Christa I. Nagel

Comparing Durvalumab, Olaparib, and Cediranib Monotherapy, Combination Therapy, or Chemotherapy in Patients with Platinum-Resistant Ovarian Cancer with Prior Bevacizumab: The Phase II NRG-GY023 Trial

Abstract Purpose: We assessed the efficacy of anti–PD-L1 durvalumab in combination with olaparib and cediranib (DOC), compared with the standard-of-care chemotherapy (SOC) in patients with platinum-resistant ovarian cancer (PROC), who had prior bevacizumab. Patients and Methods: NRG-GY023 was the first randomized four-arm superiority phase II trial enrolling patients with high-grade serous/endometrioid or clear-cell PROC with prior bevacizumab exposure. Patients were randomized 1:2:2:2 to SOC (weekly paclitaxel, topotecan, or pegylated liposomal doxorubicin), DOC, durvalumab + cediranib (DC), or olaparib + cediranib (OC). The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival, overall response rate, and safety. The design had 80% power to detect an HR of 0.5 using a one-sided, α = 0.1-level test for each comparison with the SOC with a preplanned interim analysis. Experimental arms with HR estimates (vs. SOC) >0.87 could be discontinued. Results: A total of 153 patients were enrolled between April 4, 2021, and February 1, 2023. Accrual was permanently closed on February 1, 2023, due to futility. With a data cutoff of September 9, 2024, the median PFS was 3.4, 2.9, 2.5, and 2.8 months, and median overall survival was 7.5, 8.3, 5.7, and 10.2 months for SOC, DOC, DC, and OC, respectively. The overall response rate was 4.3% [95% confidence interval (CI), 0.00–0.19], 15.9% (95% CI, 0.07–0.29), 11.9% (95% CI, 0.05–0.24), and 9.1% (95% CI, 0.03–0.20) for SOC, DOC, DC, and OC, respectively. Compared with SOC, the PFS HR estimates were 1.003 (95% CI, 0.56–1.80), 1.108 (95% CI, 0.63–1.96), and 1.021 (95% CI, 0.57–1.82) for DOC, DC, and OC, respectively. No new safety signals were observed. Conclusions: In patients with PROC with prior bevacizumab, all experimental arms failed to reach the primary objective of improving PFS compared with SOC.

Small-Molecule–Mediated Stabilization of PP2A Modulates the Homologous Recombination Pathway and Potentiates DNA Damage-Induced Cell Death

Abstract High-grade serous carcinoma (HGSC) is the most common and lethal ovarian cancer subtype. PARP inhibitors (PARPi) have become the mainstay of HGSC-targeted therapy, given that these tumors are driven by a high degree of genomic instability (GI) and homologous recombination (HR) defects. Nonetheless, approximately 30% of patients initially respond to treatment, ultimately relapsing with resistant disease. Thus, despite recent advances in drug development and an increased understanding of genetic alterations driving HGSC progression, mortality has not declined, highlighting the need for novel therapies. Using a small-molecule activator of protein phosphatase 2A (PP2A; SMAP-061), we investigated the mechanism by which PP2A stabilization induces apoptosis in patient-derived HGSC cells and xenograft (PDX) models alone or in combination with PARPi. We uncovered that PP2A genes essential for cellular transformation (B56α, B56γ, and PR72) and basal phosphatase activity (PP2A-A and -C) are heterozygously lost in the majority of HGSC. Moreover, loss of these PP2A genes correlates with worse overall patient survival. We show that SMAP-061–induced stabilization of PP2A inhibits the HR output by targeting RAD51, leading to chronic accumulation of DNA damage and ultimately apoptosis. Furthermore, combination of SMAP-061 and PARPi leads to enhanced apoptosis in both HR-proficient and HR-deficient HGSC cells and PDX models. Our studies identify PP2A as a novel regulator of HR and indicate PP2A modulators as a therapeutic therapy for HGSC. In summary, our findings further emphasize the potential of PP2A modulators to overcome PARPi insensitivity, given that targeting RAD51 presents benefits in overcoming PARPi resistance driven by BRCA1/2 mutation reversions. Watch the interview with Analisa DiFeo, PhD, recipient of the 2025 Molecular Cancer Therapeutics Award for Outstanding Journal Article: https://vimeo.com/1100470225