Jung-Min Lee

AKT1 interacts with DHX9 to Mitigate R Loop–Induced Replication Stress in Ovarian Cancer

Abstract PARP inhibitor (PARPi)–resistant BRCA-mutant (BRCAm) high-grade serous ovarian cancer (HGSOC) represents a new clinical challenge with unmet therapeutic needs. Here, we performed a quantitative high-throughput drug combination screen that identified the combination of an ATR inhibitor (ATRi) and an AKT inhibitor (AKTi) as an effective treatment strategy for both PARPi-sensitive and PARPi-resistant BRCAm HGSOC. The ATRi and AKTi combination induced DNA damage and R loop–mediated replication stress (RS). Mechanistically, the kinase domain of AKT1 directly interacted with DHX9 and facilitated recruitment of DHX9 to R loops. AKTi increased ATRi-induced R loop–mediated RS by mitigating recruitment of DHX9 to R loops. Moreover, DHX9 was upregulated in tumors from patients with PARPi-resistant BRCAm HGSOC, and high coexpression of DHX9 and AKT1 correlated with worse survival. Together, this study reveals an interaction between AKT1 and DHX9 that facilitates R loop resolution and identifies combining ATRi and AKTi as a rational treatment strategy for BRCAm HGSOC irrespective of PARPi resistance status. Significance: Inhibition of the AKT and ATR pathways cooperatively induces R loop–associated replication stress in high-grade serous ovarian cancer, providing rationale to support the clinical development of AKT and ATR inhibitor combinations. See related commentary by Ramanarayanan and Oberdoerffer, p. 793

TIME for Endometrial Cancer: Advancements and Challenges in Therapeutic Targets for the Endometrial Cancer Tumor Immune Microenvironment

Abstract Endometrial cancer is the sixth most common cancer in women worldwide and the fourth most common cancer in women in the United States. In the United States, its incidence and mortality rates have continued to increase since the late 1990s. Endometrial cancer comprises most uterine corpus carcinomas and represents a heterogeneous group of cancers varying in pathology, histology, molecular biology, immunogenicity, and prognosis. Recently, the advancement of molecular classification and subsequent clinical trials have led to new FDA approvals for the use of immune checkpoint inhibitors in endometrial cancer. However, recurrent and advanced-stage endometrial cancer continues to demonstrate high morbidity and mortality, denoting an unmet need for innovative immunotherapeutic strategies. This review explores current concepts in the endometrial cancer tumor immune microenvironment, comparing antigenicity, immunosurveillance, and immunoregulation among molecular and histologic subtypes and providing insight into which subtypes may be particularly responsive to immunotherapy. Novel immunotherapeutic strategies targeting cancer antigens, emerging immune checkpoints, immunomodulatory cytokines, and tumor-infiltrating immune cells are described, and corresponding clinical trials are presented. Integrated approaches such as immunogenic modulation, which enhances tumor susceptibility to immune attack, and immune subset conditioning, which modifies suppressive immune components within the tumor immune microenvironment, are presented as promising avenues to render “cold” tumors responsive. Together, the immunotherapies reviewed here offer potential strategies for treating patients with advanced or refractory endometrial cancer.

Ovarian cancer

Epithelial ovarian cancer (EOC) describes a group of diseases characterized by differing pathogeneses, molecular profiles, histologies and prognoses. The low incidence of each distinct histological type of EOC poses challenges for obtaining an accurate diagnosis, robust evidence to guide management, and a mechanistic understanding to ensure availability of effective therapies. Most EOCs, including high-grade serous ovarian cancer, predominantly originate from the fimbriated ends of the fallopian tube, whereas low-grade serous, clear cell, endometrioid and mucinous EOCs are thought to originate from other tissues. Despite recognized genetic susceptibilities for the disease, no effective screening is available and late-stage diagnosis remains common. Known genetic susceptibilities are addressed by risk reduction surgery including removal of both fallopian tubes and both ovaries. Management is predominantly based on adequate surgery and chemotherapy with carboplatin and paclitaxel, with the addition of anti-angiogenic therapy as indicated. The incorporation of poly(ADP-ribose) polymerase inhibitors into first-line therapy has considerably altered outcomes in some women with EOC who have defective homologous recombination DNA repair, including in those with BRCA1 and/or BRCA2 mutations. Other molecular characteristics are important in distinct types of EOC, but the use of matched targeted therapies remains under investigation, as does the role of immunotherapy for EOC, for which trial data have been disappointing to date. Translationally enriched clinical trials will be important to further explore and validate accurate biomarkers to better guide clinical care.

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.

BLM overexpression as a predictive biomarker for CHK1 inhibitor response in PARP inhibitor–resistant BRCA -mutant ovarian cancer

Poly(ADP-ribose) polymerase inhibitors (PARPis) have changed the treatment paradigm in breast cancer gene ( BRCA )–mutant high-grade serous ovarian carcinoma (HGSC). However, most patients eventually develop resistance to PARPis, highlighting an unmet need for improved therapeutic strategies. Using high-throughput drug screens, we identified ataxia telangiectasia and rad3-related protein/checkpoint kinase 1 (CHK1) pathway inhibitors as cytotoxic and further validated the activity of the CHK1 inhibitor (CHK1i) prexasertib in PARPi-sensitive and -resistant BRCA -mutant HGSC cells and xenograft mouse models. CHK1i monotherapy induced DNA damage, apoptosis, and tumor size reduction. We then conducted a phase 2 study (NCT02203513) of prexasertib in patients with BRCA -mutant HGSC. The treatment was well tolerated but yielded an objective response rate of 6% (1 of 17; one partial response) in patients with previous PARPi treatment. Exploratory biomarker analyses revealed that replication stress and fork stabilization were associated with clinical benefit to CHK1i. In particular, overexpression of Bloom syndrome RecQ helicase ( BLM ) and cyclin E1 ( CCNE1 ) overexpression or copy number gain/amplification were seen in patients who derived durable benefit from CHK1i. BRCA reversion mutation in previously PARPi-treated BRCA -mutant patients was not associated with resistance to CHK1i. Our findings suggest that replication fork–related genes should be further evaluated as biomarkers for CHK1i sensitivity in patients with BRCA -mutant HGSC.

Distinct roles of treatment schemes and BRCA2 on the restoration of homologous recombination DNA repair and PARP inhibitor resistance in ovarian cancer

Poly (ADP-ribose) polymerase inhibitors (PARPis) represent a major advance in ovarian cancer, now as a treatment and as a maintenance therapy in the upfront and recurrent settings. However, patients often develop resistance to PARPis, underlining the importance of dissecting resistance mechanisms. Here, we report different dosing/timing schemes of PARPi treatment in BRCA2-mutant PEO1 cells, resulting in the simultaneous development of distinct resistance mechanisms. PARPi-resistant variants PEO1/OlaJR, established by higher initial doses and short-term PARPi treatment, develops PARPi resistance by rapidly restoring functional BRCA2 and promoting drug efflux activity. In contrast, PEO1/OlaR, developed by lower initial doses with long-term PARPi exposure, shows no regained BRCA2 function but a mesenchymal-like phenotype with greater invasion ability, and exhibits activated ATR/CHK1 and suppressed EZH2/MUS81 signaling cascades to regain HR repair and fork stabilization, respectively. Our study suggests that PARPi resistance mechanisms can be governed by treatment strategies and have a molecular basis on BRCA2 functionality. Further, we define different mechanisms that may serve as useful biomarkers to assess subsequent treatment strategies in PARPi-resistant ovarian cancer.

Cediranib and Olaparib Combination Compared With Cediranib or Olaparib Alone, or Chemotherapy in Platinum-Resistant or Primary Platinum-Refractory Ovarian Cancer: NRG-GY005

PURPOSE We assessed the efficacy of cediranib, olaparib, and cediranib/olaparib compared with standard-of-care chemotherapy (SOC) in platinum-resistant or platinum-refractory epithelial ovarian cancer (PROC). PATIENTS AND METHODS NRG-GY005 is an open-label, four-arm, phase II/III superiority trial enrolling patients with high-grade serous/endometrioid PROC and one to three previous therapies. Key exclusion criteria included previous receipt of poly(ADP-ribose) polymerase inhibitor or receipt of antiangiogenic therapy in the recurrent setting. Treatment arms (SOC [once weekly paclitaxel, topotecan, or pegylated liposomal doxorubicin], cediranib, olaparib, or cediranib/olaparib) were equally randomized. A preplanned interim futility analysis on the basis of progression-free survival (PFS) selected treatment arms to advance to phase III. PFS and overall survival (OS) were phase III coprimary end points, with hierarchical testing of PFS followed by OS to preserve type 1 error control, designed to have 90% power for a 0.625 PFS hazard ratio (HR). OS was tested after PFS in the multiple hierarchical testing procedure. Secondary end points included objective response rate (ORR) and patient-reported outcomes. RESULTS Five hundred sixty-two eligible patients were enrolled for phase II/III. Three arms met PFS criteria to carry forward to phase III (SOC, cediranib/olaparib, and cediranib). Median PFS was 3.4, 5.2, and 4 months with SOC, cediranib/olaparib, and cediranib, respectively, with a median follow-up duration of 42.2 months. PFS HR estimates for cediranib/olaparib and cediranib ( v SOC) were 0.796 (98.3% CI, 0.597 to 1.060) and 0.972 (98.3% CI, 0.726 to 1.300), respectively. Median OS was 13.6, 12.8, and 10.5 months, and of 443 patients with measurable disease, ORR was 8.6%, 24.7%, and 13.1% for SOC, cediranib/olaparib, and cediranib, respectively. No new safety signals were identified. In patients receiving cediranib/olaparib, no statistically significant difference was observed on the NFOSI-DRS-P subscale compared with SOC (98.3% CI, –1.3 to 1.5, P = .8725). CONCLUSION The cediranib-containing arms demonstrated clinical activity on the basis of PFS but were not superior compared with SOC.

The CHK1 inhibitor prexasertib in BRCA wild-type platinum-resistant recurrent high-grade serous ovarian carcinoma: a phase 2 trial

Abstract The multi-cohort phase 2 trial NCT02203513 was designed to evaluate the clinical activity of the CHK1 inhibitor (CHK1i) prexasertib in patients with breast or ovarian cancer. Here we report the activity of CHK1i in platinum-resistant high-grade serous ovarian carcinoma (HGSOC) with measurable and biopsiable disease (cohort 5), or without biopsiable disease (cohort 6). The primary endpoint was objective response rate (ORR). Secondary outcomes were safety and progression-free survival (PFS). 49 heavily pretreated patients were enrolled (24 in cohort 5, 25 in cohort 6). Among the 39 RECISTv1.1-evaluable patients, ORR was 33.3% in cohort 5 and 28.6% in cohort 6. Primary endpoint was not evaluable due to early stop of the trial. The median PFS was 4 months in cohort 5 and 6 months in cohort 6. Toxicity was manageable. Translational research was an exploratory endpoint. Potential biomarkers were investigated using pre-treatment fresh biopsies and serial blood samples. Transcriptomic analysis revealed high levels of DNA replication-related genes (POLA1, POLE, GINS3) associated with lack of clinical benefit [defined post-hoc as PFS < 6 months]. Subsequent preclinical experiments demonstrated significant cytotoxicity of POLA1 silencing in combination with CHK1i in platinum-resistant HGSOC cell line models. Therefore, POLA1 expression may be predictive for CHK1i resistance, and the concurrent POLA1 inhibition may improve the efficacy of CHK1i monotherapy in this hard-to-treat population, deserving further investigation.

Impact of Global Enrollment on Race, Ethnicity, and Age Representation in Pivotal Gynecologic Cancer Trials Leading to US Food and Drug Administration Drug Approvals

PURPOSE To evaluate the impact of international enrollment in landmark gynecologic cancer (Gyn-Ca) trials that supported the US Food and Drug Administration (FDA) drug approvals. METHODS We examined the FDA drug approval database for approved Gyn-Ca agents between January 2014 and June 2024. We then extracted clinical trial identifiers supporting these approvals using FDA safety labels. Expected enrollment was calculated using gynecologic disease site incidence data from the US Cancer Statistics Program and compared with actual trial enrollment reported on ClinicalTrials.gov. RESULTS From 2014 to 2024, 30 Gyn-Ca trials supporting 28 FDA approvals were conducted in US/international (86.7%), international-only (10%), and US-only sites (3.3%) and enrolled 15,294 patients, with 14,053 remaining (74.0% White, 4.1% Black, 12.7% Asian, 8.7% other) after screening for trials not reporting race. Black (–11.0%; P < .0001), Hispanic/Latino (–3.5%; P < .0001), and elderly (–12.6%; P < .0001) participants were under-represented, whereas Asians (+6.8%; P < .0001) were over-represented. Asian (18.3% v 3.5% in trials with or without East Asian sites; odds ratio [OR], 6.19 [95% CI, 5.29 to 7.25]; P < .0001) and Hispanic/Latino (18.6% v 4.6% in trials with or without South American sites; OR, 4.75 [95% CI, 4.00 to 5.63]; P < .0001) enrollment was higher in trials that included East Asian and South American sites, respectively. Black enrollment did not improve despite trials including recruitment in Africa (3.2% v 4.1% Black enrollment in trials with or without African sites; OR, 0.83 [95% CI, 0.38 to 1.83]; P = .53). CONCLUSION Black, Hispanic/Latino, and elderly patients were under-represented in pivotal Gyn-Ca trials, whereas Asian patients were over-represented, compared with expected enrollment proportions. Postmarketing studies on under-represented groups should be considered to assess drug efficacy and safety in these populations.

Comprehensive RAD51C ovarian cancer variant analysis uncouples homologous recombination and replicative functions

RAD51C is a tumor suppressor gene with over 285 variants of unknown significance (VUS) found in primary ovarian tumors. RAD51C is a paralog of the recombinase RAD51, and it forms complexes with other paralogs to regulate RAD51 activity. We screened 27 ovarian cancer-derived RAD51C VUS to identify those that affect the assembly of functional tetrameric RAD51B-C-D-XRCC2 (BCDX2) complex. With yeast 3-hybrid and biochemical analyses, we identify a mutation cluster of the RAD51C Walker B region affecting protein interactions with other RAD51 paralogs. By further analyzing these variants for homologous recombination (HR), replication fork regression, DNA binding and ATPase activity, and RAD51 filament formation, we identified separation-of-function alleles that uncouple RAD51C distinct enzymatic activities with HR and replication. Thus, our analysis of RAD51C identifies additional VUS with functional defects, which will aid in pathogenicity classification and inform future strategies to treat individuals harboring RAD51C loss-of-function alleles.

Deep Learning Segmentation of Ascites on Abdominal CT Scans for Automatic Volume Quantification

Purpose To evaluate the performance of an automated deep learning method in detecting ascites and subsequently quantifying its volume in patients with liver cirrhosis and patients with ovarian cancer. Materials and Methods This retrospective study included contrast-enhanced and noncontrast abdominal-pelvic CT scans of patients with cirrhotic ascites and patients with ovarian cancer from two institutions, National Institutes of Health (NIH) and University of Wisconsin (UofW). The model, trained on The Cancer Genome Atlas Ovarian Cancer dataset (mean age [±SD], 60 years ± 11; 143 female), was tested on two internal datasets (NIH-LC and NIH-OV) and one external dataset (UofW-LC). Its performance was measured by the F1/Dice coefficient, SDs, and 95% CIs, focusing on ascites volume in the peritoneal cavity. Results On NIH-LC (25 patients; mean age, 59 years ± 14; 14 male) and NIH-OV (166 patients; mean age, 65 years ± 9; all female), the model achieved F1/Dice scores of 85.5% ± 6.1 (95% CI: 83.1, 87.8) and 82.6% ± 15.3 (95% CI: 76.4, 88.7), with median volume estimation errors of 19.6% (IQR, 13.2%-29.0%) and 5.3% (IQR: 2.4%-9.7%), respectively. On UofW-LC (124 patients; mean age, 46 years ± 12; 73 female), the model had a F1/Dice score of 83.0% ± 10.7 (95% CI: 79.8, 86.3) and median volume estimation error of 9.7% (IQR, 4.5%-15.1%). The model showed strong agreement with expert assessments, with

PARP inhibitors in ovarian cancer

Poly-ADP-ribose polymerase inhibitors (PARPis) were first approved for the treatment of epithelial ovarian cancer (EOC), where as a maintenance therapy they transformed clinical management of this disease in both patients with and without homologous recombination deficiency. In this review, we provide a historical overview of PARPi use in EOC and discuss recent updates on overall survival data, highlighting their impact on regulatory approvals. We explore their potential as combination regimens with antiangiogenic and cell-cycle checkpoint inhibitors, as well as other small molecule inhibitors, to overcome resistance mechanisms and enhance therapeutic efficacy, providing a future perspective on the use of PARPis in EOC treatment.

Testing the Combination of Cediranib and Olaparib in Comparison to Each Drug Alone or Other Chemotherapy in Recurrent Platinum-Resistant Ovarian Cancer

This randomized phase II/III trial studies how well cediranib maleate and olaparib work when given together or separately, and compares them to standard chemotherapy in treating patients with ovarian, fallopian tube, or primary peritoneal cancer that has returned (recurrent) after receiving chemotherapy with drugs that contain platinum (platinum-resistant) or continued to grow while being treated with platinum-based chemotherapy drugs (platinum-refractory). Cediranib maleate and olaparib may stop the growth of tumor cells by blocking enzymes needed for cell growth. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. It is not yet known whether giving cediranib maleate and olaparib together may cause more damage to cancer cells when compared to either drug alone or standard chemotherapy.