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HER2 is an important prognostic and therapeutic target in uterine serous carcinoma (USC). Optimal HER2 testing platforms have not been defined and guidelines for testing have changed over time. Our objective is to assess the concordance of HER2 positivity based on chromogenic in situ hybridization (CISH), immunohistochemistry (IHC), and next generation sequencing (NGS) and to determine the rate of downstream mutations that may affect response to HER2 directed therapy.Utilizing the Caris tumor registry, 2192 USC tumors were identified and analyzed using NGS (NextSeq, 592 Genes and WES, NovaSEQ), IHC, and CISH. PD-L1 expression was tested by IHC. Microsatellite instability was tested by fragment analysis, IHC, and NGS. Tumor mutational burden (TMB) was measured by totaling somatic mutations per tumor. HER2 positivity through IHC and CISH was determined based on 2007 and 2018 ASCO/CAP HER2 breast cancer guidelines.There was a higher rate of HER2 positivity by IHC when using the 2018 guidelines compared to the 2007 guidelines (16.3% vs 12.3%). Concordance between IHC and CISH was 98.9%. ERBB2 amplification was identified by NGS in 10.5% of tumors. Compared to CISH results, this corresponds to a concordance rate of 91.6% and a positive predictive value (PPV) of 60.3%. Single gene alterations in HER2 amplified tumors that may implicate HER2 therapy resistance included PI3K (33.1%), KRAS (2.5%), and PTEN (1.3%).There was high concordance between HER2 positivity based on CISH and IHC. Rate of HER2 positivity is the lowest by NGS. Ultimately these testing platforms need to be validated by response to targeted therapy.

Treatment options for advanced vulvar cancer are limited. We evaluated pembrolizumab monotherapy in patients with advanced vulvar squamous cell carcinoma (SCC) enrolled in the phase 2 multicohort, open-label KEYNOTE-158 study (NCT02628067).Eligible patients had histologically or cytologically documented advanced vulvar SCC with prior treatment failure, measurable disease per RECIST v1.1, ECOG performance status 0-1, and a tumor sample available for biomarker analysis. Pembrolizumab 200 mg was administered intravenously Q3W for up to 35 cycles (approximately 2 years). The primary endpoint was objective response rate (ORR) per RECIST v1.1 by independent central radiologic review in all patients and subgroups based on PD-L1 combined positive score (≥1 [PD-L1-positive] versus1 [PD-L1-negative]).101 patients were enrolled. Median time from first dose to data cutoff was 36.0 months. The ORR (95% CI) was 10.9% (5.6%-18.7%) among all patients, 9.5% (4.2%-17.9%) among the 84 patients with PD-L1-positive tumors, and 28.6% (3.7%-71.0%) among the 7 patients with PD-L1-negative tumors. Among patients with a response, median DOR was 20.4 (range, 2.1+ to 28.0) months. Median (95% CI) PFS and OS were 2.1 (2.0-2.1) and 6.2 (4.9-9.4) months, respectively. Treatment-related AEs occurred in 50.5% of patients (grade 3-5, 11.9%) and led to discontinuation of treatment in 5.0% of patients. Two deaths were considered treatment-related (hepatitis, n = 2).Pembrolizumab monotherapy was associated with durable responses in a subset of patients with vulvar SCC. Responses occurred regardless of tumor PD-L1 status. No new safety signals emerged; overall, pembrolizumab was well tolerated.

BACKGROUND: This report is intended to present a unique patient with acquired vaginal obstruction due to prior radiation therapy and subsequent development of hematocolpos. We present a method of surgical decompression for the hematocolpos as well as this patient’s follow-up and prevention of re-epithelialization. CASE: One patient was recruited and consented for this case study. Pre-operative evaluation, including examination and imaging, intra-operative findings, and post-operative evaluation were reported in this study. After surgical evaluation and drainage of hematocolpos via incision and drainage, a foley balloon was placed to prevent re-epithelialization. Intra-operative fluid cultures yielded no growth. At her follow-up appointment, the foley balloon was removed and the vaginal canal was intact without agglutination or re-accumulation of hematocolpos. CONCLUSIONS: This is a unique case of acquired obstruction from radiation therapy causing significant symptomatic hematocolpos. We offer a minimally invasive approach for decompression, evaluation of malignancy, and prevention of re-obstruction. Her post-operative appointment showed resolution of symptoms and patent vaginal canal. Long-term outcomes are still required, including monitoring for malignant recurrence, re-obstruction and stenosis, and sexual health. If re-epithelialization occurs, more definitive therapy will be required, including excision of the vaginal septum or hysterectomy.

ObjectivesOur study aimed to determine the publication rates of podium presentations from the 2017 and 2018 Society of Gynecologic Oncology (SGO) Annual Meetings; and to examine rates and predictors of oral presentations that resulted in publication.MethodsWe reviewed podium presentations given at the 2017 and 2018 SGO Annual Meetings. Abstracts were evaluated for publication from January 1, 2017 to March 30, 2020 and January 1, 2018 to June 30, 2021, respectively, to allow for a 3 year period of publication.ResultsIn 2017 and 2018, 43 of 75 (57.3%) and 47 of 83 (56.6%) podium presentations were published within 3 years, respectively. No significant difference was found between the mean time to publication within 3 years (13.0 months vs 14.1 months for 2017 and 2018, respectively; p=0.96). Similarly, the mean difference of journal impact factors between both years did not reach significance (6.57 and 10.7 for 2017 and 2018, respectively; p=0.09). The median impact factor (IF) was 4.54 (range: 40.3) and 4.62 (range: 70.7) in 2017 and 2018, respectively. Of the presentations published, 53.4% (2017) and 38.3% (2018) appeared in the journal Gynecologic Oncology. Significant positive correlations for the likelihood of publication were determined among the following: funding status (r=0.93) including funding involving National Institutes for Health (r=0.91) or pharmaceutical (r=0.95), clinical trial study design (r=0.94), and pre-clinical research (r=0.95) (all pConclusionsAt the 2017 and 2018 SGO Annual Meetings 57% of podium presentations were published in a peer-reviewed journal within 3 years. Publication in peer-reviewed journals is crucial for timely distribution of clinical information to the medical community.

ObjectivePreclinical evidence and early clinical trials have demonstrated the activity of SPL-108, a targeted agent that inhibits CD44 mediated induction of multidrug resistance specifically to paclitaxel and platinum agents. We conducted a phase I, open label, dose escalation study of the safety and tolerability of the combination of SPL-108 with weekly paclitaxel in patients with platinum resistant CD44+ ovarian, primary peritoneal, or fallopian tube cancer.MethodsPatients with platinum resistant histologically proven epithelial ovarian, primary peritoneal, or fallopian tube cancers and measurable disease according to RECIST (Response Evaluation Criteria in Solid Tumours) version 1.1 were selected. Tumors were tested for CD44 expression for eligibility, defined as strong (+++) or moderate (++) staining in ≥20% of the tumor tissue or diffuse + staining. Patients were treated with daily and then twice daily SPL-108 subcutaneous injections and weekly intravenous paclitaxel on days 1, 8, and 15 of a 28 day cycle. Endpoints included safety, determination of maximum tolerated dose, and efficacy. Tumors underwent comprehensive genomic profiling, and cell lines and western blotting were used to study markers of response.ResultsWe screened 16 patients, and 14 were enrolled based on CD44+ expression. A total of 86% of patients had high grade serous tumors and all had received multiple prior therapies. There were no grade 4–5 toxicities. One patient had grade 3 peripheral sensory neuropathy attributed to paclitaxel and one patient developed presumed colonic perforation attributed to the study drug. No dose reductions or treatment discontinuations were required. All patients tolerated the maximum planned dose; no maximum tolerated dose was reached. Overall response rate was 36%; 5 (36%) patients had partial response and 5 (36%) patients had stable disease.ConclusionsThe combination of SPL-108 with weekly paclitaxel was safe and well tolerated. Encouraging antitumor activity was observed, with 72% of patients deriving a clinical benefit.Trial registrationNCT03078400.

Cancer care has been greatly impacted during the COVID-19 pandemic. The number of cases and deaths caused by the COVID-19 pandemic continues to escalate throughout the United States and the world. Worldwide, over 150 million people have been diagnosed with the coronavirus and more than 3 million have died. Now that we have gained additional experience with COVID-19, we are starting to learn its full impact on oncology care and its effects on the practice of medicine and clinical research.

Background: Locally advanced cervical cancer accounts for most deaths from disease. Standard of care includes treatment with cisplatin-based chemoradiation with a 70% response rate. The addition of intravenous (IV) triapine to chemoradiation has shown promising clinical activity in phase 1 and 2 studies but comes with a more intensive treatment regimen. An ongoing phase 1 trial has finished the escalation phase, and we report the pharmacokinetics (PK) and pharmacodynamics (PD) of oral (PO) triapine. Methods: This phase 1 study followed a 3+3 design for dose escalation of oral triapine, starting with initial dose of 100 mg five days a week for five weeks combined with external beam pelvic radiation and weekly IV cisplatin. PK was determined by LC-MS/MS, and PD included methemoglobin levels at 4 h post dose. Within patient PK variability after IV and PO dosing and PO bioavailability were calculated. Results: PK data were available for 10 patients at 100 (the MTD) and 150 mg. PO parameter values were Tmax 1.3 h, t1/2 1.4 h, CL/F 104 L/h, and Vz/F 214 L. There was no discernable difference between triapine exposure at 100 vs. 150 mg PO (Cmax 520 (2.5) vs. 344 (1.9) µg/L; AUC 1209 (2.53) vs. 1034 (1.41) µg/L•h), and between patient variability at each dose level was substantial. The correlation of PO Vz/F vs Cl/F was high at R2=0.86, suggesting that the apparent clearance and volume variability is primarily due to variability in the oral bioavailability F. PO within patient variability of Cmax and AUC was also large at 43% and 55%. IV PK was less variable with lower geometric standard deviations across all parameters, including within patients where variability of Cmax and AUC was modest at 10 and 12% coefficient of variation, respectively. Oral bioavailability was estimated at 66%. We found a non-significant trend of smoking almost doubling triapine oral clearance from 68 to 156 L/h (p=0.056). There was no apparent relationship between occurrence of DLT and either IV or PO triapine AUC. Methemoglobin levels directly correlated with triapine exposure expressed as AUC or Cmax. Conclusions: Triapine PK parameter values for PO and IV administration and PO bioavailability values observed in this trial were comparable to previous reports. Correlation of methemoglobin with exposure highlights the importance of optimizing triapine exposure. Additional data may support the exploration of a dose specific to current smokers. Citation Format: Jan H. Beumer, Sarah Behr, Holly Gallion, John Vargo, Frederick Ueland, Haider Mahdi, Brian Orr, Eugenia Girda, Susan Christner, Edward Chu, Charles Kunos, Percy S. Ivy, Sarah Taylor. Pharmacokinetics, bioavailability, and pharmacodynamics of oral triapine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2800.

TPS277 Background: There is a need to develop novel immunotherapeutic approaches to enhance responses to immune checkpoint blockade. REGN7075 is a human costimulatory bispecific antibody designed to bridge epidermal growth factor receptor (EGFR)-expressing tumor cells with CD28-positive T cells to support further T-cell activation by endogenous tumor antigens. Methods: This is an open-label, Phase 1/2, first-in-human study evaluating the safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity of REGN7075 (EGFRxCD28) alone and in combination with cemiplimab (anti-programmed cell death [PD]-1) in patients with advanced solid tumors (NCT04626635). This study includes a dose-escalation (Bayesian optimal interval design; Part 1) and a dose-expansion phase (Part 2). Patients must have a protocol-defined advanced solid tumor, have an Eastern Cooperative Oncology Group performance status of 0 or 1, and be naive to anti–PD-1/anti–PD-ligand(L)1 therapy in the dose-expansion phase. In Part 1, heavily pre-treated patients with advanced solid tumors receive a lead-in of REGN7075 monotherapy every week for 3 weeks followed by combination therapy with cemiplimab 350 mg every 3 weeks. Planned dose levels (DLs) of REGN7075 are 0.03, 0.1, 0.3, 1, 3, 10, 30, 100, 300, and 900mg. Once the recommended Phase 2 dose is determined in Part 1, five tumor-specific expansion cohorts will be opened in Part 2: colorectal cancer (microsatellite stable [MSS-CRC]), non-small cell lung cancer (NSCLC, PD-L1 ≥50%), triple-negative breast cancer, cutaneous squamous cell carcinoma, and head and neck squamous cell carcinoma (PD-L1 combined positive score ≥1). Patients with MSS-CRC with RAS or BRAF wild type mutations must have received anti-EGFR therapy or anti-vascular endothelial growth factor (VEGF therapy). Primary endpoints are safety and tolerability of REGN7075 alone or in combination with cemiplimab for Part 1, and objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1 for Part 2. For Part 2, a secondary objective is to assess the effect of REGN7075 on patient-reported outcomes as measured by several validated instruments including the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and EORTC QLQ-CR29 (CRC patients only). Approximately 400 patients will be enrolled in this phase 1/2 study, including ~80 patients in Part 1 and ~320 patients in Part 2 (including ~70 in the CRC cohort). As of September 13, 2022, 30 patients were treated in the dose-escalation phase, up to the 300 mg DL for REGN7075 in combination with cemiplimab. This study is ongoing and currently open to enrollment. Clinical trial information: NCT04626635 .

BACKGROUND Hemorrhage is a leading cause of maternal death worldwide, with increased risk in women with abnormal placentation. Aortic balloon occlusion (ABO), including resuscitative endovascular balloon occlusion (REBOA), has been used for obstetrical hemorrhage for 20 years, and is associated with decreased operative blood loss, fewer transfusions, and lower rates of hysterectomy. However, the effect of aortic occlusion on fetal/neonatal outcomes is not well known. METHODS A literature review on ABO for obstetrical or traumatic hemorrhage was performed. Cases were included if fetal/neonatal outcomes were reported. Data was collected on timing of balloon inflation (pre or post-delivery), fetal/neonatal mortality, and Apgar scores. Secondary maternal outcomes included blood loss, need for hysterectomy, ABO-related complications, and mortality. RESULTS Twenty-one reports of aortic balloon occlusion in 825 cases of obstetrical hemorrhage were reviewed (nine case reports/series and twelve comparative studies). 13.5% (111/825) had aortic occlusion prior to delivery of the fetus. Comparative cohorts included 448 patients who underwent iliac artery balloon occlusion (n = 219) or no vascular balloon occlusion (n = 229). The most common neonatal outcome reported was Apgar scores, with no difference in fetal/neonatal outcomes between ABO and non-ABO patients in any study. One neonatal mortality occurred in the sole reported case of ABO use in a pregnant trauma patient at 24 weeks gestation. One maternal mortality occurred due to aortic dissection. Five comparative studies reported significantly decreased blood loss in ABO patients compared to non-ABO patients and fourstudies reported significantly lower rates of hysterectomy in ABO patients. ABO-related complications were reported in 1.6% of patients (13/825). CONCLUSION Obstetrical hemorrhage is a devastating complication, and aortic balloon occlusion may potentially decrease blood loss and reduce the hysterectomy rate without compromising fetal and neonatal outcomes. Further research is needed to determine the safety of pre-delivery aortic occlusion as this occurred in 14% of cases. TYPE OF STUDY Review. LEVEL OF EVIDENCE IV.

11551 Background: Immune checkpoint inhibitors (ICI) have limited efficacy for most sarcomas. Yet, responses are seen in particular sarcoma subtypes, highlighting the need for better predictive biomarkers. The T cell inflamed score (TIS), a gene expression signature reflective of an active tumor immune microenvironment, is associated with ICI response in multiple solid tumors. We evaluated the TIS across a large database of sarcomas to identify which histologic subtypes may benefit from ICI. Methods: Next generation sequencing of DNA (592 gene or whole exome)/RNA (whole transcriptome) was performed for 3605 sarcoma patient samples, representing 45 histologic subtypes (Caris Life Sciences, Phoenix, AZ). TIS (18 gene weighted coefficient composite value; Cristescu 2018) was calculated and the Microenvironment Cell Populations-counter tool (Becht 2016) was used to quantify immune cell populations. Results were compared to melanoma (n = 1255), a representative immunogenic tumor type. High TIS was defined as a score within the upper quartile of melanoma TIS (> 5.5). Percentage with high TIS are reported with 95% CI. Results: Median TIS was highest in inflammatory myofibroblastic tumor (IMT), epithelioid sarcoma (EPIS), myxofibrosarcoma (MFS), well differentiated liposarcoma, and solitary fibrous tumor (SFT). These did not differ significantly from melanoma (p > 0.06). Median TIS was lowest in embryonal rhabdomyosarcoma, desmoid tumor (DES), synovial sarcoma (SYNS), and Ewing sarcoma (ES). Histologic subtypes where > 10% of samples had a high TIS included IMT (29.9% ± 21.7%), MFS (23.3% ± 12.6%), pleomorphic sarcoma (PLSARC) (21.9% ± 5.8%), cutaneous angiosarcoma (ANGS) (18.4% ± 13.9%), spindle cell sarcoma (17.5% ± 7.6%), liposarcoma (LPS) (17% ± 10.7%), EPIS (15.4% ± 19.6%), visceral ANGS (13.2% ± 10.7%), pleomorphic LPS (13.6% ± 14.3%), fibrosarcoma (12.5% ± 13.2%), leiomyosarcoma (11.6%± 3.4%), malignant peripheral nerve sheath tumor (MPNST) (10.2% ± 7.7%), and perivascular epithelioid cell tumor (PEComa) (10% ± 10.7%). The relative abundance of immune and stromal cell populations was highly variable across sarcoma subtypes, yet a strong positive correlation between TIS and immune cell populations was observed for most subtypes (e.g. T cells, Spearman R range: 0.56 [P = 0.08] - 0.96 [P < 0.0001]). A notable exception was SFT, which had a relatively high median TIS but low abundance of CD8+ T cells and B cells. Conclusions: We found high median TIS and/or significant proportions of samples with a high TIS in sarcoma subtypes with previously demonstrated responsiveness to ICI, including MFS, PLSARC, LPS, and ANGS, while unresponsive tumor types such as RMS, DES, SYNS, and ES had low TIS. We further identified subtypes with high TIS but limited prior clinical data supporting ICI use, such as IMT, EPIS, MPNST, SFT, and PEComa. Our results warrant prospective exploration of TIS as a predictive biomarker for ICI use in sarcoma.

5548 Background: Clear cell carcinomas (CCC) are rare histologies outside of the kidney and are typically less sensitive to standard treatments. Genomic alterations in chromatin remodeling pathways involving ARID1A or the intracellular PI3K-mTOR signaling pathway are found in both renal and ovarian CCC. It is unclear whether CCCs originating from different anatomic sites share a common genomic landscape. This CARIS Precision Oncology Alliance project sought to determine whether CCC of different organs shared similar genomic signatures and to identify potential pathways that could be targeted in a tumor-agnostic clinical trial. Methods: CCCs (N = 861) from multiple primary tumor sites, including kidney (30.5%), ovary (39%), endometrium (23.9%), other gynecologic sites (e.g., cervix, fallopian tube, 3.3%), and miscellaneous (non-kidney or gynecologic sites, 3.3%) were analyzed at the Caris Life Sciences Laboratory (Phoenix, AZ). Using hierarchical clustering (HC) and principal component analysis (PCA), the samples were compared across 648 total genes from five metabolic gene sets consisting of angiogenesis, glycolysis, hypoxia, oxidative phosphorylation, and fatty acid metabolism. Gene Set Enrichment Analysis (GSEA) was further conducted on the samples across fifty hallmark gene sets representing specific biologic processes and expression. Samples were also analyzed for individual genomic alterations and immune-oncology associated biomarkers. PD-L1 (SP142) expression was evaluated by immunohistochemistry (positive threshold: 2+ stain intensity and ≥ 5% tumor cells). Results: HC and PCA demonstrated that renal CCC formed distinct clusters compared to non-renal CCC. Tumors from gynecologic sites could not be separated into distinct clusters. GSEA showed that the hypoxia gene set was significantly upregulated in the renal but not in non-renal CCCs. Mutations involving TP53, ARID1A, PIK3CA were found to be the most altered genes in endometrial (62%, 26%, 31%), ovarian (13%, 55%, 48%), other gynecological sites (33%, 38%, 44%), and non-gynecologic CCC (13%, 17%, 12%) respectively. PD-L1 expression, high tumor mutational burden (≥10 mutations/Mb), and deficient mismatch repair/microsatellite instability rates across sites were: kidney (11%, 2%, 2%), endometrium (13%, 12%, 7%), ovary (9%, 4%, 3%), other gynecological sites (31%, 11%, 11%), and miscellaneous sites (11%, 19%, 4%). Conclusions: Initial metabolic gene expression clustering analysis shows that CCCs do not separate by organ of origin beyond renal versus extra-renal. TP53, ARID1A, and PIK3CA were the most frequently altered genes in non-renal CCC. Out of fifty hallmark gene sets, only two were statistically significantly different among gynecological CCCs. This similarity between gynecological CCC can be leveraged by targeting pathways such as PI3K-AKT-mTOR, DNA repair, and MYC targets in a site agnostic manner. Furthermore, high PD-L1 expression is found in other gynecological sites.

TPS5602 Background: Tumor-infiltrating lymphocytes (TIL) are a heterogeneous population of T cells that recognize multiple endogenous tumor antigens but may have developed an exhausted phenotype due to the tumor microenvironment. While existing TIL therapies produce durable responses in patients with melanoma, cervical, and head and neck cancers, poor in vitro cell expansion, limited short-lived in vivo persistence, and diminishing potency restrict this approach’s broader application. DeTIL-0255 (drug-enhanced TIL [DeTIL]) is an autologous adoptive cell therapy (ACT) derived from a patient’s tumor and expanded ex vivo with NX-0255, a small-molecule inhibitor of the E3 ligase, Casitas B-lineage lymphoma proto-oncogene B (CBL-B). CBL-B is expressed in T cells, where it functions as a regulator of immune cell activation, in part by requiring CD28 co-stimulation in addition to T-cell receptor activation. Desirable properties enhanced by DeTIL-0255 when compared with TIL include increased number of stem-like CD39-/CD69-, and CD8+ T cells associated with persistence, as well as enhanced cytolytic function. ACT with T cells expanded ex vivo using NX-0255 demonstrated increased anti-tumor activity, longer survival, increased stem-like phenotype, and persistence of tumor antigen-specific T cells in mouse tumor models. Adoptive cell transfer of DeTIL-0255, therefore, may exhibit broader functional activity than conventional TIL, potentially conferring improved anti-tumor activity and response. Methods: NX-DeTIL-0255-201 is a Phase 1 multicenter, open-label study of DeTIL-0255 administered with systemic high-dose IL-2 following nonmyeloablative lymphodepleting chemotherapy in patients with advanced gynecological malignancies for whom standard therapy with proven clinical benefit does not exist, is no longer effective, or is inappropriate. The primary objectives are to evaluate the safety, tolerability, and preliminary antitumor activity of DeTIL-0255. A safety run-in will consist of 3 to 6 patients treated with DeTIL-0255 and evaluated for dose-limiting toxicity (DLT). The DLT period starts with DeTIL-0255 infusion and ends after a total of 28 days. The safety run-in will investigate DeTIL-0255 at a dose range of 1 to 150 x 109 CD3+ T cells (exact dose varying based on expansion potential of DeTIL-0255 from tumor biopsies). Following the safety run-in, cohort expansion will further evaluate the safety and antitumor activity of DeTIL-0255 in patients with recurrent/persistent platinum-resistant epithelial ovarian cancer, cervical carcinoma, and endometrial cancer. Key eligibility criteria include measurable disease, a resectable lesion for TIL harvest, ≥2 prior lines of therapy, and an Eastern Cooperative Oncology Group performance status 0 or 1. The study is expected to enroll ̃54 patients in ̃10 sites across the United States. Clinical trial information: NCT05107739.

5514 Background: Mesothelin and its binder, antigen-CA125, are highly expressed in high grade serous and endometrioid ovarian cancers (HGOC) and, can inhibit paclitaxel-induced cell death. Anetumab ravtansine (AR) is a fully-human antibody directed at the mesothelin antigen, conjugated to a tubulin polymerization inhibitor. We assessed the safety and activity of the combination AR/bevacizumab (ARB) versus weekly paclitaxel/bevacizumab (PB) in patients (pts) with platinum resistant HGOC. Methods: An initial run-in phase I assessed the safety of ARB. After determination of the recommended phase 2 dose (RP2D), a multicenter 1:1 randomized phase 2 trial was designed to evaluate the progression free survival (PFS) in pts with platinum resistant/refractory HGOC. Pts were stratified by platinum resistant or refractory and prior bevacizumab (bev). Eligibility required measurable disease and mesothelin tested positive centrally on archival tissue by IHC. No limitation on the number of prior lines of therapy. A futility analysis was planned at 35 PFS events. The control arm was weekly intravenous paclitaxel 80mg/m2 with bev 10mg/kg every 2 weeks. A CT was performed every 8 weeks for RECIST1.1 assessment. The toxicities were reported according to CTCAE version 5.1. NCT03587311. Results: 7 pts were enrolled in the run-in phase 1 and the RP2D determined as bev (10mg/kg) biweekly with AR (2.2mg/kg) weekly on a 28 day-cycle. In the phase 2, 57 pts were enrolled, 28 pts in the ARB and 29 pts in the control group. The positivity rate for mesothelin screening was 88%. Pts were heavily pre-treated, median prior lines of 3 (range (1-9) with 24 pts received prior bev (42%) and 13 pts were platinum refractory (7 in ARB and 6 in PB). At the time of 35 PFS events, one CR and 4 PR were observed (ORR = 18%) in the ARB arm, versus no CR and 16 PR in the weekly PB (ORR = 55%). The estimated median PFS was 5.3 (95% CI: 3.7-7.4) months for ARB and 9.6 (95% CI: 7.4-17.4) months for PB (HR = 1.7(95% CI: 0.9-3.4)). The median number of cycles were 4 (1, 29) and 8 (1, 19) respectively. The most common treatment-related AEs in the ARB arm were mostly grade 1/2 increase AST (71%) and ALT (64%), thrombocytopenia (61%), fatigue (57%), and peripheral neuropathy (46%). In the PB arm, the most common treatment-related AE were anemia (66%), neutropenia (59%), epistaxis (48%), fatigue (45%) and peripheral neuropathy (45%). Conclusions: At the time of futility analysis, weekly PB had better outcome than weekly ARB leading to the study termination. Molecular and blood analyses are on-going to assess potential biomarkers of response. This study highlights the importance of randomization in assessment of novel therapies and potential for re-challenge with bevacizumab. These data show that weekly PB is an effective regimen and can be considered as the control arm in platinum resistant HGOC. Clinical trial information: NCT03587311.

Objective To assess the efficacy and safety of stereotactic body radiation therapy (SBRT) for oligometastatic gynecologic malignancies. Method A comprehensive search of the PubMed, Medline, and EMBASE databases was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. “Oligometastatic” was defined as a limited number of uncontrolled/untreated metastatic lesions (typically ≤ 5), including regional nodal metastases. Primary outcomes were response rate (complete response or partial response), local control of oligometastatic lesions, and toxicity. Results Of 716 screened records, 17 studies (13 full length articles, 4 conference abstracts) were selected and analyzed as 16 unique studies. A total of 667 patients were treated with ~1071 metastatic lesions identified. Primary sites included ovarian (57.6%), cervical (27.1%), uterine (11.1%), vaginal (0.4%), vulvar (0.3%), and other/unspecified (3.4%). Most patients (65.4%) presented with a single metastatic lesion. Metastatic lesion sites included the abdomen (44.2%), pelvis (18.8%), thorax (15.5%), neck (4.6%), central nervous system (4.3%), bone (1.6%), and other/unspecified (11%). Of the lesions, 64% were nodal. Response rate (among 8 studies) ranged from 49% to 97%, with 7/8 studies reporting > 75% response rate. Local control ranged from 71% to 100%, with 14/16 studies reporting ≥ 80% local control. No grade ≥ 3 toxicities were observed in 9/16 (56%) studies. Median progression-free survival (PFS) (among 10 studies) ranged from 3.3 months to 21.7 months. Disease progression most commonly occurred outside of the SBRT radiation field (79% to 100% of failures). Conclusions SBRT for oligometastatic gynecologic malignancies is associated with favorable response and local control rates but a high rate of out-of-field progression and heterogeneous PFS. Additional study into rational combinations of SBRT and systemic therapy appears warranted to further improve patient outcomes.

ObjectiveWe prospectively evaluated patients with completely resected uterine serous carcinoma (USC) treated with radiation “sandwiched” between carboplatin/paclitaxel (C/T). The primary objective was to determine the safety profile, and the secondary outcome was to evaluate progression-free and overall survival.MethodsSurgically staged patients with completely resected USC were enrolled to receive 3 cycles of paclitaxel 175 mg/m2 and carboplatin (area under the curve, 6–7.5) every 21 days, followed by radiotherapy and an additional 3 cycles of T/C at area under the curve of 5–6 (6 cycles + radiotherapy). Toxicity was graded according to National Cancer Institute Common Toxicity Criteria, version 4.03. Kaplan-Meier and log-rank tests were used to compare survival probabilities.ResultsOne hundred forty patients were enrolled, of which 132 were evaluable, completed at least 3 cycles of chemotherapy and radiation. One hundred seven (81%) completed 6 cycles of chemotherapy and radiation. Patients with early-stage (I/II) disease have survival probabilities of 0.96 and 0.81 at 2 and 5 years. Patients with stage I USC and lymphovascular invasion have considerably worse overall survival, with 2.7 times’ higher risk of death than those without lymphovascular invasion. Patients with late-stage (III/IV) disease had overall survival probabilities of 0.64 and 0.18 at 2 and 5 years, which is far higher survival than what has been reported in single-modality trials. Interestingly, and different than what is reported in other studies, there is no difference in survival in African Americans versus whites/other races who were evaluable. Of the 779 cycles administered, 22% and 14% of cycles were associated with grades 3 and 4 hematologic toxicities, respectively. Grades 3 and 4 nonhematologic toxicities occurred in 6.9% of cycles.ConclusionsThe long-term follow-up in this study demonstrates that “sandwich” therapy is an efficacious, well-tolerated treatment approach with acceptable toxicities. Lymphovascular invasion (LVSI) is a significantly poor prognostic factor in stage I USC. Multimodal “sandwich” therapy should be considered in all USC patients who have undergone complete surgical resection and staging.

Objectives: The purpose of this retrospective study is to determine racial and social determinants associated with use of genetic testing for heritable cancer mutations in a high risk, low community resource academic institution population. Methods: Women with a personal or family history of heritable cancer (ovarian, fallopian tube, primary peritoneal, breast, colorectal, and endometrial) were identified through the electronic medical record database from August 2015 through August 2019. Demographics (age, sex, race, ethnicity), insurance, and clinical parameters including medical, surgical, social determinants, prior cancer, and family cancer history were evaluated. Patients without a heritable cancer history were excluded.Summary statistics and exact binomial testing were used for comparisons of the rate of genetic testing at the study hospital versus that of reported normative data. To examine whether the internal rates of testing are associated with either demographic or clinical factors, both bivariate and multivariate analyses were performed. For bivariate analyses, chi-square or fisher exact tests for categorical measures and either t-tests or Wilcoxon rank sum tests for continuous measures were used. The effect of the integration of panel testing, which was instituted in August 2017, was determined using a bivariate analysis comparing the groups of patients that were seen before or after August 2017. Results: Of the 344 patients analyzed, only 54 (16%) underwent genetic testing, which is significantly lower than the national average (p Conclusions: The findings of this study highlight a lower rate of genetic testing among African American women diagnosed with heritable cancers relative to national recommendations. Our results indicate that despite inclusion of panel testing, racial disparities in rates of testing persist in our vulnerable, high risk population. Interventions to overcome implicit bias and patient education should be further developed.

Objectives: Advanced vulvar carcinoma typically affects the elderly and treatment options are limited. Moderate antitumor activity of pembrolizumab (ORR, 6%) was noted in a small population of patients (pts) with PD-L1-positive vulvar cancer in the phase 1b KEYNOTE-028 study. KEYNOTE-158 ( ClinicalTrials.gov , NCT02628067) is a larger, nonrandomized, multicohort, open-label, phase 2 study that evaluates pembrolizumab in pts with previously treated advanced cancers irrespective of tumor PD-L1 expression. We report results for pts in the vulvar carcinoma cohort receiving pembrolizumab monotherapy. Methods: Enrolled pts were aged ≥18 y with histologically/cytologically documented advanced vulvar squamous cell carcinoma with prior treatment failure; measurable disease per RECIST v1.1; ECOG performance status ≤1; and tumor samples available for biomarker analysis, including PD-L1. PD-L1 positivity was defined as combined positive score ≥1 with expression evaluated using the PD-L1 IHC 22C3 pharmDx assay (Agilent Technologies, Carpinteria, CA, USA). Pts received pembrolizumab 200 mg Q3W until disease progression, unacceptable toxicity, or completion of 35 treatment cycles. Tumor imaging was performed every 9 weeks for 1 y and every 12 weeks thereafter. Response was assessed per RECIST v1.1 by independent central radiologic review. The primary endpoint was ORR. Secondary endpoints included duration of response (DOR), PFS, OS, and safety. Results: A total of 101 pts were enrolled. As of October 5, 2020, median time from start of treatment to data cutoff was 36.0 (range, 15.4–55.2) months. Median age was 64.0 (range, 31–87) y; 9 (8.9%) pts had no prior therapy, 57 (56.4%) had 1, 23 (22.8%) had 2, and 11 (10.9%) had 3 or more lines of prior therapy. Tumors were PD-L1–positive in 84 pts (83.2%), PD-L1–negative in 7 pts (6.9%), and non-evaluable/not assessed in 10 pts (9.9%). Overall, ORR was 10.9% (95% CI, 5.6–18.7); 1 pt had a CR and 10 pts had PR. Among pts with PD-L1–positive tumors, 8 of 84 (9.5%; 95% CI, 4.2–17.9) had CR or PR; among pts with PD-L1–negative tumors, 2 of 7 (28.6%; 95% CI, 3.7–71.0) had CR or PR. Among pts with a response, median DOR was 20.4 months (range, 2.1+ to 28.0). Among all enrolled pts (n=101), median PFS was 2.1 months (95% CI, 2.0–2.1) and median OS was 6.2 months (95% CI, 4.9–9.4 months). Treatment-related AEs occurred in 51 pts (50.5%), including 12 pts (11.9%) who had grade 3–5 events (no event occurred in >1 pt). There were 2 deaths (2.0%) considered related to treatment (hepatitis, n=1; fulminant hepatitis, n=1). Neither pt had comorbidities or pre-existing liver disease to contribute to these events; no other contributing factors were identified. A total of 5 pts (5.0%) discontinued because of treatment-related AEs. Immune-mediated AEs occurred in 18 pts (17.8%). Conclusions: Pembrolizumab monotherapy was associated with durable responses in a subset of pts with vulvar carcinoma (ORR, 10.9%; median DOR, 20.4 months). Responses occurred in both PD-L1-positive and PD-L1-negative pts.

Extracellular vesicles (EVs), including exosomes, are circulating nanoscale particles heavily implicated in cell signaling and can be isolated in vast numbers from human biofluids. Study of their molecular profiling and materials properties is currently underway for purposes of describing a variety of biological functions and diseases. However, the large, and as yet largely unquantified, variety of EV subpopulations differing in composition, size, and likely function necessitates characterization schemes capable of measuring single vesicles. Here we describe the first application of multispectral optical tweezers (MS-OTs) to single vesicles for molecular fingerprinting of EV subpopulations. This versatile imaging platform allows for sensitive measurement of Raman chemical composition (e.g., variation in protein, lipid, cholesterol, nucleic acids), coupled with discrimination by fluorescence markers. For exosomes isolated by ultracentrifugation, we use MS-OTs to interrogate the CD9- positive subpopulations via antibody fluorescence labeling and Raman spectra measurement. We report that the CD9-positive exosome subset exhibits reduced component concentration per vesicle and reduced chemical heterogeneity compared to the total purified EV population. We observed that specific vesicle subpopulations are present across exosomes isolated from cell culture supernatant of several clonal varieties of mesenchymal stromal cells and also from plasma and ascites isolated from human ovarian cancer patients.

To evaluate risk factors for 30-day unplanned readmission and increased length of stay (LOS) following minimally invasive surgery (MIS) for endometrial cancer.This was a retrospective, case-control study using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). Multivariable logistic regression was used to assess perioperative variables associated with readmission and increased LOS after MIS for endometrial cancer.The study population included 10,840 patients who met the criteria of having undergone MIS with a resultant endometrial malignancy confirmed on postoperative pathology. Common reasons for readmission included organ/space surgical site infection (65 cases), sepsis/septic shock (19 cases), and venous thromboembolism (20 cases). Notable risk factors for readmission included (Odds Ratio, Confidence Interval, p-value): dialysis dependence (6.77, 2.51-17.80,0.01), increased length of stay (3.00, 2.10-4.10,0.01), and preoperative weight loss (2.80, 1.06-7.17, 0.03); notable risk factors for increased LOS: ascites (8.51, 2.00-36.33,0.01), operation duration5 h (6.93, 5.29-9.25,0.01), and preoperative blood transfusion (5.37, 2.05-14.04,0.01).Identification of risk factors for adverse postoperative outcomes is necessary to inform and improve standards of care in MIS for endometrial cancer. Using nationally reported data from the ACS NSQIP, this study identifies independent risk factors for unplanned readmission and prolonged LOS, and in doing so, highlights potential avenues for quality improvement.

5580 Background: HER2 is an emerging prognostic and therapeutic target in uterine serous carcinoma (USC). Testing algorithms and platforms in breast and gastric cancers are well studied and validated, but optimal HER2 testing in uterine cancer is not yet established. We aimed to assess the concordance of chromogenic in situ hybridization (CISH), immunohistochemistry (IHC), and next generation sequencing (NGS) platforms to aid in the development of USC specific testing guidelines. We also evaluated the rate of downstream mutations that may affect response to HER2 directed therapy. Methods: A total of 2,192 USC tumors were analyzed using NGS (NextSeq, 592 Genes and WES, NovaSEQ), a subset of 1,423 tumors were also tested by IHC and CISH (Caris Life Sciences, Phoenix, AZ). HER2 positivity through IHC (4B5, Ventana) and CISH (INFORM DUAL HER2 ISH Assay, Ventana) was determined based on 2007 and 2018 ASCO/CAP HER2 breast cancer guidelines. PD-L1 expression was tested by IHC using SP142 (Spring Biosciences) (positive cut-off >1%). Microsatellite instability (MSI) was tested by fragment analysis (FA), IHC and NGS. Tumor mutational burden (TMB) was measured by totaling somatic mutations per tumor (TMB-high cut-off > 10 mutations per Mb). Statistical significance was determined using chi-square. Results: Rates of HER2 positivity were comparable using the 2018 and 2007 breast cancer guidelines (19.5% vs 17.5%; p=0.25). Based on 2018 guidelines, the concordance between IHC and CISH was 98.9%. Specifically, 229/1423 patients (16%) were IHC+/CISH+, 5 patients (0.4%) were IHC+/CISH- and 11 patients (0.8%) were IHC-/CISH+ (Table). Common pathway alterations in HER2+ USC include TP53, RTK RAS, PI3K, NOTCH, chromatin remodeling and cell cycle genes. Single gene alterations in HER2+ tumors that may implicate HER2 therapy resistance (based on pathway analyses in other tumor types) included PI3K (36%), KRAS (2.6%), and PTEN (2.1%). HER2+ tumors had low immunotherapy biomarker profiles (0.3% MSI-H, 0.8% TMB, 17.1% PD-L1). Conclusions: High concordance rates were observed between CISH and IHC. Ultimately these testing platforms need to be validated by response to HER2 targeted therapies in order to develop USC specific HER2 testing guidelines.[Table: see text]

ONC201 is a small molecule DRD2 antagonist and ClpP agonist that has prolonged antitumor efficacy and immunomodulatory properties in preclinical models. The enhanced immune modulatory nature of ONC201 was observed in a Phase I study that revealed increased infiltration of granzyme B+ and CD56+ cells, corroborating preclinical reports of NK cell intratumoral infiltration in response to ONC201. A broad induction of immune cytokines and effector molecules was observed in patients treated with ONC201, in particular among patients who experienced at least stable disease by RECIST for 12 or more weeks. Patients who had a > 50% induction in serum perforin, a cytolytic protein found in the granules of cytotoxic T lymphocytes (CTLs) and NK cells, upon ONC201 administration had better outcomes. Regressions in individual metastatic lesions were noted in a small number of EC patients. A multi-center Phase 2 study to explore the efficacy of weekly ONC201 in recurrent or metastatic Type II EC enrolled 5 patients with recurrent EC who underwent paired tumor biopsies before and 9 days after ONC201 initiation. Four of the 5 patients exhibited a 2-5-fold increase in CD4+ Thelper cells in their tumors and the majority of these patients also had CD4+FoxP3+ cells, indicating a significant population of Tregulatory cells (Treg). One patient exhibited an 80% increase in CD8+ T-cells in their tumor 8 days after initiating ONC201. Two of the patients had >2 fold induction of intratumoral granzyme B expression that was surprisingly not accompanied by NK cell infiltration, as assessed by CD56 staining. These results may be consistent with innate immune system activation by ONC201 that results in T-cell modulation. The multi-fold increase in Treg expression could be suppressing tumor cell death. As such, ONC201 dose intensification or combination with immunotherapy are being evaluated for ONC201 in the context of endometrial cancer. Citation Format: Rohinton S. Tarapore, Varun V. Prabhu, Samuel C. Mok, Chilam Au Yeung, Lorna Rodriguez, Eugenia Girda, Gina Mantia-Smaldone, Victoria Bae-Jump, Guangrong Lu, Wolfgang Oster, Joshua E. Allen. Immunomodulatory activity of selective DRD2 antagonist ONC201, an imipridone, in metastatic endometrial cancer (mEC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-145.

e18040 Background: Therapeutic options for patients with recurrent platinum resistant ovarian cancer are scarce and represent an unmet need in ovarian cancer. Chemotherapy resistance has been linked to many CD44 pathways including P-glycoprotein mediated efflux of chemotherapeutic agents. Our working hypothesis was that chemotherapy resistant ovarian tumors that expressed CD44 would revert drug resistance by using a CD44 inhibitor SPL-108, that had proven safe as a single agent. Methods: Patients with platinum refractory or resistant CD44+ ovarian tumors were eligible. We used a standard 3+3 phase I design, open-label, 2-arm trial of the combination of SPL-108 and IV paclitaxel (PTX): Arm 1 (2 cohorts) Safety Phase: Cohort 1: SPL-108 150 mg SQ Daily +80 mg PTX weekly Cohort 2: SPL-108 300mg daily +80 mg PTX weekly Arm 2 (1 cohort) Exploratory Phase: Cohort 3: SPL-108 daily dose 300 mg +80 mg PTX weekly Days 1-15 in 28 day cycles Primary end points were safety and tolerability. Secondary endpoints included determining molecular signatures of response using NGS. Tumors were sequenced at the time of recurrence or initial diagnosis. Results: Fourteen patients were enrolled in the study. Prior number of treatments ranged from 2-6, except for one patient with platinum refractory disease that progressed during first line of therapy. There was no DLT and all cohorts were completed as designed. The treatment was well tolerated. There was one instance of a bowel micro-perforation that was treated medically. This patient had platinum refractory disease and eventually underwent an interval cytoreduction. There was one patient with grade 3 neurotoxicity. Sixty-two% of the patients had clinical benefit with 36% having a PR. Forty-three % of patient had a PFS of more than 6 months. Two patients enjoyed a PR of 12 months. Molecular profiling of the tumors revealed that all tumors had TP53 alterations and the 4 patients that did not have a response had tumors with TP53 truncations or a lack of function alteration. Conclusions: Daily SPL-108 300mg SQ in combination with weekly PTX is safe and feasible. The promising clinical activity on drug resistant ovarian tumors warrants further investigation. Resistance to SPL-108 are characterized by lack of function of TP53, mostly early truncations. It is possible that SPL-108 may be reactivating TP53 by promoting its active conformation. Once TP53 is active CD44 expression is abrogated at the promoter. Therefore SPL-108 is effectively acting on CD44 through 2 different mechanisms to promote chemotherapy sensitivity. Clinical trial information: NCT03078400.

6010 Background: The efficacy of treatment for recurrent endometrial cancer (EC) remains limited. Vascular endothelial growth factor and inflammatory chemokines are proangiogenic factors and immune modulators involved in immune suppression. Reprogramming the tumor microenvironment by combining antiangiogenic and immunotherapy (IO) could enhance antitumor responses. Methods: A 2:1 randomized phase 2 trial compared the combination of cabozantinib and nivolumab (Arm A) versus nivolumab (Arm B) in recurrent EC. Primary endpoint was progression free survival (PFS) assessed by RECIST 1.1 (NCT03367741). Women with recurrent measurable EC were eligible. There were no limits on prior therapy, but at least one prior platinum-based chemotherapy was required. Patients (pts) were stratified according to MSI status and assessed by CT every 8 weeks. Cabozantinib was given at 40 mg daily (Arm A) and nivolumab at 240 mg, on D1 and D15 of a 28-day cycle for 4 cycles, followed by 480 mg every 4 weeks (Arms A & B). Pts with carcinosarcoma or prior IO were enrolled in an exploratory cohort and received combination treatment (Arm C). A baseline biopsy was required for all pts. CyTOF analysis was performed on fresh biopsies. Results: 76 evaluable pts were enrolled (Arm A: 36, Arm B: 18, Arm C: 9 carcinosarcoma, and 20 post IO including 7 pts crossed over from Arm B). 55% of pts had received ≥3 prior lines of therapy. Two pts were MSI high in Arm A and none in Arm B. The Kaplan-Meier estimated median PFS was 5.3 (95% CI: 3.5-9.5) months in Arm A and 1.9 (95% CI: 1.6-3.8) months in Arm B, with a log-rank p = 0.07, which met the significance level of 0.1 used for sample size calculation. Objective response rate (ORR) was 25% for Arm A and 16.7% for Arm B; stable disease (SD) was seen in 44.4% vs 11.1%, respectively. Clinical benefit (ORR+SD) was significantly higher in arm A vs B (p < 0.001). In Arm C-carcinosarcoma, one patient had a partial response (11.9 months duration) and four SD. In Arm C-prior IO, six pts responded and eight had SD. The most common related AEs in Arm A were diarrhea (47.2%), elevated liver enzymes (44.4%), fatigue (38.9%), anorexia, hypertension, and nausea (30.6%), mainly grade 1/2. Preliminary CyTOF analysis across treatment arms identified multiple immune subsets for further interrogation including activated CD8+ and CD4+ T cells. Conclusions: Cabozantinib plus nivolumab demonstrates improved PFS compared to nivolumab in heavily pre-treated women with recurrent EC. In-depth CyTOF analysis of the tumor microenvironment to identify predictive immune biomarkers of response is ongoing. Clinical trial information: NCT03367741.

79 Background: The Metabotropic Glutamate Receptor 1 (GRM1) is overexpressed in many solid tumors. It activates MAPK and PI3K/AKT pathways and promotes an immune-suppressive tumor microenvironment. In an immunocompetent melanoma mouse model, GRM1 blockade using riluzole or its pro-drug troriluzole (BHV-4157) and PD-1 blockade inhibit tumor growth in an additive manner. We conducted a phase Ib trial of troriluzole and the PD-1 antibody nivolumab. Methods: Patients with advanced or refractory solid tumors were treated with increasing doses of troriluzole. Troriluzole monotherapy was given for a 14-day lead-in period and then patients received troriluzole in combination with nivolumab 240 mg IV every 2 weeks. Results: We enrolled 14 patients with advanced solid tumors (melanoma=3, NSCLC=3, renal cell cancer=2, NSCLC=2, head and neck cancer=2). Eleven patients had prior therapy with anti-PD-(L)1. PK sampling demonstrated that the prodrug was cleaved efficiently without regard to food (Table). The most common TEAEs (all grades) occurring in >40% of patients were transaminitis, increased lipase and nausea. DLT occurred in 3 patients: 1) grade 3 anorexia, 2) grade 3 fatigue and, 3) atrial fibrillation. The MTD was determined to be troriluzole 140 mg QAM + 280 mg PO QHS. The response rate was 7 % (1/14); this occurred in a PD-L1 treated patient. The 6-month PFS rate was 21%. Correlative studies will be presented. Conclusions: The combination of troriluzole and nivolumab was safe and well-tolerated in this highly PD-1 refractory population. Clinical trial information: NCT03229278. [Table: see text]

OBJECTIVE: To evaluate the association of 3 hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitor (statin) use and concordant polypharmacy with disease-specific survival from endometrial cancer. METHODS: A retrospective cohort study was conducted of 985 endometrial cancer cases treated from January 1999 through December 2009 at a single institution. Disease-specific survival was estimated by Kaplan-Meier analyses. A Cox proportional hazards model was used to study factors associated with survival. All statistical tests were two-sided and performed using Stata. RESULTS: At the time of analysis, 230 patients (22% of evaluable patients) died of disease and median follow-up was 3.28 years. Disease-specific survival was greater (179/220 [81%]) for women with endometrial cancer taking statin therapy at the time of diagnosis and staging compared with women not using statins (423/570 [74%]) (log rank test, P=.03). This association persisted for the subgroup of patients with nonendometrioid endometrial tumors who were statin users (59/87 [68%]) compared with nonusers (93/193 [43%]) (log rank test, P=.02). The relationship remained significant (hazard ratio 0.63, 95% confidence interval [CI] 0.40-0.99) after adjusting for age, clinical stage, radiation, and other factors. Further evaluation of polypharmacy showed an association between concurrent statin and aspirin use with an especially low disease-specific mortality (hazard ratio 0.25, 95% CI 0.09-0.70) relative to those who used neither. CONCLUSION: Statin and aspirin use was associated with improved survival from nonendometrioid endometrial cancer.

Supplemental digital content is available in the text., Objective Patient-derived organoids (PDOs), used in multiple tumor types, have allowed evaluation of tumor characteristics from individual patients. This study aimed to assess the feasibility of applying PDO in vitro culture for endocrine-based and drug sensitivity testing in endometrial cancer. Methods Endometrial cancer cells were enzymatically dissociated from tumors retrieved from fresh hysterectomy specimens and cultured within basement membrane extract in serum-free medium. An organoid growth assay was developed to assess the inhibitory effects of a variety of drugs including endocrine treatments. Organoid cultures were also prepared for histological and immunohistochemical comparison to the tumors of origin. Results Fifteen endometrial cancer specimens were successfully cultured as PDOs. Small spherical structures formed within 24 hours, and many continued to grow to larger, denser organoids, providing the basis for an organoid growth assay. The STAT3 transcription factor inhibitor, BBI608 (Napabucasin), strongly inhibited growth in almost all PDO cultures, suggesting that stemness programing is involved in organoid formation and/or growth. Inhibition by different growth factor receptor tyrosine kinase inhibitors was observed in several PDO specimens. Four cultures were inhibited by fulvestrant, implying the importance of estrogen-receptor signaling in some PDO cultures. Organoids closely resembled their tumors of origin in both histomorphology and immunohistochemical expression. Conclusions The use of endometrial cancer PDO cultures for development of drug sensitivity testing for individual patient tumors is feasible. The potential value of the PDO model for clinical decision making will require clinical trial evaluation.

OBJECTIVE Obesity is an established risk factor for development of endometrial cancer. We hypothesized that obesity might also be associated with an earlier age at endometrial cancer diagnosis, because mechanisms that drive the obesity-endometrial cancer association might also accelerate tumorigenesis. METHODS A retrospective chart review was conducted of all cases of endometrial cancer diagnosed from 1999 to 2009 at a large medical center in New York City. The association of body mass index (BMI) with age at endometrial cancer diagnosis, comorbidities, stage, grade, and radiation treatment was examined using analysis of variance and linear regression. Overall survival by BMI category was assessed using Kaplan-Meier method and the log-rank test. RESULTS A total of 985 cases of endometrial cancer were identified. The mean age at endometrial cancer diagnosis was 67.1 years (±11.9 standard deviation) in women with a normal BMI, whereas it was 56.3 years (±10.3 standard deviation) in women with a BMI greater than 50. Age at diagnosis of endometrioid-type cancer decreased linearly with increasing BMI (y=67.89-1.86x, R=0.049, P

e17040 Background: HIPEC showed a progression free survival when incorporated into interval cytoreductive surgery for ovarian cancer patients in a recent phase lll trial. This has led to a paradigm shift at many institutions and the consideration of HIPEC. The goal of this study is to report on the initiation of this program and change in practice at a high volume cancer center over a period of 1 year. Methods: Reviewed surgical cases from 1/2018 through 1/2019 where patients were thought to have a primary ovarian or fallopian tube cancer. Variables included age, stage, histology, primary or interval debulking surgery, number of neoadjuvant (NAJ) chemotherapy cycles. HIPEC patients were selected out and variables examined included intraoperative procedures, optimal cytoreduction, type of chemotherapy administered, postoperative complications, and ability to receive consolidation chemotherapy. Results: 35 cases where ovarian cancer known or suspected preoperatively. 23 patients had primary surgery consisting of tah/bso/surgical staging/tumor debulking. 0/23 of these patients were offered HIPEC chemotherapy as an upfront strategy. 12 patients received neoadjuvant chemotherapy for recurrent (2) or advanced (10) disease. 11/12 of these patients proceeded to an interval surgery. 6/11 (54%) were planned for HIPEC. This was aborted in 1/6 because of thrombocytopenia. 5/6 patients went on to receive HIPEC. They received 3-6 cycles of NAJ chemotherapy, platinum and taxane. 3/5 also received preoperative Avastin. All had R0 resection. 1 patient had a bowel resection. Either carboplatin or cisplatin was used for HIPEC over 90 minutes. 2/5 patients had postoperative G2-3 cytopenias. 3/5 patients were able to receive consolidation chemotherapy, 2 of them within six weeks of surgery and with Avastin containing regimens. Conclusions: In a large volume center initiating a HIPEC ovarian cancer program in less than one years’ time, HIPEC was offered to 50% of patients undergoing interval debulking for Stage III or IV serous ovarian cancer after NAJ chemotherapy and in rare cases for patients with recurrent cancer planned for cytoreduction. Patients may go on to receive postoperative chemotherapy but may have prolonged cytopenias and consolidation therapy delays. HIPEC was not incorporated into an upfront surgical strategy.[Table: see text]

Objective: The objective of this study is to assess the outcome of port-a-cath (PAC) maintenance every three months in patients with gynecologic malignancies with the goal of standardizing a safe and appropriate interval that would maintain patency and minimize side effects. Methods: We performed a retrospective medical record review and evaluation of all patients with a Bard? PAC who were noted to have no evidence of disease (NED) during the years 2003 to 2010. The interval between accessions and any complications related to the presence of the PAC were recorded. Relevant complications included skin infections, bacteremia, thrombosis, and occlusions. Statistical analysis was done using the Fisher’s exact test. Results: A total of 201 patients had PAC placed and 43 patients underwent PAC accessions to maintain patency. The total number of accessions was 150 with a median number per patient of 2.0 (range 1 - 10). The mean time between flushes was 112 days (SD = 57). When comparing women in maintenance who had flushes within 90 days versus those who had flushes over 90 days apart, there was no difference in infection or occlusion rates between these groups (p = 0.515). In the Conclusion: Infections and occlusions are rare in women with gynecologic malignancies undergoing maintenance of their PAC. Longer intervals between PAC flushes do not appear to affect the outcome in our patients. Our ongoing data and follow-up confirm that extending the interval of PAC accession to every 3 months, rather than monthly, is safe, effective and convenient in the patient population with gynecologic malignancies.

TPS5608Background: Ovarian cancer often presents in advanced stages and is treated with platinum-based chemotherapy. However, many patients develop platinum-resistant disease with either failing to...

Objective To report a case of pelvic actinomycosis presenting as large, multiloculated abscesses after an in vitro fertilization (IVF) cycle for male factor infertility. Design A case report and literature review. Setting University hospital. Patient(s) A 31-year-old nulligravid woman presenting with urinary retention, pelvic pain, and fever 6 days after transvaginal oocyte retrieval and an embryo transfer for male factor infertility. Intervention(s) Intravenous and oral antimicrobial therapy, and computed tomography (CT)-guided drainage of pelvic abscesses. Main Outcome Measure(s) Clinical and radiologic resolution of symptoms and infection. Result(s) The CT scan revealed several large, multiloculated pelvic and tuboovarian abscesses. The patient defervesced after 6 days of intravenous antibiotics, but the pelvic pain did not improve. After CT-guided drainage of the pelvic abscesses, the patient's symptoms improved. The drained material was cultured, and the patient was diagnosed with pelvic actinomycosis tuboovarian abscesses, an infrequent cause of tuboovarian abscess and a rare complication of assisted reproductive technology (ART). The patient was switched from intravenous to oral antibiotics and discharged home. Conclusion(s) Pelvic Actinomyces israelii presenting as pelvic abscesses may occur as a rare complication of ART. Physicians should consider a diagnosis of tuboovarian abscess in a patient reporting fever and pelvic pain after IVF and embryo transfer.