Evolving treatment paradigms for platinum-resistant ovarian cancer: An update narrative review.

Platinum-resistant ovarian cancer (PROC) refers to disease progression within 6 months after the completion of platinum-based chemotherapy. Historically, treatment options for PROC were limited with a poor prognosis and non-platinum single agent plus bevacizumab has been the mainstay of treatment. Fortunately, there have been notable advancements in recent years, leading to an advance in treatment paradigms for this challenging disease. Various combinations of chemotherapy, targeted agents such as poly (ADP-ribose) polymerase (PARP) inhibitors, and immunotherapy are being explored for an improved treatment outcome. Antibody-drug conjugates targeting folate receptor alpha, which deliver a cytotoxic payload directly to cancer cells, have emerged as a promising therapeutic approach for PROC. WEE1 inhibitors, such as adavosertib, function by inhibiting the WEE1 kinase activity, leading to premature entry of a cell into mitosis phase and thus increased DNA damage. It has been observed that cancer cells with TP53 mutations may be more sensitive to WEE1 inhibitors. Biomarker testing such as analysis of the expression level of folate receptor alpha or mutation in TP53 may be applicable for identifying patients who are more likely to respond to the specific therapy, enabling a more personalized treatment approach. This overview summarizes key clinical findings on the efficacy and safety of theses novel biomarker-driven therapeutic approaches.

Paclitaxel-Ifosfamide-based Therapy as Salvage Treatment in Platinum-resistant Recurrent/Metastatic Head and Neck Cancer.

BACKGROUND: Treatment options are limited, and the prognosis is poor for patients with platinum-resistant recurrent metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). This study evaluated the efficacy and safety of a paclitaxel and ifosfamide (TI) regimen in patients with R/M HNSCC whose disease had progressed following platinum-based therapy. PATIENTS AND METHODS: In this retrospective study, we included 53 patients with R/M HNSCC who underwent at least one cycle of TI-based therapy, post platinum failure, between February 2020 and August 2023. Some patients received the TI regimen in combination with immunotherapy and/or cetuximab. Key metrics assessed included the objective response rate (ORR), disease control rate, and progression-free as well as overall survival. RESULTS: The study observed an ORR of 15.8% and a disease control rate of 36.8%. The median progression-free survival for the entire cohort was 3.3 months, and the median overall survival was 9.6 months. Notably, the combination of TI with immunotherapy yielded a higher ORR of 30.8%, compared to 14.3% with TI alone. The most prevalent grade 1-2 adverse events were anemia (81%), weight loss (68%) and hypernatremia (55%). CONCLUSION: The TI-based regimen demonstrated favorable efficacy and safety profile in treating R/M HNSCC. Enhanced outcomes may be attainable when combining it with immunotherapy. This study suggests that TI-based therapy could serve as a potential salvage option for this specific patient group.

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

AIM: 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. METHODS: 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. RESULTS: 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). CONCLUSION: Angiogenesis inhibitor apatinib plus chemotherapy shows better treatment efficacy than chemotherapy alone with controllable safety profile in RPR-OC patients.

Comprehensive Genomic Characterization in Ovarian Low-Grade and Chemosensitive and Chemoresistant High-Grade Serous Carcinomas.

INTRODUCTION: Genomic characterization of serous ovarian carcinoma (SOC), which includes low-grade serous carcinoma (LGSC) and high-grade serous carcinoma (HGSC), remains necessary to improve efficacy of platinum-based chemotherapy. The aim of this study was to investigate the genomic variations in these SOC groups, also in relation to chemoresponse. METHODS: Forty-five samples of SOC were retrospectively analyzed by next-generation sequencing on DNA/RNA extracts from formalin-fixed, paraffin-embedded (FFPE) tumor samples obtained at diagnosis. HGSCs were classified as platinum-resistant and platinum-sensitive. RESULTS: In the LGSC group, 44% of the carcinomas had mutually exclusive variants in the RAS/RAF pathway, while additional likely oncogenic variants in the CDKN2A, SMARCA4, and YAP1 genes were observed in the remaining LGSCs. Tumor mutation burden (TMB) was significantly lower in the intrinsically chemoresistant LGSC group than in the HGSC group. In the HGSC cohort, TP53 variants were found in 90% and homologous recombination repair (HRR) pathway variants in 41% of the neoplasms. HGSCs of the chemoresistant group without classic mutations in the HRR pathway were characterized by additional variants in FGFR2 and with an FGFR3::TACC3 fusion. In addition, HGSCs showed MYC, CCNE1, and AKT2 gains that were almost exclusively observed in the chemosensitive HGSC group. CONCLUSION: These results suggest that very low TMB and MYC, CCNE1, and AKT2 gains in SOC patients may be biomarkers related to platinum treatment efficacy. Thorough genomic characterization of SOCs prior to treatment might lead to more specific platinum-based chemotherapy strategies.

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.

Case report: Response to everolimus in a patient with platinum resistant, high grade serous ovarian carcinoma with biallelic TSC2 inactivation.

Background: Patients with platinum-resistant recurrent high grade serous ovarian carcinoma have poor outcomes and limited treatment options. Case presentation: We present a case of a 48-year-old woman with platinum-resistant high grade serous ovarian carcinoma harboring the pathogenic TSC2 R611Q variant with concomitant single copy loss of TSC2 (suggesting biallelic TSC2 inactivation) identified in targeted tumor sequencing. The patient was treated with the mTOR inhibitor everolimus, with an excellent response by imaging and a marked decrease in CA125; she remained on everolimus for 19 months until she developed progressive disease. Conclusions: While mTOR inhibition is frequently used in tumors associated with tuberous sclerosis complex (TSC), such as lymphangioleiomyomatosis and malignant perivascular epithelioid cell tumors, this is the first case of a patient with ovarian cancer harboring TSC1/2 mutations who responded to mTOR inhibition. This case highlights the utility of targeted DNA sequencing in the management of ovarian carcinoma and demonstrates the value of tumor-agnostic targeted therapies.

Impact of Bevacizumab on Clinical Outcomes in Patients With Platinum-resistant Relapsed Ovarian Cancer.

BACKGROUND/AIM: Over the past several decades, new anti-cancer drugs have been developed for the treatment of epithelial ovarian cancer. The development of drugs has led to changes in improving the prognosis of ovarian cancer patients. One of these drugs, bevacizumab, is used for advanced or recurrent ovarian cancer. In this study, we aimed to evaluate survival improvement in patients with platinum-resistant relapsed epithelial ovarian cancer (PR-ROC) after introduction of bevacizumab in real world experience. PATIENTS AND METHODS: We retrospectively divided patients with PR-ROC into two groups: bevacizumab plus chemotherapy (BEV-CT group) and chemotherapy alone (CT group). Progression-free survival (PFS), the primary endpoint, between two groups was compared to evaluate whether survival outcomes were improved. In addition, overall survival (OS) was also compared. RESULTS: A total of 154 patients were included in the study: 57 and 97 patients in the BEV-CT and CT groups, respectively. OS was significantly longer in the BEV-CT group than in the CT group. The use of bevacizumab was identified as a favorable prognostic factor for OS. In a subgroup analysis confined to second-line chemotherapy, PFS and OS were statistically different between groups. More patients in the CT group suffered hematologic adverse events of grade 3 or above than patients in the BEV-CT group. CONCLUSION: In a real-world clinical setting, introduction of bevacizumab led to improvement of OS in patients with PR-ROC with a tolerable toxicity.

A Survival Analysis of Patients with Recurrent Epithelial Ovarian Cancer Based on Relapse Type: A Multi-Institutional Retrospective Study in Armenia.

BACKGROUND: Annually, approximately 200 new ovarian cancer cases are diagnosed in Armenia, which is considered an upper-middle-income country. This study aimed to summarize the survival outcomes of patients with relapsed ovarian cancer in Armenia based on the type of recurrence, risk factors, and choice of systemic treatment. METHODS: This retrospective case-control study included 228 patients with relapsed ovarian cancer from three different institutions. RESULTS: The median age of the patients was 55. The median follow-up times from relapse and primary diagnosis were 21 and 48 months, respectively. The incidence of platinum-sensitive relapse was 81.6% (186), while platinum-resistant relapse was observed in only 18.4% (42) of patients. The median post-progression survival of the platinum-sensitive group compared to the platinum-resistant group was 54 vs. 25 months (p < 0.001), respectively, while the median survival after relapse was 25 vs. 13 months, respectively; three- and five-year post-progression survival rates in these groups were 31.2% vs. 23.8%, and 15.1% vs. 9.5%, respectively (p = 0.113). CONCLUSIONS: Overall, despite new therapeutic approaches, ovarian cancer continues to be one of the deadly malignant diseases affecting women, especially in developing countries with a lack of resources, where chemotherapy remains the primary available systemic treatment for the majority of patients. Low survival rates demonstrate the urgent need for more research focused on this group of patients with poor outcomes.

Cost-effectiveness and drug wastage of bevacizumab biosimilar with or without chemotherapy for platinum-resistant recurrent ovarian cancer.

INTRODUCTION: The cost-effectiveness of adding bevacizumab biosimilar with or without chemotherapy (CT) and drug wastage in treating platinum-resistant recurrent ovarian cancer (PRrOC) was assessed. METHODS: A three-state partitioned-survival model to compare the clinical and economic outcomes in the treatment of patients with PRrOC from a Taiwan healthcare prospective, extrapolated to two years based on data obtained from the JGOG3023 clinical trial. The primary outcomes of the model were incremental cost-effectiveness ratios (ICERs). RESULTS: In the base-case scenario, using vials of bevacizumab biosimilar (Bevbiol) plus chemotherapy, the ICER was (new Taiwan dollar) NT$ 4,555,878 per QALY gained. The incremental cost savings of an incremental 2.02 QALYs were NT$ 1,605,828 if weight-based Bevbiol plus chemotherapy were used, but the ICER remained high at the willingness-to-pay (WTP) threshold. If the cost of Bevbiol were reduced to 50% per vial, adding it to CT would be cost-effective at an acceptable WTP threshold of NTD 2,994,200, with an ICER of NT$ 2,975,484. CONCLUSIONS: Bevacizumab biosimilars in mg/kg dosage form with chemotherapy are still not cost-effective in Taiwan, but using weight-based dosing will reduce drug waste and save treatment costs.

Real-world outcomes associated with bevacizumab combined with chemotherapy in platinum-resistant ovarian Cancer.

OBJECTIVES: The addition of bevacizumab to chemotherapy for platinum-resistant (PL-R) ovarian cancer (OC) improved progression-free (PFS) but not overall survival (OS) in clinical trials. We explored real-world outcomes in Ontario, Canada, and compared survival in the pre- and post-bevacizumab era. METHODS: Administrative databases were utilized to identify all patients treated with bevacizumab for PL-R OC. Time on treatment (ToT) was used as surrogate for PFS. Median OS was determined using the Kaplan-Meier method. Factors associated with ToT/OS were identified using a Cox proportional hazard model. A before and after comparative effectiveness analysis was performed to determine mOS for patients treated pre- and post-bevacizumab approval. RESULTS: From 2017 to 2019, 176 patients received bevacizumab. Median ToT was 3 months and OS was 11 months. Sixty-four percent received liposomal doxorubicin and 34% received paclitaxel. ToT (6 vs 3 months; HR 0.44; p < 0.0001) and OS (14 vs 9 months; HR 0.45; p = 0.0089) were longer with bevacizumab/paclitaxel. OS was not significantly different pre- and post-bevacizumab funding (8 vs 9 months; HR 1.01; 0.937). Median OS increased for those receiving paclitaxel (6 vs 11 months), but those in the post group were younger, more likely to have undergone primary surgery and had less co-morbidities. CONCLUSION: Real-world outcomes with bevacizumab in PL-R OC are inferior to those in the pivotal clinical trial. Survival has not significantly improved since funding became publicly available, indicating a substantial efficacy-effectiveness gap between trial and real-world outcomes. Median OS and ToT were significantly better when bevacizumab was given with paclitaxel.

Nanoparticle Targeting in Chemo-Resistant Ovarian Cancer Reveals Dual Axis of Therapeutic Vulnerability Involving Cholesterol Uptake and Cell Redox Balance.

Platinum (Pt)-based chemotherapy is the main treatment for ovarian cancer (OC); however, most patients develop Pt resistance (Pt-R). This work shows that Pt-R OC cells increase intracellular cholesterol through uptake via the HDL receptor, scavenger receptor type B-1 (SR-B1). SR-B1 blockade using synthetic cholesterol-poor HDL-like nanoparticles (HDL NPs) diminished cholesterol uptake leading to cell death and inhibition of tumor growth. Reduced cholesterol accumulation in cancer cells induces lipid oxidative stress through the reduction of glutathione peroxidase 4 (GPx4) leading to ferroptosis. In turn, GPx4 depletion induces decreased cholesterol uptake through SR-B1 and re-sensitizes OC cells to Pt. Mechanistically, GPx4 knockdown causes lower expression of the histone acetyltransferase EP300, leading to reduced deposition of histone H3 lysine 27 acetylation (H3K27Ac) on the sterol regulatory element binding transcription factor 2 (SREBF2) promoter and suppressing expression of this key transcription factor involved in the regulation of cholesterol metabolism. SREBF2 downregulation leads to decreased SR-B1 expression and diminished cholesterol uptake. Thus, chemoresistance and cancer cell survival under high ROS burden obligates high GPx4 and SR-B1 expression through SREBF2. Targeting SR-B1 to modulate cholesterol uptake inhibits this axis and causes ferroptosis in vitro and in vivo in Pt-R OC.

Durvalumab with or without tremelimumab plus chemotherapy in HRR non-mutated, platinum-resistant ovarian cancer (KGOG 3045): A phase II umbrella trial.

AIM: We investigated the efficacy and safety of durvalumab (D) with or without tremelimumab (T) in addition to single-agent chemotherapy (CT) in patients with platinum-resistant recurrent ovarian cancer (PROC) lacking homologous recombination repair (HRR) gene mutations. PATIENTS AND METHODS: KGOG 3045 was an open-label, investigator-initiated phase II umbrella trial. Patients with PROC without HRR gene mutations who had received ≥2 prior lines of therapy were enrolled. Patients with high PD-L1 expression (TPS ≥25%) were assigned to arm A (D + CT), whereas those with low PD-L1 expression were assigned to arm B (D + T75 + CT). After completing arm B recruitment, patients were sequentially assigned to arms C (D + T300 + CT) and D (D + CT). RESULTS: Overall, 58 patients were enrolled (5, 18, 17, and 18 patients in arms A, B, C, and D, respectively). The objective response rates were 20.0, 33.3, 29.4, and 22.2%, respectively. Grade 3-4 treatment-related adverse events were observed in 20.0, 66.7, 47.1, and 66.7 of patients, respectively, but were effectively managed. Multivariable analysis demonstrated that adding T to D + CT improved progression-free survival (adjusted HR, 0.435; 95% CI, 0.229-0.824; P = 0.011). Favorable response to chemoimmunotherapy was associated with MUC16 mutation (P = 0.0214), high EPCAM expression (P = 0.020), high matrix remodeling gene signature score (P = 0.017), and low FOXP3 expression (P = 0.047). Patients showing favorable responses to D + T + CT exhibited significantly higher EPCAM expression levels (P = 0.008) and matrix remodeling gene signature scores (P = 0.031) than those receiving D + CT. CONCLUSIONS: Dual immunotherapy with chemotherapy showed acceptable response rates and tolerable safety in HRR non-mutated PROC, warranting continued clinical investigation.

Efficacy and safety of VEGF/VEGFR inhibitors for platinum-resistant ovarian cancer: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Almost all patients with ovarian cancer will experience relapse and eventually develop platinum-resistant. The poor prognosis and limited treatment options have prompted the search for novel approaches in managing platinum-resistant ovarian cancer (PROC). Therefore, a meta-analysis was conducted to evaluate the efficacy and safety of combination therapy with vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors for PROC. METHODS: A comprehensive search of online databases was conducted to identify randomized clinical trials published until December 31, 2022. Pooled hazard ratios (HR) was calculated for overall survival (OS) and progression-free survival (PFS), while pooled odds ratio (OR) was calculated for objective response rate (ORR) and treatment-related adverse events (TRAEs). Subgroup analysis was further performed to investigate the source of heterogeneity. RESULTS: In total, 1097 patients from eight randomized clinical trials were included in this meta-analysis. The pooled HRs of OS (HR = 0.72; 95% CI: 0.62-0.84, p < 0.0001) and PFS (HR = 0.52; 95% CI: 0.45-0.59, p < 0.0001) demonstrated a significant prolongation in the combination group compared to chemotherapy alone for PROC. In addition, combination therapy demonstrated a superior ORR compared to monotherapy (OR = 2.34; 95%CI: 1.27-4.32, p < 0.0001). Subgroup analysis indicated that the combination treatment of VEGF/VEGFR inhibitors and chemotherapy was significantly more effective than monochemotherapy in terms of OS (HR = 0.71; 95% CI: 0.61-0.84, p < 0.0001), PFS (HR = 0.49; 95% CI: 0.42-0.57, p < 0.0001), and ORR (OR = 2.97; 95% CI: 1.89-4.67, p < 0.0001). Although the combination therapy was associated with higher incidences of hypertension, mucositis, proteinuria, diarrhea, and hand-foot syndrome compared to monochemotherapy, these toxicities were manageable and well-tolerated. CONCLUSIONS: The meta-analysis demonstrated that combination therapy with VEGF/VEGFR inhibitors yielded better clinical outcomes for patients with PROC compared to monochemotherapy, especially when combined with chemotherapy. This analysis provides more treatment options for patients with PROC. SYSTEMATIC REVIEW REGISTRATION: [ https://www.crd.york.ac.uk/PROSPERO ], Prospective Register of Systematic Reviews (PROSPERO), identifier: CRD42023402050.

Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) Applied to Platinum-Resistant Recurrence of Ovarian Tumor: A Single-Institution Experience (ID: PARROT Trial).

BACKGROUND: We aimed to investigate the therapeutic efficacy and safety of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) in platinum-resistant recurrence of ovarian cancer and peritoneal carcinomatosis, while our secondary endpoint was to establish any changes in quality of life estimated via the EORTC QLQ-30 and QLQ-OV28 questionnaires. METHODS: In this monocentric, single-arm, phase II trial, women were prospectively recruited and every 28-42 days underwent courses of PIPAC with doxorubicin 2.1 mg/m2 followed by cisplatin 10.5 mg/m2 via sequential laparoscopy. RESULTS: Overall, 98 PIPAC procedures were performed on 43 women from January 2016 to January 2020; three procedures were aborted due to extensive intra-abdominal adhesions. The clinical benefit rate (CBR) was reached in 82% of women. Three cycles of PIPAC were completed in 18 women (45%), and 13 (32.5%) and 9 (22.5%) patients were subjected to one and two cycles, respectively. During two PIPAC procedures, patients experienced an intraoperative intestinal perforation. There were no treatment-related deaths. Nineteen patients showed no response according to the Peritoneal Regression Grading Score (PRGS) and 8 patients showed minor response according to the PRGS. Median time from ovarian cancer relapse to disease progression was 12 months (95% confidence interval [CI] 6.483-17.517), while the median overall survival was 27 months (95% CI 20.337-33.663). The EORTC QLQ-28 and EORTC QLQ-30 scores did not worsen during therapy. CONCLUSIONS: PIPAC seems a feasible approach for the treatment of this subset of patients, without any impact on their quality of life. Since this study had a small sample size and a single-center design, future research is mandatory, such as its application in addition to systemic chemotherapy.

Cytoreductive surgery is feasible in patients with limited regional platinum-resistant recurrent ovarian cancer.

INTRODUCTION: To evaluate the efficacy of cytoreductive surgery versus chemotherapy for the treatment of limited regional, platinum-resistant ovarian cancer (PROC). MATERIALS AND METHODS: The clinical records of all patients with PROC treated in our center between March 2015 and March 2022 were retrospectively reviewed. We compared the oncology outcomes of patients who received cytoreduction or chemotherapy alone at relapse and presented information about postoperative adjuvant chemotherapy. RESULTS: Among 52 patients with limited regional recurrence, 40.4% (21/52) underwent cytoreduction because of platinum resistance, and 59.6% (31/52) received chemotherapy alone. No residual disease (R0) was achieved in 20 patients (95.2%). The severe morbidity rate within 30 days after the surgery was 15%. The median follow-up was 70.6 months. Compared with the chemotherapy alone group, the surgery group with R0 had better progression-free survival (PFS) (10.6 vs. 5.1 months; hazard ratio (HR) = 0.421; P = 0.0035) and post-relapse survival (PRS) (32.6 vs. 16.3 months; HR = 0.478; P = 0.047), but there was no difference in overall survival (OS) between the two groups. Laparoscopy is associated with lesser intraoperative blood loss with no differences in survival and postoperative complications compared to the open approach (P = 0.0042). Subgroup survival analysis showed that compared with chemotherapy alone, surgery prolonged PFS in patients regardless of tumor size (greater than or equal to 4 cm or less). Surgery group patients who achieved R0 had an objective response rate (ORR) of 36.8% (7/19), among whom 40% (4/10) received platinum rechallenge chemotherapy and 33.3% (3/9) were administered non-platinum chemotherapy. CONCLUSION: When well-selected PROC patients with limited regional recurrence achieved R0, their outcomes were superior to those of patients who received only chemotherapy with an acceptable morbidity rate. Laparoscope technology could be a reliable alternative surgical approach. The reintroduction of platinum agents may be considered following surgery. Further analyses in a larger population are warranted to elucidate the risks and benefits of this surgery and adjuvant chemotherapy strategy.

Overcoming the challenges of drug development in platinum-resistant ovarian cancer.

The definition of "platinum-resistant ovarian cancer" has evolved; it now also reflects cancers for which platinum treatment is no longer an option. Standard of care for platinum-resistant ovarian cancer is single-agent, non-platinum chemotherapy with or without bevacizumab, which produces modest response rates, with the greatest benefits achieved using weekly paclitaxel. Several recent phase 3 trials of pretreated patients with prior bevacizumab exposure failed to meet their primary efficacy endpoints, highlighting the challenge in improving clinical outcomes among these patients. Combination treatment with antiangiogenics has improved outcomes, whereas combination strategies with immune checkpoint inhibitors have yielded modest results. Despite extensive translational research, there has been a lack of reliable and established biomarkers that predict treatment response in platinum-resistant ovarian cancer. Additionally, in the platinum-resistant setting, implications for the time between the penultimate dose of platinum therapy and platinum retreatment remain an area of debate. Addressing the unmet need for an effective treatment in the platinum-resistant setting requires thoughtful clinical trial design based on a growing understanding of the disease. Recent cancer drug approvals highlight the value of incorporating molecular phenotypes to better define patients who are more likely to respond to novel therapies. Clinical trials designed per the Gynecologic Cancer InterGroup recommendations-which advocate against relying solely upon the platinum-free interval-will help advance our understanding of recurrent ovarian cancer response where platinum rechallenge in the platinum-resistant setting may be considered. The inclusion of biomarkers in clinical trials will improve patient stratification and potentially demonstrate correlations with biomarker expression and duration of response. With the efficacy of antibody-drug conjugates shown for the treatment of some solid and hematologic cancers, current trials are evaluating the use of various novel conjugates in the setting of platinum-resistant ovarian cancer. Emerging novel treatments coupled with combination trials and biomarker explorations offer encouraging results for potential strategies to improve response rates and prolong progression-free survival in this population with high unmet need. This review outlines existing data from contemporary clinical trials of patients with platinum-resistant ovarian cancer and suggests historical synthetic benchmarks for non-randomized trials.

Niraparib and dostarlimab for the treatment of recurrent platinum-resistant ovarian cancer: results of a Phase II study (MOONSTONE/GOG-3032).

OBJECTIVE: This study assessed the efficacy, safety, and health-related quality of life (HRQoL) of the treatment regimen of dostarlimab, a programmed death-1 inhibitor, combined with niraparib, a poly (ADP-ribose) polymerase inhibitor, in patients with BRCA wild type (BRCAwt) recurrent platinum-resistant ovarian cancer (PROC) who had previously received bevacizumab treatment. METHODS: This Phase II, open-label, single-arm, multicenter study, conducted in the USA, enrolled patients with recurrent PROC to receive niraparib and dostarlimab until disease progression or unacceptable toxicity (up to 3 years). A preplanned interim futility analysis was performed after the first 41 patients had undergone ≥1 radiographic evaluation (approximately 9 weeks from the first treatment). RESULTS: The prespecified interim futility criterion was met and the study was therefore terminated. For the 41 patients assessed, the objective response rate (ORR) was 7.3% (95% confidence interval: 1.5-19.9); no patients achieved a complete response, 3 patients (7.3%) achieved a partial response (duration of response; 3.0, 3.8, and 9.2 months, respectively), and 9 patients (22.0%) had stable disease. In total, 39 patients (95.1%) experienced a treatment-related adverse event, but no new safety issues were observed. HRQoL, assessed using FOSI, or Functional Assessment of Cancer Therapy - Ovarian Symptom Index scores, worsened over time compared with baseline scores. CONCLUSIONS: The study was terminated due to the observed ORR at the interim futility analysis. This highlights a need for effective therapies in treating patients with recurrent BRCAwt PROC.

Targeting RAS-ERK pathway alterations with MEK inhibitors to improve chemosensitivity in high grade serous ovarian cancers.

OBJECTIVE: Assess if MEK inhibitor blockade of RAS-ERK pathway adaptive response in high grade serous ovarian cancers (HGSOC) improves platinum sensitivity. METHODS: Three HGSOC cell lines and three patient derived organoid (PDOs) samples from ascites of platinum resistant HGSOC patients were collected. Cell lines and PDOs were exposed to carboplatin and MEK inhibitors cobimetinib or trametinib. Cytotoxic effects of MEK inhibitors alone or combined with carboplatin were established. Western blots demonstrated RAS-ERK pathway blockage after MEK inhibitor treatment. RNA sequencing assessed gene expression after MEK inhibitor treatment. Cell line NF1 gene knockdown was performed with corresponding chemosensitivity levels. RESULTS: High carboplatin IC50 levels indicated platinum resistance in cell lines and PDOs. Cobimetinib induced cytotoxicity in cell lines and PDOs, while trametinib was less effective. Western blot confirmed MEK-ERK pathway blockage at minimal concentrations of MEK inhibitors in cell lines and PDOs. Phosphorylated-ERK levels of untreated cells indicated higher levels of RAS-ERK pathway activation in OVSAHO and OVCAR7 compared to OVCAR3. OVSAHO harbors a NF1 mutation and had highest levels of RAS-ERK activation. Cotreatment with carboplatin and MEK inhibitors showed varying synergistic cytotoxic effects at different combinations. Synergistic effect was most prominent in the OVSAHO carboplatin and cobimetinib combination. RNA sequencing identified downregulation of c-MYC and FOXM1 gene expression after MEK inhibitor treatment. NF1 gene knockdown showed an acquired increased IC50 compared to parental cells. CONCLUSION: MEK inhibitors block RAS-ERK pathways in platinum resistant HGSOC cells and PDOs. MEK inhibitors with carboplatin have select synergistic effects which may indicate a strategy to improve platinum sensitivity.

Randomized, two-arm, noncomparative phase 2 study of olaparib plus cediranib or durvalumab in HRR-mutated, platinum-resistant ovarian cancer: A substudy of KGOG 3045.

Choosing an optimal concomitant drug for combination with poly-ADP ribose polymerase (PARP) inhibitor based on patient-specific biomarker status may help increase to improve treatment efficacy in patients with ovarian cancer. However, the efficacy and safety of different PARP inhibitor-based combinations in patients with homologous recombination repair (HRR) mutations have not been evaluated in ovarian cancer. In this sub-study of Korean Gynecologic Oncology Group (KGOG) 3045, we compared the efficacy and safety of two olaparib-based combinations and biomarkers of patients with platinum-resistant ovarian cancer with HRR gene mutations. Patients were randomized to receive either olaparib (200 mg twice a day) + cediranib (30 mg daily) (Arm 1, n = 16) or olaparib (300 mg) + durvalumab (1,500 mg once every 4 weeks) (Arm 2, n = 14). The objective response rates for Arm 1 and Arm 2 were 50.0% and 42.9%, respectively. Most patients (83.3%) had BRCA mutations, which were similarly distributed between arms. Grade 3 or 4 treatment-related adverse events were observed in 37.5% and 35.7% of the patients, respectively, but all were managed properly. A high vascular endothelial growth factor signature was associated with favorable outcomes in Arm 1, whereas immune markers (PD-L1 expression [CPS ≥10], CD8, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio) were associated with favorable outcomes in Arm 2. The activation of homologous recombination pathway upon disease progression was associated with poor response to subsequent therapy. Based on comprehensive biomarker profiling, including immunohistochemistry, whole-exome and RNA sequencing and whole blood-based analyses, we identified biomarkers that could help inform which of the two combination strategies is appropriate given a patient's biomarker status. Our findings have the potential to improve treatment outcome for patients with ovarian cancer in the PARP inhibitor era.

Mirvetuximab soravtansine for platinum-resistant epithelial ovarian cancer.

INTRODUCTION: Mirvetuximab soravtansine (mirvetuximab) is an antibody drug conjugate (ADC) comprised of a humanized folate receptor alpha (FRα)-binding monoclonal antibody attached via a cleavable linker to the cytotoxic maytansinoid molecule, DM4. FRα is expressed in several epithelial cancers, including high grade serous ovarian cancer (HGSOC). Mirvetuximab received accelerated approval by the United States Food and Drug Administration (FDA) in November 2022 based on the results of the SORAYA trial, which tested mirvetuximab for the treatment of patients with recurrent platinum resistant HGSOC with high FRα expression and showed an overall response rate (ORR) of 32.4% and a median duration of response of 6.9 months. Mirvetuximab toxicities included low grade ocular and gastrointestinal toxicities. The National Comprehensive Cancer Network (NCCN) ovarian cancer 2023 guidelines adopted mirvetuximab as 2A, and mirvetuximab combined with bevacizumab as 2B, recommendations. AREAS COVERED: This manuscript will review the preclinical and clinical development of mirvetuximab, the toxicities associated with mirvetuximab and mitigation strategies, and future applications of mirvetuximab. EXPERT OPINION: Mirvetuximab represents the first biomarker-directed therapy with an indication specifically for the treatment of PROC. The efficacy and favorable safety profile support further development of mirvetuximab and mirvetuximab combinations in platinum sensitive and newly diagnosed ovarian cancer.