Stephanie Lheureux

Safety of antibody-drug conjugates in gynecologic cancers: current evidence and management approaches

Combined Transcriptome and Circulating Tumor DNA Longitudinal Biomarker Analysis Associates With Clinical Outcomes in Advanced Solid Tumors Treated With Pembrolizumab

PURPOSE Immune gene expression signatures are emerging as potential biomarkers for immunotherapy (IO). VIGex is a 12-gene expression classifier developed in both nCounter (Nanostring) and RNA sequencing (RNA-seq) assays and analytically validated across laboratories. VIGex classifies tumor samples into hot, intermediate-cold (I-Cold), and cold subgroups. VIGex-Hot has been associated with better IO treatment outcomes. Here, we investigated the performance of VIGex and other IO biomarkers in an independent data set of patients treated with pembrolizumab in the INSPIRE phase II clinical trial (ClinicalTrials.gov identifier: NCT02644369 ). MATERIALS AND METHODS Patients with advanced solid tumors were treated with pembrolizumab 200 mg IV once every 3 weeks. Tumor RNA-seq data from baseline tumor samples were classified by the VIGex algorithm. Circulating tumor DNA (ctDNA) was measured at baseline and start of cycle 3 using the bespoke Signatera assay. VIGex-Hot was compared with VIGex I-Cold + Cold and four groups were defined on the basis of the combination of VIGex subgroups and the change in ctDNA at cycle 3 from baseline (ΔctDNA). RESULTS Seventy-six patients were enrolled, including 16 ovarian, 12 breast, 12 head and neck cancers, 10 melanoma, and 26 other tumor types. Objective response rate was 24% in VIGex-Hot and 10% in I-Cold/Cold. VIGex-Hot subgroup was associated with higher overall survival (OS) and progression-free survival (PFS) when included in a multivariable model adjusted for tumor type, tumor mutation burden, and PD-L1 immunohistochemistry. The addition of ΔctDNA improved the predictive performance of the baseline VIGex classification for both OS and PFS. CONCLUSION Our data indicate that the addition of ΔctDNA to baseline VIGex may refine prediction for IO.

Randomized Phase II Study of Bevacizumab with Weekly Anetumab Ravtansine or Weekly Paclitaxel in Platinum-Resistant/Refractory High-Grade Ovarian Cancer (NCI Trial)

Abstract Purpose: Mesothelin (MSLN) is highly expressed in high-grade serous/endometrioid ovarian cancers (HGOC). Anetumab ravtansine (AR) is an antibody–drug conjugate directed at the MSLN antigen with a tubulin polymerization inhibitor. We assessed the safety, activity, and pharmacokinetics of the combination AR/bevacizumab (Bev; ARB) versus weekly paclitaxel/Bev (PB) in patients with platinum-resistant/refractory HGOC (prrHGOC). Patients and Methods: Following a run-in phase I study to assess ARB safety, patients with prrHGOC with centrally confirmed MSLN-positive expression were randomized to ARB or PB (weekly paclitaxel 80 mg/m2 with Bev 10 mg/kg biweekly). Patients were stratified by platinum resistance/refractory and prior Bev. The primary endpoint was progression-free survival (PFS), and secondary endpoints were overall response rate, safety, and blood-based angiome biomarker assessment. A futility analysis was planned after 35 PFS events. Results: The combination of Bev (10 mg/kg) biweekly with AR (2.2 mg/kg) weekly was well tolerated. About phase II results, MSLN positivity was 88%, and 57 patients were randomized (28 ARB and 29 PB). Forty-two percentage of patients received prior Bev, and 23% were platinum-refractory. At futility analysis, the median PFS was 5.3 and 12.7 months for ARB and PB, respectively [P = 0.03; HR = 2.02 (1.06–3.86)]. The overall response rate was 21% with ARB and 65% with PB. The most common treatment-related grade ≥3 adverse events were anemia (18%) with ARB and neutropenia (24%) with PB. Higher baseline levels of circulating IL6 were associated with worse PFS, and its levels decreased with PB treatment. Conclusions: Our study stopped at interim analysis highlighting the benefit of PB in prrHGOC as the standard of care.

Translational randomized phase II trial of cabozantinib in combination with nivolumab in advanced, recurrent, or metastatic endometrial cancer

Background Combining immunotherapy and antiangiogenic agents is a promising treatment strategy in endometrial cancer. To date, no biomarkers for response have been identified and data on post-immunotherapy progression are lacking. We explored the combination of a checkpoint inhibitor (nivolumab) and an antiangiogenic agent (cabozantinib) in immunotherapy-naïve endometrial cancer and in patients whose disease progressed on previous immunotherapy with baseline biopsy for immune profiling. Patients and methods In this phase II trial (ClinicalTrials.gov NCT03367741, registered December 11, 2017), women with recurrent endometrial cancer were randomized 2:1 to nivolumab with cabozantinib (Arm A) or nivolumab alone (Arm B). The primary endpoint was Response Evaluation Criteria in Solid Tumors-defined progression-free survival (PFS). Patients with carcinosarcoma or prior immune checkpoint inhibitor received combination treatment (Arm C). Baseline biopsy and serial peripheral blood mononuclear cell (PBMC) samples were analyzed and associations between patient outcome and immune data from cytometry by time of flight (CyTOF) and PBMCs were explored. Results Median PFS was 5.3 (90% CI 3.5 to 9.2) months in Arm A (n=36) and 1.9 (90% CI 1.6 to 3.4) months in Arm B (n=18) (HR=0.59, 90% CI 0.35 to 0.98; log-rank p=0.09, meeting the prespecified statistical significance criteria). The most common treatment-related adverse events in Arm A were diarrhea (50%) and elevated liver enzymes (aspartate aminotransferase 47%, alanine aminotransferase 42%). In-depth baseline CyTOF analysis across treatment arms (n=40) identified 35 immune-cell subsets. Among immunotherapy-pretreated patients in Arm C, non-progressors had significantly higher proportions of activated tissue-resident (CD103+CD69+) ɣδ T cells than progressors (adjusted p=0.009). Conclusions Adding cabozantinib to nivolumab significantly improved outcomes in heavily pretreated endometrial cancer. A subgroup of immunotherapy-pretreated patients identified by baseline immune profile and potentially benefiting from combination with antiangiogenics requires further investigation.

Evaluation of Innate Immune System, Body Habitus, and Sex on the Pharmacokinetics and Pharmacodynamics of Anetumab Ravtansine in Patients With Cancer

ABSTRACTAnetumab ravtansine, like other ADC drugs, has high inter‐patient variability in its pharmacokinetic (PK) and pharmacodynamic (PD) outcomes, which raises concerns about whether current dosing regimens are optimal for patients. The objective of this study was to evaluate covariates, especially body habitus and the innate immune system (IIS), which may affect anetumab ravtansine PK and PD as part of two clinical trials in patients with ovarian cancer and mesothelioma. Biomarkers of Fcγ receptors(FcγR) CD64 on IIS cells, total body weight (TBW), body surface area (BSA), and other covariates, such as sex and age, were analyzed for an association with anetumab ravtansine PK. Higher FcγR CD64, TBW, and BSA were associated with higher clearance (CL) of anetumab ravtansine (p < 0.05). However, there was no relationship between TBW or BSA and FcγR CD64. Female patients had a lower anetumab ravtansine CL (0.030 ± 0.007 L/h) compared to male patients (0.042 ± 0.006 L/h) (p < 0.05). In both studies, patients with stable disease (SD) and partial response (PR) had higher anetumab ravtansine AUC0‐inf compared to patients with progressive disease (PD). Individualizing the dose of anetumab ravtansine and potentially other ADCs based only on TBW is not optimal, whereas precision dosing of an ADC based on the inclusion of novel metrics of IIS biomarkers, body habitus, and sex may be more appropriate to reduce variability in PK exposure, reduce toxicity, and improve response.

Genomic Landscape of ctDNA and Real-World Outcomes in Advanced Endometrial Cancer

Abstract Purpose: ctDNA is a novel technique extensively studied in solid tumors, although not currently well defined in endometrial cancer. Experimental Design: A de-identified retrospective analysis of 1,988 patients with advanced/recurrent endometrial cancer was performed. In addition, an analysis of a real-world evidence cohort was completed (n = 1,266). Patients underwent ctDNA testing using Guardant360 during routine clinical care. The objective was to describe and assess molecular landscape using ctDNA. Results: Among 1,988 ctDNA samples, at least one somatic alteration was detected in 91.6% (n = 1,821). Most frequently altered genes were TP53 (64%), PIK3CA (29%), PTEN (25%), ARID1A (20%), and KRAS (14%). Overall, 18.5% had amplifications, with the majority identified in CCNE1 (40.9%), PIK3CA (22%), and EGFR (19.3%). From the real-world evidence cohort, those with TP53 mutations had a worse overall survival (OS) versus those without TP53 mutations (P = 0.02) and those with TP53 comutations had an inferior OS in comparison with TP53-mutated only (P = 0.016). Amongst these, patients with a PIK3CA comutation (P = 0.012) and CCNE1 amplification (P = 0.01) had an inferior OS compared with those with only TP53 mutations. Fifty-seven patients with newly diagnosed endometrial cancer had at least two serial ctDNA samples showing evolution in detected variants compared with baseline samples, with TP53 being the most frequent change. Conclusions: This study is one of the largest cohorts of ctDNA currently reported in endometrial cancer. The presence of TP53 mutation and other comutations detected by ctDNA have a negative effect on outcomes. This report suggests that ctDNA analysis is feasible and could become a useful biomarker for endometrial cancer.

ADAGIO: A Phase IIb, Open-Label, Single-Arm, Multicenter Study Assessing the Efficacy and Safety of Adavosertib (AZD1775) as Treatment for Recurrent or Persistent Uterine Serous Carcinoma

PURPOSE This phase IIb, single-arm, multicenter, global study (ADAGIO; ClinicalTrials.gov identifier: NCT04590248 ) assessed the efficacy and safety of adavosertib in patients with recurrent/persistent uterine serous carcinoma (USC) who had previously received platinum-based chemotherapy. METHODS Eligible patients were age 18 years and older and had histologically confirmed recurrent/persistent USC, previously treated with at least one platinum-based chemotherapy regimen, and with evidence of measurable disease. Adavosertib was administered orally at 300 mg once daily on days 1-5 and 8-12 of a 21-day cycle until discontinuation criteria were met. The primary end point was objective response rate (ORR) by blinded independent central review (BICR). Secondary end points included duration of response (DoR), progression-free survival (PFS), safety, and tolerability. Biomarkers previously associated with adavosertib response in other settings were assessed in archival tissue samples. RESULTS In 104 evaluable patients, one complete response and 26 partial responses were observed, for an ORR by BICR of 26.0% (95% CI, 17.9 to 35.5). Median DoR was 4.7 months (95% CI, 3.8 to 8.3); median PFS was 2.8 months (95% CI, 2.6 to 3.9). Biomarker analysis identified no single predictive alteration for adavosertib response, although a trend was observed for CCNE1 amplification or high cyclin E1 protein expression. Most patients (97.2%) experienced treatment-related adverse events (TRAEs), most frequently diarrhea (59.6%), nausea (59.6%), and anemia (58.7%). Grade ≥3 TRAEs occurred in 60.6% of patients, with neutropenia (21.1%) and fatigue (13.8%) most common. 17.4% of patients discontinued adavosertib due to AEs (treatment-related in 14.7%). CONCLUSION Adavosertib showed some antitumor activity in patients with recurrent/persistent USC. However, at 300 mg once daily dosing, it was not well tolerated in this population. Exploratory biomarker studies suggest CCNE1 /cyclin E1 expression may enrich for response to Wee1 inhibition in USC.

Identifying Mechanisms of Resistance by Circulating Tumor DNA in EVOLVE, a Phase II Trial of Cediranib Plus Olaparib for Ovarian Cancer at Time of PARP Inhibitor Progression

Abstract Purpose: To evaluate the use of blood cell–free DNA (cfDNA) to identify emerging mechanisms of resistance to PARP inhibitors (PARPi) in high-grade serous ovarian cancer (HGSOC). Experimental Design: We used targeted sequencing (TS) to analyze 78 longitudinal cfDNA samples collected from 30 patients with HGSOC enrolled in a phase II clinical trial evaluating cediranib (VEGF inhibitor) plus olaparib (PARPi) after progression on PARPi alone. cfDNA was collected at baseline, before treatment cycle 2, and at end of treatment. These were compared with whole-exome sequencing (WES) of baseline tumor tissues. Results: At baseline (time of initial PARPi progression), cfDNA tumor fractions were 0.2% to 67% (median, 3.25%), and patients with high ctDNA levels (>15%) had a higher tumor burden (sum of target lesions; P = 0.043). Across all timepoints, cfDNA detected 74.4% of mutations known from prior tumor WES, including three of five expected BRCA1/2 reversion mutations. In addition, cfDNA identified 10 novel mutations not detected by WES, including seven TP53 mutations annotated as pathogenic by ClinVar. cfDNA fragmentation analysis attributed five of these novel TP53 mutations to clonal hematopoiesis of indeterminate potential (CHIP). At baseline, samples with significant differences in mutant fragment size distribution had shorter time to progression (P = 0.001). Conclusions: Longitudinal testing of cfDNA by TS provides a noninvasive tool for detection of tumor-derived mutations and mechanisms of PARPi resistance that may aid in directing patients to appropriate therapeutic strategies. With cfDNA fragmentation analyses, CHIP was identified in several patients and warrants further investigation.

Overcoming PARP inhibitor resistance in ovarian cancer

Ovarian cancer (OC) is one of the most lethal tumors in women, mostly diagnosed at advanced stages. Standard of care is based on surgery and platinum-based chemotherapy which provides high rates of response, although most patients will relapse. Poly(ADP-ribose) polymerase inhibitors (PARPi) have recently been incorporated in the treatment strategy for high-grade OC, particularly for those with defects in DNA repair pathways (homologous repair deficiency (HRd)). However, some tumor cells may not respond and some others will develop mechanisms of resistance to adapt. The most known mechanism of PARPi resistance is the reversion of HRd to homologous repair proficiency driven by epigenetic and genetic changes. Ongoing research is exploring different agents that are trying to re-sensitize tumor cells,overcome or bypass resistance to PARPi. Current investigations are focused on agents that target replication stress and DNA repair pathways, improve drug delivery, and target other cross-talk pathways. A crucial challenge in practice will be to identify and select patients for the appropriate therapy or combination strategies. However, efforts are needed to decrease overlapping toxicity and define the correct schedule timing of dosing to maximize the therapeutic index.

Multi-omics Uncovering Different Faces of Clear Cell Ovarian Cancer

Summary The diagnosis of clear cell ovarian cancer relies on expert histopathology review. Further characterization from deep genomic and transcriptomic analyses can identify different subgroups. International collaboration is required to define the clinical impact and therapy opportunities in these specific subclassifications. See related article by Bolton et al., p. 4947

Clinical Validation of Human Papilloma Virus Circulating Tumor DNA for Early Detection of Residual Disease After Chemoradiation in Cervical Cancer

PURPOSE Most cervical cancers are caused by human papilloma virus (HPV), and HPV circulating tumor DNA (ctDNA) may identify patients at highest risk of relapse. Our pilot study using digital polymerase chain reaction (dPCR) showed that detectable HPV ctDNA at the end of chemoradiation (CRT) is associated with inferior progression-free survival (PFS) and that a next-generation sequencing approach (HPV-seq) may outperform dPCR. We aimed to prospectively validate HPV ctDNA as a tool for early detection of residual disease. METHODS This prospective, multicenter validation study accrued patients with stage IB-IVA cervical cancer treated with CRT between 2017 and 2022. Participants underwent phlebotomy at baseline, end of CRT, 4-6 weeks post-CRT, and 3 months post-CRT for HPV ctDNA levels. Plasma HPV genotype–specific DNA levels were quantified using both dPCR and HPV-seq. The primary end point was 2-year PFS. RESULTS With a median follow-up of 2.2 (range, 0.5-5.5) years, there were 24 PFS events among the 70 patients with HPV+ cervical cancer. Patients with detectable HPV ctDNA on dPCR at the end of CRT, 4-6 weeks post-CRT, and 3 months post-CRT had significantly worse 2-year PFS compared with those with undetectable HPV ctDNA (77% v 51%, P = .03; 82% v 15%, P < .001; and 82% v 24%, P < .001, respectively); the median lead time to recurrence was 5.9 months. HPV-seq showed similar results as dPCR. On multivariable analyses, detectable HPV ctDNA on dPCR and HPV-seq remained independently associated with inferior PFS. CONCLUSION Persistent HPV ctDNA after CRT is independently associated with inferior PFS. HPV ctDNA testing can identify, as early as at the end of CRT, patients at high risk of recurrence for future treatment intensification trials.

Cediranib and Olaparib Combination Compared With Cediranib or Olaparib Alone, or Chemotherapy in Platinum-Resistant or Primary Platinum-Refractory Ovarian Cancer: NRG-GY005

PURPOSE We assessed the efficacy of cediranib, olaparib, and cediranib/olaparib compared with standard-of-care chemotherapy (SOC) in platinum-resistant or platinum-refractory epithelial ovarian cancer (PROC). PATIENTS AND METHODS NRG-GY005 is an open-label, four-arm, phase II/III superiority trial enrolling patients with high-grade serous/endometrioid PROC and one to three previous therapies. Key exclusion criteria included previous receipt of poly(ADP-ribose) polymerase inhibitor or receipt of antiangiogenic therapy in the recurrent setting. Treatment arms (SOC [once weekly paclitaxel, topotecan, or pegylated liposomal doxorubicin], cediranib, olaparib, or cediranib/olaparib) were equally randomized. A preplanned interim futility analysis on the basis of progression-free survival (PFS) selected treatment arms to advance to phase III. PFS and overall survival (OS) were phase III coprimary end points, with hierarchical testing of PFS followed by OS to preserve type 1 error control, designed to have 90% power for a 0.625 PFS hazard ratio (HR). OS was tested after PFS in the multiple hierarchical testing procedure. Secondary end points included objective response rate (ORR) and patient-reported outcomes. RESULTS Five hundred sixty-two eligible patients were enrolled for phase II/III. Three arms met PFS criteria to carry forward to phase III (SOC, cediranib/olaparib, and cediranib). Median PFS was 3.4, 5.2, and 4 months with SOC, cediranib/olaparib, and cediranib, respectively, with a median follow-up duration of 42.2 months. PFS HR estimates for cediranib/olaparib and cediranib ( v SOC) were 0.796 (98.3% CI, 0.597 to 1.060) and 0.972 (98.3% CI, 0.726 to 1.300), respectively. Median OS was 13.6, 12.8, and 10.5 months, and of 443 patients with measurable disease, ORR was 8.6%, 24.7%, and 13.1% for SOC, cediranib/olaparib, and cediranib, respectively. No new safety signals were identified. In patients receiving cediranib/olaparib, no statistically significant difference was observed on the NFOSI-DRS-P subscale compared with SOC (98.3% CI, –1.3 to 1.5, P = .8725). CONCLUSION The cediranib-containing arms demonstrated clinical activity on the basis of PFS but were not superior compared with SOC.

First-line lenvatinib plus pembrolizumab versus chemotherapy for advanced endometrial cancer: 1-Year follow-up after final analysis of the ENGOT-en9/LEAP-001 phase 3 trial

The phase 3 ENGOT-en9/LEAP-001 trial (NCT03884101) comparing first-line lenvatinib+pembrolizumab with carboplatin+paclitaxel did not meet pre-specified statistical criteria for overall survival or progression-free survival in participants with advanced/recurrent endometrial cancer. We report results after an additional year of follow-up (overall median 54.5 [range; 46.5-69.0] months). Eligible participants were adult females with stage III to IV or recurrent, histologically confirmed endometrial cancer. Measurable or non-measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and radiographically apparent disease per blinded independent central review was required. Participants were randomly allocated 1:1 to lenvatinib+pembrolizumab or chemotherapy (paclitaxel+carboplatin). The primary end points were overall survival and progression-free survival per RECIST version 1.1 by blinded independent central review. Secondary end points included objective response rate per RECIST version 1.1 by blinded independent central review and safety. The median overall survival (95% confidence interval [CI]) was 30.9 (range; 25.4-37.6) months with lenvatinib+pembrolizumab versus 29.4 (range; 26.2-34.8) months with chemotherapy in mismatch repair-proficient endometrial cancer (hazard ratio [HR] 0.99, 95% CI 0.82 to 1.21), 37.9 (range; 32.2-43.0) versus 32.3 (range; 27.2-35.7) months in all-comers (HR 0.91, 95% CI 0.77 to 1.09), and not reached in either treatment group in mismatch repair-deficient endometrial cancer (HR 0.60, 95% CI 0.39 to 0.93]). Corresponding results for progression-free survival were 9.6 (range; 8.2-11.9) versus 10.2 (range; 8.4-10.5) months (HR 1.01, 95% CI 0.83 to 1.22), 12.5 (range; 10.3-15.1) versus 10.2 (range; 8.4-10.4) months (HR 0.92, 95% CI 0.77 to 1.10]), and 31.8 (22.5 to not reached) versus 9.0 (range; 8.2-17.1) months (HR 0.62, 95% CI 0.41-0.93). Objective response rates were 50.6% versus 54.7%, 55.7% versus 55.5%, and 72.0% versus 58.0%, respectively. No new safety signals were identified. The results were consistent with those at the final analysis. The mismatch repair-proficient, all-comer, and mismatch repair-deficient populations continued to demonstrate antitumor activity for lenvatinib+pembrolizumab after an additional year of follow-up. These results should be interpreted with caution due to the exploratory nature of the analysis. ClinicalTrials.gov No. NCT03884101.

First-Line Lenvatinib Plus Pembrolizumab Versus Chemotherapy for Advanced Endometrial Cancer: A Randomized, Open-Label, Phase III Trial

PURPOSE Lenvatinib plus pembrolizumab (len + pembro) significantly improved progression-free survival (PFS) and overall survival (OS) versus chemotherapy in previously treated advanced or recurrent endometrial cancer (aEC) in the phase III Study 309/KEYNOTE-775. We report results from the phase III, randomized, open-label European Network of Gynaecological Oncological Trial-en9/LEAP-001 study (ClinicalTrials.gov identifier: NCT03884101 ) that evaluated len + pembro versus chemotherapy in first-line aEC. METHODS Patients with stage III to IV or recurrent, radiographically apparent EC and no previous chemotherapy or disease progression ≥6 months after neo/adjuvant platinum-based chemotherapy were randomly assigned 1:1 to lenvatinib 20 mg once daily plus pembrolizumab 200 mg once every 3 weeks or paclitaxel 175 mg/m 2 plus carboplatin AUC 6 mg/mL/min once every 3 weeks. Primary end points were PFS and OS, evaluated in the mismatch repair-proficient (pMMR) and all-comers populations. Noninferiority was assessed for OS at final analysis (FA) for len + pembro versus chemotherapy (multiplicity-adjusted, one-sided nominal alpha, .0159; null hypothesis–tested hazard ratio [HR], 1.1). RESULTS Eight hundred forty-two patients were randomly assigned (len + pembro, n = 420 [pMMR population, n = 320]; chemotherapy, n = 422 [pMMR population, n = 322]). At FA (data cutoff, October 2, 2023), median PFS (95% CI) in the pMMR population was 9.6 (8.2 to 11.9) versus 10.2 (8.4 to 10.5) months with len + pembro versus chemotherapy (hazard ratio [HR], 0.99 [95% CI, 0.82 to 1.21]) and among all-comers was 12.5 (10.3 to 15.1) versus 10.2 (8.4 to 10.4) months (HR, 0.91 [95% CI, 0.76 to 1.09]; descriptive analyses). Median OS (95% CI) in the pMMR population was 30.9 (25.4 to 37.7) versus 29.4 (26.2 to 35.4) months with len + pembro versus chemotherapy (HR, 1.02 [95% CI, 0.83 to 1.26]; noninferiority P = .246, not statistically significant per multiplicity control strategy) and among all-comers was 37.7 (32.2 to 43.6) versus 32.1 (27.2 to 35.7) months (HR, 0.93 [95% CI, 0.77 to 1.12]). Grade ≥3 treatment-related adverse events occurred in 331/420 (79%) versus 274/411 (67%) treated patients. CONCLUSION First-line len + pembro did not meet prespecified statistical criteria for PFS or OS versus chemotherapy in pMMR aEC.

Preclinical Combination Targeting VEGF and PI3K in a Rare, Aggressive Mixed Endometrial Carcinoma: An Applied Case Report

Abstract We report a rare case of a young patient (VENUS 167) initially diagnosed with grade 1 endometrioid endometrial cancer, which, following endocrine treatment, presented with mixed aggressive carcinoma with three distinct histologic patterns: grade 1 endometrioid, large cell neuroendocrine, and undifferentiated carcinoma. The surgical specimen at the time of disease progression was used to establish OPTO.85, a patient-derived organoid (PDO), followed by a corresponding organoid-derived xenograft (ODX). Multi-omic analyses confirmed that OPTO.85 accurately reflected the patient’s tumor characteristics. Whole-exome sequencing analysis identified oncogenic alterations in PIK3CA, ARID1A, and CTNNB1. Further RNA sequencing and assay for transposase-accessible chromatin using sequencing analyses revealed enrichment in VEGF and Wnt signaling pathways, suggesting therapeutic vulnerabilities. A high-throughput drug screen was conducted using ApexBio-approved and epigenetic drug libraries, along with kinase inhibitor and tool compound libraries developed at the Ontario Institute of Cancer Research. The OPTO.85 PDO exhibited sensitivity to PI3K inhibitors and responsiveness to VEGF inhibition. Cediranib demonstrated synergy with BKM120, significantly reducing organoid growth. This combination also showed in vivo efficacy in the ODX model, in which dual inhibitors significantly suppressed tumor growth compared with single compounds. This case exemplifies the impact of genomic profiling and patient-derived models in identifying actionable molecular changes in rare cancers with limited therapeutic options and poor prognosis. It highlights that high-throughput sequencing for individual patient tumors and generation of patient-derived models are feasible in endometrial cancer. This preclinical model may assist clinical decision and personalized therapy requiring validation in prospective studies. Significance: This study characterizes a rare aggressive mixed endometrial carcinoma that developed after hormonal therapy. Patient-derived organoid and xenograft models revealed actionable targets in the VEGF and PI3K pathways. Combined cediranib and BKM120 treatment showed synergistic antitumor effects in vitro and in vivo. These findings highlight the potential of integrating molecular profiling and drug testing to guide personalized therapies in rare and recurrent endometrial cancers.

FDG-PET and Circulating HPV in Patients With Cervical Cancer Treated With Definitive Chemoradiation (II)

Nearly all cervical cancers are caused by the human papilloma virus (HPV), which can be detected in cancer tissue by laboratory tests. There is evidence that the virus can also be detected from a blood sample to monitor the effects of treatment. Previous studies have shown that a special test called 18F-Fluorodeoxyglucose (FDG) Positron Emission Tomography/Computed Tomography (PET-CT) at 3 months after treatment may predict survival in cervical cancer. The purpose of this study is to see how well the FDG-PET Scan and blood tests for HPV can detect leftover cervical cancer cells after treatment. This study is not a particular form of treatment and patients will receive standard of care treatment.

Cabozantinib S-malate and Nivolumab in Treating Patients With Advanced, Recurrent, or Metastatic Endometrial Cancer

This randomized phase II trial studies how well cabozantinib s-malate and nivolumab work in treating patients with endometrial cancer that has come back (recurrent) or spread to other places in the body (advanced or metastatic). Cabozantinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Immunotherapy with monoclonal antibodies, such as nivolumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving cabozantinib and nivolumab may work better in treating endometrial cancer.

Liquid Biopsy Evaluation and Repository Development at Princess Margaret

The objective of this protocol is to develop an institution-wide liquid biopsy protocol that will establish a common process for collecting blood and corresponding archived tumor specimens for future research studies at the University Health Network's Princess Margaret Cancer Centre. Circulating cell-free nucleic acids (cfNA), including cell-free DNA (cfDNA) and cell-free RNA (cfRNA), are non-invasive, real-time biomarkers that can provide diagnostic and prognostic information before cancer diagnosis, during cancer treatment, and at disease progression. Cancer research scientists and clinicians at the Princess Margaret are interested in incorporating the collection of peripheral blood samples ("liquid biopsies") into research protocols as a means of non-invasively assessing tumor progression and response to treatment at multiple time points during a patient's course of disease.

Testing the Combination of Cediranib and Olaparib in Comparison to Each Drug Alone or Other Chemotherapy in Recurrent Platinum-Resistant Ovarian Cancer

This randomized phase II/III trial studies how well cediranib maleate and olaparib work when given together or separately, and compares them to standard chemotherapy in treating patients with ovarian, fallopian tube, or primary peritoneal cancer that has returned (recurrent) after receiving chemotherapy with drugs that contain platinum (platinum-resistant) or continued to grow while being treated with platinum-based chemotherapy drugs (platinum-refractory). Cediranib maleate and olaparib may stop the growth of tumor cells by blocking enzymes needed for cell growth. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. It is not yet known whether giving cediranib maleate and olaparib together may cause more damage to cancer cells when compared to either drug alone or standard chemotherapy.

Study of the Effects of Pembrolizumab in Patients With Advanced Solid Tumors

This is a phase 2 study whose main purpose is to evaluate gene changes and immune biomarkers in patients with solid tumors during treatment with pembrolizumab and in relation to response to treatment. Pembrolizumab is a monoclonal antibody that is designed to block a protein called programmed cell death 1 ligand 1 (PD-L1) which will allow the body's immune system to kill the cancer cells.