Véronique D’Hondt

PTPN13 Participates in the Regulation of Epithelial–Mesenchymal Transition and Platinum Sensitivity in High-Grade Serous Ovarian Carcinoma Cells

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological cancers in Western countries. High-Grade Serous Ovarian Carcinoma (HGSOC) accounts for 60–70% of EOC and is the most aggressive subtype. Reduced PTPN13 expression levels have been previously correlated with worse prognosis in HGSOC. However, PTPN13’s exact role and mechanism of action in these tumors remained to be investigated. To elucidate PTPN13’s role in HGSOC aggressiveness, we used isogenic PTPN13-overexpressing clones of the OVCAR-8 cell line, which poorly expresses PTPN13, and also PTPN13 CRISPR/Cas9-mediated knockout/knockdown clones of the KURAMOCHI cell line, which strongly expresses PTPN13. We investigated their migratory and invasive capacity using a wound healing assay, their mesenchymal-epithelial transition (EMT) status using microscopy and RT-qPCR, and their sensitivity to chemotherapeutic drugs used for HGSOC. We found that (i) PTPN13 knockout/knockdown increased migration and invasion in KURAMOCHI cells that also displayed a more mesenchymal phenotype and increased expression of the SLUG, SNAIL, ZEB-1, and ZEB-2 EMT master genes; and (ii) PTPN13 expression increased the platinum sensitivity of HGSOC cells. These results suggest that PTPN13 might be a predictive marker of response to platinum salts in HGSOC.

Differential Sensitivity of Germline and Somatic BRCA Variants to PARP Inhibitor in High-Grade Serous Ovarian Cancer

Purpose: The introduction of PARP inhibitors (PARPis) as a treatment option for patients with high-grade serous ovarian cancer (HGSOC) modified the approach of BRCA testing worldwide. In this study, we aim to evaluate the impact of BRCA1 and BRCA2 variants on treatment response and survival outcomes in patients diagnosed in our institution. Methods: A total of 805 HGSOC samples underwent BRCA1 and BRCA2 variant detection by using next-generation sequencing (NGS). Among them, a pathogenic alteration was detected in 104 specimens. Clinicopathological features and germline status were recovered, and alteration types were further characterized. The clinical significance of variant type in terms of response to chemotherapy and to PARPis as well as overall survival were evaluated using univariate analysis. Results: In our cohort, 13.2% of the HGSOC samples harbored a pathogenic BRCA1 or BRCA2 variant, among which 58.7% were inherited. No difference was observed between germline and somatic variants in terms of the gene altered. Interestingly, patients with somatic variants only (no germline) demonstrated better outcomes under PARPi treatment compared to those with germline ones. Conclusion: The determination of the inheritance or acquisition of BRCA1 and BRCA2 alterations could provide valuable information for improving management strategies and predicting the outcome of patients with HGSOC.

Efficacy and Safety of Avutometinib ± Defactinib in Recurrent Low-Grade Serous Ovarian Cancer: Primary Analysis of ENGOT-OV60/GOG-3052/RAMP 201

PURPOSE This study evaluated the efficacy and safety of avutometinib (rapidly accelerated fibrosarcoma/mitogen-activated extracellular signal-regulated kinase [MEK] clamp) alone or in combination with defactinib (focal adhesion kinase inhibitor) in patients with recurrent low-grade serous ovarian cancer (LGSOC). METHODS In this phase II, open-label study, patients with recurrent, measurable LGSOC after ≥1 line of platinum chemotherapy were stratified by tumor Kirsten rat sarcoma virus homolog ( KRAS ) mutation status and randomly assigned to oral avutometinib 4.0 mg two times per week monotherapy or avutometinib 3.2 mg two times per week in combination with oral defactinib 200 mg two times per day. The combination was selected as the go-forward regimen for expansion. The primary end point was objective response rate (ORR) by blinded independent central review. RESULTS A total of 115 patients received the go-forward combination regimen. Patients had a median of 3 (range, 1-9) prior lines of therapy, including hormonal (86%), bevacizumab (51%), and MEK inhibitor (22%). Confirmed ORR was 31% (95% CI, 23% to 41%) with a median duration of response of 31.1 months (95% CI, 14.8 to 31.1). ORR was 44% in KRAS- mutant and 17% in KRAS wild-type cohorts. The median progression-free survival was 12.9 months (95% CI, 10.9 to 20.2) overall and 22.0 months (95% CI, 11.1 to 36.6) and 12.8 months (95% CI, 7.4 to 18.4) in KRAS- mutant and wild-type cohorts, respectively. The most frequent grade ≥3 treatment-related adverse events (AEs) were elevated creatine phosphokinase (24%), diarrhea (8%), and anemia (5%). Ten percent of patients discontinued because of AEs. CONCLUSION The efficacy and safety profile of avutometinib in combination with defactinib support this combination as a potential standard of care for recurrent LGSOC. A randomized phase 3 study of avutometinib and defactinib versus investigator's choice of therapy for women with recurrent LGSOC is currently enrolling (RAMP301; ClinicalTrials.gov identifier: NCT06072781 ).

ctDNA for Prognostication and Monitoring in Patients with Metastatic Endometrial Carcinoma Treated with Olaparib: Validation in the GINECO-UTOLA Trial

Abstract Purpose: ctDNA may offer a noninvasive means to evaluate tumor response and anticipate disease dynamics before radiologic changes in advanced endometrial carcinoma. Experimental Design: This ancillary analysis included patients from the multicenter, randomized, phase II GINECO-UTerin OLAparib (UTOLA) trial (NCT03745950) evaluating olaparib/placebo as maintenance after first-line platinum-based chemotherapy. Plasma samples were collected at screening after chemotherapy (baseline), 3 months (M3), and progression. ctDNA detection was assessed by a validated methylation-based Droplet Digital PCR (MethddPCR) assay targeting DNA positions universally methylated in endometrial carcinoma. Results: Among 130 evaluable patients, ctDNA was detected in 25 of 129 (19%, 1 technical fail) at baseline, 15 of 80 (19%) at M3, and 33 of 52 (63%) at progression. Baseline ctDNA positivity was independently associated with poorer progression-free survival (PFS) [median 1.81 vs. 7.39 months; adjusted HR = 5.33 (3.17–8.97)] and overall survival (OS) [10.3 vs. 24.7 months; adjusted HR = 3.98 (2.28–6.91); adjusted for age, stage IV at diagnosis, p53abn subgroup, and residual measurable lesions after chemotherapy]. Patients with baseline ctDNA had median OS of 9.36 months under olaparib versus 19.6 months under placebo (log-rank P = 0.05). Patients with increasing ctDNA at M3 had median PFS of 1.67 months, versus 9.64 months without, and median OS of 18.8 versus 25.8 months. ctDNA rising was predictive of poor postprogression OS under olaparib but not under placebo (interaction test, P < 0.001). Conclusions: MethddPCR-ctDNA is an independent prognostic biomarker for OS in advanced/metastatic endometrial carcinoma. MethddPCR-ctDNA may identify patients unlikely to benefit from PARP inhibition, guide therapeutic decisions, and should be further evaluated as a new stratification parameter in future endometrial carcinoma trials.

A Study of Avutometinib (VS-6766) + Defactinib (VS-6063) in Recurrent Low-Grade Serous Ovarian Cancer

This study will assess the safety and efficacy of avutometinib (VS-6766) in combination with defactinib versus Investigator's choice of treatments (ICT) in subjects with recurrent LGSOC who have progressed on a prior platinum-based therapy.

A Study of Avutometinib (VS-6766) v. Avutometinib (VS-6766) + Defactinib in Recurrent Low-Grade Serous Ovarian Cancer With and Without a KRAS Mutation

This study will assess the safety and efficacy of avutometinib (VS-6766) monotherapy and in combination with defactinib in subjects with recurrent Low-Grade Serous Ovarian Cancer (LGSOC)