Robert P. Edwards

Quiescent Ovarian Cancer Cells Secrete Follistatin to Induce Chemotherapy Resistance in Surrounding Cells in Response to Chemotherapy

Abstract Purpose: We recently reported that the transcription factor NFATC4, in response to chemotherapy, drives cellular quiescence to increase ovarian cancer chemoresistance. The goal of this work was to better understand the mechanisms of NFATC4-driven ovarian cancer chemoresistance. Experimental Design: We used RNA sequencing to identify NFATC4-mediated differential gene expression. CRISPR-Cas9 and FST (follistatin)-neutralizing antibodies were used to assess impact of loss of FST function on cell proliferation and chemoresistance. ELISA was used to quantify FST induction in patient samples and in vitro in response to chemotherapy. Results: We found that NFATC4 upregulates FST mRNA and protein expression predominantly in quiescent cells and FST is further upregulated following chemotherapy treatment. FST acts in at least a paracrine manner to induce a p-ATF2–dependent quiescent phenotype and chemoresistance in non-quiescent cells. Consistent with this, CRISPR knockout (KO) of FST in ovarian cancer cells or antibody-mediated neutralization of FST sensitizes ovarian cancer cells to chemotherapy treatment. Similarly, CRISPR KO of FST in tumors increased chemotherapy-mediated tumor eradication in an otherwise chemotherapy-resistant tumor model. Suggesting a role for FST in chemoresistance in patients, FST protein in the abdominal fluid of patients with ovarian cancer significantly increases within 24 hours of chemotherapy exposure. FST levels decline to baseline levels in patients no longer receiving chemotherapy with no evidence of disease. Furthermore, elevated FST expression in patient tumors is correlated with poor progression-free, post–progression-free, and overall survival. Conclusions: FST is a novel therapeutic target to improve ovarian cancer response to chemotherapy and potentially reduce recurrence rates.

Phase I Trial Combining Chemokine-Targeting with Loco-Regional Chemoimmunotherapy for Recurrent, Platinum-Sensitive Ovarian Cancer Shows Induction of CXCR3 Ligands and Markers of Type 1 Immunity

Abstract Purpose: Increased prevalence of cytotoxic T lymphocytes (CTL) in the tumor microenvironment (TME) predicts positive outcomes in patients with epithelial ovarian cancer (EOC), whereas the regulatory T cells (Treg) predict poor outcomes. Guided by the synergistic activity of TLR3 ligands, IFNα, and COX-2 blockers in selectively enhancing CTL-attractants but suppressing Treg-attractants, we tested a novel intraperitoneal chemoimmunotherapy combination (CITC), to assess its tolerability and TME-modulatory impact in patients with recurrent EOC. Patients and Methods: Twelve patients were enrolled in phase I portion of the trial NCT02432378, and treated with intraperitoneal cisplatin, intraperitoneal rintatolimod (dsRNA, TLR3 ligand), and oral celecoxib (COX-2 blocker). Patients in cohorts 2, 3, and 4 also received intraperitoneal IFNα at 2, 6, and 18 million units (MU), respectively. Primary objectives were to evaluate safety, identify phase 2 recommended dose (P2RD), and characterize changes in the immune TME. Peritoneal resident cells and intraperitoneal wash fluid were profiled via NanoString and Meso Scale Discovery (MSD) multiplex assay, respectively. Results: The P2RD of IFNα was 6 MU. Median progression-free survival and overall survival were 8.4 and 30 months, respectively. Longitudinal sampling of the peritoneal cavity via intraperitoneal washes demonstrated local upregulation of IFN-stimulated genes (ISG), including CTL-attracting chemokines (CXCL-9, -10, -11), MHC I/II, perforin, and granzymes. These changes were present 2 days after chemokine modulation and subsided within 1 week. Conclusions: The chemokine-modulating intraperitoneal-CITC is safe, tolerable, and associated with ISG changes that favor CTL chemoattraction and function. This combination (plus DC vaccine) will be tested in a phase II trial. See related commentary by Aranda et al., p. 1993

Twice daily template-based interstitial brachytherapy for gynecologic cancers: What is the optimal dose?

Several factors of template-based interstitial brachytherapy in gynecologic cancers, including large tumor size, invasion into adjacent organs or fistula, dose heterogeneity, and twice daily fractionation cause inherent dose-escalation effects, potentially increasing toxicity. This study reports a single-institutional dose escalation experience in twice daily template-based interstitial brachytherapy treatments to demonstrate tumor control and toxicity outcomes, with the hypothesis that with image-based planning dose-escalation with interstitial brachytherapy is safe and efficacious. Patients treated with template-based interstitial brachytherapy at our institution from 2006 to 2022 were identified. Over time, HDR brachytherapy boost dose at our institution has been dose-escalated from 18.75 Gy in 5 fractions to 27.5 Gy in 5 fractions. Local control and survival outcomes were analyzed using the Kaplan-Meier method and log-rank test to compare between groups. Formal tumor control probability (TCP) analysis was performed using logistic dose-response modeling. 214 patients were identified with median follow-up of 28.1 months (IQR 8.2-58.7). Total HDR dose correlated significantly with local and locoregional control when analyzed as a continuous variable, and when dichotomized around median dose of 25 Gy (p = 0.024). TCP analysis showed a dose-response effect between HR CTV D90 and local control in the entire cohort, and separately in cervical and vaginal cancer subsets. The actuarial 5-year incidence of grade 3 or worse toxicity was 6.1%, and there was no significant association between toxicity and total HDR dose or HR CTV D90. In patient treated with twice-daily template-based interstitial brachytherapy for gynecologic cancers brachytherapy dose correlates with local control with no significant association between brachytherapy dose and toxicity, thus suggesting room for dose-escalation.

A Phase II Basket Trial of Dual Anti–CTLA-4 and Anti–PD-1 Blockade in Rare Tumors SWOG S1609: Vulvar Cancers

Abstract Purpose: Dual PD-1/CTLA-4 inhibition shows promise in various malignancies. The SWOG S1609 Dual Anti–CTLA-4 and Anti–PD-1 Blockade in Rare Tumors (DART) trial presents initial results of ipilimumab/nivolumab in vulvar cancers. Patients and Methods: DART is a prospective/open-label/multicenter (1,016 US sites)/multicohort phase II clinical trial of ipilimumab (1 mg/kg intravenously every 6 weeks) plus nivolumab (240 mg intravenously every 2 weeks). The primary endpoint was objective response rate [ORR; confirmed complete response and partial response (PR)] per RECISTv1.1, whereas progression-free survival (PFS), overall survival, clinical benefit rate (CBR; ORR plus stable disease ≥6 months), and toxicity were secondary endpoints. Results: Sixteen evaluable patients (median age, 55.5 years; 0–6 prior therapies; no prior immunotherapy) were analyzed, all of whom had squamous cell carcinoma histology. The ORR was 18.8% (3/16), CBR was 25% (4/16), and CBR plus unconfirmed PR rate was 31% (5/16); the PFS was 34.1, 16.7. 15.5, 7.2, and 7.0 months for these five patients, respectively. The median PFS and overall survival were 2.2 and 7.6 months, respectively. The most common adverse events were diarrhea, fatigue, pruritus, anorexia, and nausea (25%, n = 4 each). Grade 3 to 4 adverse events occurred in 25% of patients (n = 4). There was one grade 1 to 2 adverse event (6.7%) that led to discontinuation and one (6.7%) grade 5 death adverse event. Conclusions: Ipilimumab plus nivolumab in vulvar cancers resulted in an objective response in 3 of 16 patients, all of whom had durable responses lasting over 1 year. Notably, two additional patients experienced durable stable disease and unconfirmed PR. Correlative studies to determine response and resistance markers are ongoing.

Intensive Locoregional Chemoimmunotherapy for Recurrent Ovarian Cancer Plus Intranodal DC Vaccines

This study will evaluate the immunologic and potential clinical effectiveness of intensive locoregional sequential intraperitoneal (IP) cisplatin (IPC) with intravenous (iv) paclitaxel followed by peritoneal infusion of a chemokine modulatory (CKM) regimen composed of a cocktail of IP rintatolimod and interferon-alpha (IFNα) for patients with advanced stage ovarian cancer (III-IV) at primary neoadjuvant setting. In the safety phase I phase, we determined the tolerable dose of IPC-CKM. In this phase 2 we will add intradermal (ID) autologous αDC1 vaccines (known to be nontoxic) to the tolerable IPC-CKM regimen. The effectiveness will be determined by rate of complete pathologic response.