. The median annual ovarian cases was 40 [range: 2 to 68]. The 7 programs serve diverse racial/ethnic distribution of patients with ovarian cancer ranging from 55% Black to 60% Asian and 30% Pacific Islander. Five programs have a multidisciplinary team for ovarian cancer. All 5 multidisciplinary teams included gynecologic oncology and pathology; 3 teams also included medical oncology and or radiology colleague(s). Sites assessed their level of care for 7 domains of quality care from 1 (lowest) to 5 (highest). The average score was 4.0 for Care Coordination and Patient Education, Treatment Planning, and Disease Surveillance. Diagnosis and Initial Management scored on average 3.8, Equity in Care 3.25, Prevention and Screening 3.25, and Quality of Life 3.2. Sites ranked areas of interest for future QI projects (1 = area of most interest, 7 = area of least interest). The highest ranked domains were Care Coordination and Patient Education as well as Diagnosis and Initial management (average rankings 2.8). These were followed by Quality of Life (average 3.0), Prevention and Screening (Average 3.8), Treatment Planning (Average 4.4), Equity in Care (Average 5.0), and Disease Surveillance (Average 6.2). Conclusions: This assessment will be used to identify 4 additional sites for Phase II QI workshops. Findings from these projects will be combined, summarized, and disseminated to inform future education opportunities and QI initiatives. This initiative aims to help organize and standardize the care of patients with ovarian cancer and improve patient care coordination.

Epithelial ovarian cancer is the leading cause of death from gynecologic cancer in the United States, with less than half of patients living >5 years following diagnosis. The NCCN Guidelines for Ovarian Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with ovarian, fallopian tube, and primary peritoneal cancers. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including revised guidance on alternative chemotherapy regimens for patients with advanced age and/or comorbidities, a new algorithm for recurrent low-grade serous carcinoma based on developing research and novel therapeutic agents, and updated language regarding tumor molecular analysis applications in ovarian cancer.

256 Background: Ovarian cancer is the leading cause of gynecologic cancer mortality in the US. Given the high burden of disease and complexities in the provision of quality care, a multidisciplinary team approach is critical to optimal care delivery. In 2019, the Association of Community Cancer Centers (ACCC) launched a multiphase, stakeholder-driven initiative to improve care for this patient population. Results of a national survey of cancer programs to identify the needs of patients are reported here. Methods: A 20 question survey was developed by an expert steering committee including gynecologic oncologists, pathologists, genetic counselors, a nurse navigator, and cancer center administrators. The instrument was designed to collect data about cancer programs, key ovarian cancer patient needs, and barriers to and opportunities for improving ovarian cancer care. The online survey was open for participation for 4 weeks using the Qualtrics platform and distributed via email to ACCC and Society of Gynecologic Oncology members. Results: We received 26 total responses from Comprehensive Community (26%), NCI-Designed Comprehensive (22%), Academic Comprehensive (22%), and Integrated Network (13%) Cancer Programs. Annual ovarian cancer cases ranged from 22 to 190 (median: 50.5). 85% of programs has a multidisciplinary team for ovarian cancer and 61% were part of a referral network. On average, programs has 1.5 phase II and 2 phase III clinical trials currently available for ovarian cancer (all programs had at least 1 trial available). Palliative care and comprehensive symptom management was integrated into the first appointment (15%), integrated at the time of recurrence (4%), and most frequently, available by consult (81%). We assessed genetic testing practices at each program. Aggregated across programs, 79% of patients received germline multipanel testing, 71% germline BRCA only, 50% somatic multigene, and 51% somatic BRCA only. The frequency of consultations included: genetic counseling (75%), nurse navigation (75%), social work (50%), dietetics (40%), financial counseling (25%). Genetic evaluations were typically ordered by Gynecologic Oncology (88%), genetic counseling (4%), or both (8%). When asked what topic they would choose for a quality improvement project, genetic testing and counseling was the most frequent choice (46%), followed by clinical trials enrollment and availability (23%), multidisciplinary team care (19%), education on best practices (15%), palliative care (15%), and ancillary services (15%). Conclusions: Multidisciplinary care for ovarian cancer was common across a range of cancer programs but integration of palliative care, social work, dietetics, and financial counseling could be improved. Expanding clinical trials and genetic testing and counseling were the most frequently identified opportunities to improve ovarian cancer care.

11506 Background: Uterine leiomyosarcoma (uLMS) is an aggressive sarcoma subtype with frequent metastatic relapse. After failure of front-line chemotherapy, remaining options provide limited benefit (trabectedin: ORR 11%, mPFS 4.0 mos; pazopanib: ORR 11%, median PFS 2.9 mos; dacarbazine: ORR 9%, mPFS 1.5 mos). Recent molecular studies suggest uLMS harbors characteristic defects in the homologous recombination (HR) DNA repair pathway, including somatic biallelic BRCA2 deletion in 10%, implicating potential sensitivity to PARP-inhibitor based treatment approaches. In preclinical uLMS models in which temozolomide (T, an oral equivalent to dacarbazine) or the PARP inhibitor olaparib (O) showed limited single agent activity, the combination of T + O was highly effective in inhibiting uLMS tumor growth and promoting apoptosis. Methods: NCI protocol #10250 is a single-arm, open-label, multi-center phase II study evaluating T + O in advanced uLMS. Pts had progression on ≥ 1 prior line and ECOG PS ≤ 2. Pts received T 75 mg/m2 PO daily + O 200 mg PO BID days 1-7 in 21-day cycles. Primary endpoint was ORR. A one-stage binomial design was used. If ≥ 5/22 responded, the treatment was considered promising (95% power; α = 0.06). All pts underwent paired tumor biopsies. Correlative assays to evaluate for HR deficiency (whole exome sequencing/RNAseq, RAD51 foci formation) and for intrinsic PARP inhibitor resistance (SLFN11 expression) will be correlated with response. Results: 22 patients were evaluable (median age 55, median prior treatment lines 3). Median follow-up was 10.8 mos. Primary endpoint, ORR within 6 mos of initiating treatment, was 23% (5/22). Overall ORR was 27% (6/22). Median PFS was 6.9 mos (95% CI: 5.4 mos – not estimable (NE)). Median duration of response (DOR) was 12.0 mos (95% CI: 9.5 mos – NE). Hematologic toxicity was common (grade 3/4 neutropenia, 77%; thrombocytopenia 32%) but manageable with dose modification. Correlative assays are ongoing with plans to present at the meeting. An immunohistochemical assay for RAD51 foci has been adapted for uLMS samples and clearly distinguishes BRCA2- deleted and wild-type tumors. Conclusions: NCI 10250 met the prespecified primary efficacy endpoint of ORR in a population of patients with heavily pre-treated uLMS. Responses are durable (median DOR 12 mos). Correlative assays are being completed to evaluate whether uLMS tumors with HR deficiency or with preserved SLFN11 expression are most sensitive to T + O and may underlie durable responses. A randomized study of the combination is planned. Clinical trial information: NCT03880019.

TPS11570 Background: Soft tissue sarcoma (STS) is a heterogenous malignancy of mesenchymal origin and includes more than 50 biologically distinct subtypes. Leiomyosarcoma (LMS), a neoplasm of smooth muscle origin, represents up to 20% of STS. The uterus is the most common site of origin in women. Advanced uterine LMS (uLMS) is initially treated with gemcitabine + docetaxel or anthracycline-based chemotherapy but overall survival remains < 24 mos. Besides recurrent alterations in RB1, TP53 and ATRX, insight into cancer biology of uLMS remains limited. Recently, whole exome and transcriptomic sequencing studies suggest uLMS harbors characteristic defects in the homologous recombination (HR) DNA repair pathway and thus features of BRCAness. HR-deficient cancers are unable to efficiently repair double-stranded DNA breaks and appear sensitive to treatment with poly ADP-ribose polymerase (PARP) inhibitors. In preclinical studies, the combination of temozolomide (T), an alkylating agent, and olaparib (O), a PARP inhibitor, was synergistic and markedly suppressed proliferation of uLMS models. A recent phase II study in small cell lung cancer defined the RP2D for T + O where the chief toxicity was myelosuppression. Methods: NCI Protocol #10250 is a single-arm, open-label, multi-center phase II clinical trial of T + O in patients with advanced uLMS. Eligible pts have ECOG PS ≤ 2, progression on ≥ 1 prior line of therapy and disease measurable by RECIST v1.1 and amenable to image-guided biopsy. Pts receive T 75 mg/m2 PO daily + O 200 mg PO BID on days 1-7 in 21-day cycles. The 1° endpoint is objective response rate (ORR). A one-stage binomial design is used to evaluate for an ORR ≤ 10% (null hypothesis) versus ≥ 35% (alternative hypothesis). The design calls for 22 patients. If 5/22 respond, the treatment is promising. This design yields 93% power and 1-sided type I error of 6%. 2° endpoints include progression free survival and safety. All pts undergo tumor biopsies pre-treatment and during cycle 2. Tissue is used for correlative analysis interrogating uLMS for features of BRCAness through (a) whole exome sequencing/RNAseq to evaluate for alterations in HR pathway component genes, (b) RAD51 foci formation by immunohistochemistry as a functional marker of HR pathway activity and (c) protein expression of Schlafen family member number 11 (SLFN11), an emerging biomarker for PARPi. Tumors are also evaluated for MGMT protein expression, a known determinant of sensitivity to T. The study opened to accrual 10/2019. Clinical trial information: NCT03880019.

BACKGROUNDPreclinical evidence has suggested that sustained adrenergic activation can promote ovarian cancer growth and metastasis. The authors examined the impact of beta‐adrenergic blockade on the clinical outcome of women with epithelial ovarian, primary peritoneal, or fallopian tube cancers (collectively, epithelial ovarian cancer [EOC]).METHODSA multicenter review of 1425 women with histopathologically confirmed EOC was performed. Comparisons were made between patients with documented beta‐blocker use during chemotherapy and those without beta‐blocker use.RESULTSThe median age of patients in the current study was 63 years (range, 21‐93 years). The sample included 269 patients who received beta‐blockers. Of those, 193 (71.7%) were receiving beta‐1–adrenergic receptor selective agents, and the remaining patients were receiving nonselective beta antagonists. The primary indication for beta‐blocker use was hypertension but also included arrhythmia and postmyocardial infarction management. For patients receiving any beta‐blocker, the median overall survival (OS) was 47.8 months versus 42 months for nonusers (P =.04). The median OS based on beta‐blocker receptor selectivity was 94.9 months for those receiving nonselective beta‐blockers versus 38 months for those receiving beta‐1–adrenergic receptor selective agents (P<.001). Hypertension was associated with decreased OS compared with no hypertension across all groups. However, even among patients with hypertension, a longer median OS was observed among users of a nonselective beta‐blocker compared with nonusers (38.2 months vs 90 months; P<.001).CONCLUSIONSUse of nonselective beta‐blockers in patients with EOC was associated with longer OS. These findings may have implications for new therapeutic approaches. Cancer 2015;121:3435–43. © 2015 American Cancer Society.