Joyce Liu

Single-Stranded DNA Gap Accumulation Is a Functional Biomarker for USP1 Inhibitor Sensitivity

Abstract Recent studies suggest that PARP and POLQ inhibitors confer synthetic lethality in BRCA1-deficient tumors by accumulation of single-stranded DNA (ssDNA) gaps at replication forks. Loss of USP1, a deubiquitinating enzyme, is also synthetically lethal with BRCA1 deficiency, and USP1 inhibitors are now undergoing clinical development for these cancers. Herein, we show that USP1 inhibitors also promote the accumulation of ssDNA gaps during replication in BRCA1-deficient cells, and this phenotype correlates with drug sensitivity. USP1 inhibition increased monoubiquitinated proliferating cell nuclear antigen at replication forks, mediated by the ubiquitin ligase RAD18, and knockdown of RAD18 caused USP1 inhibitor resistance and suppression of ssDNA gaps. USP1 inhibition overcame PARP inhibitor resistance in a BRCA1-mutated xenograft model and induced ssDNA gaps. Furthermore, USP1 inhibition was synergistic with PARP and POLQ inhibition in BRCA1-mutant cells, with enhanced ssDNA gap accumulation. Finally, in patient-derived ovarian tumor organoids, sensitivity to USP1 inhibition alone or in combination correlated with the accumulation of ssDNA gaps. Assessment of ssDNA gaps in ovarian tumor organoids represents a rapid approach for predicting response to USP1 inhibition in ongoing clinical trials. Significance: USP1 inhibitors kill BRCA1-deficient cells and cause ssDNA gap accumulation, supporting the potential of using ssDNA gap detection as a functional biomarker for clinical trials on USP1 inhibitors.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial

PURPOSE To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779 ) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC). METHODS Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples. RESULTS Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)–deficient, and 17.1% were HR repair (HRR)–mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy. CONCLUSION Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

Treatment Approaches for Platinum-Resistant Ovarian Cancer

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors’ suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology , to patients seen in their own clinical practice.

A Phase II, Two-Stage Study of Letrozole and Abemaciclib in Estrogen Receptor–Positive Recurrent Endometrial Cancer

PURPOSE Estrogen receptor (ER)–positive endometrial cancers (ECs) are characterized by phosphatidylinositol 3-kinase (PI3K) and receptor tyrosine kinase (RTK)/RAS/β-catenin (CTNNB1) pathway alterations in approximately 90% and 80% of cases, respectively. Extensive cross-talk between ER, PI3K, and RTK/RAS/CTNNB1 pathways leads to both ligand-dependent and ligand-independent ER transcriptional activity as well as upregulation of cyclin D1 which, in complex with cyclin-dependent kinases 4 and 6 (CDK4 and CDK6), is a critical regulator of cell cycle progression and a key mediator of resistance to hormonal therapy. We hypothesized that the combination of the aromatase inhibitor letrozole and CDK4/6 inhibitor abemaciclib would demonstrate promising activity in this setting. METHODS We conducted a phase II, two-stage study of letrozole/abemaciclib in recurrent ER-positive EC. Eligibility criteria included measurable disease, no limit on prior therapies, and all EC histologies; prior hormonal therapy was allowed. Primary end points were objective response rate by RECIST 1.1 and progression-free survival (PFS) rate at 6 months. RESULTS At the data cutoff date (December 03, 2021), 30 patients (28 with endometrioid EC) initiated protocol therapy; 15 (50%) patients had prior hormonal therapy. There were nine total responses (eight confirmed), for an objective response rate of 30% (95% CI, 14.7 to 49.4), all in endometrioid adenocarcinomas. Median PFS was 9.1 months, PFS at 6 months was 55.6% (95% CI, 35.1 to 72), and median duration of response was 7.4 months. Most common ≥ grade 3 treatment-related adverse events were neutropenia (20%) and anemia (17%). Responses were observed regardless of grade, prior hormonal therapy, mismatch repair, and progesterone receptor status. Exploratory tumor profiling revealed several mechanistically relevant candidate predictors of response ( CTNNB1, KRAS, and CDKN2A mutations) or absence of response ( TP53 mutations), which require independent validation. CONCLUSION Letrozole/abemaciclib demonstrated encouraging and durable evidence of activity in recurrent ER positive endometrioid EC.

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.

ADAGIO: A Phase IIb, Open-Label, Single-Arm, Multicenter Study Assessing the Efficacy and Safety of Adavosertib (AZD1775) as Treatment for Recurrent or Persistent Uterine Serous Carcinoma

PURPOSE This phase IIb, single-arm, multicenter, global study (ADAGIO; ClinicalTrials.gov identifier: NCT04590248 ) assessed the efficacy and safety of adavosertib in patients with recurrent/persistent uterine serous carcinoma (USC) who had previously received platinum-based chemotherapy. METHODS Eligible patients were age 18 years and older and had histologically confirmed recurrent/persistent USC, previously treated with at least one platinum-based chemotherapy regimen, and with evidence of measurable disease. Adavosertib was administered orally at 300 mg once daily on days 1-5 and 8-12 of a 21-day cycle until discontinuation criteria were met. The primary end point was objective response rate (ORR) by blinded independent central review (BICR). Secondary end points included duration of response (DoR), progression-free survival (PFS), safety, and tolerability. Biomarkers previously associated with adavosertib response in other settings were assessed in archival tissue samples. RESULTS In 104 evaluable patients, one complete response and 26 partial responses were observed, for an ORR by BICR of 26.0% (95% CI, 17.9 to 35.5). Median DoR was 4.7 months (95% CI, 3.8 to 8.3); median PFS was 2.8 months (95% CI, 2.6 to 3.9). Biomarker analysis identified no single predictive alteration for adavosertib response, although a trend was observed for CCNE1 amplification or high cyclin E1 protein expression. Most patients (97.2%) experienced treatment-related adverse events (TRAEs), most frequently diarrhea (59.6%), nausea (59.6%), and anemia (58.7%). Grade ≥3 TRAEs occurred in 60.6% of patients, with neutropenia (21.1%) and fatigue (13.8%) most common. 17.4% of patients discontinued adavosertib due to AEs (treatment-related in 14.7%). CONCLUSION Adavosertib showed some antitumor activity in patients with recurrent/persistent USC. However, at 300 mg once daily dosing, it was not well tolerated in this population. Exploratory biomarker studies suggest CCNE1 /cyclin E1 expression may enrich for response to Wee1 inhibition in USC.

Overall Survival With Maintenance Olaparib at a 7-Year Follow-Up in Patients With Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation: The SOLO1/GOG 3004 Trial

PURPOSE In SOLO1/GOG 3004 (ClinicalTrials.gov identifier: NCT01844986 ), maintenance therapy with the poly(ADP-ribose) polymerase inhibitor olaparib provided a sustained progression-free survival benefit in patients with newly diagnosed advanced ovarian cancer and a BRCA1 and/or BRCA2 (BRCA) mutation. We report overall survival (OS) after a 7-year follow-up, a clinically relevant time point and the longest follow-up for any poly(ADP-ribose) polymerase inhibitor in the first-line setting. METHODS This double-blind phase III trial randomly assigned patients with newly diagnosed advanced ovarian cancer and a BRCA mutation in clinical response to platinum-based chemotherapy to maintenance olaparib (n = 260) or placebo (n = 131) for up to 2 years. A prespecified descriptive analysis of OS, a secondary end point, was conducted after a 7-year follow-up. RESULTS The median duration of treatment was 24.6 months with olaparib and 13.9 months with placebo, and the median follow-up was 88.9 and 87.4 months, respectively. The hazard ratio for OS was 0.55 (95% CI, 0.40 to 0.76; P = .0004 [ P < .0001 required to declare statistical significance]). At 7 years, 67.0% of olaparib patients versus 46.5% of placebo patients were alive, and 45.3% versus 20.6%, respectively, were alive and had not received a first subsequent treatment (Kaplan-Meier estimates). The incidence of myelodysplastic syndrome and acute myeloid leukemia remained low, and new primary malignancies remained balanced between treatment groups. CONCLUSION Results indicate a clinically meaningful, albeit not statistically significant according to prespecified criteria, improvement in OS with maintenance olaparib in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation and support the use of maintenance olaparib to achieve long-term remission in this setting; the potential for cure may also be enhanced. No new safety signals were observed during long-term follow-up.

Phase I and Randomized Phase II Study of Ruxolitinib With Frontline Neoadjuvant Therapy in Advanced Ovarian Cancer: An NRG Oncology Group Study

PURPOSE The interleukin-6/Janus kinase (JAK)/signal transducers and activators of transcription 3 axis is a reported driver of chemotherapy resistance. We hypothesized that adding the JAK1/2 inhibitor ruxolitinib to standard chemotherapy would be tolerable and improve progression-free survival (PFS) in patients with ovarian cancer in the upfront setting. MATERIALS AND METHODS Patients with ovarian/fallopian tube/primary peritoneal carcinoma recommended for neoadjuvant chemotherapy were eligible. In phase I, treatment was initiated with dose-dense paclitaxel (P) 70 mg/m2 once daily on days 1, 8, and 15; carboplatin AUC 5 intravenously day 1; and ruxolitinib 15 mg orally (PO) twice a day, every 21 days (dose level 1). Interval debulking surgery (IDS) was required after cycle 3. Patients then received three additional cycles of chemotherapy/ruxolitinib, followed by maintenance ruxolitinib. In the randomized phase II, patients were randomly assigned to paclitaxel/carboplatin with or without ruxolitinib at 15 mg PO twice a day for three cycles, IDS, followed by another three cycles of chemotherapy/ruxolitinib, without further maintenance ruxolitinib. The primary phase II end point was PFS. RESULTS Seventeen patients were enrolled in phase I. The maximum tolerated dose and recommended phase II dose were established to be dose level 1. One hundred thirty patients were enrolled in phase II with a median follow-up of 24 months. The regimen was well tolerated, with a trend toward higher grade 3 to 4 anemia (64% v 27%), grade 3 to 4 neutropenia (53% v 37%), and thromboembolic events (12.6% v 2.4%) in the experimental arm. In the randomized phase II, the median PFS in the reference arm was 11.6 versus 14.6 in the experimental, hazard ratio (HR) for PFS was 0.702 (log-rank P = .059). The overall survival HR was 0.785 ( P = .24). CONCLUSION Ruxolitinib 15 mg PO twice a day was well tolerated with acceptable toxicity in combination with paclitaxel/carboplatin chemotherapy. The primary end point of prolongation of PFS was achieved in the experimental arm, warranting further investigation.

Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses

PURPOSE The multicenter, open-label, randomized phase 2 NCI-9944 study ( NCT02595892 ) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation). METHODS We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib. RESULTS At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06). CONCLUSION The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.

Serial Circulating Tumor DNA Sequencing to Monitor Response and Define Acquired Resistance to Letrozole/Abemaciclib in Endometrial Cancer

PURPOSE In a phase II study, letrozole/abemaciclib demonstrated an objective response rate of 30% and a median progression-free survival (PFS) of 9.1 months in recurrent estrogen receptor–positive endometrial cancer (EC). While tissue-based tumor profiling revealed several mechanistically relevant candidate baseline genomic predictors of response, circulating tumor DNA (ctDNA) is a less invasive alternative to monitor therapeutic efficacy and define acquired resistance. METHODS Serial plasma specimens were obtained at baseline, C2D1, C3D1, C8D1, the time of objective response, and the time of progression. Samples were analyzed using the Guardant Reveal assay to assess methylation-based tumor fraction (TF), with the Guardant360 assay providing genotyping of >700 genes in samples with detectable ctDNA. Treatment response was assessed using a measure of the relative change in TF pre- versus on-treatment. RESULTS A total of 99 of 102 (97%) samples from 28 patients were successfully analyzed. Patients with above median baseline TF exhibited worse median PFS (2.0 months v 16.5 months, P < .005, hazard ratio [HR], 24.1) and worse overall survival (OS) (10.7 months v not yet reached, P < .005, HR, 14.8). Patients with molecular response (MR) after the first or second cycle of letrozole/abemaciclib therapy had significantly better median PFS and OS regardless of the cutoff used for definition of MR. ctDNA analysis of postprogression specimens identified several acquired genomic alterations associated with resistance to letrozole/abemaciclib therapy in more than half of the patients, including PI3K pathway, receptor tyrosine kinase ( FGFR1 , 2 and ERBB2 alterations), cell cycle pathway ( RB1 and CCNE1 alterations), and ESR1 and MAPK pathway alterations. Two of the three patients with mismatch repair–deficient ECs acquired ESR1 mutations at the time of progression. CONCLUSION Baseline and on-treatment ctDNA dynamics may provide an early indication of benefit from letrozole/abemaciclib in EC. ctDNA at the time of progression may identify resistance alterations that may inform subsequent therapy.

RESOLVE: Abemaciclib + Letrozole +/- Metformin, Zotatifin, or Gedatolisib in Endometrial or Low-Grade Serous Ovarian Cancer

This research study is studying a combination of targeted therapies as a possible treatment for estrogen-receptor positive (ER+) endometrial cancer and low-grade serous ovarian cancer. The drugs involved in this study are: * Abemaciclib (also known as Verzenio™) * Letrozole (also known as Femara®) * Metformin (also known as Glucophage®) * Zotatifin (also known as eFT226) * Gedatolisib (also known as PF-05212384)

A Study to Evaluate the Efficacy and Safety of Novel Treatment Combinations in Participants With Ovarian Cancer

This study will evaluate the efficacy and safety of niraparib and novel treatment combinations of niraparib as described within each cohort-specific supplement in participants with ovarian, fallopian tube, or primary peritoneal cancer. Cohort A (single arm) includes participants with recurrent ovarian cancer. Cohort B will not be initiated. Cohort C (randomized-2 arms) includes participants with newly diagnosed ovarian cancer.

Ruxolitinib Phosphate, Paclitaxel, and Carboplatin in Treating Patients With Stage III-IV Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer

This phase I/II trial studies the side effects and the best dose of ruxolitinib phosphate when given together with paclitaxel and carboplatin and to see how well they work in treating patients with stage III-IV epithelial ovarian, fallopian tube, or primary peritoneal cancer. Ruxolitinib phosphate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as paclitaxel and carboplatin, 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. Giving ruxolitinib phosphate together with paclitaxel and carboplatin may be a better treatment for epithelial ovarian, fallopian tube, or primary peritoneal cancer compared to paclitaxel and carboplatin alone.

Olaparib Maintenance Monotherapy in Patients With BRCA Mutated Ovarian Cancer Following First Line Platinum Based Chemotherapy.

Olaparib Monotherapy in Patients with BRCA Mutated Ovarian Cancer following First Line Platinum Based Chemotherapy.