Bringing new medicines to women with epithelial ovarian cancer: what is the unmet medical need?

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.

A Targeted Thorium-227 Conjugate Demonstrates Efficacy in Preclinical Models of Acquired Drug Resistance and Combination Potential with Chemotherapeutics and Antiangiogenic Therapies

Targeted alpha therapies (TAT) are an innovative class of therapies for cancer treatment. The unique mode-of-action of TATs is the induction of deleterious DNA double-strand breaks. Difficult-to-treat cancers, such as gynecologic cancers upregulating the chemoresistance P-glycoprotein (p-gp) and overexpressing the membrane protein mesothelin (MSLN), are promising targets for TATs. Here, based on the previous encouraging findings with monotherapy, we investigated the efficacy of the mesothelin-targeted thorium-227 conjugate (MSLN-TTC) both as monotherapy and in combination with chemotherapies and antiangiogenic compounds in ovarian and cervical cancer models expressing p-gp. MSLN-TTC monotherapy showed equal cytotoxicity in vitro in p-gp-positive and -negative cancer cells, while chemotherapeutics dramatically lost activity on p-gp-positive cancer cells. In vivo, MSLN-TTC exhibited dose-dependent tumor growth inhibition with treatment/control ratios of 0.03-0.44 in various xenograft models irrespective of p-gp expression status. Furthermore, MSLN-TTC was more efficacious in p-gp-expressing tumors than chemotherapeutics. In the MSLN-expressing ST206B ovarian cancer patient-derived xenograft model, MSLN-TTC accumulated specifically in the tumor, which combined with pegylated liposomal doxorubicin (Doxil), docetaxel, bevacizumab, or regorafenib treatment induced additive-to-synergistic antitumor efficacy and substantially increased response rates compared with respective monotherapies. The combination treatments were well tolerated and only transient decreases in white and red blood cells were observed. In summary, we demonstrate that MSLN-TTC treatment shows efficacy in p-gp-expressing models of chemoresistance and has combination potential with chemo- and antiangiogenic therapies.

Discovery and development of botanical natural products and their analogues as therapeutics for ovarian cancer

Covering: 2015 through the end of July 2022Ovarian cancer is one of the most common cancers affecting the female reproductive organs and has the highest mortality rate among gynecological cancers. Although botanical drugs and their derivatives, namely members of the taxane and camptothecin families, represent significant therapeutics currently available for the treatment of ovarian cancer, new drugs that have alternative mechanisms of action are still needed to combat the disease. For this reason, many efforts to identify additional novel compounds from botanical sources, along with the further development of existing therapeutics, have continued to appear in the literature. This review is designed to serve as a comprehensive look at both the currently available small-molecule therapeutic options and the recently reported botanically-derived natural products currently being studied and developed as potential future therapeutics that could one day be used against ovarian cancer. Specifically, key properties, structural features, and biological data are highlighted that are important for the successful development of potential agents. Recently reported examples are specifically discussed in the context of "drug discovery attributes," including the presence of structure-activity relationship, mechanism of action, toxicity, and pharmacokinetic studies, to help indicate the potential for future development and to highlight where these compounds currently exist in the development process. The lessons learned from both the successful development of the taxanes and camptothecins, as well as the strategies currently being employed for new drug development, are expected to ultimately help guide the future development of botanical natural products for ovarian cancer.

Efficacy and safety of rucaparib treatment in patients with BRCA-mutated, relapsed ovarian cancer: final results from Study 10

BACKGROUND

Study 10, a four-part Phase 1/2 study, evaluated oral rucaparib monotherapy in patients with advanced solid tumours. Here we report the final efficacy and safety results in heavily pretreated patients with ovarian cancer who received rucaparib in Study 10 Parts 2A and 2B.

METHODS

Parts 2A and 2B (Phase 2 portions) enrolled patients with relapsed, high-grade, platinum-sensitive or platinum-resistant, BRCA-mutated ovarian cancer who had received 2-4 (Part 2A) or 3-4 (Part 2B) prior chemotherapies. Patients received oral rucaparib 600 mg twice daily (starting dose). The primary endpoint was the investigator-assessed objective response rate (ORR) by RECIST v1.1.

RESULTS

Fifty-four patients were enrolled: 42 in Part 2A (all had platinum-sensitive disease) and 12 in Part 2B (4 with platinum-sensitive disease; 8 with platinum-resistant disease). ORR was 59.3% (95% CI 45.0-72.4%). The median time to onset of the most common nonhaematological treatment-emergent adverse events (TEAEs) was typically early (<56 days) and was later for haematological TEAEs (53-84 days). The median duration of grade ≥3 TEAEs was ≤13 days.

CONCLUSIONS

In patients with relapsed, platinum-sensitive or platinum-resistant germline BRCA-mutant high-grade ovarian cancer who had received ≥2 prior chemotherapies, rucaparib had robust antitumour activity with a safety profile consistent with prior reports.

CLINICAL TRIAL REGISTRATION

NCT01482715.

The deubiquitinase USP8 regulates ovarian cancer cell response to cisplatin by suppressing apoptosis

The identification of therapeutic approaches to improve response to platinum-based therapies is an urgent need for ovarian carcinoma. Deubiquitinases are a large family of ubiquitin proteases implicated in a variety of cellular functions and may contribute to tumor aggressive features through regulation of processes such as proliferation and cell death. Among the subfamily of ubiquitin-specific peptidases, USP8 appears to be involved in modulation of cancer cell survival by still poorly understood mechanisms. Thus, we used ovarian carcinoma cells of different histotypes, including cisplatin-resistant variants with increased survival features to evaluate the efficacy of molecular targeting of USP8 as a strategy to overcome drug resistance/modulate cisplatin response. We performed biochemical analysis of USP8 activity in pairs of cisplatin-sensitive and -resistant cells and found increased USP8 activity in resistant cells. Silencing of USP8 resulted in decreased activation of receptor tyrosine kinases and increased sensitivity to cisplatin in IGROV-1/Pt1 resistant cells as shown by colony forming assay. Increased cisplatin sensitivity was associated with enhanced cisplatin-induced caspase 3/7 activation and apoptosis, a phenotype also observed in cisplatin sensitive cells. Increased apoptosis was linked to FLIP_L decrease and cisplatin induction of caspase 3 in IGROV-1/Pt1 cells, cisplatin-induced claspin and survivin down-regulation in IGROV-1 cells, thereby showing a decrease of anti-apoptotic proteins. Immunohistochemical staining on 65 clinical specimens from advanced stage ovarian carcinoma indicated that 40% of tumors were USP8 positive suggesting that USP8 is an independent prognostic factor for adverse outcome when considering progression free survival as a clinical end-point. Taken together, our results support that USP8 may be of diagnostic value and may provide a therapeutic target to improve the efficacy of platinum-based therapy in ovarian carcinoma.

Predicting 180-day mortality for women with ovarian cancer using machine learning and patient-reported outcome data

Contrary to national guidelines, women with ovarian cancer often receive treatment at the end of life, potentially due to the difficulty in accurately estimating prognosis. We trained machine learning algorithms to guide prognosis by predicting 180-day mortality for women with ovarian cancer using patient-reported outcomes (PRO) data. We collected data from a single academic cancer institution in the United States. Women completed biopsychosocial PRO measures every 90 days. We randomly partitioned our dataset into training and testing samples. We used synthetic minority oversampling to reduce class imbalance in the training dataset. We fitted training data to six machine learning algorithms and combined their classifications on the testing dataset into an unweighted voting ensemble. We assessed each algorithm's accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) using testing data. We recruited 245 patients who completed 1319 PRO assessments. The final voting ensemble produced state-of-the-art results on the task of predicting 180-day mortality for ovarian cancer paitents (Accuracy = 0.79, Sensitivity = 0.71, Specificity = 0.80, AUROC = 0.76). The algorithm correctly identified 25 of the 35 women in the testing dataset who died within 180 days of assessment. Machine learning algorithms trained using PRO data offer encouraging performance in predicting whether a woman with ovarian cancer will die within 180 days. This model could be used to drive data-driven end-of-life care and address current shortcomings in care delivery. Our model demonstrates the potential of biopsychosocial PROM information to make substantial contributions to oncology prediction modeling. This model could inform clinical decision-making Future research is needed to validate these findings in a larger, more diverse sample.

Caffeic acid phenethyl ester targets ubiquitin-specific protease 8 and synergizes with cisplatin in endometrioid ovarian carcinoma cells

Deubiquitinases (DUBs) mediate the removal of ubiquitin from diverse proteins that participate in the regulation of cell survival, DNA damage repair, apoptosis and drug resistance. Previous studies have shown an association between activation of cell survival pathways and platinum-drug resistance in ovarian carcinoma cell lines. Among the strategies available to inhibit DUBs, curcumin derivatives appear promising, thus we hypothesized their use to enhance the efficacy of cisplatin in ovarian carcinoma preclinical models. The caffeic acid phenethyl ester (CAPE), inhibited ubiquitin-specific protease 8 (USP8), but not proteasomal DUBs in cell-free assays. When CAPE was combined with cisplatin in nine cell lines representative of various histotypes a synergistic effect was observed in TOV112D cells and in the cisplatin-resistant IGROV-1/Pt1 variant, both of endometrioid type and carrying mutant TP53. In the latter cells, persistent G1 accumulation upon combined treatment associated with p27^kip1 protein levels was observed. The synergy was not dependent on apoptosis induction, and appeared to occur in cells with higher USP8 levels. In vivo antitumor activity studies supported the advantage of the combination of CAPE and cisplatin in the subcutaneous model of cisplatin-resistant IGROV-1/Pt1 ovarian carcinoma as well as CAPE activity on intraperitoneal disease. This study reveals the therapeutic potential of CAPE in cisplatin-resistant ovarian tumors as well as in tumors expressing USP8.

Pilot Study of Combination Gemogenovatucel-T (Vigil) and Durvalumab in Women With Relapsed BRCA-wt Triple-Negative Breast or Ovarian Cancer

Background:

Gemogenovatucel-T (Vigil) is a triple-function autologous tumor cell immunotherapy which expresses granulocyte-macrophage colony-stimulating factor and decreases expression of furin and downstream TGF-β1 and TGF-β2. Vigil has suggested survival benefit in frontline maintenance ovarian cancer patients who are BRCA-wt. In addition, Vigil demonstrates relapse-free and overall survival advantage in homologous recombination-proficient patients with OC. Further evidence of clinical benefit and safety has been demonstrated in combination with atezolizumab.

Methods:

In this pilot study (NCT02725489), the concurrent combination of the programmed death-ligand 1 (PD-L1) inhibitor durvalumab and Vigil was explored in advanced BRCA-wt relapsed triple-negative breast cancer (TNBC) patients and stage III-IV recurrent/refractory OC patients. Patients received the combination regimen of Vigil (1 × 10e6-10e7 cells/dose intradermally, up to 12 doses) and durvalumab (1500 mg/dose intravenous infusion, up to 12 months) once every 4 weeks. The primary objective was to evaluate safety of this combination. The study included 13 BRCA-wt patients (TNBC, n = 8; OC, n = 5).

Results:

The most common treatment-emergent adverse events (⩾20%) in all patients included injection-site reaction (92.3%), myalgia (38.5%), bruise at injection site (23.1%), and pruritus (23.1%). Three grade 3 treatment-related adverse events were observed and related to durvalumab. There were no grade 4/5 treatment-related adverse events. Median progression-free survival was 7.1 months and the median overall survival was not reached. Prolonged progression-free survival was improved in patients with PD-L1+ tumors (n = 8, hazard ratio = 0.304, 95% confidence interval, 0.0593-1.56, 1-sided P = .04715) compared with those with PD-L1− tumors.

Conclusions:

Vigil plus durvalumab was well tolerated and showed promising clinical activity in advanced BRCA-wt TNBC and stage III-IV recurrent/refractory OC patients.

Phase 1 study of the ATR inhibitor berzosertib in combination with cisplatin in patients with advanced solid tumours

BACKGROUND

Berzosertib (formerly M6620, VX-970) is a highly potent and selective, first-in-class ataxia telangiectasia-mutated and Rad3-related protein kinase (ATR) inhibitor. We assessed the safety, tolerability, pharmacokinetics, and preliminary efficacy of berzosertib plus cisplatin.

METHODS

Adult patients with advanced solid tumours refractory or resistant to standard of care therapies received ascending doses of cisplatin (day 1) and berzosertib (days 2 and 9) every 3 weeks (Q3W).

RESULTS

Thirty-one patients received berzosertib (90-210 mg/m²) and cisplatin (40-75 mg/m²) across seven dose levels. The most common grade ≥3 treatment-emergent adverse events were neutropenia (20.0%) and anaemia (16.7%). There were two dose-limiting toxicities: a grade 3 hypersensitivity reaction and a grade 3 increase in alanine aminotransferase. Berzosertib 140 mg/m² (days 2 and 9) and cisplatin 75 mg/m² (day 1) Q3W was determined as the recommended Phase 2 dose. Cisplatin had no apparent effect on berzosertib pharmacokinetics. Of the 31 patients, four achieved a partial response (two confirmed and two unconfirmed) despite having previously experienced disease progression following platinum-based chemotherapy.

CONCLUSIONS

Berzosertib plus cisplatin is well tolerated and shows preliminary clinical activity in patients with advanced solid tumours, warranting further evaluation in a Phase 2 setting.

CLINICAL TRIALS IDENTIFIER

NCT02157792.

Chemotherapy with or without avelumab followed by avelumab maintenance versus chemotherapy alone in patients with previously untreated epithelial ovarian cancer (JAVELIN Ovarian 100): an open-label, randomised, phase 3 trial

BACKGROUND

Although most patients with epithelial ovarian cancer respond to frontline platinum-based chemotherapy, around 70% will relapse within 3 years. The phase 3 JAVELIN Ovarian 100 trial compared avelumab (anti-PD-L1 monoclonal antibody) in combination with chemotherapy followed by avelumab maintenance, or chemotherapy followed by avelumab maintenance, versus chemotherapy alone in patients with treatment-naive epithelial ovarian cancer.

METHODS

JAVELIN Ovarian 100 was a global, open-label, three-arm, parallel, randomised, phase 3 trial run at 159 hospitals and cancer treatment centres in 25 countries. Eligible women were aged 18 years and older with stage III-IV epithelial ovarian, fallopian tube, or peritoneal cancer (following debulking surgery, or candidates for neoadjuvant chemotherapy), and had an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned (1:1:1) via interactive response technology to receive chemotherapy (six cycles; carboplatin dosed at an area under the serum-concentration-time curve of 5 or 6 intravenously every 3 weeks plus paclitaxel 175 mg/m² every 3 weeks or 80 mg/m² once a week [investigators' choice]) followed by avelumab maintenance (10 mg/kg intravenously every 2 weeks; avelumab maintenance group); chemotherapy plus avelumab (10 mg/kg intravenously every 3 weeks) followed by avelumab maintenance (avelumab combination group); or chemotherapy followed by observation (control group). Randomisation was in permuted blocks of size six and stratified by paclitaxel regimen and resection status. Patients and investigators were masked to assignment to the two chemotherapy groups without avelumab at the time of randomisation until completion of the chemotherapy phase. The primary endpoint was progression-free survival assessed by blinded independent central review in all randomly assigned patients (analysed by intention to treat). Safety was analysed in all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02718417. The trial was fully enrolled and terminated at interim analysis due to futility, and efficacy is no longer being assessed.

FINDINGS

Between May 19, 2016 and Jan 23, 2018, 998 patients were randomly assigned (avelumab maintenance n=332, avelumab combination n=331, and control n=335). At the planned interim analysis (data cutoff Sept 7, 2018), prespecified futility boundaries were crossed for the progression-free survival analysis, and the trial was stopped as recommended by the independent data monitoring committee and endorsed by the protocol steering committee. Median follow-up for progression-free survival for all patients was 10·8 months (IQR 7·1-14·9); 11·1 months (7·0-15·3) for the avelumab maintenance group, 11·0 months (7·4-14·5) for the avelumab combination group, and 10·2 months (6·7-14·0) for the control group. Median progression-free survival was 16·8 months (95% CI 13·5-not estimable [NE]) with avelumab maintenance, 18·1 months (14·8-NE) with avelumab combination treatment, and NE (18·2 months-NE) with control treatment. The stratified hazard ratio for progression-free survival was 1·43 (95% CI 1·05-1·95; one-sided p=0·99) with the avelumab maintenance regimen and 1·14 (0·83-1·56; one-sided p=0·79) with the avelumab combination regimen, versus control treatment. The most common grade 3-4 adverse events were anaemia (69 [21%] patients in the avelumab maintenance group, 63 [19%] in the avelumab combination group, and 53 [16%] in the control group), neutropenia (91 [28%], 99 [30%], and 88 [26%]), and neutrophil count decrease (49 [15%], 45 [14%], and 59 [18%]). Serious adverse events of any grade occurred in 92 (28%) patients in the avelumab maintenance group, 118 (36%) in the avelumab combination group, and 64 (19%) in the control group. Treatment-related deaths occurred in one (<1%) patient in the avelumab maintenance group (due to atrial fibrillation) and one (<1%) patient in the avelumab combination group (due to disease progression).

INTERPRETATION

Although no new safety signals were observed, results do not support the use of avelumab in the frontline treatment setting. Alternative treatment regimens are needed to improve outcomes in patients with advanced epithelial ovarian cancer.

FUNDING

Pfizer and Merck KGaA, Darmstadt, Germany.

Verticillin A Causes Apoptosis and Reduces Tumor Burden in High-Grade Serous Ovarian Cancer by Inducing DNA Damage

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy in women worldwide and the fifth most common cause of cancer-related deaths among U.S. women. New therapies are needed to treat HGSOC, particularly because most patients develop resistance to current first-line therapies. Many natural product and fungal metabolites exhibit anticancer activity and represent an untapped reservoir of potential new agents with unique mechanism(s) of action. Verticillin A, an epipolythiodioxopiperazine alkaloid, is one such compound, and our recent advances in fermentation and isolation are now enabling evaluation of its anticancer activity. Verticillin A demonstrated cytotoxicity in HGSOC cell lines in a dose-dependent manner with a low nmol/L IC₅₀ Furthermore, treatment with verticillin A induced DNA damage and caused apoptosis in HGSOC cell lines OVCAR4 and OVCAR8. RNA-Seq analysis of verticillin A-treated OVCAR8 cells revealed an enrichment of transcripts in the apoptosis signaling and the oxidative stress response pathways. Mass spectrometry histone profiling confirmed reports that verticillin A caused epigenetic modifications with global changes in histone methylation and acetylation marks. To facilitate in vivo delivery of verticillin A and to monitor its ability to reduce HGSOC tumor burden, verticillin A was encapsulated into an expansile nanoparticle (verticillin A-eNP) delivery system. In an in vivo human ovarian cancer xenograft model, verticillin A-eNPs decreased tumor growth and exhibited reduced liver toxicity compared with verticillin A administered alone. This study confirmed that verticillin A has therapeutic potential for treatment of HGSOC and that encapsulation into expansile nanoparticles reduced liver toxicity.

Network Pharmacology-Based and Clinically Relevant Prediction of the Potential Targets of Chinese Herbs in Ovarian Cancer Patients

Reports increasingly suggest that Chinese herbal medicine (CHM) has been used to treat ovarian cancer (OvCa) with a good curative effect; however, the molecular mechanisms underlying CHM are still unclear. In this retrospective study, we explored CHM's molecular targets for the treatment of OvCa based on clinical data and network pharmacology. We used the Kaplan-Meier method and Cox regression analysis to verify the survival rate of 202 patients with CHM-treated OvCa. The association between CHM and survival time was analyzed by bivariate correlation. A target network of CHM active ingredients against OvCa was established via network pharmacology. Cox regression analysis showed that CHM is an independent favorable prognostic factor. The median survival time was 91 months in the CHM group and 65 months in the non-CHM group. The survival time of FIGO stage III patients in the two groups was 91 months and 52 months, and the median survival period of FIOG stage IV patients was 60 months and 22 months, respectively (p < 0.001). Correlation analysis demonstrated that 12 herbs were closely associated with prognosis, especially in regard to the long-term benefits. Bioinformatics analysis indicated that the anti-OvCa activity of these 12 herbs occurs mainly through the regulation of apoptosis-related protein expression, which promotes OvCa cell apoptosis and inhibits OvCa development. They also regulate the progress of OvCa treatment by promoting or inhibiting protein expression on the p53 signaling pathway and by inhibiting the NF-κB signaling pathway by directly inhibiting NF-κB.

Real world experience of poly (ADP-ribose) polymerase inhibitor use in a community oncology practice

OBJECTIVE

This study aims to describe the real-world experience, including the clinical and financial burden, associated with PARP inhibitors in a large community oncology practice.

METHODS

Retrospective chart review identified patients prescribed olaparib, niraparib or rucaparib for maintenance therapy or treatment of recurrent ovarian, primary peritoneal or fallopian tube cancer across twelve gynecologic oncologists between December 2016 and November 2018. Demographic, financial and clinical data were extracted. One PARP cycle was defined as a single 28-day period. For patients treated with more than one PARPi, each course was described separately.

RESULTS

A total of 47 patients and 506 PARP cycles were identified (122 olaparib, 24%; 89 rucaparib, 18%; 294 niraparib, 58%). Incidence of grade ≥ 3 adverse events were similar to previously reported. Toxicity resulted in dose interruption, reduction and discontinuation in 69%, 63% and 29% respectively. Dose interruptions were most frequent for niraparib but resulted in fewer discontinuations (p-value 0.01). Mean duration of use was 7.46 cycles (olaparib 10.52, rucaparib 4.68, niraparib 7.34). Average cost of PARPi therapy was $8018 per cycle. A total of 711 phone calls were documented (call rate 1.4 calls/cycle) with the highest call volume required for care coordination, lab results and toxicity management.

CONCLUSIONS

Although the toxicity profile was similar to randomized clinical trials, this real-world experience demonstrated more dose modifications and discontinuations for toxicity management than previously reported. Furthermore, the clinical and financial burden of PARP inhibitors may be significant and future studies should assess the impact on patient outcomes.

Tamrintamab pamozirine (SC-003) in patients with platinum-resistant/refractory ovarian cancer: Findings of a phase 1 study

OBJECTIVE

Epithelial ovarian carcinoma (EOC) is diagnosed at advanced stage in the majority of women and, despite being initially chemosensitive, eventually recurs and develops resistance to known therapies. SC-003 is a pyrrolobenzodiazepine-based antibody-drug conjugate targeting dipeptidase 3 (DPEP3), a membrane-bound dipeptidase associated with tumor-initiating cells in patient-derived EOC xenograft models. This first-in-human phase 1a/1b study evaluated the safety/tolerability, pharmacokinetics, and preliminary antitumor activity of SC-003 alone or in combination with budigalimab (formerly ABBV-181), an antibody targeting PD-1, in patients with platinum-resistant/refractory EOC (NCT02539719).

METHODS

Patients received SC-003 at 1 of 6 dose levels (0.025-0.4 mg/kg) every 3 weeks (Q3W), utilizing a standard 3 + 3 design (dose-limiting toxicity [DLT] period: 21 days). Patients with DPEP3-positive tumors were enrolled in the dose-expansion phase of the study and treated with SC-003 monotherapy or in combination with budigalimab.

RESULTS

Seventy-four patients (n = 29, dose escalation; n = 45, dose expansion; n = 3 budigalimab combination) were enrolled and received ≥1 dose of study drug. One DLT occurred (grade 3 ileus) but was considered unrelated to study drug. The MTD for the Q3W schedule was 0.3 mg/kg and the SC-003 doses selected for the dose-expansion phase of the study were 0.3 mg/kg and 0.2 mg/kg. The most common treatment-emergent adverse events were fatigue, nausea, decreased appetite, pleural effusion, abdominal pain, and peripheral edema. The overall response rate was low (4%), and responses were not durable. Post-hoc examination of antitumor activity suggested a higher response rate in patients with higher DPEP3 expression.

CONCLUSIONS

SC-003 lacked the requisite safety profile and antitumor activity to warrant further development.

Real-world direct healthcare costs of treating recurrent high-grade serous ovarian cancer with cytotoxic chemotherapy

Aim: To describe the direct healthcare costs associated with repeated cytotoxic chemotherapy treatments for recurrent high-grade serous cancer (HGSC) of the ovaries. Patients & methods: Retrospective review of 66 women with recurrent stage III/IV HGSC ovarian cancer treated with repeated lines of cytotoxic chemotherapy in a Canadian University Tertiary Center. Results: Mean cost of treatment of first relapse was CAD$52,227 increasing by 38% for two, and 86% for three or more relapses with median overall survival of 36.0, 50.7 and 42.8 months, respectively. In-hospital care accounted for 71% and chemotherapy drugs accounted for 17% of the total costs. Conclusion: After the third relapse of HGSC, cytotoxic chemotherapy did not prolong survival but was associated with substantially increased healthcare costs.

Survivin Promotes Piperlongumine Resistance in Ovarian Cancer

Ovarian cancer is one of the most fatal female malignancies while targeting apoptosis is critical for improving ovarian cancer patients' lives. Survivin is regarded as the most robust anti-apoptosis protein, and its overexpression in ovarian cancer is related to poor survival and apoptosis resistance. Piperlongumine (PL) extracted from peppers is defined as an active alkaloid/amide and exhibits a broad spectrum of antitumor effects. Here, we demonstrate that PL induces the rapid depletion of survivin protein levels via reactive oxygen species (ROS)-mediated proteasome-dependent pathway in vitro, while exerting a remarkable inhibitory influence on the proliferation of ovarian cancer cells. Overexpression of survivin raises the survival rate of ovarian cancer cells to PL. Moreover, PL inhibits ovarian cancer cells xenograft tumor growth and downregulates survivin in vivo. Our findings reveal a previously unrecognized mechanism of PL in suppressing survivin expression as well as survivin promotes piperlongumine resistance in ovarian cancer and suggest that ROS-mediated proteasome-dependent pathway can be exploited to overcome apoptosis resistance triggered by aberrant expression of survivin.

Maintenance therapy for recurrent epithelial ovarian cancer: current therapies and future perspectives - a review

Epithelial ovarian cancer (EOC) is usually diagnosed late at an advanced stage. Though EOC initially responds to treatment, the recurrence rate is pretty high. The efficacy of different targeted therapies reduces with each recurrence. Hence there is need of effective maintenance therapy in recurrent EOC. Recently, polyADP-ribose polymerase (PARP) inhibitors (PARPi) have been approved both for initial treatment of EOC and as its maintenance treatment. PARPi have also been found to act regardless of BRCA status or homologous recombination (HR) deficiency. Several trials testing PARPi early in maintenance therapy are in progress and their results will shed light on the optimal timing of maintenance therapy that gives the most benefit with least toxicity. Right patient selection for maintenance treatment is also a challenge. Hence, though PARPi are emerging as a promising maintenance treatment in recurrent EOC with prolongation of progression free survival (PFS), results from further trials and overall survival (OS) data from current trials are awaited to fulfill the gaps in understanding the role of this pathway in treatment of EOC. This review discusses the current therapies for EOC, challenges in the treatment of recurrent EOC, recent developments and trials in recurrent EOC maintenance with special focus on PARPi and future perspectives.

Efficacy and Safety of Avelumab for Patients With Recurrent or Refractory Ovarian Cancer: Phase 1b Results From the JAVELIN Solid Tumor Trial

Importance

Current treatment options for progressive ovarian cancer provide limited benefit, particularly in patients whose disease has become resistant to platinum-based chemotherapy.

Objective

To assess the efficacy and safety of avelumab, an anti-programmed death-ligand 1 agent, in a cohort of patients with previously treated recurrent or refractory ovarian cancer.

Design, Setting, and Participants

In an expansion cohort of a phase 1b, open-label study (JAVELIN Solid Tumor), 125 patients with advanced ovarian cancer who had received chemotherapy including a platinum agent were enrolled between November 6, 2013, and August 27, 2015. Statistical analysis was performed from December 31, 2016, to October 9, 2018.

Intervention

Patients received avelumab, 10 mg/kg, every 2 weeks until disease progression, unacceptable toxic effects, or withdrawal from the study.

Main Outcomes and Measures

Prespecified end points in this cohort included confirmed best overall response (per Response Evaluation Criteria In Solid Tumors, version 1.1), immune-related best overall response, duration of response, progression-free survival, overall survival, results of programmed death-ligand 1 expression-based analyses, and safety.

Results

A total of 125 women (median age, 62.0 years [range, 27-84 years]) who had received a median of 3 prior lines of treatment (range, 0-10) for advanced disease were enrolled in the study. Patients received avelumab for a median of 2.8 months (range, 0.5-27.4 months), with a median follow-up of 26.6 months (range, 16-38 months). A confirmed objective response occurred in 12 patients (9.6%; 95% CI, 5.1%-16.2%), including a complete response in 1 patient (0.8%) and a partial response in 11 patients (8.8%). The 1-year progression-free survival rate was 10.2% (95% CI, 5.4%-16.7%) and median overall survival was 11.2 months (95% CI, 8.7-15.4 months). Infusion-related reactions occurred in 25 patients (20.0%). Other frequent treatment-related adverse events (any grade event occurring in ≥10% of patients) were fatigue (17 [13.6%]), diarrhea (15 [12.0%]), and nausea (14 [11.2%]). Grade 3 or higher treatment-related adverse events occurred in 9 patients (7.2%), of which only the level of lipase increased (3 [2.4%]) occurred in more than 1 patient. Twenty-one patients (16.8%) had an immune-related adverse event of any grade. No treatment-related deaths occurred.

Conclusions and Relevance

Avelumab demonstrated antitumor activity and acceptable safety in heavily pretreated patients with recurrent or refractory ovarian cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT01772004.

Efficacy and Safety of Avelumab for Patients With Recurrent or Refractory Ovarian Cancer: Phase 1b Results From the JAVELIN Solid Tumor Trial

Importance

Current treatment options for progressive ovarian cancer provide limited benefit, particularly in patients whose disease has become resistant to platinum-based chemotherapy.

Objective

To assess the efficacy and safety of avelumab, an anti-programmed death-ligand 1 agent, in a cohort of patients with previously treated recurrent or refractory ovarian cancer.

Design, Setting, and Participants

In an expansion cohort of a phase 1b, open-label study (JAVELIN Solid Tumor), 125 patients with advanced ovarian cancer who had received chemotherapy including a platinum agent were enrolled between November 6, 2013, and August 27, 2015. Statistical analysis was performed from December 31, 2016, to October 9, 2018.

Intervention

Patients received avelumab, 10 mg/kg, every 2 weeks until disease progression, unacceptable toxic effects, or withdrawal from the study.

Main Outcomes and Measures

Prespecified end points in this cohort included confirmed best overall response (per Response Evaluation Criteria In Solid Tumors, version 1.1), immune-related best overall response, duration of response, progression-free survival, overall survival, results of programmed death-ligand 1 expression-based analyses, and safety.

Results

A total of 125 women (median age, 62.0 years [range, 27-84 years]) who had received a median of 3 prior lines of treatment (range, 0-10) for advanced disease were enrolled in the study. Patients received avelumab for a median of 2.8 months (range, 0.5-27.4 months), with a median follow-up of 26.6 months (range, 16-38 months). A confirmed objective response occurred in 12 patients (9.6%; 95% CI, 5.1%-16.2%), including a complete response in 1 patient (0.8%) and a partial response in 11 patients (8.8%). The 1-year progression-free survival rate was 10.2% (95% CI, 5.4%-16.7%) and median overall survival was 11.2 months (95% CI, 8.7-15.4 months). Infusion-related reactions occurred in 25 patients (20.0%). Other frequent treatment-related adverse events (any grade event occurring in ≥10% of patients) were fatigue (17 [13.6%]), diarrhea (15 [12.0%]), and nausea (14 [11.2%]). Grade 3 or higher treatment-related adverse events occurred in 9 patients (7.2%), of which only the level of lipase increased (3 [2.4%]) occurred in more than 1 patient. Twenty-one patients (16.8%) had an immune-related adverse event of any grade. No treatment-related deaths occurred.

Conclusions and Relevance

Avelumab demonstrated antitumor activity and acceptable safety in heavily pretreated patients with recurrent or refractory ovarian cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT01772004.

A phase II evaluation of elesclomol sodium and weekly paclitaxel in the treatment of recurrent or persistent platinum-resistant ovarian, fallopian tube or primary peritoneal cancer: An NRG oncology/gynecologic oncology group study

OBJECTIVE

Preclinical data suggest elesclomol increases oxidative stress and enhances sensitivity to cytotoxic agents. The objective of this prospective multicenter phase 2 trial was to estimate the activity of IV elesclomol plus weekly paclitaxel in patients with platinum-resistant recurrent ovarian, tubal or peritoneal cancer through the frequency of objective tumor responses (ORR).

METHODS

Patients with measurable disease, acceptable organ function, performance status ≤ 2, and one prior platinum containing regimen were eligible. A two-stage design was utilized with a target sample size of 22 and 30 subjects, respectively. Prior Gynecologic Oncology Group studies within the same population involving single agent taxanes showed an ORR of approximately (20%) and served as a historical control for direct comparison. The present study was designed to determine if the regimen had an ORR of ≥40% with 90% power.

RESULTS

Fifty-eight patients were enrolled, of whom 2 received no study treatment and were inevaluable. The median number of cycles was 3 (268 total cycles, range 1-18). The number of patients responding was 11 (19.6%; 90% CI 11.4% to 30.4%) with one complete response. The median progression-free survival and overall survival was 3.6 months and 13.3 months, respectively. The median ORR duration was 9.2 months. Percentages of subjects with grade 3 toxicity included: Neutropenia 9%; anemia 5%; metabolic 5%; nausea 4%; infection 4%; neurologic (mostly neuropathy) 4%; and vascular (mostly thromboembolism) 4%. There were no grade 4 toxicities reported.

CONCLUSIONS

This combination was well tolerated but is unworthy of further investigation based on the proportion responding [ClinicalTrials.gov Identifier: NCT00888615].

Phyllanthusmin Derivatives Induce Apoptosis and Reduce Tumor Burden in High-Grade Serous Ovarian Cancer by Late-Stage Autophagy Inhibition

High-grade serous ovarian cancer (HGSOC) is a lethal gynecological malignancy with a need for new therapeutics. Many of the most widely used chemotherapeutic drugs are derived from natural products or their semi-synthetic derivatives. We have developed potent synthetic analogues of a class of compounds known as phyllanthusmins, inspired by natural products isolated from Phyllanthus poilanei Beille. The most potent analogue, PHY34, had the highest potency in HGSOC cell lines in vitro and displayed cytotoxic activity through activation of apoptosis. PHY34 exerts its cytotoxic effects by inhibiting autophagy at a late stage in the pathway, involving the disruption of lysosomal function. The autophagy activator, rapamycin, combined with PHY34 eliminated apoptosis, suggesting that autophagy inhibition may be required for apoptosis. PHY34 was readily bioavailable through intraperitoneal administration in vivo where it significantly inhibited the growth of cancer cell lines in hollow fibers, as well as reduced tumor burden in a xenograft model. We demonstrate that PHY34 acts as a late-stage autophagy inhibitor with nanomolar potency and significant antitumor efficacy as a single agent against HGSOC in vivo This class of compounds holds promise as a potential, novel chemotherapeutic and demonstrates the effectiveness of targeting the autophagic pathway as a viable strategy for combating ovarian cancer. Mol Cancer Ther; 17(10); 2123-35. ©2018 AACR.

Anetumab ravtansine inhibits tumor growth and shows additive effect in combination with targeted agents and chemotherapy in mesothelin-expressing human ovarian cancer models

Despite the recent advances in the treatment of ovarian cancer, it remains an area of high unmet medical need. Epithelial ovarian cancer is associated with high levels of mesothelin expression, and therefore, mesothelin is an attractive candidate target for the treatment of this disease. Herein, we investigated the antitumor efficacy of the mesothelin-targeting antibody-drug conjugate (ADC) anetumab ravtansine as a novel treatment option for ovarian cancer in monotherapy and in combination with the antitumor agents pegylated liposomal doxorubicin (PLD), carboplatin, copanlisib and bevacizumab. Anetumab ravtansine showed potent antitumor activity as a monotherapy in ovarian cancer models with high mesothelin expression. No activity was seen in mesothelin-negative models. The combination of anetumab ravtansine with PLD showed additive anti-proliferative activity in vitro, which translated into improved therapeutic in vivo efficacy in ovarian cancer cell line- and patient-derived xenograft (PDX) models compared to either agents as a monotherapy. The combination of anetumab ravtansine with the PI3Kα/δ inhibitor copanlisib was additive in the OVCAR-3 and OVCAR-8 cell lines in vitro, showing increased apoptosis in response to the combination treatment. In vivo, the combination of anetumab ravtansine with copanlisib resulted in more potent antitumor activity than either of the treatments alone. Likewise, the combination of anetumab ravtansine with carboplatin or bevacizumab showed improved in vivo efficacy in the ST081 and OVCAR-3 models, respectively. All combinations were well-tolerated. Taken together, these data support the development of anetumab ravtansine for ovarian cancer treatment and highlight its suitability for combination therapy with PLD, carboplatin, copanlisib, or bevacizumab.

Avelumab (anti-PD-L1) in platinum-resistant/refractory ovarian cancer: JAVELIN Ovarian 200 Phase III study design

Avelumab is a human anti-PD-L1 checkpoint inhibitor with clinical activity in multiple solid tumors. Here, we describe the rationale and design for JAVELIN Ovarian 200 (NCT02580058), the first randomized Phase III trial to evaluate the role of checkpoint inhibition in women with ovarian cancer. This three-arm trial is comparing avelumab administered alone or in combination with pegylated liposomal doxorubicin versus pegylated liposomal doxorubicin alone in patients with platinum-resistant/refractory recurrent ovarian, fallopian tube or peritoneal cancer. Eligible patients are not preselected based on PD-L1 expression and may have received up to three prior lines of chemotherapy for platinum-sensitive disease, but none for resistant disease. Overall survival and progression-free survival are primary end points, and secondary end points include biomarker evaluations and pharmacokinetics.

Leptin Regulation of Cancer Stem Cells in Breast and Gynecologic Cancer

It is well established that obesity increases the incidence and worsens the prognosis of women's cancer. For breast cancer, women with obesity exhibit more than a twofold increase in the odds of being diagnosed with cancer, with a greater risk of advanced stage at diagnosis, and ≤40% greater risk of recurrence and death than their normal-weight counterparts. These findings are similar in gynecologic cancers, where women who are obese with a body mass index (BMI) >40 kg/m2 have up to six times greater risk of developing endometrial cancer and a 9.2% increase in mortality with every 10% increase in BMI. Likewise, patients with obesity exhibit a twofold higher risk of premenopausal ovarian cancer, and patients who are obese with advanced stage ovarian cancer have shown a shorter time to recurrence and poorer overall survival. Obesity is accompanied by changes in expression of adipose factors that act on local tissues and systemically. Once obesity was recognized as a factor in cancer incidence and progression, the adipose cytokine (adipokine) leptin became the focus of intense investigation as a putative link, with nearly 3000 publications on the topic. Leptin has been shown to increase cell proliferation, inhibit apoptosis, promote angiogenesis, and increase therapeutic resistance. These characteristics are associated with a subset of cells in both liquid and solid tumors known as cancer stem cells (CSCs), or tumor initiating cells. We will review the literature discussing leptin's role in breast and gynecologic cancer, focusing on its role in CSCs, and consider goals for targeting future therapy in this arena to disrupt tumor initiation and progression in women's cancer.