Uterine serous carcinoma and uterine carcinosarcoma: molecular features, clinical advances, and emerging therapies.

Endometrial cancer, including high-grade subtypes, has a rising incidence and mortality. Uterine serous carcinoma (USC) and uterine carcinosarcoma (UCS) make up a small but increasing proportion of endometrial cancer cases and account for a significant portion of endometrial cancer mortality. Despite being molecularly and clinically distinct, both USC and UCS have a poor prognosis. Thus far, there have been few therapeutic strategies directed at these endometrial cancer subtypes. This review summarizes the genomic and molecular features of USC and UCS, clinical advances in the treatment of primary advanced and recurrent endometrial cancer, and novel molecularly-driven treatment strategies.

Improving the palliative-procedure decision-making process for patients with peritoneal carcinomatosis: A secondary analysis.

BACKGROUND: Peritoneal carcinomatosis (PC) is common in patients with advanced gynecologic and gastrointestinal cancers. Frequently, patients with PC undergo palliative surgery or procedures to manage disease-related complications and side effects. However, there are limited data regarding patients' and family caregivers' decision-making processes about these procedures. Thus, we sought to describe the decision-making experiences of patients with PC who elect to pursue palliative surgical procedures and their family caregivers. METHODS: We conducted a secondary analysis of qualitative data collected during a pilot randomized controlled trial of BOLSTER, a nurse-led telehealth intervention for patients with PC and their caregivers after an acute hospitalization and palliative procedure. Participants in both study arms described their experiences in semi-structured interviews. We re-analyzed coded qualitative data with a focus on understanding decision-making experiences surrounding palliative surgery and procedures using conventional content analysis. RESULTS: Interviews from 32 participants, 23 patients and 9 caregivers, were analyzed. Participants reported their decision-making was complicated by illness uncertainty and a desire for clear, effective communication with surgical and medical oncology teams. Participants requested more information about the impact of palliative procedures on their daily life. Several also noted that, without improved understanding, a misalignment between patient and family caregiver goals and palliative procedures may inadvertently increase suffering. CONCLUSION: Discussions related to patients' goals and preferences can improve the quality of treatment decision-making in patients with PC and their caregivers. Future research should test interventions to improve advanced cancer patients' illness understanding and decision-making surrounding palliative surgery and procedures.

Feasibility and acceptability of a nurse-led telehealth intervention (BOLSTER) to support patients with peritoneal carcinomatosis and their caregivers: A pilot randomized clinical trial.

OBJECTIVE: Patients with advanced gynecologic (GYN) and gastrointestinal (GI) cancers frequently develop peritoneal carcinomatosis (PC), which limits prognosis and diminishes health-related quality of life (HRQoL). Palliative procedures may improve PC symptoms, yet patients and caregivers report feeling unprepared to manage ostomies, catheters, and other complex needs. Our objectives were to (1) assess the feasibility of an efficacy trial of a nurse-led telehealth intervention (BOLSTER) for patients with PC and their caregivers; and (2) assess BOLSTER's acceptability, potential to improve patients' HRQoL and self-efficacy, and potential impact on advance care planning (ACP). METHODS: Pilot feasibility RCT. Recently hospitalized adults with advanced GYN and GI cancers, PC, and a new complex care need and their caregivers were randomized 1:1 to BOLSTER or enhanced discharge planning (EDP). We defined feasibility as a ≥ 50% approach-to-consent ratio and acceptability as ≥70% satisfaction with BOLSTER. We assessed patients' HRQoL and self-efficacy at baseline and six weeks, then compared the proportion experiencing meaningful improvements by arm. ACP documentation was identified using natural language processing. RESULTS: We consented 77% of approached patients. In the BOLSTER arm, 91.0% of patients and 100.0% of caregivers were satisfied. Compared to EDP, more patients receiving BOLSTER experienced improvements in HRQoL (68.4% vs. 40.0%) and self-efficacy for managing symptoms (78.9% vs. 35.0%) and treatment (52.9% vs. 42.9%). The BOLSTER arm had more ACP documentation. CONCLUSIONS: BOLSTER is a feasible and acceptable intervention with the potential to improve patients' HRQoL and promote ACP. An efficacy trial comparing BOLSTER to usual care is underway. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03367247; PI: Wright.

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.

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.

A phase 2 trial exploring the significance of homologous recombination status in patients with platinum sensitive or platinum resistant relapsed ovarian cancer receiving combination cediranib and olaparib.

OBJECTIVE: Combination cediranib/olaparib has reported activity in relapsed ovarian cancer. This phase 2 trial investigated the activity of cediranib/olaparib in relapsed ovarian cancer and its association with homologous recombination deficiency (HRD). METHODS: Seventy patients were enrolled to cohorts of either platinum-sensitive or platinum-resistant ovarian cancer and received olaparib tablets 200 mg twice daily and cediranib tablets 30 mg once daily under a continuous dosing schedule. HRD testing was performed on pre-treatment, on-treatment and archival biopsies by sequencing key homologous recombination repair (HRR) genes and by genomic LOH analysis. The primary objective for the platinum-sensitive cohort was the association of HRD, defined as presence of HRR gene mutation, with progression-free survival (PFS). The primary objective for the platinum-resistant cohort was objective response rate (ORR), with a key secondary endpoint evaluating the association of HRD status with activity. RESULTS: In platinum-sensitive ovarian cancer (N = 35), ORR was 77.1% (95% CI 59.9-89.6%) and median PFS was 16.4 months (95% CI 13.2-18.6). Median PFS in platinum-sensitive HRR-HRD cancers (N = 22) was 16.8 months (95% CI 11.3-18.6), and 16.4 months (95% CI 9.4-NA) in HRR-HR proficient cancers (N = 13; p = 0.57). In platinum-resistant ovarian cancer (N = 35), ORR was 22.9% (95% CI 10.4-40.1%) with median PFS 6.8 months (95% CI 4.2-9.1). Median PFS in platinum-resistant HRR-HRD cancers (N = 7) was 10.5 months (95% CI 3.6-NA) and 5.6 months (95% CI 3.6-7.6) in HRR-HR proficient cancers (N = 18; p = 0.23). CONCLUSIONS: Cediranib/olaparib had clinical activity in both platinum-sensitive and -resistant ovarian cancer. Presence of HRR gene mutations was not associated with cediranib/olaparib activity in either setting.

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.

Combined aromatase, CDK4/6 and PI3K blockade using letrozole/abemaciclib/LY3023414 in endometrial cancer.

Several lines of preclinical evidence indicate that combining PI3K and CDK4/6 inhibitors may further enhance the efficacy of hormonal therapy by overcoming de novo and acquired resistance to PI3K and CDK4/6 blockade. We evaluated the combination of abemaciclib, letrozole and LY3023414 (an orally available, selective inhibitor of the class I PI3K isoforms and mTORC1/2) in recurrent endometrial cancer (EC). This study was terminated prematurely after 5 patients initiated protocol therapy due to discontinuation of further development of LY3023414. We report our findings from these patients, including one with recurrent endometrioid EC with AKT1, CTNNB1 and ESR1 hotspot mutations who had previously progressed through letrozole/everolimus and achieved a partial response to letrozole/abemaciclib/LY3023414.

Phase I/II Study of Combined BCL-xL and MEK Inhibition with Navitoclax and Trametinib in KRAS or NRAS Mutant Advanced Solid Tumors.

PURPOSE: MEK inhibitors (MEKi) lack monotherapy efficacy in most RAS-mutant cancers. BCL-xL is an anti-apoptotic protein identified by a synthetic lethal shRNA screen as a key suppressor of apoptotic response to MEKi. PATIENTS AND METHODS: We conducted a dose escalation study (NCT02079740) of the BCL-xL inhibitor navitoclax and MEKi trametinib in patients with RAS-mutant tumors with expansion cohorts for: pancreatic, gynecologic (GYN), non-small cell lung cancer (NSCLC), and other cancers harboring KRAS/NRAS mutations. Paired pretreatment and day 15 tumor biopsies and serial cell-free (cf)DNA were analyzed. RESULTS: A total of 91 patients initiated treatment, with 38 in dose escalation. Fifty-eight percent had ≥3 prior therapies. A total of 15 patients (17%) had colorectal cancer, 19 (11%) pancreatic, 15 (17%) NSCLC, and 32 (35%) GYN cancers. The recommended phase II dose (RP2D) was established as trametinib 2 mg daily days 1 to 14 and navitoclax 250 mg daily days 1 to 28 of each cycle. Most common adverse events included diarrhea, thrombocytopenia, increased AST/ALT, and acneiform rash. At RP2D, 8 of 49 (16%) evaluable patients achieved partial response (PR). Disease-specific differences in efficacy were noted. In patients with GYN at the RP2D, 7 of 21 (33%) achieved a PR and median duration of response 8.2 months. No PRs occurred in patients with colorectal cancer, NSCLC, or pancreatic cancer. MAPK pathway inhibition was observed in on-treatment tumor biopsies. Reductions in KRAS/NRAS mutation levels in cfDNA correlated with clinical benefit. CONCLUSIONS: Navitoclax in combination with trametinib was tolerable. Durable clinical responses were observed in patients with RAS-mutant GYN cancers, warranting further evaluation in this population.

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.

Rational Combinations of PARP Inhibitors with HRD-Inducing Molecularly Targeted Agents.

Cancers with wild-type BRCA, homologous recombination proficiency, or de novo or acquired resistance to PARP inhibition represent a growing population of patients who may benefit from combinatorial PARP inhibitor strategies. We review targeted inhibitors of angiogenesis, epigenetic regulators, and PI3K, MAPK, and other cellular signaling pathways as inducers of homologous recombination deficiency, providing support for the use of PARP inhibitors in contexts not previously considered susceptible to PARP inhibition.

Pilot randomized trial of an acceptance-based telehealth intervention for women with ovarian cancer and PARP inhibitor-related fatigue.

OBJECTIVE: Poly(ADP-ribose) polymerase inhibitors (PARPi) have dramatically changed treatment for advanced ovarian cancer, but nearly half of patients experience significant fatigue. We conducted a two-site pilot randomized trial to evaluate the feasibility, acceptability, and preliminary efficacy of a brief, acceptance-based telehealth intervention (REVITALIZE) designed to reduce fatigue interference in patients on PARPi. METHODS: From June 2021 to April 2022, 44 participants were randomized 1:1 to REVITALIZE (6 weekly one-on-one sessions+booster) or enhanced usual care. Feasibility was defined as: ≥50% approach-to-consent among potentially eligible patients and ≥70% completion of 12-week follow-up assessment; acceptance was <20% participants reporting burden and <20% study withdrawal. Fatigue, anxiety, depression, and quality of life were assessed at baseline, 4-, 8- and 12-weeks. RESULTS: Among 44 participants (mean age = 62.5 years, 81.8% stage III/IV disease), the study was feasible (56.4% approach-to-consent ratio, 86.3% completion of 12-week assessment) and acceptable (0% reporting burden, 11.3% study withdrawal). At 12-week follow-up, REVITALIZE significantly reduced fatigue interference (Cohen's d = 0.94, p = .008) and fatigue severity (d = 0.54, p = .049), and improved fatigue levels (d = 0.62, p = .04) relative to enhanced usual care. REVITALIZE also showed promise for improved fatigue self-efficacy, fatigue catastrophizing, anxiety, depression, and quality of life (ds = 0.60-0.86, p ≥ .05). Compared with enhanced usual care, REVITALIZE participants had fewer PARPi dose reductions (6.7% vs. 19.0%), and dose delays (6.7% vs. 23.8%). CONCLUSIONS: Among fatigued adults with ovarian cancer on PARPi, a brief, acceptance-based telehealth intervention was feasible, acceptable, and demonstrated preliminary efficacy in improving fatigue interference, severity, and levels. REVITALIZE is a novel, scalable telehealth intervention worthy of further investigation.

STING agonism overcomes STAT3-mediated immunosuppression and adaptive resistance to PARP inhibition in ovarian cancer.

BACKGROUND: Poly (ADP-ribose) polymerase (PARP) inhibition (PARPi) has demonstrated potent therapeutic efficacy in patients with BRCA-mutant ovarian cancer. However, acquired resistance to PARPi remains a major challenge in the clinic. METHODS: PARPi-resistant ovarian cancer mouse models were generated by long-term treatment of olaparib in syngeneic Brca1-deficient ovarian tumors. Signal transducer and activator of transcription 3 (STAT3)-mediated immunosuppression was investigated in vitro by co-culture experiments and in vivo by analysis of immune cells in the tumor microenvironment (TME) of human and mouse PARPi-resistant tumors. Whole genome transcriptome analysis was performed to assess the antitumor immunomodulatory effect of STING (stimulator of interferon genes) agonists on myeloid cells in the TME of PARPi-resistant ovarian tumors. A STING agonist was used to overcome STAT3-mediated immunosuppression and acquired PARPi resistance in syngeneic and patient-derived xenografts models of ovarian cancer. RESULTS: In this study, we uncover an adaptive resistance mechanism to PARP inhibition mediated by tumor-associated macrophages (TAMs) in the TME. Markedly increased populations of protumor macrophages are found in BRCA-deficient ovarian tumors that rendered resistance to PARPi in both murine models and patients. Mechanistically, PARP inhibition elevates the STAT3 signaling pathway in tumor cells, which in turn promotes protumor polarization of TAMs. STAT3 ablation in tumor cells mitigates polarization of protumor macrophages and increases tumor-infiltrating T cells on PARP inhibition. These findings are corroborated in patient-derived, PARPi-resistant BRCA1-mutant ovarian tumors. Importantly, STING agonists reshape the immunosuppressive TME by reprogramming myeloid cells and overcome the TME-dependent adaptive resistance to PARPi in ovarian cancer. This effect is further enhanced by addition of the programmed cell death protein-1 blockade. CONCLUSIONS: We elucidate an adaptive immunosuppression mechanism rendering resistance to PARPi in BRCA1-mutant ovarian tumors. This is mediated by enrichment of protumor TAMs propelled by PARPi-induced STAT3 activation in tumor cells. We also provide a new strategy to reshape the immunosuppressive TME with STING agonists and overcome PARPi resistance in ovarian cancer.

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/ß-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.

Cediranib in Combination with Olaparib in Patients without a Germline BRCA1/2 Mutation and with Recurrent Platinum-Resistant Ovarian Cancer: Phase IIb CONCERTO Trial.

PURPOSE: The efficacy, safety, and tolerability of cediranib plus olaparib (cedi/ola) were investigated in patients with nongermline-BRCA-mutated (non-gBRCAm) platinum-resistant recurrent ovarian cancer. PATIENTS AND METHODS: PARP inhibitor-naïve women aged ≥18 years with platinum-resistant non-gBRCAm ovarian cancer, ECOG performance status of 0-2, and ≥3 prior lines of therapy received cediranib 30 mg once daily plus olaparib 200 mg twice daily in this single-arm, multicenter, phase IIb trial. The primary endpoint was objective response rate (ORR) by independent central review (ICR) using RECIST 1.1. Progression-free survival (PFS), overall survival (OS), and safety and tolerability were also examined. RESULTS: Sixty patients received cedi/ola, all of whom had confirmed non-gBRCAm status. Patients had received a median of four lines of chemotherapy; most (88.3%) had received prior bevacizumab. ORR by ICR was 15.3%, median PFS was 5.1 months, and median OS was 13.2 months. Forty-four (73.3%) patients reported a grade ≥3 adverse event (AE), with one patient experiencing a grade 5 AE (sepsis), considered unrelated to the study treatment. Dose interruptions, reductions, and discontinuations due to AEs occurred in 55.0%, 18.3%, and 18.3% of patients, respectively. Patients with high global loss of heterozygosity (gLOH) had ORR of 26.7% [4/15; 95% confidence interval (CI), 7.8-55.1], while ORR was 12.5% (4/32; 95% CI, 3.5-29.0) in the low gLOH group. CONCLUSIONS: Clinical activity was shown for the cedi/ola combination in heavily pretreated, non-gBRCAm, platinum-resistant patients with ovarian cancer despite failing to meet the target ORR of 20%, highlighting a need for further biomarker studies.

Evaluation of Treatment With Talazoparib and Avelumab in Patients With Recurrent Mismatch Repair Proficient Endometrial Cancer.

Importance: Although the activity of pembrolizumab and lenvatinib (the only US Food and Drug Administration-approved immunotherapy for mismatch repair proficient endometrial cancer [MMRP EC]) is compelling, there are no biomarkers of response and most patients do not tolerate, do not respond to, or develop resistance to this regimen, highlighting the need for additional, potentially biomarker-driven therapeutic approaches for patients with recurrent MMRP EC. Objective: To assess the potential positive outcomes and safety of the combination of the polyadenosine diphosphate-ribose polymerase inhibitor talazoparib and the programmed cell death ligand 1 (PD-L1) inhibitor avelumab in recurrent MMRP EC. Design, Settings, and Participants: This investigator-initiated, open-label, single-arm, 2-stage, phase 2 study nonrandomized controlled trial patients at 4 institutions in the US. Key eligibility criteria included measurable disease, unlimited prior therapies, and all endometrial cancer histologies. Interventions: Talazoparib, 1 mg, orally, daily, and avelumab, 10 mg/kg, intravenously, every 2 weeks, were administered until disease progression or unacceptable toxic effects. Main Outcomes and Measures: Statistical considerations were developed for 2 coprimary objectives of objective response rate and rate of progression-free survival at 6 months, with a 2-stage design that allowed for early discontinuation for futility. Prespecified exploratory objectives included the association of immunogenomic features (determined by targeted-panel next-generation sequencing and immunohistochemistry) with activity. Results: Thirty-five female patients (mean [SD] age, 67.9 [8.41] years) received protocol therapy; 9 (25.7%) derived clinical benefit after meeting at least 1 of the 2 coprimary end points. Four patients (11.4%) exhibited confirmed objective response rates (4 partial responses), and 8 (22.9%) survived progression free at 6 months. The most common grade 3 and 4 treatment-related toxic effects were anemia (16 [46%]), thrombocytopenia (10 [29%]), and neutropenia (4 [11%]); no patient discontinued receipt of therapy because of toxic effects. Tumors with homologous recombination repair alterations were associated with clinical benefit from treatment with avelumab and talazoparib. Tumor mutational burden, tumor-infiltrating lymphocytes, and PD-L1 status were not associated with clinical benefit. Conclusions and Relevance: The results of this nonrandomized controlled trial suggest that treatment with avelumab and talazoparib demonstrated a favorable toxic effect profile and met the predetermined criteria to be considered worthy of further evaluation in MMRP EC. Immunogenomic profiling provided insights that may inform ongoing and future studies of polyadenosine diphosphate-ribose polymerase and PD-L1 inhibitor combinations in endometrial cancer. Trial Registration: ClinicalTrials.gov Identifier: NCT02912572.

Satellite repeat RNA expression in epithelial ovarian cancer associates with a tumor-immunosuppressive phenotype.

Aberrant expression of viral-like repeat elements is a common feature of epithelial cancers, and the substantial diversity of repeat species provides a distinct view of the cancer transcriptome. Repeatome profiling across ovarian, pancreatic, and colorectal cell lines identifies distinct clustering independent of tissue origin that is seen with coding gene analysis. Deeper analysis of ovarian cancer cell lines demonstrated that human satellite II (HSATII) satellite repeat expression was highly associated with epithelial-mesenchymal transition (EMT) and anticorrelated with IFN-response genes indicative of a more aggressive phenotype. SATII expression - and its correlation with EMT and anticorrelation with IFN-response genes - was also found in ovarian cancer RNA-Seq data and was associated with significantly shorter survival in a second independent cohort of patients with ovarian cancer. Repeat RNAs were enriched in tumor-derived extracellular vesicles capable of stimulating monocyte-derived macrophages, demonstrating a mechanism that alters the tumor microenvironment with these viral-like sequences. Targeting of HSATII with antisense locked nucleic acids stimulated IFN response and induced MHC I expression in ovarian cancer cell lines, highlighting a potential strategy of modulating the repeatome to reestablish antitumor cell immune surveillance.

A phase II study of MK-2206, an AKT inhibitor, in uterine serous carcinoma.

Uterine serous carcinoma (USC) is an uncommon subtype of endometrial cancer with a poor prognosis. USCs have genomic alterations in the PI3K pathway. A prior phase II study of AKT inhibitor MK-2206 (an allosteric AKT inhibitor, primarily affecting AKT1 and AKT2) in endometrial cancers resulted in progression-free survival (PFS) of ≥6 months in five out of seven patients with USC. To further assess the activity of MK-2206 in USC, we designed a phase II, single-stage assessment of MK-2206 in patients with advanced or recurrent high-grade serous endometrial cancer, who had received up to two lines of prior therapy. MK-2206 (135 mg) was administered orally once per week, in continuous 28-day cycles. Fourteen patients received treatment. The most common treatment-related adverse events were diarrhea (36%), acneiform rash (36%), nausea (29%), fatigue (29%), and hyperglycemia (21%); most events were grade 1-2. One confirmed partial response was observed in a patient who was also alive and progression-free at 6 months. One additional patient was alive and progression-free at 6 months. The clinical benefit rate was 14.3% (95% CI: 1.8 to 42.8). Five patients had stable disease (35.7%) and seven had progressive disease (50%); one was unevaluable. Median PFS was 2 months (95% CI: 1.6 to 4.4) and median overall survival was 6.4 months (95% CI: 5.1 to not reached). In summary, MK-2206 had limited activity in USC, although a few patients achieved sustained progression-free intervals in this study and in the previously reported phase II trial of MK-2206. Further investigations are needed to identify features associated with response.

Improved T-cell Immunity Following Neoadjuvant Chemotherapy in Ovarian Cancer.

PURPOSE: Although local tissue-based immune responses are critical for elucidating direct tumor-immune cell interactions, peripheral immune responses are increasingly recognized as occupying an important role in anticancer immunity. We evaluated serial blood samples from patients with advanced epithelial ovarian cancer (EOC) undergoing standard-of-care neoadjuvant carboplatin and paclitaxel chemotherapy (including dexamethasone for prophylaxis of paclitaxel-associated hypersensitivity reactions) to characterize the evolution of the peripheral immune cell function and composition across the course of therapy. EXPERIMENTAL DESIGN: Serial blood samples from 10 patients with advanced high-grade serous ovarian cancer treated with neoadjuvant chemotherapy (NACT) were collected before the initiation of chemotherapy, after the third and sixth cycles, and approximately 2 months after completion of chemotherapy. T-cell function was evaluated using ex vivo IFNγ ELISpot assays, and the dynamics of T-cell repertoire and immune cell composition were assessed using bulk and single-cell RNA sequencing (RNAseq). RESULTS: T cells exhibited an improved response to viral antigens after NACT, which paralleled the decrease in CA125 levels. Single-cell analysis revealed increased numbers of memory T-cell receptor (TCR) clonotypes and increased central memory CD8+ and regulatory T cells throughout chemotherapy. Finally, administration of NACT was associated with increased monocyte frequency and expression of HLA class II and antigen presentation genes; single-cell RNAseq analyses showed that although driven largely by classical monocytes, increased class II gene expression was a feature observed across monocyte subpopulations after chemotherapy. CONCLUSIONS: NACT may alleviate tumor-associated immunosuppression by reducing tumor burden and may enhance antigen processing and presentation. These findings have implications for the successful combinatorial applications of immune checkpoint blockade and therapeutic vaccine approaches in EOC.