Platinum-resistant Ovarian Cancer Research Articles

A phase III randomized, double-blinded, placebo-controlled study of suvemcitug combined with chemotherapy for platinum-resistant ovarian cancer (SCORES).

LBA5516 Background: Suvemcitug is a new-generation recombinant humanized anti-VEGF rabbit monoclonal antibody. In the previous P1b study, Suvemcitug demonstrated its favorable safety profile and efficacy signals when combo with chemotherapy in platinum-resistant ovarian cancer (PROC). SCORES is the first randomized, double-blind, placebo-controlled phase III clinical trial to confirm the efficacy of Suvemcitug combo with chemo in PROC, whether or not previously received antiangiogenic agents or PARP inhibitors. Methods: Eligible patients had progressed during platinum-based therapy or within 6 months after ≥4 cycles of platinum-based therapy with at least one measurable lesion. After the investigators chose chemotherapy (CT) (weekly paclitaxel 80 mg/ m2 d1, 8, 15 & 22 q4w, pegylated liposomal doxorubicin 40 mg/m2 d1 q4w or topotecan 4 mg/m2 d1, 8 & 15 q4w), patients were randomly assigned (2:1) to either Suvemcitug (1.5 mg/kg q2w) or placebo combine with CT until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS) by blinded independent review committee (BIRC) according to the RECIST 1.1. Key secondary end point is the overall survival (OS). Results: A total of 421 patients were enrolled between June 2021 and June 2023 in China. As the data cut off of the primary efficacy analysis (8 December 2023), 197 PFS events (70.1%) in Suvemcitug arm and 111 PFS events (79.3%) in placebo arm had occurred with the median follow-up of 14.36 and 14.26 months, respectively. The median PFS by BIRC was 5.49 months in Suvemcitug arm versus 2.73 months in placebo arm (hazard ratio[HR] 0.46, p<0.0001). OS data are immature. 42.7% and 50.7% of patients are deceased in Suvemcitug arm or placebo arm respectively, and there is a trend of OS benefit trend: median OS 16.07 months vs. 14.88 months, HR 0.79, p=0.1244. Efficacy results are summarized below. Treatment-emergent adverse events (TRAEs) occurred in all patients in Suvemcitug arm, with the most common being neutrophil count decreased, white blood cell count decreased and platelet count decreased. No Suvemcitug-related grade 5 TEAE occurred. Conclusions: To the best of our knowledge, this is the first double-blinded phase III study demonstrated promising antitumor activity of anti-angiogenic agent in patients with PROC. The improvement in PFS, ORR and DCR gained by adding Suvemcitug to single-agent CT was observed with no new safety concern. Clinical trial information: NCT04908787 . [Table: see text]

The efficacy, safety, and beneficiary population of angiogenesis inhibitor apatinib plus chemotherapy in recurrent platinum-resistant ovarian cancer patients: A comparative cohort study.

Angiogenesis inhibitor apatinib targets vascular endothelial growth factor receptors and improves the outcomes of patients with gynecologic malignancy. This study aimed to evaluate the efficacy and safety of angiogenesis inhibitor apatinib plus chemotherapy in recurrent platinum-resistant ovarian cancer (RPR-OC) patients. This study retrieved 67 RPR-OC patients who received apatinib plus chemotherapy or chemotherapy alone and divided them into apatinib + chemo (N = 30) and chemo alone (N = 37) groups according to the actual medication. Objective response rate (36.7% vs. 16.2%, p = 0.056) and disease control rate (80.0% vs. 59.5%, p = 0.072) showed an increased trend in apatinib + chemo group versus chemo alone group. The progression-free survival (PFS) (p = 0.010) and overall survival (OS) (p = 0.042) were prolonged in apatinib + chemo group versus chemo alone group. The median (95%confidence interval [CI]) PFS was 5.9 (5.5-6.3) months in apatinib + chemo group and 3.8 (2.0-5.6) months in chemo alone group. The median (95%CI) OS was 20.5 (16.5-24.5) months in apatinib + chemo group and 13.6 (8.6-18.6) months in chemo alone group. Apatinib plus chemotherapy was independently related with better PFS (hazard ratio [HR]: 0.354, p < 0.001) and OS (HR: 0.116, p < 0.001). Subgroup analyses indicated that patients with a more serious disease condition might benefit more from apatinib plus chemotherapy. No difference was found in adverse events of all grade or grade ≥3 between the two groups (all p > 0.05). Angiogenesis inhibitor apatinib plus chemotherapy shows better treatment efficacy than chemotherapy alone with controllable safety profile in RPR-OC patients.

Comparison of target agent treatment strategies for platinum-resistant recurrent ovarian cancer: A Bayesian network meta-analysis.

We aimed to compare 7 newer immunotherapies and targeted therapies for platinum-resistant relapsed ovarian cancer. We conducted a comprehensive search of PubMed, EMBASE, and Cochrane Library electronic databases for phase III trials involving platinum-resistant recurrent ovarian cancer (PRrOC) patients treated with immunotherapy or targeted therapy in combination with chemotherapy. The quality of the included trials was assessed using the GRADE method. The primary outcome of comparison was progression-free survival, and secondary outcomes included overall survival and safety. This analysis included 7 randomized phase III controlled trials, encompassing 2485 PRrOC patients. Combining bevacizumab plus chemotherapy and lurbinectedin demonstrated statistically significant differences in progression-free survival compared to all other regimens of interest. However, no statistically significant differences were observed in the overall survival. Nivolumab and mirvetuximab exhibited fewer serious adverse events than the other regimens of interest. Our findings indicate that bevacizumab combined with chemotherapy and lurbinectedin monotherapy has significant efficacy in patients with PRrOC. For patients with PRrOC who have exhausted treatment options, nivolumab and mirvetuximab may be considered as alternatives because of their better safety profiles.

Mirvetuximab soravtansine: A breakthrough in targeted therapy for platinum-resistant ovarian cancer.

Ovarian cancer, ranked as the second leading cause of gynecologic malignancy-related deaths globally, poses a formidable challenge despite advances in early detection and treatment modalities. This paper explores the efficacy and safety of mirvetuximab soravtansine, the first folate receptor alpha (FRα)-targeting antibody-drug conjugate, in platinum-resistant ovarian cancer expressing FRα. A review of 4 key studies involving 453 participants consistently demonstrates mirvetuximab soravtansine's clinically meaningful antitumor activity and favorable safety profile. Clinical implications emphasize mirvetuximab soravtansine's pivotal role in targeted therapy, especially for high FRα-expressing tumors, potentially reshaping platinum-resistant ovarian cancer management. The combination therapy approach introduces a novel dimension, suggesting enhanced therapeutic outcomes. Even in heavily pretreated patients, mirvetuximab soravtansine's favorable tolerability positions it as a viable option. The reliability of archival tissue for FRα assessment simplifies patient selection, streamlining accessibility to targeted therapies. However, identified gaps, including limited diversity in patient populations, sparse quality of life data, and the need for long-term safety information, indicate areas for future research. Exploration of additional biomarkers predicting mirvetuximab soravtansine responsiveness is essential for personalized treatment.

FT-Raman and FTIR spectroscopy as a tools showing marker of platinum-resistant phenomena in women suffering from ovarian cancer

Platinum-resistant phenomena in ovarian cancer is very dangerous for women suffering from this disease, because reduces the chances of complete recovery. Unfortunately, until now there are no methods to verify whether a woman with ovarian cancer is platinum-resistant. Importantly, histopathology images also were not shown differences in the ovarian cancer between platinum-resistant and platinum-sensitive tissues. Therefore, in this study, Fourier Transform InfraRed (FTIR) and FT-Raman spectroscopy techniques were used to find chemical differences between platinum-resistant and platinum-sensitive ovarian cancer tissues. Furthermore, Principal Component Analysis (PCA) and machine learning methods were performed to show if it possible to differentiate these two kind of tissues as well as to propose spectroscopy marker of platinum-resistant. Indeed, obtained results showed, that in platinum-resistant ovarian cancer tissues higher amount of phospholipids, proteins and lipids were visible, however when the ratio between intensities of peaks at 1637 cm−1 (FTIR) and at 2944 cm−1 (Raman) and every peaks in spectra was calculated, difference between groups of samples were not noticed. Moreover, structural changes visible as a shift of peaks were noticed for C–O–C, C–H bending and amide II bonds. PCA clearly showed, that PC1 can be used to differentiate platinum-resistant and platinum-sensitive ovarian cancer tissues, while two-trace two-dimensional correlation spectra (2T2D-COS) showed, that only in amide II, amide I and asymmetric CH lipids vibrations correlation between two analyzed types of tissues were noticed. Finally, machine learning algorithms showed, that values of accuracy, sensitivity and specificity were near to 100% for FTIR and around 95% for FT-Raman spectroscopy. Using decision tree peaks at 1777 cm−1, 2974 cm−1 (FTIR) and 1714 cm−1, 2817 cm−1 (FT-Raman) were proposed as spectroscopy marker of platinum-resistant.

Once daily cediranib and weekly paclitaxel to prevent malignant bowel obstruction in at-risk patients with platinum-resistant ovarian cancer (CEBOC): a single-arm, phase II safety trial

ObjectiveCytotoxic chemotherapy for ovarian cancer can be augmented by co-administration of vascular endothelial growth factor inhibitors but these are contraindicated in patients with bowel obstruction due to the risk of...

Development of a Prognostic Risk Model Based on Oxidative StressRelated Genes for Platinum-Resistant Ovarian Cancer Patients.

Ovarian Cancer (OC) is a heterogeneous malignancy with poor outcomes. Oxidative stress plays a crucial role in developing drug resistance. However, the relationships between Oxidative Stress-related Genes (OSRGs) and the prognosis of platinum-resistant OC remain unclear. This study aimed to develop an OSRGs-based prognostic risk model for platinum-resistant OC patients. Gene Set Enrichment Analysis (GSEA) was performed to determine the expression difference of OSRGs between platinum-resistant and -sensitive OC patients. Cox regression analyses were used to identify the prognostic OSRGs and establish a risk score model. The model was validated by using an external dataset. Machine learning was used to determine the prognostic OSRGs associated with platinum resistance. Finally, the biological functions of selected OSRG were determined via in vitro cellular experiments. Three gene sets associated with oxidative stress-related pathways were enriched (p < 0.05), and 105 OSRGs were found to be differentially expressed between platinum-resistant and - sensitive OC (p < 0.05). Twenty prognosis-associated OSRGs were identified (HR: 0:562-5.437; 95% CI: 0.319-20.148; p < 0.005), and seven independent OSRGs were used to construct a prognostic risk score model, which accurately predicted the survival of OC patients (1-, 3-, and 5-year AUC=0.69, 0.75, and 0.67, respectively). The prognostic potential of this model was confirmed in the validation cohort. Machine learning showed five prognostic OSRGs (SPHK1, PXDNL, C1QA, WRN, and SETX) to be strongly correlated with platinum resistance in OC patients. Cellular experiments showed that WRN significantly promoted the malignancy and platinum resistance of OC cells. The OSRGs-based risk score model can efficiently predict the prognosis and platinum resistance of OC patients. This model may improve the risk stratification of OC patients in the clinic.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial.

To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC). Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples. Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)-deficient, and 17.1% were HR repair (HRR)-mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy. Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

Gene expression markers in peripheral blood and outcome in patients with platinum-resistant ovarian cancer: A study of the European GANNET53 consortium.

Disease progression is a major problem in ovarian cancer. There are very few treatment options for patients with platinum-resistant ovarian cancer (PROC), and therefore, these patients have a particularly poor prognosis. The aim of the present study was to identify markers for monitoring the response of 123 PROC patients enrolled in the Phase I/II GANNET53 clinical trial, which evaluated the efficacy of Ganetespib in combination with standard chemotherapy versus standard chemotherapy alone. In total, 474 blood samples were collected, comprising baseline samples taken before the first administration of the study drugs and serial samples taken during treatment until further disease progression (PD). After microfluidic enrichment, 27 gene transcripts were analyzed using quantitative polymerase chain reaction and their utility for disease monitoring was evaluated. At baseline, ERCC1 was associated with an increased risk of PD (hazard ratio [HR] 1.75, 95% confidence interval [CI]: 1.20-2.55; p = 0.005), while baseline CDH1 and ESR1 may have a risk-reducing effect (CDH1 HR 0.66, 95% CI: 0.46-0.96; p = 0.024; ESR1 HR 0.58, 95% CI: 0.39-0.86; p = 0.002). ERCC1 was observed significantly more often (72.7% vs. 53.9%; p = 0.032) and ESR1 significantly less frequently (59.1% vs. 78.3%; p = 0.018) in blood samples taken at radiologically confirmed PD than at controlled disease. At any time during treatment, ERCC1-presence and ESR1-absence were associated with short PFS and with higher odds of PD within 6 months (odds ratio 12.77, 95% CI: 4.08-39.97; p < 0.001). Our study demonstrates the clinical relevance of ESR1 and ERCC1 and may encourage the analysis of liquid biopsy samples for the management of PROC patients.

Phase 1b study of batiraxcept in combination with durvalumab in patients with platinum-resistant ovarian cancer

Combining an immune checkpoint inhibitor with batiraxcept (AVB-S6-500), an AXL inhibitor that acts via selective binding to growth arrest-specific protein 6 (GAS6), may improve anti-tumor immunity in platinum-resistant ovarian cancer (PROC). This phase 1b trial of durvalumab in combination with escalating doses of batiraxcept enrolled patients with recurrent PROC (NCT04019288). The primary objective was to determine the toxicity profile of the combination. Eleven patients were enrolled on the trial. No dose-limiting toxicities were observed, and no objective responses were noted. Median progression free survival (PFS) was 1.81months (95% confidence interval (CI) 1.71-2.40), and median overall survival (OS) was 4.53months (95% CI 2.10-24.74). Batiraxcept effectively reduced serum GAS6 levels at 1-h post-treatment, resulting in trough levels below the limit of detection in all cases but one. In conclusion, the combination of batiraxcept and durvalumab was safe and tolerable but did not demonstrate anti-tumor activity in a heterogenous population of patients with recurrent PROC.

Biomarker-driven targeted therapy in patients with recurrent platinum-resistant epithelial ovarian cancer (BRIGHT): protocol for an open-label, multicenter, umbrella study.

Platinum-resistant, recurrent ovarian cancer has an abysmal prognosis with limited treatment options. Poly-(ADP-ribose)-polymerase (PARP), angiogenesis, and immune checkpoint inhibitors might improve the outcomes of platinum-resistant, recurrent ovarian cancer, but accurate patient selections for those therapies remain a significant clinical challenge. To evaluate the efficacy and safety of biomarker-driven combinatorial therapies of pamiparib, tislelizumab, bevacizumab, and nab-paclitaxel in platinum-resistant, recurrent ovarian cancer. A precision medicine combination of PARP inhibitors, anti-angiogenic therapy, immunotherapy, and chemotherapy will improve disease outcomes of platinum-resistant, recurrent ovarian cancer by accounting for genomic and immunologic features. The BRIGHT Trial is a prospective, open-label, multicenter, phase II, umbrella study planning to enroll 160 patients with serous, endometrioid, or clear cell platinum-resistant, recurrent ovarian cancer from 11 clinical centers in China. Patients are assigned to one of three experimental arms based on biomarkers. Patients with BRCA1/2 mutations will receive pamiparib plus bevacizumab (arm 1, n=40) regardless of CD8+ tumor-infiltrating lymphocytes count. Patients with wild-type BRCA1/2 (BRCAwt) and ≥3 CD8+ tumor-infiltrating lymphocytes count will receive the combination of tislelizumab, bevacizumab, and nab-paclitaxel (arm 2, n=50), while BRCAwt patients with <3 CD8+ tumor-infiltrating lymphocytes count will receive bevacizumab plus dose-dense nab-paclitaxel (arm 3, n=50). After completing patient enrollment in arm 2, another 20 BRCAwt patients with ≥3 CD8+ tumor-infiltrating lymphocytes count will be included as an arm 2 expansion. Treatment will continue until disease progression or intolerable toxicity, and all adverse events will be recorded. Eligible patients include those aged ≥18 with serous, endometrioid, or clear cell ovarian cancer, platinum-resistant recurrence, and Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Objective response rate (ORR) assessed by the investigators by the RECIST 1.1 criteria. 160 patients. Recruitment is estimated to be completed by 2024 and results may be published by 2027. ClinicalTrials.gov: NCT05044871.

Phase 1a dose escalation study of ivonescimab (AK112/SMT112), an anti-PD-1/VEGF-A bispecific antibody, in patients with advanced solid tumors

BackgroundStudies showed that vascular endothelial growth factor (VEGF) inhibitors could improve therapeutic efficacy of PD-1/PD-L1 antibodies by transforming the immunosuppressive tumor microenvironment (TME) into an immunoresponsive TME. Ivonescimab is a...

Abstract CT139: Immunological activity of oncolytic adenovirus encoding TNFα and IL-2 (TILT-123) in combination with pembrolizumab in platinum resistant or refractory ovarian cancer patients

Abstract Background TILT-123 (Ad5/3-E2F-D24-hTNFα-IRES-hIL-2) is a serotype chimeric dual safety device oncolytic adenovirus armed with tumor necrosis factor alpha and interleukin-2. It was designed to improve efficacy of T-cell therapies such as immune checkpoint blockade or adoptive cell transfer. We present biological and immunological endpoints from an open-label phase 1 dose escalation study of TILT-123 in combination with anti-PD-1 pembrolizumab in platinum resistant or refractory ovarian cancer patients. Experimental procedures In this dose escalation trial (NCT05271318), patients were first injected with an intravenous (i.v.) dose of TILT-123 ranging from 3x1011 to 4x1012 virus particles (VP), followed by five intratumoural (i.t.) or intraperitoneal (i.p.) injections ranging from 1x1011 to 5x1011 VP. Patients also received intravenous injections of 200 mg pembrolizumab every three weeks starting 36 days after the first dose of TILT-123. The primary endpoint was safety, while efficacy by RECIST1.1 was a secondary endpoint. Collection of tumor biopsies, circulating immune cells, serum, saliva, urine and feces enabled multi-omic evaluation of mechanism of action and identification of predictive biomarkers. Summary of data As of January 2nd 2024, 15 patients received trial therapy. No dose-limiting toxicities were observed and the most frequent AEs associated with therapy included chills and nausea (&amp;gt;10% of patients). Stable disease by RECIST 1.1 was seen in 67% in 12 evaluable patients. TILT-123 replication was detected in both injected and non-injected tumors as assessed by qPCR and anti-hexon IHC. Multiplex immunofluorescence demonstrated induction of robust immunological activity in both injected and non-injected tumors, including significant increase in granzyme B+, PD-1+ CD4+ and CD8+ T cells as well as PD-1+ NK cells. Baseline intratumoral CD4+, FOXP3+ regulatory T cells were not associated with clinical response. Tertiary lymphoid structures and lymphoid aggregates were identified in patients showing long term disease control. Low to medium titers of neutralizing antibodies against 5/3 chimeric adenovirus were detected in 57% of patients at baseline and were not a predictive factor of disease control. No patients had high titers at baseline. Conclusion TILT-123 in combination with anti-PD-1 pembrolizumab was safe and resulted in disease control in both platinum resistant and refractory ovarian cancer patients. Analysis of biological samples revealed insights into mechanism of action, including an immune profile predictive of clinical response. These results, together with those from four other trials (NCT04695327, NCT04217473, NCT06125197 and NCT05222932) set the stage for continued clinical evaluation of TILT-123. Citation Format: James H. Clubb, Matthew S. Block, Johanna Mäenpää, Santeri Pakola, Lyna Haybout, Dafne C. Quixabeira, Tatiana Kudling, Mirte van der Heijden, Elise Jirovec, Tuomo Alanko, Daniel A. Adamo, Susan Ramadan, Jorma Sormunen, Juha Kononen, Julia W. Cohen, Nadena Singh, John Goldfinch, Suvi Sorsa, Riikka Havunen, Claudia Kistler, João M. Santos, Víctor Cervera-Carrascon, Akseli Hemminki. Immunological activity of oncolytic adenovirus encoding TNFα and IL-2 (TILT-123) in combination with pembrolizumab in platinum resistant or refractory ovarian cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT139.

A Phase I Trial of Nab-Paclitaxel/Bevacizumab (AB160) Nano-Immunoconjugate Therapy for Gynecologic Malignancies.

AB160 is a 160-nm nano-immunoconjugate consisting of nab-paclitaxel (ABX) nanoparticles noncovalently coated with bevacizumab (BEV) for targeted delivery into tissues expressing high levels of VEGF. Preclinical data showed that AB160 resulted in greater tumor targeting and tumor inhibition compared with sequential treatment with ABX then BEV. Given individual drug activity, we investigated the safety and toxicity of AB160 in patients with gynecologic cancers. A 3+3 phase I trial was conducted with three potential dose levels in patients with previously treated endometrial, cervical, and platinum-resistant ovarian cancer to ascertain the recommended phase II dose (RP2D). AB160 was administered intravenously on days 1, 8, and 15 of a 28-day cycle (ABX 75-175 mg/m2, BEV 30-70 mg/m2). Pharmacokinetic analyses were performed. No dose-limiting toxicities (DLT) were seen among the three dose levels tested. Grade 3/4 toxicities included neutropenia, thromboembolic events, and leukopenia. DL2 (ABX 150 mg/m2, BEV 60 mg/m2) was chosen as the RP2D. Seven of the 19 patients with measurable disease (36.8%) had confirmed partial responses (95% confidence interval, 16.3%-61.6%). Pharmacokinetic analyses demonstrated that AB160 allowed 50% higher paclitaxel dosing and that paclitaxel clearance mirrored that of therapeutic antibodies. The safety profile and clinical activity of AB160 supports further clinical testing in patients with gynecologic cancers; the RP2D is DL2 (ABX 150 mg/m2, BEV 60 mg/m2).

Ovarian cancer immunotherapy: non-standard solution — non-standard respons

Ovarian cancer is a serious problem in clinical oncology due to the frequent detection of the disease in late stages, as well as the extremely low effectiveness of treatment at the stage of development of resistance to platinum drugs. The use of immunotherapy in this setting is not a standard option, but several early phase trials of its potential effectiveness are described in the literature. This clinical case presents a successful experience with the use of immune checkpoint inhibitors in a pretreated patient with platinum-resistant metastatic ovarian cancer, which was accompanied by various immune-related adverse events.

Abstract 7209: Overcoming platinum resistance of high-grade serous ovarian cancer targeting the activated JAK/STAT pathways via extracellular vesicles

Abstract High-grade serous ovarian cancer (HGSOC) is the most common subtype of ovarian cancer. While HGSOC usually responds to initial treatment, most cases eventually relapse and develop platinum-resistant ovarian cancer (PROC). The molecular definition of PROC is still unclear, and overcoming PROC has been the biggest challenges. Extracellular vesicles (EVs) have an essential role in cell-to-cell communication within both the primary and distant microenvironments. In this study. we aimed to identify molecular mechanisms of PROC via EVs to suggest novel therapeutic strategies. Platinum responses were categorized by primary treatment-free interval of platinum less than 6 months as PROC, and more than 36 months as platinum good response. Ascites and tumor tissues have been collected prior to initial chemotherapy in patients with HGSOC for analysis according to platinum response. mRNA sequencing in tumor tissues identified significantly upregulated JAK/STAT pathways in PROC. The JAK/STAT family was highly expressed in PROC than the good response group, and also increased than adjusted normal ovaries and fallopian tubes. In addition, PROC cell lines and PROC patient-derived xenograft model tumor tissues showed high JAK expression. Small RNA sequencing for HGSOC tissues and ascites-EVs revealed that miR-135a-5p and miR-221-5p were highly expressed in both PROC tissues and ascites, and the expression of the two miRNAs had a positive correlation between tissues and ascites. Overexpression of the two miRNAs in HGSOC cell lines resulted in higher JAK family expression and resistance to cisplatin. JAK inhibitors (JAKi) had equivalent efficacy for platinum-sensitive/resistant HGSOC cell lines and JAKi highly suppress tumor growth in the PROC mouse model. In addition, suppression of JAK family expression in PROC cell lines significantly increased sensitivity to cisplatin. JAKi also had a synergistic effect with cisplatin for PROC cell lines. IPA analyses in mRNA sequencing in tumor tissues, TGF-β was highly expressed in upstream regulators in PROC, and TGF-β stimulation resulted in the upregulation of the two miRNAs in mesothelial cells, but not in HGSOC cell lines and fibroblasts. In summary, we here demonstrate novel molecular mechanisms of PROC via EVs and provided the rationale for JAK-targeted therapy for PROC. EV-miRNAs can regulate the PROC activated JAK/STAT pathway and can be diagnostic and therapeutic biomarkers for PROC definition or JAKi indications, suggesting that patient stratification in precision medicine for initial treatment of HGSOC. Citation Format: Kazuhiro Suzuki, Akira Yokoi, Kousuke Yoshida, Yusuke Yamamoto, Hiroaki Kajiyama. Overcoming platinum resistance of high-grade serous ovarian cancer targeting the activated JAK/STAT pathways via extracellular vesicles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7209.

Abstract 7135: Preclinical effects of Tumor Treating Fields (TTFields) with PARP inhibitors in ovarian cancer

Abstract Purpose: Among gynecological malignancies, ovarian cancer is the leading cause of mortality. Poly (ADP-ribose) polymerase inhibitors (PARPi) represent standard-of-care treatment for selected cases of advanced epithelial ovarian cancer. PARPi exhibit sensitivity in homologues recombination deficient (HRD) tumors, in which there are mutations in the Fanconi Anemia (FA)-BRCA pathway, while about 75% of ovarian cancer patients are homologues recombination proficient (HRP). TTFields are non-invasive electric fields that disrupt cellular processes critical for cancer cell viability and tumor progression. Recent research showed that TTFields induce an HRD-like state (also known as BRCAness state) in various cancer types. The current study aims to investigate the impact of TTFields applied together with PARPi in ovarian cancer preclinical models. Methods: In vitro, A2780 (HRP), OVCAR3 (HRD), and A2780cis (platinum-resistant) ovarian cancer cells were treated with TTFields (1 V/cm RMS, 200 kHz, 72 h), alone or with addition of PARPi (olaparib or niraparib, at various concentrations). Efficacy was measured by analyzing cell count, colony formation, and apoptosis induction. The overall effect was calculated by multiplying cell count with colony formation. TTFields-treated cells were evaluated for the expression of FA-BRCA pathway proteins and for formation of γH2AX, a DNA damage marker, using Western blot and fluorescent microscopy, respectively. In vivo, ID8-fLuc (HRP) cells were inoculated intraperitoneally to 6-8-week-old C57BL/6 mice. Seven days post inoculation, mice were treated with sham-vehicle, TTFields, olaparib (50 mg/kg), or both over a period of four weeks. Tumor growth was analyzed using bioluminescent imaging at treatment cessation, and survival analysis was performed. Results: TTFields application resulted in reduced cell count, increased overall effect, and increased apoptosis in vitro. When TTFields were applied together with PARPi, a high and moderate synergistic interaction was shown respectively the BRCA wild-type A2780 cells and the platinum-resistant A2780cis cells. However, in the BRCA mutant OVCAR-3 cells the effect was additive. A downregulation of FA-BRCA protein expression was confirmed after TTFields treatment of the ovarian cells, with consequent DNA damage. In the tumor-bearing mice, TTFields and olaparib co-treatment resulted in reduced tumor volume and a survival benefit relative to the monotherapies and to control-treated mice. Conclusions: The data suggest potential advantages for TTFields concomitant with PARPi in ovarian cancer, even without underlying BRCA mutations - consistent with the BRCAness state induced by TTFields - and also suggests benefits in platinum-resistant ovarian cancer. Citation Format: Yani Berckmans, Hila Ene, Kerem Ben-Meir, Antonia Martinez-Conde, Roni Monin, Bieke Van den Ende, Sara Van Mechelen, Roni Frechtel-Gerzi, Hila Gabay, Rotem Engelman, Eyal Dor-On, Adi Haber, Moshe Giladi, Uri Weinberg, Yoram Palti, Ignace Vergote, An Coosemans. Preclinical effects of Tumor Treating Fields (TTFields) with PARP inhibitors in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7135.

Abstract 954: An evaluation of the combination of metformin and Y15 for the treatment of platinum-resistant ovarian cancer

Abstract Ovarian cancer is the fifth leading cause of cancer mortality among women. This high mortality rate is linked to the development of resistance to first-line chemotherapy with platinum compounds which has been attributed in part to increased activity of focal adhesion kinase (FAK). The anti-diabetic drug Metformin was previously shown to inhibit the proliferation and migration of ovarian cancer cells and thus, the combination of a FAK inhibitor, Y15, and Metformin may be a promising treatment for platinum-resistant ovarian cancer (PROC). The objective of this study was to evaluate the combination of Y15 and Metformin on PROC cell viability and the mechanism of cell death. An MTT assay was used to analyze cell viability in PROC OVCAR3 cells after 48 h of treatment by measuring the absorbance at 570 nm with a microplate reader. Western blot was used to determine the protein levels of the apoptosis marker cleaved PARP and the autophagy marker LC3B-II. The exposure of OVCAR3 platinum-resistant ovarian cancer cells to Metformin (4.5 mM) + Y15 (5.5 µM) resulted in a significantly enhanced cytotoxicity (32.6 ± 1.8%) compared to single drug treatment with either Metformin (4.5 mM) (65.0 ± 4.2%) or Y15 (5.5 µM) (66.0 ± 4.8%). A combination of Metformin (7.8 mM) + Y15 (5.5 µM) also resulted in a significantly enhanced cytotoxicity (22.8 ± 1.5%) compared to single drug treatment with either Metformin (7.8 mM) (50.7 ± 3.7%) or Y15 (5.5 µM) (66.0 ± 4.8%). Cells treated with the combination of Metformin and Y15 for 24, 48, and 72-hours showed an increase in cleaved PARP compared to the control, Metformin alone and Y15 alone. For Metformin alone, there was an increase in cleaved PARP compared to the control at all timepoints and increased from 24 hours to 72 hours. For Y15 alone, the amount of cleaved PARP was also higher compared to the control at all time points, however, decreased over time from 24 hours to 72 hours. Cells treated with Metformin, Y15, and a combination of Metformin and Y15 showed no conversion of LC3B-I to LC3B-II, which occurs during autophagy. Thus, it is concluded that the mechanism of cell death for both Metformin and Y15 is through apoptosis and not autophagy and apoptosis is enhanced with the combination of the drugs. The delivery of Metformin and Y15 can result in an additive effect on cell viability through apoptosis and can be further explored as a promising approach for the treatment of PROC. Citation Format: Manuel A. Duarte, Kristal Garcia, Marco A. Arriaga, Sue Anne Chew, Arkene S. Levy, Isabela Mendez. An evaluation of the combination of metformin and Y15 for the treatment of platinum-resistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 954.

Abstract 7551: Combined epigenetic therapy and immune checkpoint blockade drive reshaping of the tumor microenvironment of platinum resistant ovarian cancer

Abstract Introduction: Immunotherapy has demonstrated modest effectiveness for patients with platinum-resistant ovarian cancer, which is in part related to the immunosuppressive tumor microenvironment (TME) of ovarian cancers. Epigenetic modulators in combination with immune checkpoint inhibitors (ICIs) may represent a potential way to sensitize ovarian cancer to immunotherapy by TME reprogramming. Methods: We evaluated the effect of epigenetic modulation in combination with ICI by comprehensive transcriptomic analyses of serially biopsied platinum-resistant/refractory ovarian cancer. Leveraging serial tumor samples from 30 patients that received oral azacitidine and pembrolizumab in the TRIO026 phase II clinical trial (NCT02900560), we performed bulk RNA sequencing and direct digital counting of 770 target genes using molecular barcodes (nCounter, NanoString) for 72 serial tumor samples, prior to treatment initiation and 6 weeks on-therapy. RNA sequencing of ~200 million reads for each sample was used for differential gene expression and gene set enrichment analysis (GSEA) and cell type deconvolution. Target gene expression data was normalized and analyzed for differential gene and pathway expression. Results: Differential gene expression analyses revealed an upregulation of inflammatory and cytolytic genes (IFNG, GZMA and GZMH; FDR-adjusted p=0.0184) as well as the co-inhibitory molecule CTLA-4 (FDR-adjusted p=0.0184). GSEA revealed an enrichment of IFNG response, natural killer cell mediated cytotoxicity, neutrophil degranulation, inflammatory response, and antigen processing/presentation related gene sets on-therapy (FDR-adjusted p &amp;lt; 0.001). Target gene expression analyses orthogonally confirmed these findings, which were also concordant with pathway scoring analyses showing an increased score for immune inflammatory pathways such as INFG signaling (Wilcoxon rank sum test p=0.01). Immune cell subset deconvolution suggested TME reshaping driven by a greater density of intra-tumoral T cells on-therapy (Wilcoxon rank sum test p=0.012). Higher IFNG, CXCL13, CXCR5 expression, CD8 T cell and NK cell density were associated with longer time on treatment, both at baseline and at the on-therapy timepoint. GSEA revealed an upregulation of interferon gamma, adaptive immunity, antigen presentation as well as conserved immune response gene sets on-therapy, for the patients attaining longer time on-treatment. Conclusion: Combination epigenetic and immunotherapy induces an inflammatory response and reshaping of the tumor microenvironment that may enhance their clinical efficacy, highlighting the therapeutic potential of utilizing epigenetic modulators as a way to sensitize platinum-resistant ovarian cancer to immune checkpoint inhibition. Citation Format: Blair V. Landon, Guneet Kaleka, Archana Balan, Julia L. Boland, Christopher Cherry, Gavin Pereira, Cynthia Zahnow, Boris Winterhoff, Stephen Baylin, Victor E. Velculescu, Gottfried E. Konecny, John A. Glaspy, Valsamo Anagnostou. Combined epigenetic therapy and immune checkpoint blockade drive reshaping of the tumor microenvironment of platinum resistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7551.

Abstract 7533: PVRIG is uniquely expressed in tumor dendritic cells-rich niches on stem-like memory T cells and its blockade may induce immune infiltration and activation in non-inflamed tumors

Abstract Poorly immune infiltrated cancers pose a significant challenge, with current immunotherapies yielding limited clinical success. Stem-like memory T cells (TSCM) have been identified as a T cell subgroup which possess enhanced proliferative capacity that could expand and differentiate upon dendritic cells (DCs) priming. In this study we investigated the expression of the recently discovered inhibitory receptor PVRIG and its ligand, PVRL2, in the tumor microenvironment (TME). Leveraging single cell RNA sequencing (scRNAseq) data from diverse cancer indications, we found that in CD8+ T cells, PVRIG clusters with early differentiation/TSCM genes, unlike other immune checkpoints that cluster with genes related to T cells exhaustion. In agreement with the scRNAseq data, PVRIG protein expression was markedly increased on CD28+CD8+ early-memory T cells across cancer indications. PVRL2, was dominantly expressed on intratumoral DC subsets on both scRNA and protein levels. The observation that PVRIG is uniquely expressed by TSCM cells, and PVRL2 by DCs, led us to evaluate whether these cell populations physically co-localize in the TME, thus potentially allowing PVRIG/PVRL2 interaction. Employing spatial transcriptomic analysis in surgically resected CRC lesions we showed that while CTLA4, PD1, and TIM3 were mainly expressed by tumor infiltrating T cells, PVRIG and other genes of the DNAM-1 axis were intensely expressed by TSCM in specialized immune aggregates, as well as by T cells in tumor bed. High resolution spatial mapping of interacting immune and adjacent cells revealed pairs of activated LAMP3+PVRL2+ DCs interacting with CD28+PVRIG+ CD8 T cells in the intratumoral immune aggregates. Thus, PVRIG/PVRL2 interaction may limit TSCM priming by DCs and blocking this interaction may unleash potent TSCM proliferation, differentiation, and infiltration into the tumor regions. To gain a more comprehensive understanding on the intratumor effects induced by PVRIG blockade, we evaluated the immune response in the TME of patients with poorly immune infiltrated tumors, platinum resistant ovarian cancer and MSS-CRC, indications typically less responsive to immune checkpoint inhibitors. Treatment with COM701, anti-PVRIG antibody, as monotherapy or in combination with nivolumab resulted in an increased tumor T cell infiltration, accompanied by TCR clonality expansion, which were associated with clinical benefit. In summary, our study identifies PVRIG as uniquely expressed on TSCM in the TME, with its ligand PVRL2 expressed on activated DCs. Blockade of PVRIG/PVRL2 interaction by COM701 antibody emerges as a promising strategy to induce potent T cell responses, providing a novel approach overcoming resistance to immunotherapy in immune excluded tumors. Citation Format: Zoya Alteber, Gady Cojocaru, Roy Zvi Granit, Inbal Barbiro, Assaf Wool, Masha Frenkel, Amit Novik, Adi Shuchami, Yu Liang, Vered Daniel Carmi, Niv Sabath, Rob Foreman, Natalia Petrenko, Jiang He, Yossef Kliger, Henry Adewoye, Pierre Ferre, Zurit Levine, Eran Ophir. PVRIG is uniquely expressed in tumor dendritic cells-rich niches on stem-like memory T cells and its blockade may induce immune infiltration and activation in non-inflamed tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7533.