Prognostic impact and causality of age on oncological outcomes in women with endometrial cancer: a multimethod analysis of the randomised PORTEC-1, PORTEC-2, and PORTEC-3 trials

BACKGROUND

Numerous studies have shown that older women with endometrial cancer have a higher risk of recurrence and cancer-related death. However, it remains unclear whether older age is a causal prognostic factor, or whether other risk factors become increasingly common with age. We aimed to address this question with a unique multimethod study design using state-of-the-art statistical and causal inference techniques on datasets of three large, randomised trials.

METHODS

In this multimethod analysis, data from 1801 women participating in the randomised PORTEC-1, PORTEC-2, and PORTEC-3 trials were used for statistical analyses and causal inference. The cohort included 714 patients with intermediate-risk endometrial cancer, 427 patients with high-intermediate risk endometrial cancer, and 660 patients with high-risk endometrial cancer. Associations of age with clinicopathological and molecular features were analysed using non-parametric tests. Multivariable competing risk analyses were performed to determine the independent prognostic value of age. To analyse age as a causal prognostic variable, a deep learning causal inference model called AutoCI was used.

FINDINGS

Median follow-up as estimated using the reversed Kaplan-Meier method was 12·3 years (95% CI 11·9-12·6) for PORTEC-1, 10·5 years (10·2-10·7) for PORTEC-2, and 6·1 years (5·9-6·3) for PORTEC-3. Both overall recurrence and endometrial cancer-specific death significantly increased with age. Moreover, older women had a higher frequency of deep myometrial invasion, serous tumour histology, and p53-abnormal tumours. Age was an independent risk factor for both overall recurrence (hazard ratio [HR] 1·02 per year, 95% CI 1·01-1·04; p=0·0012) and endometrial cancer-specific death (HR 1·03 per year, 1·01-1·05; p=0·0012) and was identified as a significant causal variable.

INTERPRETATION

This study showed that advanced age was associated with more aggressive tumour features in women with endometrial cancer, and was independently and causally related to worse oncological outcomes. Therefore, our findings suggest that older women with endometrial cancer should not be excluded from diagnostic assessments, molecular testing, and adjuvant therapy based on their age alone.

FUNDING

None.

Uterine adenosarcoma: Clinical significance of histological classification and SNP array analysis

Mullerian adenosarcoma is a rare malignant biphasic tumor. The mesenchymal component may be low or high grade, with or without sarcomatous overgrowth (SO). Little is known about the molecular heterogeneity of these tumors. In this study, we aim to reclassify a large retrospective monocentric cohort of uterine adenosarcomas according to tumor grade and SO, to evaluate the clinical significance of pathological classification and to correlate with copy-number variations inferred from single nucleotide polymorphism array. Of the 67 uterine adenosarcomas, 18 (26.9%) were low grade without SO, 7 (10.4%) low grade with SO, 8 (11.9%) high grade without SO and 34 (50.7%) high grade with SO. SO, necrosis and RMS were more frequent in high grade than low grade adenosarcomas (p < 0.001). Low-rank test showed that recurrence-free survival was significantly shortened in high grade than low grade adenosarcomas (p = 0.035) and SO was associated with shortened overall and recurrence-free survival (p = 0.038 and p = 0.009, respectively). High-grade tumors displayed complex genomic profiles with multiple segmental losses including TP53, ATM and PTEN genes. The median genomic index was significantly higher in high grade than low grade tumors (27 [3-60] vs 5,3 [0-16], p < 0.0001) and was significantly higher in presence of SO in low grade tumors (12,8 [10-16] vs 2,6 [0-10], p = 0.0006). We propose to report sarcomatous overgrowth with the tumor grade for prognostication in adenosarcoma and representative sampling is crucial for evaluation of these histological criteria.

Bevacizumab, olaparib, and durvalumab in patients with relapsed ovarian cancer: a phase II clinical trial from the GINECO group

Most patients with advanced ovarian cancer (AOC) ultimately relapse after platinum-based chemotherapy. Combining bevacizumab, olaparib, and durvalumab likely drives synergistic activity. This open-label phase 2 study (NCT04015739) aimed to assess activity and safety of this triple combination in female patients with relapsed high-grade AOC following prior platinum-based therapy. Patients were treated with olaparib (300 mg orally, twice daily), the bevacizumab biosimilar FKB238 (15 mg/kg intravenously, once-every-3-weeks), and durvalumab (1.12 g intravenously, once-every-3-weeks) in nine French centers. The primary endpoint was the non-progression rate at 3 months for platinum-resistant relapse or 6 months for platinum-sensitive relapse per RECIST 1.1 and irRECIST. Secondary endpoints were CA-125 decline with CA-125 ELIMination rate constant K (KELIM-B) per CA-125 longitudinal kinetics over 100 days, progression free survival and overall survival, tumor response, and safety. Non-progression rates were 69.8% (90%CI 55.9%-80.0%) at 3 months for platinum-resistant relapse patients (N = 41), meeting the prespecified endpoint, and 43.8% (90%CI 29.0%-57.4%) at 6 months for platinum-sensitive relapse (N = 33), not meeting the prespecified endpoint. Median progression-free survival was 4.1 months (95%CI 3.5-5.9) and 4.9 months (95%CI 2.9-7.0) respectively. Favorable KELIM-B was associated with better survival. No toxic deaths or major safety signals were observed. Here we show that further investigation of this triple combination may be considered in AOC patients with platinum-resistant relapse.

Molecular and Clinicopathologic Characterization of Mismatch Repair-Deficient Endometrial Carcinoma Not Related to MLH1 Promoter Hypermethylation

Universal tumor screening in endometrial carcinoma (EC) is increasingly adopted to identify individuals at risk of Lynch syndrome (LS). These cases involve mismatch repair-deficient (MMRd) EC without MLH1 promoter hypermethylation (PHM). LS is confirmed through the identification of germline MMR pathogenic variants (PV). In cases where these are not detected, emerging evidence highlights the significance of double-somatic MMR gene alterations as a sporadic cause of MMRd, alongside POLE/POLD1 exonuclease domain (EDM) PV leading to secondary MMR PV. Our understanding of the incidence of different MMRd EC origins not related to MLH1-PHM, their associations with clinicopathologic characteristics, and the prognostic implications remains limited. In a combined analysis of the PORTEC-1, -2, and -3 trials (n = 1254), 84 MMRd EC not related to MLH1-PHM were identified that successfully underwent paired tumor-normal tissue next-generation sequencing of the MMR and POLE/POLD1 genes. Among these, 37% were LS associated (LS-MMRd EC), 38% were due to double-somatic hits (DS-MMRd EC), and 25% remained unexplained. LS-MMRd EC exhibited higher rates of MSH6 (52% vs 19%) or PMS2 loss (29% vs 3%) than DS-MMRd EC, and exclusively showed MMR-deficient gland foci. DS-MMRd EC had higher rates of combined MSH2/MSH6 loss (47% vs 16%), loss of >2 MMR proteins (16% vs 3%), and somatic POLE-EDM PV (25% vs 3%) than LS-MMRd EC. Clinicopathologic characteristics, including age at tumor onset and prognosis, did not differ among the various groups. Our study validates the use of paired tumor-normal next-generation sequencing to identify definitive sporadic causes in MMRd EC unrelated to MLH1-PHM. MMR immunohistochemistry and POLE-EDM mutation status can aid in the differentiation between LS-MMRd EC and DS-MMRd EC. These findings emphasize the need for integrating tumor sequencing into LS diagnostics, along with clear interpretation guidelines, to improve clinical management. Although not impacting prognosis, confirmation of DS-MMRd EC may release patients and relatives from burdensome LS surveillance.

ESGO-ESMO-ESP consensus conference recommendations on ovarian cancer: pathology and molecular biology and early, advanced and recurrent disease

The European Society of Gynaecological Oncology, the European Society for Medical Oncology (ESMO) and the European Society of Pathology held a consensus conference (CC) on ovarian cancer on 15-16 June 2022 in Valencia, Spain. The CC panel included 44 experts in the management of ovarian cancer and pathology, an ESMO scientific advisor and a methodologist. The aim was to discuss new or contentious topics and develop recommendations to improve and harmonise the management of patients with ovarian cancer. Eighteen questions were identified for discussion under four main topics: (i) pathology and molecular biology, (ii) early-stage disease and pelvic mass in pregnancy, (iii) advanced stage (including older/frail patients) and (iv) recurrent disease. The panel was divided into four working groups (WGs) to each address questions relating to one of the four topics outlined above, based on their expertise. Relevant scientific literature was reviewed in advance. Recommendations were developed by the WGs and then presented to the entire panel for further discussion and amendment before voting. This manuscript focuses on the recommendation statements that reached a consensus, their voting results and a summary of evidence supporting each recommendation.

[Current post-surgical treatment strategies in first-line ovarian cancer]

Although the management of epithelial ovarian cancer has evolved significantly over the past few years, it remains a public health issue, as most patients are diagnosed at an advanced stage and relapse after first line treatment. Chemotherapy remains the standard adjuvant treatment for International Federation of Gynecology and Obstetrics (FIGO) stage I and II tumors, with some exceptions. For FIGO stage III/IV tumors, carboplatin- and paclitaxel-based chemotherapy are the standard of care, in combination with targeted therapies, especially bevacizumab and/or poly-(ADP-ribose) polymerase inhibitors, that have become a key milestone of first-line treatment. Our decision making for the maintenance therapy is based on the FIGO stage, tumor histology, timing of surgery (i.e. primary or interval debulking surgery), residual tumor, response to chemotherapy, BRCA mutation and homologous recombination (HR) status.

Atezolizumab plus bevacizumab and chemotherapy for metastatic, persistent, or recurrent cervical cancer (BEATcc): a randomised, open-label, phase 3 trial

BACKGROUND

The GOG240 trial established bevacizumab with chemotherapy as standard first-line therapy for metastatic or recurrent cervical cancer. In the BEATcc trial (ENGOT-Cx10-GEICO 68-C-JGOG1084-GOG-3030), we aimed to evaluate the addition of an immune checkpoint inhibitor to this standard backbone.

METHODS

In this investigator-initiated, randomised, open-label, phase 3 trial, patients from 92 sites in Europe, Japan, and the USA with metastatic (stage IVB), persistent, or recurrent cervical cancer that was measurable, previously untreated, and not amenable to curative surgery or radiation were randomly assigned 1:1 to receive standard therapy (cisplatin 50 mg/m2 or carboplatin area under the curve of 5, paclitaxel 175 mg/m2, and bevacizumab 15 mg/kg, all on day 1 of every 3-week cycle) with or without atezolizumab 1200 mg. Treatment was continued until disease progression, unacceptable toxicity, patient withdrawal, or death. Stratification factors were previous concomitant chemoradiation (yes vs no), histology (squamous cell carcinoma vs adenocarcinoma including adenosquamous carcinoma), and platinum backbone (cisplatin vs carboplatin). Dual primary endpoints were investigator-assessed progression-free survival according to Response Evaluation Criteria in Solid Tumours version 1.1 and overall survival analysed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT03556839, and is ongoing.

FINDINGS

Between Oct 8, 2018, and Aug 20, 2021, 410 of 519 patients assessed for eligibility were enrolled. Median progression-free survival was 13·7 months (95% CI 12·3-16·6) with atezolizumab and 10·4 months (9·7-11·7) with standard therapy (hazard ratio [HR]=0·62 [95% CI 0·49-0·78]; p<0·0001); at the interim overall survival analysis, median overall survival was 32·1 months (95% CI 25·3-36·8) versus 22·8 months (20·3-28·0), respectively (HR 0·68 [95% CI 0·52-0·88]; p=0·0046). Grade 3 or worse adverse events occurred in 79% of patients in the experimental group and in 75% of patients in the standard group. Grade 1-2 diarrhoea, arthralgia, pyrexia, and rash were increased with atezolizumab.

INTERPRETATION

Adding atezolizumab to a standard bevacizumab plus platinum regimen for metastatic, persistent, or recurrent cervical cancer significantly improves progression-free and overall survival and should be considered as a new first-line therapy option.

FUNDING

F Hoffmann-La Roche.

Homologous recombination deficiency (HRD) testing on cell-free tumor DNA from peritoneal fluid

BACKGROUND

Knowing the homologous recombination deficiency (HRD) status in advanced epithelial ovarian cancer (EOC) is vital for patient management. HRD is determined by BRCA1/BRCA2 pathogenic variants or genomic instability. However, tumor DNA analysis is inconclusive in 15-19% of cases. Peritoneal fluid, available in > 95% of advanced EOC cases, could serve as an alternative source of cell-free tumor DNA (cftDNA) for HRD testing. Limited data show the feasibility of cancer panel gene testing on ascites cfDNA but no study, to date, has investigated HRD testing.

METHODS

We collected ascites/peritoneal washings from 53 EOC patients (19 from retrospective cohort and 34 from prospective cohort) and performed a Cancer Gene Panel (CGP) using NGS for TP53/HR genes and shallow Whole Genome Sequencing (sWGS) for genomic instability on cfDNA.

RESULTS

cfDNA was detectable in 49 out of 53 patients (92.5%), including those with limited peritoneal fluid. Median cfDNA was 3700 ng/ml, with a turnaround time of 21 days. TP53 pathogenic variants were detected in 86% (42/49) of patients, all with HGSOC. BRCA1 and BRCA2 pathogenic variants were found in 14% (7/49) and 10% (5/49) of cases, respectively. Peritoneal cftDNA showed high sensitivity (97%), specificity (83%), and concordance (95%) with tumor-based TP53 variant detection. NGS CGP on cftDNA identified BRCA2 pathogenic variants in one case where tumor-based testing failed. sWGS on cftDNA provided informative results even when tumor-based genomic instability testing failed.

CONCLUSION

Profiling cftDNA from peritoneal fluid is feasible, providing a significant amount of tumor DNA. This fast and reliable approach enables HRD testing, including BRCA1/2 mutations and genomic instability assessment. HRD testing on cfDNA from peritoneal fluid should be offered to all primary laparoscopy patients.

RAD51 as a biomarker for homologous recombination deficiency in high-grade serous ovarian carcinoma: robustness and interobserver variability of the RAD51 test

The RAD51 test is emerging as a promising biomarker for the assessment of functional homologous recombination deficiency (HRD). Yet, the robustness and reproducibility of the immunofluorescence-based RAD51 test, in different academic laboratories, have not been systematically investigated. Therefore, we tested the performance of the RAD51 assay in formalin-fixed paraffin-embedded (FFPE) high-grade serous ovarian carcinoma (HGSOC) samples in four European laboratories. Here, we confirm that subtle differences in staining procedures result in low variability of RAD51 and γH2AX scores. However, substantial variability in RAD51 scoring was observed in some samples, likely due to complicating technical and biological features, such as high RAD51 signal-to-noise ratio and RAD51 heterogeneity. These results support the need to identify and perform additional quality control steps and/or automating image analysis. Altogether, resolving technical issues should be a priority, as identifying tumours with functional HRD is urgently needed to guide the individual treatment of HGSOC patients. Follow-up studies are needed to define the key tissue quality requirements to assess HRD by RAD51 in FFPE tumour samples, as this test could help in guiding the individual treatment of HGSOC patients.

Circulating Tumor DNA from Ascites as an alternative to tumor sampling for genomic profiling in ovarian cancer patients

Genomic testing is crucial for the management of ovarian cancer. DNA from biopsies at diagnostic laparoscopies or interval debulking surgery after neoadjuvant chemotherapy, has a high failure rate. At relapse, biopsies may not be feasible. The aim of our study was to evaluate the feasibility and usefulness of measuring genomic instability score (GIS) on cell-free DNA (cfDNA) from ascites.Patients enrolled in a prospective study (NCT03010124) consented to analysis of biological samples. CfDNA was extracted from 1 to 4 ml of double-centrifuged fresh ascites. Targeted Next-generation sequencing (NGS) including TP53 mutation (TP53m) was performed on cfDNA to confirm the presence of tumor cfDNA. Single Nucleotide Polymorphism Array estimating somatic copy number alterations (SCNA) was performed to calculate GIS for Homologous-Recombination deficiency (HRD).Twenty nine ascites were collected from 20 patients with suspected or confirmed OC. 93% (27/29) samples had detectable cfDNA (median 1120 ng [24-5732]) even when obtained during chemotherapy. A deleterious mutation was identified in 100%, with high allelic frequencies (median 60% [3.3-87%]), confirming that cfDNA was tumoral. SCNA analyses on 17 patients showed 11 high GIS, and 6 low GIS. 4 patients with confirmed BRCA mutation had a high GIS on ascites. When available from the same patient, SCNA profiles on ascites and tumor were superimposable.Ascites is frequent at diagnosis and relapse and yields large amounts of tumoral cfDNA. SCNA analysis on ascitic cfDNA is feasible and can detect the same HRD scar as tumor testing. Ascites could provide an alternative to tumor sampling for HRD and BRCA testing.

Pooled Safety Analysis of Single-Agent Lurbinectedin in Patients With Advanced Solid Tumours

BACKGROUND

Lurbinectedin was approved by FDA and other health regulatory agencies for treating adults with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy. Safety profile at approved dose (3.2 mg/m2 every 3 weeks) was acceptable and manageable in 105 adult SCLC patients from a phase II basket trial. This study analyses safety data from several solid tumours treated at the lurbinectedin-approved dose.

METHODS

Data were pooled from 554 patients: 335 from all nine tumour-specific cohorts of the phase II basket trial and 219 from a randomised phase III trial (CORAIL) in platinum-resistant ovarian cancer. Events and laboratory abnormalities were graded using NCI-CTCAE v.4.

RESULTS

Most common tumours were ovarian (n = 219, 40%), SCLC (n = 105, 19%) and endometrial (n = 73, 13%). Transient haematological laboratory abnormalities were the most frequent grade 3 or more events: neutropenia (41%), leukopenia (30%), anaemia (17%) and thrombocytopenia (10%). Most common treatment-emergent non-haematological events (any grade) were transient transaminase increases (alanine aminotransferase [66%], aspartate aminotransferase [53%]), fatigue (63%), nausea (57%), constipation (32%), vomiting (30%) and decreased appetite (25%). Dose reductions were mostly due to haematological toxicities, but most patients (79%) remained on full lurbinectedin dose. Serious events mostly consisted of haematological disorders. Eighteen treatment discontinuations (3%) and seven deaths (1%) were due to treatment-related events.

CONCLUSIONS

This analysis confirms a manageable safety profile for lurbinectedin in patients with advanced solid tumours. Findings are consistent with those reported in patients with relapsed SCLC, Ewing sarcoma, germline BRCA1/2 metastatic breast cancer, neuroendocrine tumours and ovarian cancer.

Lurbinectedin in patients with pretreated endometrial cancer: results from a phase 2 basket clinical trial and exploratory translational study

Second-line treatment of endometrial cancer is an unmet medical need. Lurbinectedin showed promising antitumor activity in a phase I study in combination with doxorubicin in advanced endometrial cancer. This phase 2 Basket trial evaluated lurbinectedin 3.2 mg/m2 1-h intravenous infusion every 3 weeks in a cohort of 73 patients with pretreated endometrial cancer. The primary endpoint was overall response rate (ORR) according to RECIST v1.1. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS), safety and an exploratory translational study. Confirmed complete (CR) and partial response (PR) was reported in two and six patients, respectively (ORR = 11.3%; 95%CI, 5.0-21.0%). Median DoR was 9.2 months (95%CI, 3.4-18.0 months), median PFS was 2.6 months (95%CI, 1.4-4.0 months) and median OS was 9.3 months (95%CI, 6.1-12.8 months). Molecular subtypes showed differences in PFS rate at 6 months (p53abn 23.7% vs. "No Specific Molecular Profile" [NSMP] 42.9%) and median OS (p53abn 6.6 months vs. NSMP 16.1 months). The most common treatment-related adverse events (mostly grade 1/2) were fatigue (54.8% of patients), nausea (50.7%), vomiting (26.0%) decreased appetite (17.8%). and constipation, (19.2%). The most common grade 3/4 toxicity was neutropenia (43.8%; grade 4, 19.2%; febrile neutropenia, 4.1%). In conclusion, considering the exploratory aim of this trial and the hints of antitumor activity observed together with a predictable and manageable safety profile, further biomarker-based development of lurbinectedin is recommended in this indication in combination with other agents. Clinicaltrials.gov identifier: NCT02454972.

Clinical Relevance of BRCA1 Promoter Methylation Testing in Patients with Ovarian Cancer

PURPOSE

Homologous recombination deficiency (HRD) is closely related to PARP inhibitor (PARPi) benefit in ovarian cancer. The capacity of BRCA1 promoter methylation to predict prognosis and HRD status remains unclear. We aimed to correlate BRCA1 promoter methylation levels in patients with high-grade ovarian cancer to HRD status and clinical behavior to assess its clinical relevance.

EXPERIMENTAL DESIGN

This is a retrospective monocentric analysis of patients centrally tested for genomic instability score (GIS) by MyChoice CDx (Myriad Genetics). The detection of BRCA1 promoter methylation and quantification of methylation levels were performed by quantitative droplet digital PCR methodology. High BRCA1 methylation was defined as ≥70% and deemed to be associated with homozygous silencing.

RESULTS

Of 100 patients, 11% harbored a deleterious BRCA1/2 mutation. GIS was considered positive (score ≥ 42) for 52 patients and negative for 48 patients. Using a 70% cutoff, 19% (15/79) of BRCA wild-type ovarian cancer had high BRCA1 methylation levels. All of the highly methylated tumors were classified as HRD, achieving a positive predictive value of 100%. We detected 14% (11/79) low-methylated tumors (1%-69%), and all of them were also classified as HRD. Mean GIS was 61.5 for BRCAmut, 66.4 for high-BRCAmeth, 58.9 for low-BRCAmeth, and 33.3 for BRCAwt unmethylated (P < 0.001). Low methylation levels detected in samples previously exposed to chemotherapy appeared to be associated with poor outcome post-platinum.

CONCLUSIONS

Patients with ovarian cancer with high levels of BRCA1 hypermethylation are very likely to have high GIS and therefore represent good candidates for PARPi treatment. These results may be highly relevant to other tumor types for HRD prediction. See related commentary by Garg and Oza, p. 2957.

Combined Tumor-Based BRCA1/2 and TP53 Mutation Testing in Ovarian Cancer

Somatic/germline BRCA1/2 mutations (m)/(likely) pathogenic variants (PV) (s/gBRCAm) remain the best predictive biomarker for PARP inhibitor efficacy. As >95% of high-grade serous ovarian cancers (HGSOC) have a somatic TP53m, combined tumor-based BRCA1/2 (tBRCA) and TP53 mutation testing (tBRCA/TP53m) may improve the quality of results in somatic BRCAm identification and interpretation of the 'second hit' event, i.e., loss of heterozygosity (LOH). A total of 237 patients with HGSOC underwent tBRCA/TP53m testing. The ratio of allelic fractions (AFs) for tBRCA/TP53m was calculated to estimate the proportion of cells carrying BRCAm and to infer LOH. Among the 142/237 gBRCA results, 16.2% demonstrated a pathogenic/deleterious variant (DEL) gBRCA1/2m. Among the 195 contributive tumor samples, 43 DEL of tBRCAm (22.1%) were identified (23 gBRCAm and 20 sBRCAm) with LOH identified in 37/41 conclusive samples. The median AF of TP53m was 0.52 (0.01-0.93), confirming huge variability in tumor cellularity. Initially, three samples were considered as wild type with <10% cellularity. However, additional testing detected a very low AF (<0.05) in both BRCA1/2m and TP53m, thus reidentifying them as sBRCA1/2m. Combined tBRCA/TP53m testing is rapid, sensitive, and identifies somatic and germline BRCA1/2m. AF TP53m is essential for interpreting sBRCA1/2m in low-cellularity samples and provides indirect evidence for LOH as the 'second hit' of BRCA1/2-related tumorigenesis.

Recommandations pour la pratique clinique Nice/Saint-Paul-de-Vence 2022–2023 : prise en charge du cancer de l'endomètre localisé

Recommendations for clinical practice, Nice/Saint-Paul-de-Vence 2022-2023: Management of localized endometrial cancer Endometrial cancer is the most frequent gynecological cancers in industrialized countries and its incidence increases. The newmolecularclassification allows determination of the risk of recurrence and helps orienting therapeutic management. Surgery remains the cornerstone of treatment. Minimally invasive approach must be preferred for stages I and II. Surgery includes hysterectomy with bilateral adnexectomy, sentinel lymph node biopsy even in high risk diseases and omentectomy for non-endometrioid tumors (except in case of clear cells tumors). Fertility preservation can be proposed in low grade, stage I tumors without myometrial involvement. In stage III/IV disease, lymph node debulking without totallymphadenectomy is indicated. In case of peritoneal carcinomatosis, first-line cytoreductive surgery is recommended if complete resection can be achieved. Adjuvant therapy is not recommended in low risk tumors. In intermediate risk tumors, curietherapy is indicated. In tumors with high-intermediate risk, curietherapy and external radiotherapy are indicated according to prognostic factors (stage II, lymphovascular invasion); adjuvant chemotherapy can be considered on a case-by-case basis. In high risk tumors, chemotherapy and external radiotherapy are recommended using a concomitant or sequential approach.

Prise en charge des carcinomes ovariens de haut grade séreux et/ou endométrioïdes de stades avancés (III-IV) et testing HRD-BRCA en 2023 : actualisation selon les données publiées et/ou présentées en 2022

Management of high grade, serous and/or endometrioid, advanced (stages III-IV) ovarian carcinomas and HRD-BRCA testing in 2023: update according to data published/presented in 2022 Molecular analysis of ovarian carcinomas must be now systematically performed to determine BRCA1 and BRCA2 status as well as genomic instability score. Several types of tests are available. From a clinical perspective, new data from phase III clinical trials presented in 2022 confirm the key role of PARP inhibitors in first-line medical treatment of high-grade serous ovarian cancers. A new algorithm that includes all new evidence is proposed for selection of first-line therapy.

Olaparib plus bevacizumab first-line maintenance in ovarian cancer: final overall survival results from the PAOLA-1/ENGOT-ov25 trial

BACKGROUND

In the PAOLA-1/ENGOT-ov25 primary analysis, maintenance olaparib plus bevacizumab demonstrated a significant progression-free survival (PFS) benefit in newly diagnosed advanced ovarian cancer patients in clinical response after first-line platinum-based chemotherapy plus bevacizumab, irrespective of surgical status. Prespecified, exploratory analyses by molecular biomarker status showed substantial benefit in patients with a BRCA1/BRCA2 mutation (BRCAm) or homologous recombination deficiency (HRD; BRCAm and/or genomic instability). We report the prespecified final overall survival (OS) analysis, including analyses by HRD status.

PATIENTS AND METHODS

Patients were randomized 2:1 to olaparib (300 mg bid; up to 24 months) plus bevacizumab (15 mg/kg q3w; 15 months total) or placebo plus bevacizumab. Analysis of OS, a key secondary endpoint in hierarchical testing, was planned for ∼60% maturity or 3 years after the primary analysis.

RESULTS

After median follow-up of 61.7 and 61.9 months in the olaparib and placebo arms, respectively, median OS was 56.5 versus 51.6 months in the ITT (hazard ratio [HR]=0.92, 95% CI 0.76-1.12; P=0.4118). Subsequent poly(ADP-ribose) polymerase (PARP) inhibitor therapy was received by 105 (19.6%) olaparib patients versus 123 (45.7%) placebo patients. In the HRD-positive population, OS was longer with olaparib plus bevacizumab (HR=0.62, 95% CI 0.45-0.85; 5-year OS rate, 65.5% versus 48.4%); at 5 years, updated PFS also showed a higher proportion of olaparib plus bevacizumab patients without relapse (HR=0.41, 95% CI 0.32-0.54; 5-year PFS rate, 46.1% versus 19.2%). Myelodysplastic syndrome, acute myeloid leukemia, aplastic anemia, and new primary malignancy incidence remained low and balanced between arms.

CONCLUSIONS

Olaparib plus bevacizumab provided clinically meaningful OS improvement for first-line patients with HRD-positive ovarian cancer. These prespecified exploratory analyses demonstrated improvement despite a high proportion of patients in the placebo arm receiving PARP inhibitors post-progression, confirming the combination as one of the standards of care in this setting with the potential to enhance cure.

Abstract 5695: Deep learning risk prediction model of distant recurrence from H&E endometrial cancer slides

Accurate risk prediction of distant recurrence (DR) is crucial for personalized adjuvant systemic therapy of endometrial cancer (EC) stage I-III patients, as DR is associated with a 5-year overall survival of 10-20%. Risk stratification and treatment recommendation are currently based on histopathological and molecular markers, which is challenging due to high inter-observer variability and testing costs respectively. Deep Learning (DL) models can predict prognosis by identifying relevant visual features from H&E whole slide images (WSIs) at different resolutions without prior assumptions. Here, we developed and tested the first interpretable state-of-the-art DL model for WSI-based risk prediction of DR of stage I-III EC (DeREC) from the randomized PORTEC-1/-2/-3 trials and three clinical cohorts with long-term follow-up data. We used one representative H&E WSI each from 1761 EC patients, excluding those who received adjuvant chemotherapy as it lowers the risk of DR. We randomly sampled 20% as a held-out internal test set (N=353 with 62 events; 8.45 year median follow-up) and performed a 5-fold cross-validation on the training set (N=1408). WSIs were partitioned into 360 micron patches at 40x magnification. DeREC combined self-supervised representation learning of patches using a multi-resolution vision transformer and a WSI-level graph attention-based time-to-event prediction model. The model performance of correctly ranking patients by predicted risk scores and true time to DR was measured with the concordance-index and compared with a Cox’ Proportional Hazards (CPH) model fitted on histopathological variables (histotype, grade, lymphovascular space invasion, stage). Discriminative quality of the predicted risk groups was investigated with Kaplan-Meier analysis and the log-rank test. Most predictive patches by predicted risk groups were reviewed by an expert gynecopathologist for identification of prognostic morphological features. DeREC achieved a concordance-index of 0.764 [95%CI 0.754-0.773] on 5-fold cross validation and 0.757 on the test set, as compared to 0.704 [95%CI 0.662-0.746] with CPH. Predicted risk groups around quartiles 1 and 3 accurately stratified patients between low (N=89), intermediate (N=175), high (N=89) risk of DR (p&lt;0.0001). Among the predicted low-risk group only 3 (3.37%) patients relapsed whereas intermediate and high-risk groups counted 27 (15.43%) and 32 (35.96%) events respectively. DeREC is the first DL model accurately distinguishing EC patients at high risk of DR from those at low risk using one H&E WSI, which would aid decisions on adjuvant treatment. DeREC outperformed standard statistical prediction methods using histopathological variables, indicating that it identified prognostic visual features which can be further investigated. Future development includes the integration of clinicopathological and molecular information.

Citation Format: Sarah Fremond, Sonali Andani, Jurriaan Barkey Wolf, Gitte Ørtoft, Estrid Høgdall, Jouke Dijkstra, Jan J. Jobsen, Ina M. Jürgenliemk-Schulz, Ludy CHW Lutgens, Melanie E. Powell, Naveena Singh, Linda R. Mileshkin, Helen J. Mackay, Alexandra Leary, Dionyssios Katsaros, Hans W. Nijman, Stephanie M. de Boer, Remi A. Nout, Vincent T.H.B.M Smit, Carien L. Creutzberg, Nanda Horeweg, Viktor H. Koelzer, Tjalling Bosse. Deep learning risk prediction model of distant recurrence from H&E endometrial cancer slides. [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 5695.

A RAD51 functional assay as a candidate test for homologous recombination deficiency in ovarian cancer

RATIONALE

Homologous recombination deficiency (HRD), defined as BRCA1/2 mutation (BRCAmut) or high genomic instability, is used to identify ovarian cancer (OC) patients most likely to benefit from PARP inhibitors. While these tests are useful, they are imperfect. Another approach is to measure the capacity of tumor cells to form RAD51 foci in the presence of DNA damage using an immunofluorescence assay (IF). We aimed to describe for the first time this assay in OC and correlate it to platinum response and BRCAmut.

METHODS

Tumor samples were prospectively collected from the randomized CHIVA trial of neoadjuvant platinum +/- nintedanib. IF for RAD51, GMN and gH2AX was performed on FFPE blocks. Tumors were considered RAD51-low if ≤10% of GMN-positive tumor cells had ≥5 RAD51 foci. BRCAmut were identified by NGS.

RESULTS

155 samples were available. RAD51 assay was contributive for 92% of samples and NGS available for 77%. gH2AX foci confirmed the presence of significant basal DNA damage. 54% of samples were considered HRD by RAD51 and presented higher overall response rates to neoadjuvant platinum (P = 0.04) and longer progression-free survival (P = 0.02). In addition, 67% of BRCAmut were HRD by RAD51. Among BRCAmut, RAD51-high tumors seem to harbor poorer response to chemotherapy (P = 0.02).

CONCLUSIONS

We evaluated a functional assay of HR competency. OC demonstrate high levels of DNA damage, yet 54% fail to form RAD51 foci. These RAD51-low OC tend to be more sensitive to neoadjuvant platinum. The RAD51 assay also identified a subset of RAD51-high BRCAmut tumors with unexpected poor platinum response.

Direct prediction of Homologous Recombination Deficiency from routine histology in ten different tumor types with attention-based Multiple Instance Learning: a development and validation study

Background

Homologous Recombination Deficiency (HRD) is a pan-cancer predictive biomarker that identifies patients who benefit from therapy with PARP inhibitors (PARPi). However, testing for HRD is highly complex. Here, we investigated whether Deep Learning can predict HRD status solely based on routine Hematoxylin & Eosin (H&E) histology images in ten cancer types.

Methods

We developed a fully automated deep learning pipeline with attention-weighted multiple instance learning (attMIL) to predict HRD status from histology images. A combined genomic scar HRD score, which integrated loss of heterozygosity (LOH), telomeric allelic imbalance (TAI) and large-scale state transitions (LST) was calculated from whole genome sequencing data for n=4,565 patients from two independent cohorts. The primary statistical endpoint was the Area Under the Receiver Operating Characteristic curve (AUROC) for the prediction of genomic scar HRD with a clinically used cutoff value.

Results

We found that HRD status is predictable in tumors of the endometrium, pancreas and lung, reaching cross-validated AUROCs of 0.79, 0.58 and 0.66. Predictions generalized well to an external cohort with AUROCs of 0.93, 0.81 and 0.73 respectively. Additionally, an HRD classifier trained on breast cancer yielded an AUROC of 0.78 in internal validation and was able to predict HRD in endometrial, prostate and pancreatic cancer with AUROCs of 0.87, 0.84 and 0.67 indicating a shared HRD-like phenotype is across tumor entities.

Conclusion

In this study, we show that HRD is directly predictable from H&E slides using attMIL within and across ten different tumor types.

Interpretable deep learning model to predict the molecular classification of endometrial cancer from haematoxylin and eosin-stained whole-slide images: a combined analysis of the PORTEC randomised trials and clinical cohorts

BACKGROUND

Endometrial cancer can be molecularly classified into POLE^mut, mismatch repair deficient (MMRd), p53 abnormal (p53abn), and no specific molecular profile (NSMP) subgroups. We aimed to develop an interpretable deep learning pipeline for whole-slide-image-based prediction of the four molecular classes in endometrial cancer (im4MEC), to identify morpho-molecular correlates, and to refine prognostication.

METHODS

This combined analysis included diagnostic haematoxylin and eosin-stained slides and molecular and clinicopathological data from 2028 patients with intermediate-to-high-risk endometrial cancer from the PORTEC-1 (n=466), PORTEC-2 (n=375), and PORTEC-3 (n=393) randomised trials and the TransPORTEC pilot study (n=110), the Medisch Spectrum Twente cohort (n=242), a case series of patients with POLE^mut endometrial cancer in the Leiden Endometrial Cancer Repository (n=47), and The Cancer Genome Atlas-Uterine Corpus Endometrial Carcinoma cohort (n=395). PORTEC-3 was held out as an independent test set and a four-fold cross validation was performed. Performance was measured with the macro and class-wise area under the receiver operating characteristic curve (AUROC). Whole-slide images were segmented into tiles of 360 μm resized to 224 × 224 pixels. im4MEC was trained to learn tile-level morphological features with self-supervised learning and to molecularly classify whole-slide images with an attention mechanism. The top 20 tiles with the highest attention scores were reviewed to identify morpho-molecular correlates. Predictions of a nuclear classification deep learning model serve to derive interpretable morphological features. We analysed 5-year recurrence-free survival and explored prognostic refinement by molecular class using the Kaplan-Meier method.

FINDINGS

im4MEC attained macro-average AUROCs of 0·874 (95% CI 0·856-0·893) on four-fold cross-validation and 0·876 on the independent test set. The class-wise AUROCs were 0·849 for POLE^mut (n=51), 0·844 for MMRd (n=134), 0·883 for NSMP (n=120), and 0·928 for p53abn (n=88). POLE^mut and MMRd tiles had a high density of lymphocytes, p53abn tiles had strong nuclear atypia, and the morphology of POLE^mut and MMRd endometrial cancer overlapped. im4MEC highlighted a low tumour-to-stroma ratio as a potentially novel characteristic feature of the NSMP class. 5-year recurrence-free survival was significantly different between im4MEC predicted molecular classes in PORTEC-3 (log-rank p<0·0001). The ten patients with aggressive p53abn endometrial cancer that was predicted as MMRd showed inflammatory morphology and appeared to have a better prognosis than patients with correctly predicted p53abn endometrial cancer (p=0·30). The four patients with NSMP endometrial cancer that was predicted as p53abn showed higher nuclear atypia and appeared to have a worse prognosis than patients with correctly predicted NSMP (p=0·13). Patients with MMRd endometrial cancer predicted as POLE^mut had an excellent prognosis, as do those with true POLE^mut endometrial cancer.

INTERPRETATION

We present the first interpretable deep learning model, im4MEC, for haematoxylin and eosin-based prediction of molecular endometrial cancer classification. im4MEC robustly identified morpho-molecular correlates and could enable further prognostic refinement of patients with endometrial cancer.

FUNDING

The Hanarth Foundation, the Promedica Foundation, and the Swiss Federal Institutes of Technology.

Response to first line platinum-based chemotherapy in mismatch repair deficient (MMRd)/ microsatellite instability high (MSI-high) endometrial carcinoma

BACKGROUND

Around 15% of metastatic endometrial carcinoma (EC) are MMRd/MSI-H improving response to immune checkpoint inhibitors (ICI). So far, few data existed considering the chemotherapy (CT) sensitivity in MMRd/MSI-H EC, especially response to first-line platinum-based treatment.

PATIENTS AND METHODS

We performed a multicentric retrospective analysis reporting the response to first line platinum CT in MMRd/MSI-H EC patients. The primary endpoints were objective response rate (ORR) and progression-free survival (PFS) with first line platinum-based CT.

RESULTS

A total of 112 patients MMRd/MSI-H EC from 8 centers were identified. Median overall survival was 58.0 months (95% CI: 45.3-95.1). Among them, 78 patients received first line platinum CT in recurrent/metastatic setting. With a median follow up of 32.6 months (min: 0.03; max: 135.0), ORR and DCR (disease control rate) were 50% (95% CI: 38.5-61.5) and 68% (95% CI: 56.4-78.1), respectively. Median PFS and OS from first line platinum-based CT was 7.8 months (95% CI: 6.0-9.0) and 51.9 months (95% CI: 28.0-NE), respectively. Median PFS with ICI in second line (n = 48) was 10.7 months (95% CI: 3.4-NE) from ICI initiation.

CONCLUSION

ORR in first line metastatic MMRd/MSI-H EC is consistent with efficacy in an all comer metastatic EC population.

Overall Survival With Maintenance Olaparib at a 7-Year Follow-Up in Patients With Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation: The SOLO1/GOG 3004 Trial

PURPOSE

In SOLO1/GOG 3004 (ClinicalTrials.gov identifier: NCT01844986), maintenance therapy with the poly(ADP-ribose) polymerase inhibitor olaparib provided a sustained progression-free survival benefit in patients with newly diagnosed advanced ovarian cancer and a BRCA1 and/or BRCA2 (BRCA) mutation. We report overall survival (OS) after a 7-year follow-up, a clinically relevant time point and the longest follow-up for any poly(ADP-ribose) polymerase inhibitor in the first-line setting.

METHODS

This double-blind phase III trial randomly assigned patients with newly diagnosed advanced ovarian cancer and a BRCA mutation in clinical response to platinum-based chemotherapy to maintenance olaparib (n = 260) or placebo (n = 131) for up to 2 years. A prespecified descriptive analysis of OS, a secondary end point, was conducted after a 7-year follow-up.

RESULTS

The median duration of treatment was 24.6 months with olaparib and 13.9 months with placebo, and the median follow-up was 88.9 and 87.4 months, respectively. The hazard ratio for OS was 0.55 (95% CI, 0.40 to 0.76; P = .0004 [P < .0001 required to declare statistical significance]). At 7 years, 67.0% of olaparib patients versus 46.5% of placebo patients were alive, and 45.3% versus 20.6%, respectively, were alive and had not received a first subsequent treatment (Kaplan-Meier estimates). The incidence of myelodysplastic syndrome and acute myeloid leukemia remained low, and new primary malignancies remained balanced between treatment groups.

CONCLUSION

Results indicate a clinically meaningful, albeit not statistically significant according to prespecified criteria, improvement in OS with maintenance olaparib in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation and support the use of maintenance olaparib to achieve long-term remission in this setting; the potential for cure may also be enhanced. No new safety signals were observed during long-term follow-up.

Clinical and molecular characteristics of ARIEL3 patients who derived exceptional benefit from rucaparib maintenance treatment for high-grade ovarian carcinoma

OBJECTIVE

ARIEL3 (NCT01968213) is a placebo-controlled randomized trial of the poly(ADP-ribose) polymerase inhibitor rucaparib as maintenance treatment in patients with recurrent high-grade ovarian carcinoma who responded to their latest line of platinum therapy. Rucaparib improved progression-free survival across all predefined subgroups. Here, we present an exploratory analysis of clinical and molecular characteristics associated with exceptional benefit from rucaparib.

METHODS

Patients were randomized 2:1 to receive rucaparib 600 mg twice daily or placebo. Molecular features (genomic alterations, BRCA1 promoter methylation) and baseline clinical characteristics were evaluated for association with exceptional benefit (progression-free survival ≥2 years) versus progression on first scan (short-term subgroup) and other efficacy outcomes.

RESULTS

Rucaparib treatment was significantly associated with exceptional benefit compared with placebo: 79/375 (21.1%) vs 4/189 (2.1%), respectively (p < 0.0001). Exceptional benefit was more frequent among patients with favorable baseline clinical characteristics and with carcinomas harboring molecular evidence of homologous recombination deficiency (HRD). A comparison between patients who derived exceptional benefit from rucaparib and those in the short-term subgroup revealed both clinical markers (no measurable disease at baseline, complete response to latest platinum, longer penultimate platinum-free interval) and molecular markers (BRCA1, BRCA2, RAD51C, and RAD51D alterations and genome-wide loss of heterozygosity) significantly associated with exceptional benefit.

CONCLUSIONS

Exceptional benefit in ARIEL3 was more common in, but not exclusive to, patients with favorable clinical characteristics or molecular features associated with HRD. Our results suggest that rucaparib can deliver exceptional benefit to a diverse set of patients with recurrent high-grade ovarian carcinoma.

Therapy-related Myeloid Neoplasms Following PARP Inhibitors: Real-life Experience

PURPOSE

To provide insights into the diagnosis and management of therapy-related myeloid neoplasms (t-MN) following PARP inhibitors (PARPi).

EXPERIMENTAL DESIGN

In a French cancer center, we identified and described the profiles of 13 t-MN diagnosed among 37 patients with ovarian cancer referred to hematology consultation for cytopenia under PARPi. Next, we described these 13 t-MN post-PARPi among 37 t-MN post ovarian cancer according to PARPi exposure. Finally, we described 69 t-MN post-PARPi in a national cohort.

RESULTS

From 2016 to 2021, cumulative incidence of t-MN was 3.5% (13/373) among patients with ovarian cancer treated with PARPi. At time of hematologic consultation, patients with t-MN had a longer PARPi exposure (9 vs. 3 months, P = 0.01), lower platelet count (74 vs. 173 G/L, P = 0.0005), and more cytopenias (2 vs. 1, P = 0.0005). Compared with t-MN not exposed to PARPi, patients with t-MN-PARPi had more BRCA1/2 germline mutation (61.5% vs. 0%, P = 0.03) but similar overall survival (OS). In the national cohort, most t-MN post-PARPi had a complex karyotype (61%) associated with a high rate of TP53 mutation (71%). Median OS was 9.6 months (interquartile range, 4-14.6). In multivariate analysis, a longer time between end of PARPi and t-MN (HR, 1.046; P = 0.02), olaparib compared with other PARPi (HR, 5.82; P = 0.003) and acute myeloid leukemia (HR, 2.485; P = 0.01) were associated with shorter OS.

CONCLUSIONS

In a large series, we described a high incidence of t-MN post-PARPi associated with unfavorable cytogenetic and molecular abnormalities leading to poor OS. Early detection is crucial, particularly in cases of delayed cytopenia.

Comparison of global treatment guidelines for locally advanced cervical cancer to optimize best care practices: A systematic and scoping review

BACKGROUND

Survival outcomes for cervical cancer differ between countries and world regions. Locally advanced cervical cancer (LACC) is associated with poorer outcomes than early-stage disease. Country-specific variations in diagnostic and treatment recommendations might contribute to differences in LACC outcomes among countries.

OBJECTIVE

We compared international and country-specific guidelines for LACC diagnostic imaging and treatment recommendations.

METHODS

A systematic literature review and targeted search were used to identify cervical cancer treatment guidelines published between January 1999-August 2021. Guidelines were identified via literature databases, health technology assessment databases, disease-specific websites, and health organization websites. The targeted search included guidelines from countries in regions known to have high cervical cancer prevalence or mortality. Non-English guidelines were translated by native speakers or online translation services.

RESULTS

Forty-six guidelines from 31 countries, regions, and international organizations were compared (41/46 using staging criteria, 27 of which used 2009 FIGO). Most guidelines recommended imaging tests for diagnosis and staging. Chest X-ray, intravenous pyelogram, CT, and MRI were commonly recommended for diagnosis and staging while MRI and PET-CT were recommended for the assessment of lymph node status and distant metastases, with a preference for PET-CT over MRI. There was global consensus for cisplatin-based concurrent chemoradiation as primary treatment for stages IIB to IVA, with few exceptions. Treatment recommendations for stages IB2 to IIA2 varied. Most guidelines agreed on adjuvant concurrent chemoradiation after radical hysterectomy when there is a high recurrence risk, and adjuvant radiotherapy when there is an intermediate recurrence risk. Recommendations for other adjuvant and neoadjuvant therapies varied among the guidelines.

CONCLUSIONS

Differences among treatment guidelines by LACC stage might be influenced by staging criteria used, resource availability, and prevention program effectiveness. Addressing these areas may unify guidelines and improve global outcomes. Review and update of guidelines will be important as novel LACC therapies become available.

p53 immunohistochemistry in endometrial cancer: clinical and molecular correlates in the PORTEC-3 trial

Standard molecular classification of endometrial cancers (EC) is now endorsed by the WHO and identifies p53-abnormal (p53abn) EC as the subgroup with the poorest prognosis and the most likely to benefit from adjuvant chemo(radio)therapy. P53abn EC are POLE wildtype, mismatch repair proficient and show abnormal immunohistochemical (IHC) staining for p53. Correct interpretation of routinely performed p53 IHC has therefore become of paramount importance. We aimed to comprehensively investigate abnormal p53 IHC patterns and their relation to clinicopathological and molecular features. Tumor material of 411 molecularly classified high-risk EC from consenting patients from the PORTEC-3 clinical trial were collected. p53 IHC was successful in 408 EC and was considered abnormal when the tumor showed a mutant expression pattern (including subclonal): overexpression, null or cytoplasmic. The presence of pathogenic mutations was determined by next generation sequencing (NGS). Abnormal p53 expression was observed in 131/408 (32%) tumors. The most common abnormal p53 IHC pattern was overexpression (n = 89, 68%), followed by null (n = 12, 9%) and cytoplasmic (n = 3, 2%). Subclonal abnormal p53 staining was observed in 27 cases (21%), which was frequently but not exclusively, associated with POLE mutations and/or MMRd (n = 22/27; p < 0.001). Agreement between p53 IHC and TP53 NGS was observed in 90.7%, resulting in a sensitivity and specificity of 83.6% and 94.3%, respectively. Excluding POLEmut and MMRd EC, as per the WHO-endorsed algorithm, increased the accuracy to 94.5% with sensitivity and specificity of 95.0% and 94.1%, respectively. Our data shows that awareness of the abnormal p53 IHC patterns are prerequisites for correct EC molecular classification. Subclonal abnormal p53 expression is a strong indicator for POLEmut and/or MMRd EC. No significant differences in clinical outcomes were observed among the abnormal p53 IHC patterns. Our data support use of the WHO-endorsed algorithm and combining the different abnormal p53 IHC patterns into one diagnostic entity (p53abn EC).

Overcoming resistance to αPD-1 of MMR-deficient tumors with high tumor-induced neutrophils levels by combination of αCTLA-4 and αPD-1 blockers

BACKGROUND

Clinical studies have highlighted the efficacy of anti-programmed death 1 (αPD-1) monoclonal antibodies in patients with DNA mismatch repair-deficient (MMRD) tumors. However, the responsiveness of MMRD cancers to αPD-1 therapy is highly heterogeneous, and the origins of this variability remain not fully understood.

METHODS

4T1 and CT26 mouse tumor cell lines were inactivated for the MMRD gene Msh2, leading to a massive accumulation of mutations after serial passages of cells. Insertions/deletion events and mutation load were evaluated by whole exome sequencing. Mice bearing highly mutated MMRD tumor or parental tumors were treated with αPD-1 and tumor volume was monitored. Immune cell type abundance was dynamically assessed in the tumor microenvironment and the blood by flow cytometry. Neutrophils were depleted in mice using αLY6G antibody, and regulatory T (Treg) cell population was reduced with αCD25 or anti-cytotoxic T-lymphocytes-associated protein 4 (αCTLA-4) antibodies. Patients with MMRD tumors treated with immune checkpoint blockade-based therapy were retrospectively identified and neutrophil-to-lymphocyte ratio (NLR) was evaluated and examined for correlation with clinical benefit.

RESULTS

By recapitulating mismatch repair deficiency in different mouse tumor models, we revealed that elevated circulating tumor-induced neutrophils (TIN) in hypermutated MMRD tumors hampered response to αPD-1 monotherapy. Importantly, depletion of TIN using αLy-6G antibody reduced Treg cells and restored αPD-1 response. Conversely, targeting Treg cells by αCD25 or αCTLA-4 antibodies limited peripheral TIN accumulation and elicited response in αPD-1-resistant MMRD tumors, highlighting a crosstalk between TIN and Treg cells. Thus, αPD-1+αCTLA-4 combination overcomes TIN-induced resistance to αPD-1 in mice bearing MMRD tumors. Finally, in a cohort of human (high microsatellite instability)/MMRD tumors we revealed that early on-treatment change in the NLR ratio may predict resistance to αPD-1 therapy.

CONCLUSIONS

TIN countered αPD-1 efficacy in MMRD tumors. Since αCTLA-4 could restrict TIN accumulation, αPD-1+αCTLA-4 combination overcomes αPD-1 resistance in hosts with hypermutated MMRD tumors displaying abnormal neutrophil accumulation.

Abstract CT022: CheckMate 848: A randomized, open-label, phase 2 study of nivolumab in combination with ipilimumab or nivolumab monotherapy in patients with advanced or metastatic solid tumors of high tumor mutational burden

High tumor mutational burden assessed in tissue biopsies (tTMB-H) or blood (bTMB-H) is associated with clinical efficacy in patients treated with immunotherapies. CheckMate 848 (NCT03668119) is a prospective phase 2 study of nivolumab (NIVO) with or without ipilimumab (IPI) in patients with advanced or metastatic solid tumors that are tTMB-H or bTMB-H (≥ 10 mutations/megabase) who were immunotherapy-naive and refractory to standard local therapies.

The primary endpoint was objective response rate (ORR) in patients with tTMB-H or bTMB-H, assessed by FoundationOne® CDx-based and Clinical Trial Assays (Foundation Medicine), respectively. The study was not powered to compare NIVO + IPI vs NIVO. We present the interim and final analyses for the tTMB-H and bTMB-H cohorts, respectively (≥ 12 months follow-up, database lock June 2021).

Of 1954 screened patients, 212 were randomized 2:1 to NIVO 240 mg Q2W + IPI 1 mg/kg Q6W or NIVO 480 mg Q4W for ≤ 24 months, and 201 (135 tTMB-H; 147 bTMB-H) were refractory to standard therapies. Of &gt; 40 tumor types, colorectal (10.8%), small-cell lung (7.5%), breast (7.1%), and uterine (7.1%) were the most common. ORR and survival outcomes with NIVO + IPI were improved in patients with tTMB-H. The responses were independent of bTMB-H status in the tTMB-H cohort but improved with tTMB-H status in the bTMB-H cohort (Table). The safety profile of NIVO + IPI was manageable, and clinical outcomes with NIVO were comparable with previous studies. The impact of TMB cutoff, PD-L1 expression, and microsatellite instability were explored.

In conclusion, NIVO + IPI demonstrated clinical efficacy with a manageable safety profile in patients with advanced or metastatic solid tumors that are tTMB-H or bTMB-H and refractory to standard therapies, with increased efficacy observed in patients with tTMB-H.

NIVO + IPI tTMB-H cohort bTMB-H cohorta Patients, n (%)b,c 68 (32.1) 80 (37.7) Number of prior treatments, median (range) 2 (0–7) 2 (1–9) ORR, n (%)c, 95% CI 24 (35.3), 24.1–47.8 18 (22.5), 13.9–33.2 ORR in patients with bTMB-H by tTMBc: &lt; 10 mut/Mb (n = 31), n (%), 95% CI NA 3 (9.7), 2.0–25.8 ≥ 10 mut/Mb (n = 39), n (%), 95% CI NA 13 (33.3), 19.1–50.2 ≥ 10 to &lt; 16 mut/Mb (n = 18), n (%), 95% CI NA 3 (16.7), 3.6–41.4 ≥ 16 mut/Mb (n = 21), n (%), 95% CI NA 10 (47.6), 25.7–70.2 ORR in patients with tTMB-H by bTMBc: &lt; 10 mut/Mb (n = 20), n (%), 95% CI 7 (35.0), 15.4–59.2 NA ≥ 10 mut/Mb (n = 43), n (%), 95% CI 16 (37.2), 23.0–53.3 NA ≥ 10 to &lt; 16 mut/Mb (n = 12), n (%), 95% CI 3 (25.0), 5.5–57.2 NA ≥ 16 mut/Mb (n = 31), n (%), 95% CI 13 (41.9), 24.5–60.9 NA Percentage of responders (≥ 9 months) (95% CI) 91 (68–98) 88 (61–97) Median PFS, months (95% CI)c 4.1 (2.8–11.3) 2.8 (2.3–3.0) Median OS, months (95% CI)c 14.5 (7.7–NE) 8.5 (5.8–10.5) aThe bTMB cohort was randomized prior to December 20, 2019. bOut of 212 randomized patients; data presented in this table are from patients who were refractory to standard therapies. cMinimum follow-up 12 months. bTMB, blood tumor mutational burden; NA, not applicable; NE, not evaluable; PFS, progression-free survival; OS, overall survival; tTMB, tissue tumor mutational burden.

Citation Format: Michael Schenker, Mauricio Burotto, Martin Richardet, Tudor Ciuleanu, Anthony Goncalves, Neeltje Steeghs, Patrick Schöffski, Paolo A. Ascierto, Michele Maio, Iwona Lugowska, Lorena Lupinacci, Alexandra Leary, Jean-Pierre Delord, Julieta Grasselli, David S. Tan, Jennifer E. Friedmann, Jacqueline Vuky, Marina Tschaika, Ruta Slepetis, Georgia D. Kollia, Misena Pacius, Ning Huang, Parul Doshi, Jonathan Baden, Massimo Di Nicola. CheckMate 848: A randomized, open-label, phase 2 study of nivolumab in combination with ipilimumab or nivolumab monotherapy in patients with advanced or metastatic solid tumors of high tumor mutational burden [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT022.

Abstract CT005: Safety and efficacy of olaparib combined to metronomic cyclophosphamide and metformin in recurrent advanced/metastatic endometrial cancer patients: ENDOLA trial

Objectives: In patients with recurrent advanced endometrial carcinomas (EC), innovative treatments are needed after platinum chemotherapy. EC are characterized by frequent defective DNA repair, along with alterations of PI3K-AKT-mTor, and IGF1R pathways. In preclinical studies, the activity of PARP inhibitor is increased by the inhibition of PI3K-AKT pathway. Metformin inhibits the PI3K-AKT-mTor signaling pathway, and reduces IGF1 circulating levels. Metronomic cyclophosphamide may increase the activity of PARP inhibitors through DNA alkylating and anti-angiogenic effects. ENDOLA trial was meant to assess the safety and efficacy of the triplet olaparib (PARP 1-3 inhibitor) + metronomic cyclophosphamide + metformin in patients with advanced EC

Methods: ENDOLA trial (NCT02755844) was an academic French prospective multicenter phase I/II open-label dose-escalation study meant to assess the safety, the Recommended Phase II trial Dose (RP2D), and the efficacy of olaparib combined to metronomic cyclophosphamide 50 mg PO QD and metformin 500 mg PO TID in patients with recurrent advanced EC. In the phase I part, olaparib was dose-escalated from PO 150 mg to 300 mg BID with a continual reassessment method (CRM), aiming at defining the RP2D. In the phase II part, the cohort was expanded to assess the efficacy of the triplet in terms of non-progression rate at 10 weeks (H0= 20%; H1= 50%; 1-sided α risk=0.01; power = 90%).

Results: From Sept 2016 to Nov 2019, 35 patients enrolled, and 31 were assessable (median age: 69, IQR: 62-72; endometrioid: n=18 (51.4%); serous: n=11 (35.5%); carcinosarcoma: n=2 (6.5%)). In the phase I part (17 patients), 1 DLT (5.9%) was observed: grade 3 fatigue during cycle 1 at 150 mg. Dose-escalation was possible up to 300 mg BID, that was the RP2D. In the phase II part (14 patients), the overall response rate was 20.8%, and the disease-control rate was 66.6 %. The non-progression rate at 10 weeks was 61.5% (95% CI 42.8-80.2). The median PFS was 5.1 months, including 7.5 months (5.1-8.9) for endometrioid, and 4.3 months (2.7-5.8) for serous carcinomas. Treatment-related serious adverse-events (AEs) occurred in 3 patients (grade 3 fatigue; grade 4 lymphopenia; grade 4 lymphopenia & neutropenia). The most frequent grade 3-4 treatment-related AEs were lymphopenia (32.3%); anemia (16.1%); neutropenia (16.1%); and fatigue (12.9%).

Conclusions: In heavily pre-treated patients with advanced EC, olaparib 300 mg BID could be safely combined to metformin 1500 mg/day and metronomic cyclophosphamide 50 mg/day. With a 61.5% non-progression rate at 10 weeks, the 1st-objective was reached. The 5.1 month median PFS (7.5 for endometrioid and 4.3 for serous) is promising compared to those observed with chemotherapy or immunotherapy-based combination in KEYNOTE-775 (Colombo et al. Proc ESMO 2021). Investigation in phase III is warranted.

Citation Format: Benoit You, Alexandra Leary, Manuel Rodrigues, Philippe Follana, Cyril Abdeddaim, Florence Joly, Sylvie Bin, Laurent Villeneuve, Marine Alexandre, Florent Boutitie, Delphine Maucort-Boulch, Verane Schwiertz, Gilles Freyer. Safety and efficacy of olaparib combined to metronomic cyclophosphamide and metformin in recurrent advanced/metastatic endometrial cancer patients: ENDOLA trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT005.

Phase Ib INEOV neoadjuvant trial of durvalumab +/- tremelimumab with platinum chemotherapy for patients (pts) with unresectable ovarian cancer (OC): Final complete resection and pathological response rates

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Background: We have shown that neoadjuvant carboplatin and paclitaxel (NACP) increased tumor infiltrating lymphocytes and PDL1 expression in OC pts. INEOV evaluated NACP with durvalumab (D) +/- tremelimumab (T) in pts with unresectable OC. We previously reported that NACP with D+/-T was feasible and safe but the addition of T did not improve interval debulking surgery (IDS) rates after 3 cycles (C3) (ESMO 2021). Here we provide an update with longer follow up including data on delayed IDS performed after 6 cycles of neoadjuvant treatment. Key secondary endpoints include complete resection (CC0) and complete pathological response rates. Methods: Pts with stage IIIC/IV OC were randomized to NACP + D (1125mg) alone (arm A) or with T (75mg once at C2) (arm B). Interval debulking surgery (IDS) was planned after C3, or delayed after C6. Pts in arm A not operable after C3 crossed over to arm B, pts in arm B crossed over to standard of care (SOC). Pts were assessed for delayed IDS after C6. Complete pathological response (pCR) was defined as no residual tumor cells found on any surgical specimens, or no residual tumor cells on any samples outside the ovary at IDS. Results: Sixty four (N = 64) of 66 pts (IIIC/IV: 70%/30%) randomized were evaluable. After C3, 66% (21/32) of pts in arm A and 59% (19/32) in arm B had IDS. The 11 pts in arm A not candidate for IDS after C3 crossed over to arm B until C6 and 5/11 benefited from delayed IDS. The 13 pts in arm B inoperable at C3 went on to receive SOC (NACP +/- bevacizumab), and 5/13 became eligible for delayed IDS after C6. Overall, IDS was performed in 50 of 64 evaluable pts, and most (45/50) achieved macroscopically complete resection (CC0), so that the overall CC0 rate was 70% (45/64), with no significant difference between arms (CC0 = 75% vs 65% in arm A vs B). Among the 50 pts who had IDS, complete pathological responses were observed in 18% of pts. Conclusions: Taking into account the whole treatment strategy including delayed IDS after 6 cycles of neoadjuvant treatment, we have shown that neoadjuvant CP with D+/- T results in encouraging CC0 (70%) and pCR (18%) rates. However there was no apparent benefit to the addition of T to D. Studies are ongoing to describe the immune features predictive of pCR as well as the impact of treatment on the immune microenvironment. Clinical trial information: NCT03249142.

Efficacy and safety of rucaparib maintenance treatment in patients from ARIEL3 with platinum-sensitive, recurrent ovarian carcinoma not associated with homologous recombination deficiency

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Background: In ARIEL3 (NCT01968213), rucaparib maintenance treatment led to significant improvement vs placebo for the primary endpoint of investigator-assessed progression-free survival (PFS) in patients (pts) with platinum-sensitive, recurrent ovarian carcinoma responsive to the last line of platinum therapy (Coleman et al. Lancet. 2017;390:1949–61). The largest benefit was observed in pts with carcinomas with a BRCA mutation or high loss of heterozygosity (LOH), a marker of homologous recombination deficiency (HRD). However, rucaparib also improved PFS in pts with carcinomas negative by HRD test (ie, BRCA wild-type with low LOH), a subset of pts for which there is no identified molecular mechanism conferring PARP inhibitor sensitivity. Among these pts (rucaparib, n = 107; placebo, n = 54), median PFS was 6.7 vs 5.4 months, respectively (HR, 0.58 [95% CI 0.40–0.85]; P= 0.0049), and 31.8% vs 4.3% were progression-free at 1 yr. In this post hoc exploratory analysis, we further evaluated the efficacy of rucaparib maintenance vs placebo in this subset of pts. Methods: Pts were randomized 2:1 to oral rucaparib (600 mg BID) or placebo. For this analysis, investigator-assessed PFS and safety were evaluated in pts with HRD-negative carcinoma, defined as BRCA wild-type with genomic LOH < 16% using Foundation Medicine’s T5 NGS assay. Results: Visit cutoff dates for efficacy and safety were Apr 15, 2017, and Dec 31, 2019. Across subgroups based on demographic or disease characteristics, the trend of rucaparib benefit vs placebo was consistently observed in pts with HRD-negative carcinoma (Table). The safety profile of rucaparib in the HRD-negative population was consistent with that of the overall safety population reported previously. Conclusions: Rucaparib maintenance reduced risk of progression in pts with ovarian carcinomas, including those not associated with HRD, regardless of clinical prognostic factors. [Table: see text]

TEDOVA/GINECO-OV244b/ENGOT-ov58 trial: Neo-epitope based vaccine OSE2101 alone or in combination with pembrolizumab versus best supportive care (BSC) as maintenance in platinum-sensitive recurrent ovarian cancer with disease control after platinum

TPS5614

Background: Besides PARP inhibitors and bevacizumab, there are no approved maintenance therapies after platinum based chemotherapy for patients with a platinum sensitive relapsed epithelial ovarian cancer (OC). Immune checkpoint inhibitors (ICI) as single agents have limited activity in OC. One attractive strategy is to turn OC from immunogenic “cold” to “hot” tumors via vaccination with tumor-associated antigens (TAAs). OSE2101 is a multiple-neoepitope vaccine restricted to HLA-A2-positive patients (45% of OC patients) targeting 5 TAAs: TP53, MAGE2, MAGE3, CEA and HER2. These neo-epitopes are modified to increase both major histocompatibility complex and the T cell receptor binding affinity. The proof of concept for this approach was recently demonstrated with OSE2101 improving overall survival in a phase III trial in lung cancer progressing after ICI (Besse et al. 2021). The combination of OSE2101 with an ICI may most effectively harness anti-tumor immunity. Methods: TEDOVA is an international randomized open-label, phase II trial evaluating the benefit of maintenance by OSE2101 alone or in combination with PD1 inhibition (pembrolizumab) after platinum based chemotherapy in relapsed OC, previously treated with bevacizumab (if eligible) and a PARP inhibitor (if eligible). Patients (N=180) with CR/PR/SD at the end of chemotherapy are randomized (1:1:2) to: Observation/BSC (Arm A), OSE2101 alone (Arm B), or OSE2101 in combination with pembrolizumab (Arm C). Experimental treatments are continued until progression, or intolerance, for up to 2 years. The primary endpoint is progression-free survival (PFS). Secondary endpoints include overall response rate, safety, time to subsequent first or second treatment (TTST-1, TTST-2) and overall survival. 180 HLA-A*02 positive patients will be randomized. HLA-A*02 negative patients will be followed in a separate observational cohort. The sample size is calculated to provide 90% power to detect an improvement in PFS for Arm C vs Arm A with a HR of 0.57. Three one-sided Log-rank tests will be considered in a pre-defined sequence: H1: C (OSE2101+pembrolizumab) vs A (BSC); H2: C (OSE2101+pembrolizumab) vs B (OSE2101) and H3: B vs A. The type I error will be α=5%. The type II error will be β=10%. Tests will be one-sided. Status: The TEDOVA/GINECO-OV244b/ENGOT-ov58 trial is currently recruiting. Clinical trial information: NCT04713514.

Therapy related myeloid neoplasms (t-MNs) following PARP inhibitors (PARPi): Real-life experience

7057

Background: PARPi have shown promising results in several cancers, especially breast (BC) and ovarian cancer (OC), but may be associated with an increased risk of t-MNs. A careful monitoring of hematologic toxicity to exclude this risk is necessary. Here we described, in a real-life setting, the management of these adverse effect. Methods: First,we described, in a large cancer center, the profile of t-MN patients among OC patients treated with PARPi addressed in hematological consultation for cytopenias. Secondly, we compared t-MN post OC characteristics according to previous exposition to PARPi. Lastly, we described a large national observatory of 69 t-MNs post PARPi to decipher specific characteristics of these t-MNs. Results: From 2016 to 2021, among 373 PARPi treated patients for OC, 37 (10%) were explored for cytopenia’s leading to 13 (3,5%) t-MNs diagnosis. No differences were seen in terms of age, BRCA1/2 status, type of PARPi, hemoglobin level but patients with t-MNs developed delayed cytopenias post-PARPi initiation (11 months vs to 4 months, p = 0.01), had a longer PARPi exposition (9 months vs 3 months, p = 0.01), lower platelets level (74 G/L vs 173 G/L, p = 0.0005), more cytopenias (2 vs 1, p = 0.0005). 77% of t-MNs patients had a TP53 mutated t-MNs, 33% of patients w/o t-MNs had TP53 mutated clonal hematopoiesis. In the last 20 years, 37 patients were addressed for t-MN post OC at our institute, with an increased incidence of 50% during the last 6 years. Compared to t-MN not exposed to PARPi, t-MN-PARPi patients had more BRCA1/2 predisposition (61.5% vs 0% p = 0.03), their OC tended to be non-progressive (CR/PR/SD = 62.5% vs 38.5%, p = 0.3) and tend to have more TP53 mutated t-MNs (77% vs 47%, p = 0.1). Median OS for t-MNs post PARPi was poor at 8.2 months (CI95% [2.03-18.7]) but not significantly different form other t-MNs (p = 0.8). We then studied 69 t-MNs-PARPi including 28 AML and 41 MDS in patient with history of OC (75%), BC (9%) or both (16%). Median age was 64 years, 80% received Olaparib, 72.5% had a BRCA1/2 predisposition. Median time between cancer diagnosis and initiation of PARPi was 44 months and median duration of PARPi treatment was 14 months. History of haematological toxicity secondary to PARPi was reported in 51% of patients. Karyotype was often complex (61%) associated with a high rate of TP53 mutation (70.5%). Median OS was 9.7 months (CI95%, 5.3-13.9). In multivariate analysis, a longer delay between the end of PARPi treatment and t-NM diagnosis (HR 1.046, p = 0.02), as well Olaparib treatment compared to others PARPi (HR 5.82, p = 0.003 and AML diagnosis (HR 2.485, p = 0.01) were associated with shorter OS. Conclusions: We describe in a large series a higher incidence of t-MNs post PARPi than previously reported. Unfavorable cytogenetic and molecular abnormalities associated with these t-MNS explained the poor OS. Early detection is crucial particularly in case of delayed appearance of cytopenias.

Immune tumor microenvironnement (iTME) post-neoadjuvant chemotherapy, beyond PD-L1: Novel immune targets in ovarian cancer, data from the CHIVA trial, a GINECO/GINEGEPS study

5554

Background: Antibodies targeting PDL1 or PD1 have been disappointing so far in the treatment of ovarian cancer (OC). A greater understanding of the complex iTME and of the impact of chemotherapy on immune features could uncover promising immune targets. We previously reported that neoadjuvant chemotherapy (NACT) increased CD4+ and CD8+ immune cells (IC) and depleted FOXP3+ suppressive T-regs in OC iTME. Here we aimed to describe the expression of PDL1 as well as other co-regulatory molecules in OC and their changes under NACT. Methods: Tumor samples and clinical data were prospectively collected from patients (pts) in the randomized CHIVA trial of NACT +/- nintedanib. Samples were evaluable for immune profiling for 116-124 pts at diagnosis and 89-107 at surgery after 3 cycles of NACT. IC stained for CD4, CD8 were scored as number of IC+/mm². Expression of immune co-regulatory molecules PDL1, TIM3, LAG3 and IDO was scored as percentage of positive cells, and tumors were classified as PDL1/TIM3/IDO/LAG3 positive if > 1% of IC and/or tumor cells (TC) were positive. Highly sensitive pts, defined as objective response to NACT and prolonged median progression-free survival (mPFS > 24months), were compared to refractory pts (progressing during or within 3mo of platinum). Results: As expected, about one third (36%) of tumors were PDL1+ at diagnosis. In contrast, the prevalence of other co-regulatory molecules was higher with 52%, 54% and 93% of tumors being positive for IDO, LAG3 and TIM3, respectively. There was no significant change in PDL1 expression with NACT. However, in paired samples NACT significantly increased IDO and LAG3 expression (p < 0.05), such that 60% and 66% of tumors post-NACT were positive for IDO and LAG3, respectively. TIM3 expression remained high post-NACT with 92% of positive tumors. Highly sensitive tumors (vs refractory tumors) had significantly higher IC expression of TIM3 after NACT (24% vs 6%, p = 0.005), and were significantly more infiltrated by CD4+ (441 vs 228 cells/mm2, p = 0.04) and CD8+ (460 vs 225 cells/mm2, p = 0.045) T cells. Conclusions: Other immune targets beyond PDL1 are highly expressed in OC. In addition NACT appears to prime the iTME by increasing effector T cell infiltration and the expression of other relevant co-regulatory molecules (LAG3, TIM3 and IDO). Future studies could be performed by priming the iTME with NACT and testing novel immune therapies based on target expression in samples obtained at interval debulking surgery.

PemBOv trial: Pembrolizumab plus bevacizumab with or without pegylated liposomal doxorubicin-based chemotherapy in patients with platinum-resistant ovarian cancer

5575

Background: Few platinum resistant ovarian cancer (PROvC) patients respond to anti-PD1 monotherapy (ORR 7.6%) with little impact on survival (OS 10.1 mo). Among responders the median duration of response is impressive (18.7 mo) (Hamanishi 2021). Methods: We have evaluated the combination of pembrolizumab (200mg), with bevacizumab (400mg) for 6 cycles plus minus peglyated liposomal doxorubicin (PLD) q3w in PROvC patients with no limit in previous treatment lines, allowed to be previously treated with bevacizumab. An initial safety run evaluated the dual combination of pembrolizumab plus PLD (cohort A). The triple combination was evaluated at MTD-1 and at MTD of PLD (30mg/m2 q3w) (cohort C). The dual combination of pembrolizumab + bevacizumab was run in parallel (cohort B). This is an open label phase I trial with a modified toxicity probability interval design. The evaluation criteria endpoints were safety and efficacy. Pharmacokinetics of bevacizumab were evaluated. NCT03596281 Results: A total of 47 patients (pts) were enrolled between January 2019 and February 2021. Median age was 70 years (38-77). 30/12 pts (63.8/25.5%) had an initial FIGO stage III/IV, 44 pts (93.6%) had a HGSOC. 40 pts (85.1%) underwent surgery, out of which 13 pts (32.5%) had a primary debulking. BRCA mutations were present in 9 pts (19.1%). Pts had a median of 3 previous treatment lines (0-13), including pretreatment with antiangiogenic agents in 36 (76.6%) and PARP inhibitors in 21 pts (44.7%). No DLT was reported. Grade 3/4 treatment-related adverse events were reported in 2 pts (30%), 4 (20%) and 11 (50%) in cohorts A, B and C respectively. The ORR was 0, 26.3 (95% CI 6.5-46.1) and 30% (9.9-50.1) with a DCR of 0, 78.9 and 75% in cohorts A, B and C respectively. According to investigator assessment, the median PFS was 2.1, 4.7 and 4.8 mo (table). The blinded independent central review is currently under evaluation. A large inter-patient variability in bevacizumab plasma concentrations was observed among patients. The 400 mg flat dosing achieved residual concentrations similar to that of 5 mg/kg Q2W or 7.5 mg/kg q3w (51± 30 μg/ml in cohort B and 63 ± 55 μg/ml in cohort C (p>0.05) after C1). Overall, 22 % of pts of cohort B and 18 % of cohort C showed trough levels below the targeted threshold (i.e. < 25 μg/ml). Correlative studies are ongoing. Conclusions: Short-term flat dose bevacizumab potentiates the response to anti-PD1 therapy even in the absence of chemotherapy in heavily pre-treated PROvC patients. The long-term treatment with bevacizumab could potentially improve the outcome. The combination of anti-PD-1 plus anti-angiogenic agents should be a backbone for the treatment of PROvC patients. Clinical trial information: NCT03596281. [Table: see text]

Endometrioid Borderline Ovarian Tumor: Clinical Characteristics, Prognosis, and Managements

BACKGROUND

Endometrioid borderline ovarian tumor (EBOT) is a rare subtype of borderline ovarian malignancies. This study was designed to determine the prognosis of a series of EBOT.

METHODS

This is a retrospective review of patients with EBOT treated in or referred to our institutions and a centralized, histological review by a reference pathologist. Data on the clinical characteristics, management (surgical and medical), and oncologic outcomes of patients were required for inclusion.

RESULTS

Forty-eight patients were identified. Median age was 52 years (range 14-89). Fourteen patients underwent a conservative surgery and 32 a bilateral salpingo-oophorectomy (unknown in 2 cases). Two patients had bilateral tumors. Forty-three patients had stage I disease, and five patients had stage II disease (10%). Stromal microinvasion and intraepithelial carcinoma was observed in 6 (12%) and 13 (27%) patients respectively. Endometriosis was histologically associated in 12 patients (25%). Synchronous endometrial disease was found in 7 (24%) of 29 patients with endometrial histological evaluation. The median follow-up was 72 months (range 6-146). Two patients developed a recurrence after cystectomy in form of borderline disease (5%). No death related to EBOT occurred.

CONCLUSIONS

Peritoneal restaging surgery should be performed if not realized initially, because 5% of EBOTS are diagnosed at stage II-III. Fertility-sparing surgery seems a safe option in selected patients. Because synchronous endometrial diseases, including endometrial carcinoma are frequent, systematic hysterectomy (or endometrial sampling in case of fertility-sparing surgery) is mandatory. Prognosis is generally excellent. Recurrence is a rare event (6%), but it can occur in the form of invasive disease.