Efficacy and safety of niraparib as maintenance treatment in older patients (≥ 70 years) with recurrent ovarian cancer: Results from the ENGOT-OV16/NOVA trial

OBJECTIVE

To analyze the safety and efficacy of niraparib in patients aged ≥70 years with recurrent ovarian cancer in the ENGOT-OV16/NOVA trial.

METHODS

The trial enrolled 2 independent cohorts with histologically diagnosed recurrent ovarian, fallopian tube, or peritoneal cancer who responded to platinum rechallenge, on the basis of germline breast cancer susceptibility gene mutation (gBRCAmut) status. Patients were randomized 2:1 to receive niraparib (300 mg) or placebo once daily until disease progression. The primary endpoint was progression-free survival (PFS) by blinded independent central review. Adverse events (AEs) of special interest were based on the known safety profile of poly(ADP-ribose) polymerase inhibitors.

RESULTS

Patients aged ≥70 years in the gBRCAmut cohort receiving niraparib (n = 14) had not yet reached a median PFS compared with a median PFS of 3.7 months for the same age group in the placebo arm (hazard ratio [HR], 0.09 [95% confidence interval (CI), 0.01 to 0.73]). Non-gBRCAmut patients aged ≥70 years receiving niraparib (n = 47) had a median PFS of 11.3 months compared with 3.8 months in the placebo arm (HR, 0.35 [95% CI, 0.18 to 0.71]). Median duration of follow-up in the niraparib arm was 17.3 months in patients ≥70 years and 17.2 months in patients <70 years. Frequency, severity of AEs, and dose reductions in the niraparib arm were similar in patients aged <70 and ≥ 70 years population. The most common grade ≥ 3 AEs in patients ≥70 years were hematologic: thrombocytopenia event (34.4%), anemia event (13.1%), and neutropenia event (16.4%).

CONCLUSIONS

For patients ≥70 years of age receiving niraparib as maintenance treatment in the ENGOT-OV16/NOVA trial, PFS benefits and incidence of any grade or serious treatment-emergent AEs were comparable to results in the younger population. Use of niraparib should be considered in this population.

A randomized phase II study of cabozantinib versus weekly paclitaxel in the treatment of persistent or recurrent epithelial ovarian, fallopian tube or primary peritoneal cancer: An NRG Oncology/Gynecologic Oncology Group study

INTRODUCTION

Cabozantinib is a receptor tyrosine kinases inhibitor that targets MET (c-MET), VEGF receptor 2 (VEGFR2), RET, AXL, KIT, FLT-3, and TIE-2 and previously showed promising single agent activity in recurrent ovarian cancer.

METHODS

This was an open label, 1:1 randomized study of cabozantinib 60 mg orally (PO) daily versus weekly paclitaxel 80 mg/m² given 3 out of 4 weeks (NCT01716715); 111 patients were enrolled. Eligibility included persistent or recurrent epithelial ovarian, fallopian tube, or primary peritoneal carcinoma and at least one but no >3 prior chemotherapy regimens.

RESULTS

Median PFS was similar for both treatment groups and was 5.3 months for cabozantinib and 5.5 months for weekly paclitaxel (HR 1.11 (90% CI 0.77-1.61, p = 0.64)). Secondary analyses of overall survival (OS) and event free survival (EFS) showed that cabozantinib did not perform as well as weekly paclitaxel. Median OS for cabozantinib was 19.4 months and was not reached for weekly paclitaxel (HR 2.27 (90% CI 1.17-4.41, p = 0.04). EFS was also worse in the cabozantinib arm, 3.5 months, compared to weekly paclitaxel at 5.0 months (HR 1.81 (90% CI 1.24-2.63, p = 0.01). Overall response rate (ORR) was less for cabozantinib compared to weekly paclitaxel (7% versus 24.1%). Gastrointestinal toxicities, specifically nausea, diarrhea, and abdominal pain were worse in the cabozantinib arm.

CONCLUSIONS

Median PFS was similar for cabozantinib and weekly paclitaxel. However, OS, EFS, and ORR were worse for cabozantinib compared to weekly paclitaxel. Cabozantinib given at this dose and schedule cannot be recommended as a treatment for recurrent ovarian cancer.

PARP Inhibition Elicits STING-Dependent Antitumor Immunity in Brca1-Deficient Ovarian Cancer

PARP inhibitors have shown promising clinical activities for patients with BRCA mutations and are changing the landscape of ovarian cancer treatment. However, the therapeutic mechanisms of action for PARP inhibition in the interaction of tumors with the tumor microenvironment and the host immune system remain unclear. We find that PARP inhibition by olaparib triggers robust local and systemic antitumor immunity involving both adaptive and innate immune responses through a STING-dependent antitumor immune response in mice bearing Brca1-deficient ovarian tumors. This effect is further augmented when olaparib is combined with PD-1 blockade. Our findings thus provide a molecular mechanism underlying antitumor activity by PARP inhibition and lay a foundation to improve therapeutic outcome for cancer patients.

Targeting MYC dependency in ovarian cancer through inhibition of CDK7 and CDK12/13

High-grade serous ovarian cancer is characterized by extensive copy number alterations, among which the amplification of MYC oncogene occurs in nearly half of tumors. We demonstrate that ovarian cancer cells highly depend on MYC for maintaining their oncogenic growth, indicating MYC as a therapeutic target for this difficult-to-treat malignancy. However, targeting MYC directly has proven difficult. We screen small molecules targeting transcriptional and epigenetic regulation, and find that THZ1 - a chemical inhibiting CDK7, CDK12, and CDK13 - markedly downregulates MYC. Notably, abolishing MYC expression cannot be achieved by targeting CDK7 alone, but requires the combined inhibition of CDK7, CDK12, and CDK13. In 11 patient-derived xenografts models derived from heavily pre-treated ovarian cancer patients, administration of THZ1 induces significant tumor growth inhibition with concurrent abrogation of MYC expression. Our study indicates that targeting these transcriptional CDKs with agents such as THZ1 may be an effective approach for MYC-dependent ovarian malignancies.

Prediction of DNA Repair Inhibitor Response in Short-Term Patient-Derived Ovarian Cancer Organoids

Based on genomic analysis, 50% of high-grade serous ovarian cancers (HGSC) are predicted to have DNA repair defects. Whether this substantial subset of HGSCs actually have functional repair defects remains unknown. Here, we devise a platform for functional profiling of DNA repair in short-term patient-derived HGSC organoids. We tested 33 organoid cultures derived from 22 patients with HGSC for defects in homologous recombination (HR) and replication fork protection. Regardless of DNA repair gene mutational status, a functional defect in HR in the organoids correlated with PARP inhibitor sensitivity. A functional defect in replication fork protection correlated with carboplatin and CHK1 and ATR inhibitor sensitivity. Our results indicate that a combination of genomic analysis and functional testing of organoids allows for the identification of targetable DNA damage repair defects. Larger numbers of patient-derived organoids must be analyzed to determine whether these assays can reproducibly predict patient response in the clinic.Significance: Patient-derived ovarian tumor organoids grow rapidly and match the tumors from which they are derived, both genetically and functionally. These organoids can be used for DNA repair profiling and therapeutic sensitivity testing and provide a rapid means of assessing targetable defects in the parent tumor, offering more suitable treatment options. Cancer Discov; 8(11); 1404-21. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1333.

Reducing infusion wait time: Redesigning medication order verification workflow at a comprehensive cancer center

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Background: Many factors contribute to long wait times for cancer patients on the day of their infusion. At Dana-Farber Cancer Institute (DFCI), a contributing factor is patient flow between exam and infusion. Order verification affects patient flow and begins when the following two criteria are met: provider signed an order and the patient’s scheduled infusion appointment arrives. Patients often check-in to infusion before their scheduled infusion appointment. Order verification has three sequential steps: nurse verification, pharmacist 1 verify (V1), and pharmacist 2 verify (V2). Methods: A team of pharmacists, nurses, providers, and process improvement leads designed a pilot in which V1 moved before nurse verification, concurrent with patient check-in to infusion. Further, V1 began as soon as an order was signed; the pharmacist did not wait for a patient’s scheduled infusion appointment. Nurse verification and V2 occurred in sequence after V1. Timestamp data were extracted from Epic and analyzed via Tableau to assess reduction in verification throughput, defined as time between infusion check-in and V2. Fourteen providers and one pharmacist joined a 6-week pilot to adopt the redesigned workflow beginning 4/23/18. Results: At baseline, time between check-in and V2 was consistent for pilot and non-pilot orders. During the pilot, time between check-in and V2 was shorter for pilot orders, showing a sustained decrease of approximately 10 minutes. The table below provides time in minutes between infusion check-in and V2 for pilot and non-pilot orders at baseline (3/12/18-4/20/18) and following workflow redesign (4/23/18-6/1/18). Conclusions: Implementing the pilot workflow reduced order verification throughput time and enabled drug preparation to begin sooner. Expanding this workflow to all medication orders can decrease infusion wait time at DFCI.[Table: see text]

Reducing infusion wait time: An initiative to increase early signing of medication orders by providers at a comprehensive cancer center

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Background: Many factors contribute to long wait times for oncology patients on the day of their infusion appointment. At Dana-Farber Cancer Institute (DFCI), one of the main causes of delay to infusion start is providers not signing medication orders in advance of patients checking in for their infusion appointment. We conducted a project to improve provider order signing behavior on the gynecology cancer patient infusion floor at DFCI. Methods: A data working group was formed which consisted of the infusion floor medical leads, nurse lead, pharmacy lead, and analytics and process improvement leads. Starting in February 2018, the working group shared baseline order signing data from September 2017 through January 2018 with the Gynecology Cancer Group. Descriptive and timestamp data from Epic were extracted and cleaned via Tableau to analyze the percentage of non-investigational medication orders, including chemotherapy, that were signed after a patient checked into infusion and the distributions of late order signing times. Results: Gynecology cancer patient providers had higher late order signing percentages at baseline (September 2017 through January 2018) than after sharing those data, which occurred from February through May 2018. The table below provides medication order counts and late order signing percentages by month. Although late signing percentages decreased after sharing the baseline data, the distribution of how late the late orders were signed did not show improvement, staying at an average of 20 minutes late. Conclusions: Sharing late order signing data with providers on a routine basis reduced late signing percentages. Initiating this process with all disease groups is crucial so that downstream workflows can start sooner and patient wait times reduced.[Table: see text]

Abstract IA01: PARP inhibitors as single agents and in combinations for ovarian cancer: What lies ahead?

Poly (ADP ribose) polymerase (PARP) inhibitors are an exciting and promising new class of anticancer drugs. Initial clinical trials of PARP inhibitors began over a decade ago following the discovery that PARP inhibitors in vitro had heightened anticancer activity in BRCA mutated cancer cells compared to BRCA wild-type cells. PARP inhibitor clinical development has taken several strategies, including single-agent and combination testing. Single-agent PARP inhibitors have been used as either primary treatment of recurrent ovarian cancer or as maintenance treatment following anticancer response after platinum-based chemotherapy. Three PARP inhibitors are now FDA approved for recurrent ovarian cancer, all as single agents: 1) olaparib for patients with recurrent germline BRCA mutated ovarian cancer who have received 3 or more prior lines of chemotherapy and also as maintenance therapy post-platinum therapy for patients with platinum sensitive recurrence who are in response to platinum-based chemotherapy and regardless of BRCA or tumor HR status; 2) rucaparib for patients with BRCA mutated ovarian cancer (either deleterious tumor or germline mutation) who have received at least 2 prior lines of chemotherapy; and 3) niraparib for platinum-sensitive recurrent ovarian cancer patients as maintenance therapy who are in response to platinum-based chemotherapy and regardless of BRCA or tumor HR status. Because of the myelosuppression observed with PARP inhibitors, combining these agents with chemotherapy has been difficult and has required lowering the doses of either the PARP inhibitor and/or the chemotherapy agents and often abbreviating the treatment schedule; several negative phase III studies have been reported. Combining PARP inhibitors with biologic agents is another strategy currently being tested in clinical trials and one that avoids overlapping toxicities. The combination of the PARP inhibitor olaparib and the antivascular endothelial growth factor receptor agent cediranib has shown promising phase II results against olaparib alone, especially in BRCA wild-type ovarian cancer. These results have led to phase III studies comparing the olaparib and cediranib combination to standard therapies (NCT02502266 and NCT02446600). Other studies are under way testing PARP inhibitors with other biologic agents such as immunotherapy agents and other targeted agents such as ATR inhibitors, PI3 kinase inhibitors, and heat shock protein 90 inhibitors.

Citation Format: Ursula A. Matulonis. PARP inhibitors as single agents and in combinations for ovarian cancer: What lies ahead? [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr IA01.

BRAF and AXL oncogenes drive RIPK3 expression loss in cancer

Necroptosis is a lytic programmed cell death mediated by the RIPK1-RIPK3-MLKL pathway. The loss of Receptor-interacting serine/threonine-protein kinase 3 (RIPK3) expression and necroptotic potential have been previously reported in several cancer cell lines; however, the extent of this loss across cancer types, as well as its mutational drivers, were unknown. Here, we show that RIPK3 expression loss occurs progressively during tumor growth both in patient tumor biopsies and tumor xenograft models. Using a cell-based necroptosis sensitivity screen of 941 cancer cell lines, we find that escape from necroptosis is prevalent across cancer types, with an incidence rate of 83%. Genome-wide bioinformatics analysis of this differential necroptosis sensitivity data in the context of differential gene expression and mutation data across the cell lines identified various factors that correlate with resistance to necroptosis and loss of RIPK3 expression, including oncogenes BRAF and AXL. Inhibition of these oncogenes can rescue the RIPK3 expression loss and regain of necroptosis sensitivity. This genome-wide analysis also identifies that the loss of RIPK3 expression is the primary factor correlating with escape from necroptosis. Thus, we conclude that necroptosis resistance of cancer cells is common and is oncogene driven, suggesting that escape from necroptosis could be a potential hallmark of cancer, similar to escape from apoptosis.

Abstract 139: DNA damage and immunoprofiling with highly multiplexed tissue immunofluorescence (t-CycIF) in high-grade serous ovarian cancer

Immune checkpoint blockade (ICB) has emerged as a new promising therapeutic approach in multiple cancers, however, the responses to single-agent ICBs have been modest in high-grade serous ovarian cancer (HGSOC). Preclinical- and early clinical data show promising efficacy of combining DNA damaging agents with immunotherapy. An improved understanding of the interplay between DNA damage in cancer cells and anti-tumor immune responses may therefore accelerate the development of rational drug combinations and identify predictive biomarkers. The majority of HGSOC are deficient in homologous recombination (HR) DNA repair, and use alternative, error-prone DNA repair pathways, that have been shown to be associated with increased immune recognition (Strickland et al, 2016). Compelling evidence has shown that DNA damaging agents increase the expression of immune-regulatory genes, such as MCH class I antigens, and interferons in HR deficient tumors. Further, HR deficient tumor exhibit an increased response to ICBs, and DNA damage-driven activation of interferon signalling has been shown to overcome resistance to ICBs (Wang et al, 2016). To reveal the relationship between intrinsic and treatment-induced DNA damage and the HGSOC immune microenvironment we are employing a novel, high-multiplex tissue cyclic immunofluorescence (t-CycIF) platform (Lin et al, 2016& 2017) allowing for the simultaneous detection of up to 60 different antigens at single cell resolution. Utilizing t-CycIF we are in the process of profiling the DNA damage and immune responses in three unique HGSOC clinical cohorts including i) tumors with inherent DNA repair deficiencies ii) pre- and post DNA damaging therapy iii) tumors collected in an innovative clinical trial combining Poly- ADP Ribose Polymerase inhibitor (PARPi) Niraparib and ICB Pembrolizumab. Using this high-dimensional, quantitative data we are mapping the abundance, spatial arrangement and functional state of cancer cells, immune cells, and stroma in the HGSOC microenvironment. The highly multiplexed t-CycIF data are processed with established computational algorithms and correlated with clinical outcomes. Our preliminary data shows that t-CycIF sensitively captures immune cell subpopulations, tumor heterogeneity and DNA damage in HGSOC. We anticipate that t-CycIF could accelerate the development of rational strategies for combining DNA damaging agents with immunotherapy to ultimately improve the treatment and outcomes of patients with ovarian cancer.

Citation Format: Anniina Farkkila, Sameer S. Chopra, Jia-Ren Lin, Zoltan Maliga, Bose Koruchupakkal, Kyle C. Strickland, Brooke E. Howitt, Sandro Santagata, Ursula A. Matulonis, Kevin Elias, Elizabeth M. Swisher, Panagiotis A. Konstantinopoulos, Peter Sorger, Alan D. D'Andrea. DNA damage and immunoprofiling with highly multiplexed tissue immunofluorescence (t-CycIF) in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 139.

PARP Inhibitors in Ovarian Cancer: A Trailblazing and Transformative Journey

PARP inhibitors have transformed treatment for ovarian cancer, a cancer notable for homologous recombination (HR) deficiencies and aberrant DNA repair, especially in the high-grade serous subtype. PARP inhibitors are now approved for recurrent ovarian cancer as maintenance following response to platinum chemotherapy and BRCA-mutated (BRCAm) cancer treatment. Clin Cancer Res; 24(17); 4062-5. ©2018 AACRSee related article by Ison et al., p. 4066.

Management of newly diagnosed or recurrent ovarian cancer

The treatment of newly diagnosed or recurrent ovarian cancer has changed significantly in recent years, with an increased number of treatment options available. Surgery and combination treatment with carboplatin and paclitaxel are the standard of care for patients with newly diagnosed disease, although the use of neoadjuvant chemotherapy is increasing. Clinical strategies have also evolved along with the understanding that ovarian cancer is not one disease but rather comprises several with different histologic and underlying genetic characteristics. The most common histologic type is high-grade serous carcinoma, which is associated with underlying DNA repair deficiencies and copy number alterations. Other, less common histologic types include endometrioid (both low- and high-grade) as well as low-grade serous, mucinous, and clear cell carcinomas. Antivascular agents (specifically bevacizumab) and poly(ADP-ribose) polymerase (PARP) inhibitors have received regulatory approval for many aspects of treatment. PARP inhibitors, which inhibit DNA repair, have shown the greatest activity in those ovarian cancers that harbor deleterious BRCA mutations, and they have also demonstrated activity in the maintenance setting after a response to and completion of platinum-based chemotherapy in patients with sensitive recurrent ovarian cancer regardless of BRCA status. Newer or experimental strategies to improve both up-front and second-line or later treatment include the addition of biologic agents to chemotherapy; the use of newer combination strategies that employ antivascular agents, PARP inhibitors, and immuno-oncology drugs; and the use of new agents such as antibody-drug conjugates.

Epigenetic Reprogramming Strategies to Reverse Global Loss of 5-Hydroxymethylcytosine, a Prognostic Factor for Poor Survival in High-grade Serous Ovarian Cancer

Purpose: A major challenge in platinum-based cancer therapy is the clinical management of chemoresistant tumors, which have a largely unknown pathogenesis at the level of epigenetic regulation.Experimental Design: We evaluated the potential of using global loss of 5-hydroxymethylcytosine (5-hmC) levels as a novel diagnostic and prognostic epigenetic marker to better assess platinum-based chemotherapy response and clinical outcome in high-grade serous tumors (HGSOC), the most common and deadliest subtype of ovarian cancer. Furthermore, we identified a targetable pathway to reverse these epigenetic changes, both genetically and pharmacologically.Results: This study shows that decreased 5-hmC levels are an epigenetic hallmark for malignancy and tumor progression in HGSOC. In addition, global 5-hmC loss is associated with a decreased response to platinum-based chemotherapy, shorter time to relapse, and poor overall survival in patients newly diagnosed with HGSOC. Interestingly, the rescue of 5-hmC loss restores sensitivity to platinum chemotherapy in vitro and in vivo, decreases the percentage of tumor cells with cancer stem cell markers, and increases overall survival in an aggressive animal model of platinum-resistant disease.Conclusions: Consequently, a global analysis of patient 5-hmC levels should be included in future clinical trials, which use pretreatment with epigenetic adjuvants to elevate 5-hmC levels and improve the efficacy of current chemotherapies. Identifying prognostic epigenetic markers and altering chemotherapeutic regimens to incorporate DNMTi pretreatment in tumors with low 5-hmC levels could have important clinical implications for newly diagnosed HGSOC disease. Clin Cancer Res; 24(6); 1389-401. ©2017 AACR.

A review of mirvetuximab soravtansine in the treatment of platinum-resistant ovarian cancer

Resistance to platinum-based therapy poses a significant clinical challenge for the management of advanced ovarian cancer, a leading cause of cancer mortality among women. Mirvetuximab soravtansine is a novel antibody–drug conjugate that targets folate receptor-α, a validated molecular target for therapeutic intervention in this disease. Here, we examine mirvetuximab soravtansine's mechanism of action and pharmacology, and review its clinical evaluation in ovarian cancer to date. We focus on the favorable tolerability and encouraging signals of efficacy that have emerged, most notably in patients with platinum-resistant disease. Ongoing Phase III monotherapy and Phase Ib/II combination trials evaluating its activity in the setting of platinum resistance are emphasized, which will help define its role in the evolving landscape of ovarian cancer therapy.