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Targeting the ataxia telangiectasia and RAD3-related (ATR) enzyme represents a promising anticancer strategy for tumors with DNA damage response (DDR) defects and replication stress, including inactivation of ataxia telangiectasia mutated (ATM) signaling. We report the dose-escalation portion of the phase I first-in-human trial of oral ATR inhibitor BAY 1895344 intermittently dosed 5 to 80 mg twice daily in 21 patients with advanced solid tumors. The MTD was 40 mg twice daily 3 days on/4 days off. Most common adverse events were manageable and reversible hematologic toxicities. Partial responses were achieved in 4 patients and stable disease in 8 patients. Median duration of response was 315.5 days. Responders had ATM protein loss and/or deleterious ATM mutations and received doses ≥40 mg twice daily. Overall, BAY 1895344 is well tolerated, with antitumor activity against cancers with certain DDR defects, including ATM loss. An expansion phase continues in patients with DDR deficiency.Significance:Oral BAY 1895344 was tolerable, with antitumor activity in heavily pretreated patients with various advanced solid tumors, particularly those with ATM deleterious mutations and/or loss of ATM protein; pharmacodynamic results supported a mechanism of action of increased DNA damage. Further study is warranted in this patient population.See related commentary by Italiano, p. 14.This article is highlighted in the In This Issue feature, p. 1

Supplementary Data from Tiling Path Genomic Profiling of Grade 3 Invasive Ductal Breast Cancers

Purpose: To identify therapeutic targets in ovarian clear cell carcinomas, a chemoresistant and aggressive type of ovarian cancer.Experimental Design: Twelve ovarian clear cell carcinoma cell lines were subjected to tiling path microarray comparative genomic hybridization and genome-wide expression profiling analysis. Regions of high-level amplification were defined and genes whose expression levels were determined by copy number and correlated with gene amplification were identified. The effects of inhibition of PPM1D were assessed using short hairpin RNA constructs and a small-molecule inhibitor (CCT007093). The prevalence of PPM1D amplification and mRNA expression was determined using chromogenic in situ hybridization and quantitative real-time reverse transcription-PCR in a cohort of pure ovarian clear cell carcinomas and on an independent series of unselected epithelial ovarian cancers.Results: Array-based comparative genomic hybridization analysis revealed regions of high-level amplification on 1q32, 1q42, 2q11, 3q24-q26, 5p15, 7p21-p22, 11q13.2-q13.4, 11q22, 17q21-q22, 17q23.2, 19q12-q13, and 20q13.2. Thirty-four genes mapping to these regions displayed expression levels that correlated with copy number gains/amplification. PPM1D had significantly higher levels of mRNA expression in ovarian clear cell carcinoma cell lines harboring gains/amplifications of 17q23.2. PPM1D inhibition revealed that PPM1D expression and phosphatase activity are selectively required for the survival of ovarian clear cell carcinoma cell lines with 17q23.2 amplification. PPM1D amplification was significantly associated with ovarian clear cell carcinoma histology (P = 0.0003) and found in 10% of primary ovarian clear cell carcinomas. PPM1D expression levels were significantly correlated with PPM1D gene amplification in primary ovarian clear cell carcinomas.Conclusion: Our data provide strong circumstantial evidence that PPM1D is a potential therapeutic target for a subgroup of ovarian clear cell carcinomas.

Purpose:RET is an estrogen response gene with preclinical studies demonstrating cross-talk between the RET and estrogen receptor (ER) pathways. We investigate the role of lenvatinib, a multikinase inhibitor with potent activity against RET, in patients with metastatic breast cancer.Patients and Methods:Patients with advanced ER+/HER2− breast cancer were treated with lenvatinib plus letrozole in a phase Ib/II trial. Primary objectives included safety and recommended phase II dose (RP2D) determination in phase Ib, and objective response rates (ORR) in phase II dose expansion.Results:Sixteen patients were recruited in dose finding, where deescalating doses of lenvatinib from 20 to 14 mg were investigated. Lenvatinib 14 mg plus letrozole 2.5 mg daily was determined as RP2D. Thirty-one patients with 5 median lines of prior therapy in the metastatic setting (range, 0–11) were recruited in dose expansion. In this cohort, ORR was 23.3% [95% confidence interval (CI) 9.9%–42.3%], with median duration of response (DoR) of 6.9 months [interquartile range (IQR) 5.9 to 13.1]. Clinical benefit rate ≥6 months (CBR) was 50.0% (95% CI, 31.3%–68.7%). Similar efficacy was observed in the subgroup of 25 patients who progressed on prior CDK4/6 inhibitor therapy [ORR 20.0% (95% CI, 6.8%–40.7%), median DoR 6.9 months (IQR 5.9–13.1), and CBR 52.0% (95% CI, 31.3%–72.2%)]. Pharmacodynamic studies showed target modulation, with paired tumor biopsies indicating downregulation of RET/pERK and improved vascular normalization index.Conclusions:Lenvatinib plus letrozole had manageable toxicity, with target engagement and preliminary antitumor activity observed, supporting further assessment in randomized studies.

Supplementary Table from Phase Ib/II Dose Expansion Study of Lenvatinib Combined with Letrozole in Postmenopausal Women with Hormone Receptor–Positive Breast Cancer

Supplementary Figure S1; Supplementary Tables S1-S4.

Supplementary Data from PPM1D Is a Potential Therapeutic Target in Ovarian Clear Cell Carcinomas

Supplementary Data from Phase Ib/II Dose Expansion Study of Lenvatinib Combined with Letrozole in Postmenopausal Women with Hormone Receptor–Positive Breast Cancer

Purpose: To characterize the molecular genetic profiles of grade 3 invasive ductal carcinomas of no special type using high-resolution microarray-based comparative genomic hybridization (aCGH) and to identify recurrent amplicons harboring putative therapeutic targets associated with luminal, HER-2, and basal-like tumor phenotypes.Experimental Design: Ninety-five grade 3 invasive ductal carcinomas of no special type were classified into luminal, HER-2, and basal-like subgroups using a previously validated immunohistochemical panel. Tumor samples were microdissected and subjected to aCGH using a tiling path 32K BAC array platform. Selected regions of recurrent amplification were validated by means of in situ hybridization. Expression of genes pertaining to selected amplicons was investigated using quantitative real-time PCR and gene silencing was done using previously validated short hairpin RNA constructs.Results: We show that basal-like and HER-2 tumors are characterized by “sawtooth” and “firestorm” genetic patterns, respectively, whereas luminal cancers were more heterogeneous. Apart from confirming known amplifications associated with basal-like (1q21, 10p, and 12p), luminal (8p12, 11q13, and 11q14), and HER-2 (17q12) cancers, we identified previously unreported recurrent amplifications associated with each molecular subgroup: 19q12 in basal-like, 1q32.1 in luminal, and 14q12 in HER-2 cancers. PPM1D gene amplification (17q23.2) was found in 20% and 8% of HER-2 and luminal cancers, respectively. Silencing of PPM1D by short hairpin RNA resulted in selective loss of viability in tumor cell lines harboring the 17q23.2 amplification.Conclusions: Our results show the power of aCGH analysis in unraveling the genetic profiles of specific subgroups of cancer and for the identification of novel therapeutic targets.

Supplementary Figure from Phase Ib/II Dose Expansion Study of Lenvatinib Combined with Letrozole in Postmenopausal Women with Hormone Receptor–Positive Breast Cancer

Purpose: Ovarian clear cell carcinomas (OCCC) are a drug-resistant and aggressive type of epithelial ovarian cancer. We analyzed the molecular genetic profiles of OCCCs to determine whether distinct genomic subgroups of OCCCs exist.Experimental design: Fifty pure primary OCCCs were subjected to high-resolution microarray-based comparative genomic hybridization (aCGH). Unsupervised hierarchical clustering using Ward's linkage analysis was performed to identify genomic subgroups of OCCCs. Survival analysis was performed using Kaplan–Meier method and log-rank test. Cox-regression analysis was used to identify independent predictors of outcome. Differentially amplified regions between genomic subgroups of OCCCs were identified using a multi-Fisher's exact test.Results: Hierarchical cluster analysis revealed two distinct clusters of OCCCs with different clinical outcomes. Patients from cluster-1 had a significantly shorter median progression-free survival (PFS) than those from cluster-2 (11 vs. 65 months, P = 0.009), although estimates for ovarian cancer–specific survival (OCS) did not reach statistical significance (P = 0.065). In multivariate analysis, suboptimal debulking surgery and genomic cluster were independently prognostic for PFS. Recurrently amplified genomic regions with a significantly higher prevalence in cluster-1 than cluster-2 OCCCs were identified and validated. HER2 gene amplification and protein overexpression was observed in 14% of OCCCs, suggesting that this may constitute a potential therapeutic target for a subgroup of these tumors.Conclusions: OCCCs constitute a heterogeneous disease at the genomic level despite having similar histological features. The pattern of genomic aberrations in subgroups of OCCCs is of clinical significance. We have identified recurrently amplified regions that may harbor potential therapeutic targets for subgroups of OCCCs. Clin Cancer Res; 17(6); 1521–34. ©2011 AACR.

Clear cell endometrial carcinoma represents an uncommon and poorly understood entity. Data from molecular/genomic profiling highlighted the importance of various signatures in assessing the prognosis of endometrial cancer according to four classes of risk (POLE mutated, MMRd, NSMP, and p53 abnormal). Unfortunately, data specific to clear cell histological subtype endometrial cancer are lacking. More recently, data has emerged to suggest that most of the patients (more than 80%) with clear cell endometrial carcinoma are characterized by p53 abnormality or NSMP type. This classification has important therapeutic implications. Although it is an uncommon entity, clear cell endometrial cancer patients with POLE mutation seem characterized by a good prognosis. Chemotherapy is effective in patients with NSMP (especially in stage III and IV) and patients with p53 abnormal disease (all stages). While, preliminary data suggested that patients with MMRd are less likely to benefit from chemotherapy. The latter group appears to benefit much more from immune checkpoint inhibitors: recent data from clinical trials on pembrolizumab plus lenvatinib and nivolumab plus cabozantinib supported that immunotherapy plus tyrosine kinase inhibitors (TKI) would be the most appropriate treatment for recurrent non-endometrioid endometrial cancer (including clear cell carcinoma) after the failure of platinum-based chemotherapy. Moreover, ongoing clinical trials testing the anti-tumor activity of innovative products will clarify the better strategies for advanced/recurrent clear cell endometrial carcinoma. Further prospective evidence is urgently needed to better characterize clear cell endometrial carcinoma.

The adjuvant and post-surgical treatment of gynaecological cancers has historically been guided by the estimation of relapse risk based on clinicopathological factors determined at the time of cancer diagnosis. The recent advancement of genomic and molecular characterisation of gynaecological cancers has begun to shift paradigms in the selection of adjuvant treatment strategy. Recent data regarding the predictive and/or prognostic value of molecular tests in the treatment of advanced ovarian cancer as well as early stage endometrial cancer have been the first such examples to enter adjuvant treatment guidelines for these diseases. In this article, we discuss the current state and future development of molecular assays for gynaecological cancers and how they impact upon treatment selection for ovarian, endometrial and cervical cancers in the post-surgical setting.

Little is known about the immune environment of ovarian clear cell carcinoma (OCCC) and its impact on various ethnic backgrounds. The aim of this OCCC immune-related gene expression signatures (irGES) study was to address the interaction between tumour and immune environment of ethnically-diverse Asian and Caucasian populations and to identify relevant molecular subsets of biological and clinical importance. Our study included 264 women from three different countries (Singapore, Japan, and the UK) and identified four novel immune subtypes (PD1-high, CTLA4-high, antigen-presentation, and pro-angiogenic subtype) with differentially expressed pathways, and gene ontologies using the NanoString nCounter PanCancer Immune Profiling Panel. The PD1-high and CTLA4-high subtypes demonstrated significantly higher PD1, PDL1, and CTLA4 expression, and were associated with poorer clinical outcomes. Mismatch repair (MMR) protein expression, assessed by immunohistochemistry, revealed that about 5% of OCCCs had deficient MMR expression. The prevalence was similar across the three countries and appeared to cluster in the CTLA4-high subtype. Our results suggest that OCCC from women of Asian and Caucasian descent shares significant clinical and molecular similarities. To our knowledge, our study is the first study to include both Asian and Caucasian women with OCCC and helps to shine light on the impact of ethnic differences on the immune microenvironment of OCCC. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Background The optimal treatment and molecular landscape of recurrent clear cell carcinoma of the vulva (VCCC) are unknown. No reported data exist regarding the efficacy of anti-programmed death 1 (PD-1) immune checkpoint inhibition in VCCC. We report on a patient with chemotherapy-refractory recurrent VCCC, who was found to have high tumor programmed death-ligand 1 (PD-L1) combined positive score (CPS), and subsequently experienced a durable partial response (PR), after treatment with off-label fifth-line pembrolizumab. Case presentation A forty-year-old Filipino woman presented to our center with recurrent VCCC that had progressed on multiple prior lines of cytotoxic chemotherapy. She had a large 25 cm fungating left groin tumor causing marked lower limb lymphedema, pain and limited mobility. PD-L1 CPS by immunohistochemistry was 45. She was treated with off-label pembrolizumab monotherapy and had a dramatic clinical, biochemical and radiological partial response. The progression-free survival of this patient's VCCC after treatment with pembrolizumab, defined as the time from initiation of pembrolizumab until disease progression (by Response Evaluation Criteria in Solid Tumors (version 1.1)), was 8 months. While receiving pembrolizumab, she was diagnosed with concurrent secondary myelodysplastic syndrome with excess blasts (MDS-EB), thought to be related to her prior exposure to multiple lines of cytotoxic chemotherapy. This eventually progressed to acute myeloid leukemia (AML), leading to her demise. Overall survival from time of initiation of pembrolizumab till death was 16 months. Conclusion Pembrolizumab was active in this patient with chemotherapy-refractory VCCC which harbored high PD-L1 CPS. Further studies to determine the role of immune check-point blockade in the treatment of VCCC are warranted.

Treatment approaches for relapsed ovarian cancer have evolved over the past decade from a calendar-based decision tree to a patient-oriented biologically driven algorithm. Nowadays, platinum-based chemotherapy should be offered to all patients with a reasonable chance of responding to this therapy. The treatment-free interval for platinum is only one of many factors affecting patients' eligibility for platinum re-treatment. Bevacizumab increases the response to chemotherapy irrespective of the cytotoxic regimen and can be valuable in patients with an urgent need for symptom relief (e.g. pleural effusion, ascites). For patients with recurrent high-grade ovarian cancer, which responds to platinum-based treatment, maintenance therapy with a poly(ADP-ribose) polymerase inhibitor can be offered, regardless of the BRCA mutation status. Here we review contemporary decision-making processes in the systemic treatment of relapsed ovarian cancer.

Endometrial cancer incidence and mortality are rising among all ethnic groups. Carboplatin plus paclitaxel is the established frontline treatment for advanced/recurrent disease; however, subsequent treatment with traditional cytotoxic chemotherapy is challenging. The molecular characterization of endometrial cancer has provided important insights into the biological drivers of carcinogenesis, which has allowed for the development of newer precision immunotherapies and targeted therapies, including pembrolizumab, dostarlimab, and lenvatinib. Until recently, platinum rechallenge was often considered at the time of recurrence, given the lack of other available therapeutic options; however, "platinum sensitivity" in endometrial cancer is subjective and largely based on expert opinion and/or practitioner experience. Small retrospective studies have tried to provide guidance on the utility of platinum rechallenge, but they are limited by variable patient characteristics and small sample sizes. The applicability of these retrospective studies to contemporary clinical practice is difficult in the setting of changing patient demographics, a better understanding of endometrial cancer drivers, and the recent approvals of immune checkpoint inhibitors and the combination of lenvatinib plus pembrolizumab in the second-line setting. The primary focus of this review is to distill the available data regarding platinum-doublet chemotherapy rechallenge and highlight recent pivotal developments in endometrial cancer treatment, as well as future directions.

Cervical cancer is a global health problem which disproportionally affects women in low- and middle- income countries. The World Health Organization recently launched its global strategy to eliminate this disease in the next two decades. For those women diagnosed today with cervical cancer better strategies are needed to improve outcome and reduce treatment-related morbidity. Clinical trials are critical to shaping future treatment, and much has been achieved already. However, such opportunities are limited in low resource settings, and the Cervical Cancer Research Network is dedicated to expanding access to new technologies in surgery, radiation, and medical oncology. In this article we review the status of the trials portfolio and outline future objectives, including the launch of a number of research grants for aspiring or established researchers in low- and middle-income settings

Elevated levels of replicative stress in gynecological cancers arising from uncontrolled oncogenic activation, loss of key tumor suppressors, and frequent defects in the DNA repair machinery are an intrinsic vulnerability for therapeutic exploitation. The presence of replication stress activates the DNA damage response and downstream checkpoint proteins including ataxia telangiectasia and Rad3 related kinase (ATR), checkpoint kinase 1 (CHK1), and WEE1-like protein kinase (WEE1), which trigger cell cycle arrest while protecting and restoring stalled replication forks. Strategies that increase replicative stress while lowering cell cycle checkpoint thresholds may allow unrepaired DNA damage to be inappropriately carried forward in replicating cells, leading to mitotic catastrophe and cell death. Moreover, the identification of fork protection as a key mechanism of resistance to chemo- and poly (ADP-ribose) polymerase inhibitor therapy in ovarian cancer further increases the priority that should be accorded to the development of strategies targeting replicative stress. Small molecule inhibitors designed to target the DNA damage sensors, such as inhibitors of ataxia telangiectasia-mutated (ATM), ATR, CHK1 and WEE1, impair smooth cell cycle modulation and disrupt efficient DNA repair, or a combination of the above, have demonstrated interesting monotherapy and combinatorial activity, including the potential to reverse drug resistance and have entered developmental pipelines. Yet unresolved challenges lie in balancing the toxicity profile of these drugs in order to achieve a suitable therapeutic index while maintaining clinical efficacy, and selective biomarkers are urgently required. Here we describe the premise for targeting of replicative stress in gynecological cancers and discuss the clinical advancement of this strategy.

Cervical cancer constitutes a significant health burden for women globally. While most patients with early-stage disease can be cured with radical surgery or chemoradiotherapy, patients with high-risk locally advanced disease or with recurrent/metastatic disease have a poor prognosis with standard treatments. Immunotherapies are a rational treatment for this HPV-driven cancer that commonly expresses programmed cell death ligand-1. Before 2021, pembrolizumab was the only United States Food and Drug Administration-approved immunotherapy in cervical cancer, specifically for the second-line recurrent or metastatic (r/m) setting. In late 2021, the antibody-drug conjugate tisotumab vedotin was approved for second-line r/m cervical cancer and pembrolizumab combined with chemotherapy ± bevacizumab was approved for first-line r/m disease based on results from KEYNOTE-826. Moreover, with at least 2 dozen additional immunotherapy clinical trials in the second-line and first-line r/m setting, as well as in locally advanced disease, the treatment landscape for cervical cancer may eventually encounter a potential paradigm shift. Pivotal trials of immunotherapies for cervical cancer that were recently approved or with the potential for regulatory consideration through 2024 are reviewed. As immunotherapy has the opportunity to establish new standards of care in the treatment of cervical cancers, new biomarkers to identify the ideal patient populations for these therapies may also become important. However, issues with access, affordability, and compliance in low- and middle-income countries are anticipated.

Purpose: RET is an estrogen response gene with preclinical studies demonstrating cross-talk between the RET and estrogen receptor (ER) pathways. We investigate the role of lenvatinib, a multikinase inhibitor with potent activity against RET, in patients with metastatic breast cancer. Patients and Methods: Patients with advanced ER+/HER2− breast cancer were treated with lenvatinib plus letrozole in a phase Ib/II trial. Primary objectives included safety and recommended phase II dose (RP2D) determination in phase Ib, and objective response rates (ORR) in phase II dose expansion. Results: Sixteen patients were recruited in dose finding, where deescalating doses of lenvatinib from 20 to 14 mg were investigated. Lenvatinib 14 mg plus letrozole 2.5 mg daily was determined as RP2D. Thirty-one patients with 5 median lines of prior therapy in the metastatic setting (range, 0–11) were recruited in dose expansion. In this cohort, ORR was 23.3% [95% confidence interval (CI) 9.9%–42.3%], with median duration of response (DoR) of 6.9 months [interquartile range (IQR) 5.9 to 13.1]. Clinical benefit rate ≥6 months (CBR) was 50.0% (95% CI, 31.3%–68.7%). Similar efficacy was observed in the subgroup of 25 patients who progressed on prior CDK4/6 inhibitor therapy [ORR 20.0% (95% CI, 6.8%–40.7%), median DoR 6.9 months (IQR 5.9–13.1), and CBR 52.0% (95% CI, 31.3%–72.2%)]. Pharmacodynamic studies showed target modulation, with paired tumor biopsies indicating downregulation of RET/pERK and improved vascular normalization index. Conclusions: Lenvatinib plus letrozole had manageable toxicity, with target engagement and preliminary antitumor activity observed, supporting further assessment in randomized studies.

Cancer metabolism is associated with enhanced lipogenesis required for rapid growth and proliferation. However, the magnitude of dysregulation of diverse lipid species mostly remains to be characterized, particularly in rare cancers such as ovarian clear cell carcinoma (OCCC). Here we implemented a robust sample preparation workflow together with targeted LC-MS/MS to identify the lipidomic changes in formalin-fixed paraffin-embedded specimen from OCCC as compared to uninvolved contralateral ovarian tissue. We quantitated 342 lipid species representing 28 lipid classes. We observed differential regulation of diverse lipid species belonging to several glycerophospholipid classes and trihexosylceramide. A number of unsaturated lipid species were increased whereas saturated lipid showed a decrease in OCCC as compared to the controls. We also carried out total fatty acid analysis and observed increase in the levels of several unsaturated fatty acids with concomitant increase in the index of stearoyl-CoA desaturase (SCD) in OCCC. We confirmed the upregulation of SCD, the rate-limiting enzyme for the synthesis of monounsaturated fatty acids, by immunohistochemistry (IHC) assays. Hence, by carrying out mass spectrometry analysis of archival tissue samples, we were able to provide novel insights into the lipidomic alterations of OCCC.

Numerous retrospective studies have demonstrated that the density of intra-tumoral immune cell infiltration is prognostic in epithelial ovarian cancer (OC). These observations together with reports of programmed death ligand-1 (PD-L1) expression in advanced OC provided the rationale for investigating the benefit of programmed death-1 (PD1) or PD-L1 inhibition in OC. Unfortunately clinical trials to date evaluating PD1/PD-L1 inhibition in patients with relapsed OC have been disappointing. In this review we will discuss early results from single agent PD1/PD-L1 inhibitors and the strategies to enhance benefit from immune-oncology agents in OC, including proposing anti-PD-L1 in combination with other agents (cytotoxics, anti-angiogenics, poly(ADP-ribose) polymerase. (PARP) inhibitors, targeted therapies or other immunotherapies), as well as evaluating these agents earlier in the disease course, or in biomarker selected patients.

The replication stress response (RSR) involves a downstream kinase cascade comprising ataxia telangiectasia-mutated (ATM), ATM and rad3-related (ATR), checkpoint kinases 1 and 2 (CHK1/2), and WEE1-like protein kinase (WEE1), which cooperate to arrest the cell cycle, protect stalled forks, and allow time for replication fork repair. In the presence of elevated replicative stress, cancers are increasingly dependent on RSR to maintain genomic integrity. An increasing number of drug candidates targeting key RSR nodes, as monotherapy through synthetic lethality, or through rational combinations with immune checkpoint inhibitors and targeted therapies, are demonstrating promising efficacy in early phase trials. RSR targeting is also showing potential in reversing PARP inhibitor resistance, an important area of unmet clinical need. In this review, we introduce the concept of targeting the RSR, detail the current landscape of monotherapy and combination strategies, and discuss emerging therapeutic approaches, such as targeting Polθ.

The efficacy of poly(ADP-ribose) polymerase inhibitors (PARPi) is restricted by inevitable drug resistance, while their use in combination with chemotherapy and targeted agents is commonly associated with dose-limiting toxicities. Immune checkpoint blockade (ICB) has demonstrated durable responses in different solid tumors and is well-established across multiple cancers. Despite this, single agent activity is limited to a minority of patients and drug resistance remains an issue. Building on the monotherapy success of both drug classes, combining PARPi with ICB may be a safe and well-tolerated strategy with the potential to improve survival outcomes. In this review, we present the preclinical, translational, and clinical data supporting the combination of DNA damage response (DDR) and ICB as well as consider important questions to be addressed with future research.

Inhibitors of the mitotic kinase PLK1 yield objective responses in a subset of refractory cancers. However, PLK1 overexpression in cancer does not correlate with drug sensitivity, and the clinical development of PLK1 inhibitors has been hampered by the lack of patient selection marker. Using a high-throughput chemical screen, we discovered that cells deficient for the tumor suppressor ARID1A are highly sensitive to PLK1 inhibition. Interestingly this sensitivity was unrelated to canonical functions of PLK1 in mediating G2-M cell cycle transition. Instead, a whole-genome CRISPR screen revealed PLK1 inhibitor sensitivity in ARID1A deficient cells to be dependent on the mitochondrial translation machinery. We find that ARID1A knocked-out (KO) cells have an unusual mitochondrial phenotype with aberrant biogenesis, increased oxygen consumption/ expression of oxidative phosphorylation genes, but without increased ATP production. Using expansion microscopy and biochemical fractionation, we see that a subset of PLK1 localizes to the mitochondria in interphase cells. Inhibition of PLK1 in ARID1A KO cells further uncouples oxygen consumption from ATP production, with subsequent membrane depolarization and apoptosis. Knockdown of a key subunit of the mitochondrial ribosome reverses PLK1-inhibitor induced apoptosis in ARID1A deficient cells, confirming specificity of the phenotype. Together, these findings highlight a novel interphase role for PLK1 in maintaining mitochondrial fitness under metabolic stress, and a strategy for therapeutic use of PLK1 inhibitors. To translate these findings, we describe a quantitative microscopy assay for assessment of ARID1A protein loss, which could offer a novel patient selection strategy for the clinical development of PLK1 inhibitors in cancer.Statement of significanceCurrently, no predictive biomarkers have been identified for PLK1 inhibitors in cancer treatment. We show that ARID1A loss sensitizes cells to PLK1 inhibitors through a previously unrecognized vulnerability in mitochondrial oxygen metabolism.

Purpose: Patients with recurrent ovarian clear cell carcinoma (OCCC) have limited effective options due to chemoresistance. A phase II study was designed to assess the activity of ENMD-2076, an oral multitarget kinase selective against Aurora A and VEGFR. Patients and Methods: This multicenter phase II study included patients with recurrent OCCC who received prior platinum-based chemotherapy. Primary endpoints were objective response and 6-month progression-free survival (PFS) rates. Correlative analyses include ARID1A and PTEN expression by IHC and gene sequencing with a targeted custom capture next-generation sequencing panel. Results: Forty patients were enrolled with a median age of 54, of which 38 patients were evaluable. ENMD-2076 was well tolerated with main related grade 3 toxicities being hypertension (28%), proteinuria (10%), and diarrhea (10%). Best response was partial response for 3 patients (1 unconfirmed) and stable disease for 26 patients. The overall 6-month PFS rate was 22% and differed according to ARID1A expression (ARIDIA− vs. ARID1A+; 33% vs. 12%, P = 0.023). PTEN-positive expression was observed in 20 of 36 patients, and there was no correlation with outcome. Median PFS in patients with PI3KCA wild-type versus PI3KCA-mutated group was 5 versus 3.7 months (P = 0.049). Molecular profiling showed variants in PI3KCA (27%), ARID1A (26%), and TP53 (7%). The patient with the longest treatment duration (22 months) was PTEN wild-type, diploid PTEN with putative biallelic inactivation of ARID1A. Conclusions: Single-agent ENMD-2076 did not meet the preset bar for efficacy. Loss of ARID1A correlated with better PFS on ENMD-2076 and warrants further investigation as a potential predictive biomarker.

The recognition of homologous recombination deficiency (HRD) as a frequent feature of high-grade serous ovarian cancer (HGSOC) has transformed treatment paradigms. Poly(ADP-ribose) polymerase inhibitors (PARPis), developed based on the rationale of synthetic lethality that predicates antitumor efficacy in tumors harboring underlying HRD, now represents an important class of therapy for HGSOC. Recent data have drawn attention to the assessment of homologous recombination DNA repair (HRR) as a prognostic and predictive biomarker in HGSOC, leading to increasing debate on the optimal means of defining and evaluating HRD, both genotypically and phenotypically. At present, clinical-grade assays such as myChoice CDx and FoundationOne CDx are approved companion diagnostics which can identify patients with HRD-positive HGSOC by diagnosing a ‘genomic scar’ reflecting underlying genomic instability. Yet despite the rapid maturation of this field, tumoral HRD status has been recognized to be dynamic over time and with treatment pressure. In practice, this means that restoration of HRR through mechanisms of platinum and PARPi resistance are not adequately represented by genomic scar assays, and contribute toward discordance with clinical PARPi response, or lack-thereof. It is thus critical that HRD testing is optimized to address the controversies of diverse HRD testing methodology, appropriate thresholds for HRD identification, and relevant timepoints for HRD testing, in order to realize the potential for PARPis to maximally benefit patients with HGSOC. Here, we discuss the premise of HRD testing in HGSOC, current methodologies for HRD identification and their performance in the clinic, highlight upcoming strategies, and discuss the challenges faced in moving this field forward., Highlights • The assessment of HRD is as an important prognostic and predictive biomarker in HGSOC. • HRD assays diagnosing a ‘genomic instability scar’ can identify patients with HGSOC likely to benefit from frontline PARPi. • Future HRD assays must address diverse testing methodology, optimal thresholds, and functional HRR status.

Early relapse after platinum chemotherapy in epithelial ovarian cancer (EOC) portends poor survival. A‐priori identification of platinum resistance is therefore crucial to improve on standard first‐line carboplatin–paclitaxel treatment. The DNA repair pathway homologous recombination (HR) repairs platinum‐induced damage, and the HR recombinase RAD51 is overexpressed in cancer. We therefore designed a REMARK‐compliant study of pre‐treatment RAD51 expression in EOC, using fluorescent quantitative immunohistochemistry (qIHC) to overcome challenges in quantitation of protein expression in situ. In a discovery cohort (n = 284), RAD51‐High tumours had shorter progression‐free and overall survival compared to RAD51‐Low cases in univariate and multivariate analyses. The association of RAD51 with relapse/survival was validated in a carboplatin monotherapy SCOTROC4 clinical trial cohort (n = 264) and was predominantly noted in HR‐proficient cancers (Myriad HRDscore, Quantitative immunohistochemistry (qIHC) reveals that high expression of the DNA repair protein RAD51 in epithelial ovarian cancer (EOC) is associated with early relapse after platinum chemotherapy, and also with decreased cytotoxic T‐cell infiltration into tumors.

Background Cancer metabolism is associated with enhanced lipogenesis required for rapid growth and proliferation. However, the magnitude of dysregulation of diverse lipid species mostly remain to be characterized, particularly in understudied cancers such as ovarian clear cell carcinoma (OCCC). Further, formalin-fixed paraffin-embedded (FFPE) specimen represent valuable and readily available resources for laboratory investigations but are still underutilized for lipidomics studies. Here we implemented an integrated workflow to investigate lipidomic alterations in OCCC, utilizing FFPE specimen. Methods Lipid extraction of FFPE specimen was carried out by using 1-butanol and methanol in 1:1 (v/v), followed by targeted LC-MS/MS to identify the lipidomic changes in FFPE specimen from OCCC (n=14) as compared to uninvolved contralateral ovarian tissue (n=14). Immunohistochemistry (IHC) assays were implemented to evaluate the expression levels of stearoyl-CoA desaturase (SCD), the rate-limiting enzyme for the synthesis of monounsaturated fatty acids, in OCCC and control tissue specimen. Results We quantified 340 lipid species representing 29 lipid classes. We observed differential regulation of unsaturated lipid species belonging to several glycerophospholipid classes including ether-linked phospholipids, and trihexosylceramide species. We confirmed upregulation of SCD in OCCC by IHC assays. Conclusions By using lipidomic and IHC analysis of archival tissue samples, we were able to provide novel insights into the molecular alterations in OCCC. We show the feasibility of using FFPE specimen to carry out detailed lipidomic analysis of archival cancer samples.

Objective To evaluate the cost-effectiveness of olaparib as a maintenance treatment versus routine surveillance (RS) in patients with BRCA mutated (BRCAm) advanced ovarian cancer (OC) following response to first-line platinum-based chemotherapy in Singapore. Methods A 4-health state partitioned survival model was developed to simulate the lifetime (50 years) incremental cost-effectiveness ratio (ICER) of olaparib versus RS from a healthcare payer perspective. Progression-free survival, time to second disease progression, and overall survival were estimated using SOLO-1 data and extrapolated beyond the trial period using parametric survival models. Any patient who remained progression-free at year 7 was assumed to be no longer at risk of progression. Mortality rates were based on all-cause mortality, adjusted based on BRCA1/2 mutation. Health state utilities and adverse event frequencies were from SOLO-1. Drug costs were from local public healthcare institutions. Healthcare resource usage and costs were from local clinician input and publications. A 3% discount rate was applied to costs and outcomes. Deterministic and probabilistic sensitivity analyses (PSA) were performed to assess the robustness of results. Results The base-case analysis of olaparib maintenance therapy versus RS resulted in an ICER of Singapore dollar (SGD) 19,822 per quality-adjusted life-year (QALY) gained. The ICER was most sensitive to variations in the discount rate. PSA demonstrated that olaparib had an 87% probability of being cost-effective versus RS at a willingness-to-pay of SGD 60,000 per QALY gained. Conclusion Olaparib has a high potential of being a cost-effective maintenance treatment versus RS for patients with BRCA1/2m advanced OC after response to first-line chemotherapy in Singapore.

Background The optimal treatment of BRCA wild-type patients with platinum-sensitive recurrent ovarian cancer remains unknown. Recently, there is an increase in the evidence to support the role of the combination of a poly(adenosine diphosphate-ribose) polymerase inhibitor, anti-angiogenic agents, and immunotherapy as maintenance therapy in BRCA wild-type patients with platinum-sensitive recurrence. We hypothesized that adding pembrolizumab and bevacizumab to olaparib maintenance can increase progression-free survival (PFS) in BRCA wild-type patients with platinum-sensitive recurrent ovarian cancer. Methods BRCA wild-type patients who received two previous courses of platinum-containing therapy, achieved complete or partial response to last treatment, and the treatment-free interval is >6 months after the penultimate platinum-based chemotherapy offered olaparib maintenance with pembrolizumab and bevacizumab. Forty-four patients will be included from 4 sites across Singapore and Korea. The primary endpoint of the study is 6-month PFS rate. Trial registration ClinicalTrials.gov Identifier: NCT04361370, Clinical Research Information Service Identifier: KCT0005144.

Serum cytokine and chemokine networks may reflect the complex systemic immunological interactions in cancer patients. Studying groups of cytokines and their networks may help to understand their clinical biology. A total of 178 cases of ovarian cancer were analyzed in this study, including 73 high-grade serous (HGSC), 66 clear cell (CCC) and 39 endometrioid carcinomas. Suspension cytokine arrays were performed with the patients’ sera taken before the primary surgery. Associations between each cytokine and clinicopathological factors were analyzed in all patients using multivariate linear regression models, and cluster analyses were performed for each histotype. In the multivariate analyses, twelve of 27 cytokines were correlated with histotypes. Cluster analyses in each histotype revealed 2 cytokine signatures S1 and S2 in HGSC, and similarly C1 and C2 in CCC. Twenty-two of 27 cytokines were commonly clustered in HGSC and CCC. Signature S1 and C1 included IL-2,6,8,15, chemokines and angiogenic factors, whereas signature S2 and C2 included IL-4,5,9,10,13, TNF-α and G-CSF. Four subgroups based on a high or low level for each signature were identified, and this cluster-based classification demonstrated significantly different progression-free and overall survivals for CCC patients (P = 0.00097 and P = 0.017).

Purpose Low-dose fractionated whole abdominal radiation therapy (LDFWART) has synergistic activity with paclitaxel in preclinical models. The aim of this phase 1 trial was to determine the recommended phase 2 dose and preliminary activity of weekly paclitaxel (wP) concurrent with LDFWART in patients with platinum-resistant ovarian cancer (PROC). Methods and Materials Patients were enrolled at de-escalating dose levels of wP (part A), starting at 80 mg/m2, concurrent with fixed-dose LDFWART delivered in 60 cGy fractions twice-daily, 2 days per week, for 6 continuous weeks. After completing the 6-week course of wP + LDFWART, patients received wP until disease progression. Dose-limiting toxicity was evaluated during the first 3 weeks of wP + LDFWART. At wP (80 mg/m2) + LDFWART, no dose-limiting toxicities were observed; this was the established maximum tolerated dose. The trial was expanded (part B) with 7 additional patients with platinum-resistant, high-grade serous ovarian cancer to confirm toxicity and activity. Results A total of 10 heavily pretreated patients were recruited (3 patients to part A, 7 patients to part B). They had received a median of 5 prior lines of therapy, and 70% of patients had received prior wP; 60% of patients completed 6 weeks of wP + LDFWART. Common related grade ≥3 adverse events were neutropenia (60%) and anemia (30%). Median progression-free survival was 3.2 months, and overall survival was 13.5 months. Of patients evaluable for response, 33% (3 of 9) achieved confirmed biochemical response (CA125 decrease >50% from baseline), 11% (1) achieved a partial response, and 5 patients had stable disease, giving a disease control rate of 66.7% (6 of 9). Four patients had durable disease control of ≥12 weeks, completing 12 to 21 weeks of wP. Conclusions The recommended phase 2 dose of wP + LDFWART for 6 weeks is 80 mg/m2. Encouraging efficacy in heavily pretreated PROC patients was observed, suggesting that further development of this therapeutic strategy in PROC should be considered.

Targeting the ataxia telangiectasia and RAD3-related (ATR) enzyme represents a promising anticancer strategy for tumors with DNA damage response (DDR) defects and replication stress, including inactivation of ataxia telangiectasia mutated (ATM) signaling. We report the dose-escalation portion of the phase I first-in-human trial of oral ATR inhibitor BAY 1895344 intermittently dosed 5 to 80 mg twice daily in 21 patients with advanced solid tumors. The MTD was 40 mg twice daily 3 days on/4 days off. Most common adverse events were manageable and reversible hematologic toxicities. Partial responses were achieved in 4 patients and stable disease in 8 patients. Median duration of response was 315.5 days. Responders had ATM protein loss and/or deleterious ATM mutations and received doses ≥40 mg twice daily. Overall, BAY 1895344 is well tolerated, with antitumor activity against cancers with certain DDR defects, including ATM loss. An expansion phase continues in patients with DDR deficiency. Significance: Oral BAY 1895344 was tolerable, with antitumor activity in heavily pretreated patients with various advanced solid tumors, particularly those with ATM deleterious mutations and/or loss of ATM protein; pharmacodynamic results supported a mechanism of action of increased DNA damage. Further study is warranted in this patient population. See related commentary by Italiano, p. 14. This article is highlighted in the In This Issue feature, p. 1

BackgroundHomologous recombination deficiency (HRD) in ovarian cancer confers increased sensitivity to Poly-ADP-Ribose-Polymerase (PARP) inhibitors and platinum. The homologous recombination (HR) mediator RAD51, however, is commonly overexpressed, potentially driving unregulated HR. Due to non-quantitative measurements and heterogeneous cohorts, the clinical relevance of RAD51 expression in ovarian cancer is unclear.MethodsFluorescent immunohistochemistry and multispectral imaging were used to quantitate RAD51 expression, in relation to other markers, in independent cohorts of ovarian carcinomas from British Columbia Cancer (BCC n=284) and the phase III SCOTROC4 trial (n=268). Independent cohorts (TCGA n=566, GSE9891 n=267, GSE26712 n=185 and GSE3149 n=146) were used for mRNA expression and immune infiltration analyses.ResultsRAD51-High tumours had shorter progression-free and overall survival compared to RAD51-Low cases in both BCC and SCOTROC4. The negative prognostic significance of high RAD51 was primarily evident in cases classified “HRD negative” by the Myriad genomic scar assay. Unexpectedly, overexpression of RAD51 in ovarian cancer cell lines did not affect sensitivity to platinum or PARP inhibitors, but modified the expression of immune-regulatory genes. Accordingly, tumours with high RAD51 mRNA showed consistent changes in immunomodulatory transcripts across four independent ovarian cancer cohorts. In-situ multiplexed imaging confirmed that high RAD51 tumours correlated with tumour exclusion of cytotoxic-T-cells, possibly explaining their poor outcomes after chemotherapy.ConclusionsHigh RAD51 expression, in conjunction with a HRD score Statement of Translational RelevanceHomologous recombination deficiency (HRD) in ovarian cancer confers increased sensitivity to Poly-ADP-Ribose-Polymerase (PARP) inhibitors and platinum. Currently, methods to identify patients who do poorly on first-line platinum based chemotherapy in ovarian cancer represent an unmet clinical need. In this report we show that RAD51 expression can identify patients with primary platinum resistance in two large cohorts, including a unique phase-III trial of carboplatin as adjuvant monotherapy. The clinical relevance of a positive genomic scar HRD score, a biomarker for assessing HRD status, in predicting benefit to PARP inhibitors has been established following recent phase 3 trials in first line and 2nd line maintenance treatment of ovarian cancer. Our findings suggest that HRD negative ovarian tumours may be further stratified by RAD51 expression status in the context of platinum sensitivity, and may serve to guide future trials of HRD targeted agents.

PURPOSE. The TRK pathway controls appetite, balance, and pain sensitivity. While these functions are reflected in the on-target adverse effects (AEs) observed with TRK inhibition, these AEs remain under-recognized, and pain upon drug withdrawal has not previously been reported. As TRK inhibitors are approved by multiple regulatory agencies for TRK or ROS1 fusion-positive cancers, characterizing these AEs and corresponding management strategies is crucial. METHODS. Patients with advanced or unresectable solid tumors treated with a TRK inhibitor were retrospectively identified in a search of clinical databases. Among these patients, the frequency, severity, duration, and management outcomes of AEs including weight gain, dizziness or ataxia, and withdrawal pain were characterized. RESULTS. Ninety-six patients with 15 unique cancer histologies treated with a TRK inhibitor were identified. Weight gain was observed in 53% (95% CI, 43%-62%) of patients and increased with time on TRK inhibition. Pharmacologic intervention, most commonly with GLP-1 analogs or metformin, appeared to result in stabilization or loss of weight. Dizziness, with or without ataxia, was observed in 41% (95% CI, 31%-51%) of patients with a median time to onset of 2 weeks (range, 3 days to 16 months). TRK inhibitor dose reduction was the most effective intervention for dizziness. Pain upon temporary or permanent TRK inhibitor discontinuation was observed in 35% (95% CI, 24%-46%) of patients; this was more common with longer TRK inhibitor use. TRK inhibitor re-initiation was the most effective intervention for withdrawal pain. CONCLUSIONS. TRK inhibition-related AEs including weight gain, dizziness, and withdrawal pain occur in a substantial proportion of patients receiving TRK inhibitors. This safety profile is unique relative to other anticancer therapies and warrants careful monitoring. These on-target toxicities are manageable with pharmacologic intervention and dose modification.

BackgroundThe optimal treatment of recurrent ovarian clear cell carcinoma remains unknown. There is increasing rationale to support the role of immune checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis in ovarian clear cell carcinoma.Primary objectiveTo evaluate the efficacy of durvalumab (MEDI-4736) compared with standard chemotherapy in patients with recurrent ovarian clear cell carcinoma.Study hypothesisPatients with recurrent ovarian clear cell carcinoma treated with durvalumab will have improved progression-free survival compared with those treated with chemotherapy of physician’s choice.Trial designThe MOCCA study is a multicenter, open-label, randomized phase II trial in patients with recurrent ovarian clear cell carcinoma, which recruited from eight sites across Gynecologic Cancer Group Singapore (GCGS), Korean Gynecologic-Oncology Group (KGOG), and Australia New Zealand Gynecological Oncology Group (ANZGOG). Enrolled patients were randomized in a 2:1 ratio to receive durvalumab or physician’s choice of chemotherapy until disease progression, intolerable toxicity, or withdrawal of patient consent.Major inclusion/exclusion criteriaEligible patients required histologically documented diagnosis of recurrent ovarian clear cell carcinoma, as evidenced by WT1 negativity. All patients must have been of Eastern Cooperative Oncology Group (ECOG) performance status 2 or better, and have had previous treatment with, and progressed or recurred after prior platinum-based chemotherapy. No more than four prior lines of treatment were allowed and prior immune checkpoint inhibitor treatment was not permitted.Primary endpointsThe primary endpoint was the median progression-free survival following treatment with durvalumab, compared with physician’s choice of chemotherapy. Progression-free survival was defined as the time from the first day of treatment to the first observation of disease progression, or death due to any cause, or last follow-up.Sample sizeThe target sample size was 46 patients.Estimated dates for completing accrual and presenting resultsAccrual has been completed and results are expected to be presented by mid-2021.Trial registrationClinicaltrials.gov: NCT03405454.

Optimal treatment for advanced cervical cancer after first line chemotherapy remains undefined. Immune checkpoint inhibition with pembrolizumab, a programmed cell death protein 1(PD-1) inhibitor, is under investigation. We analyzed the micro-environmental and molecular genetic profile of tumors from 4 patients with metastatic cervical cancer treated with off-label second-line pembrolizumab in an effort to identify predictive biomarkers. All patients received 2 mg/kg of pembrolizumab, 3-weekly until disease progression. Immunohistochemistry(IHC) for PD-1, PD-L1, CD3 and CD8, as well as next generation sequencing (NGS) for 50 cancer-related genes were performed on tumor samples. All patients tolerated treatment well with no discontinuation of treatment due to toxicity. One patient experienced dramatic and prolonged partial response, and remains stable on pembrolizumab with a progression free survival (PFS) of 21 months at the time of reporting of this series. Three patients experienced disease progression as best response. In the exceptional responder, there was no tumoral expression of PD-L1, however, combined positive score (CPS) for PD-L1 was 1 and we identified somatic mutations in ERBB4(R612W), PIK3CA(E542K) and RB1(E365K). In 2 patients, despite progressive disease defined by RECIST v1.1, symptom stabilization on pembrolizumab was observed. The tumors of both patients had PD-1 expression in ≥1% of stromal lymphocytes. All patients with response or clinical benefit had CPS for PD-L1 ≥ 1. NGS revealed PIK3CA mutations in 3 tumors. Pembrolizumab is a promising therapeutic option in advanced cervical cancer. Further evaluation of biomarkers may guide optimal patient selection., Highlights • 1 of 4 patients receiving second line pembrolizumab, experienced dramatic and durable response. • All patients with response or clinical benefit had CPS for PD-L1 ≥ 1. • Germline BRCA1 mutation was detected in 1 patient, but she was a non-responder. • All tumors had somatic mutation in PIK3CA or PTEN.

Cervical cancer remains one of the most common cancers in women around the world however therapeutic options in the advanced and recurrent setting are limited. Immune checkpoint inhibitors (ICI) have been considered an attractive option given the viral etiology of cervical cancer although the majority of patients do not benefit from their use. This review summarises current knowledge and use of immune checkpoint blockade in cervical cancer as well as discussing the challenges faced in their clinical application, namely, the role of biomarker-driven ICI use, potential mechanisms of resistance, strategies to overcome such resistance and additional immunotherapy options beyond ICI.

The value of precision oncology initiatives in Asian contexts remains unresolved. Here, we review the institutional implementation of prospective molecular screening to facilitate accrual of patients into biomarker-driven clinical trials, and to explore the mutational landscape of advanced tumors occurring in a prospective cohort of Asian patients (n = 396) with diverse cancer types. Next-generation sequencing (NGS) and routine clinicopathological assays, such as immunohistochemistry, copy number analysis and in situ hybridization tests, were performed on tumor samples. Actionable biomarker results were used to identify eligibility for early-phase, biomarker-driven clinical trials. Overall, NGS was successful in 365 of 396 patients (92%), achieving a mean depth of 1,943× and coverage uniformity of 96%. The median turnaround time from sample receipt to return of genomic results was 26.0 days (IQR, 19.0-39.0 days). Reportable mutations were found in 300 of 365 patients (82%). Ninety-one percent of patients at study enrollment indicated consent to receive incidental findings and willingness to undergo genetic counseling if required. The most commonly mutated oncogenes included KRAS (19%), PIK3CA (16%), EGFR (5%), BRAF (3%) and KIT (3%); while the most frequently mutated tumor suppressor genes included TP53 (40%), SMARCB1 (12%), APC (8%), PTEN (6%) and SMAD4 (5%). Among 23 patients enrolled in genotype-matched trials, median progression-free survival was 2.9 months (IQR, 1.5-4.0 months). Nine of 20 evaluable patients (45%; 95% CI, 23.1-68.5%) derived clinical benefit, including 3 partial responses and 6 with stable disease lasting ≥ 8 weeks.

Background Current recommendation for locally advanced cervical cancer includes pelvic external beam radiation therapy (EBRT) with concurrent chemotherapy followed by brachytherapy. Involvement of pelvic lymph nodes is an important prognostic factor in locally advanced cervical cancer and recurrence commonly occurs despite definitive treatment. To date, there is no standard guideline on whether an EBRT boost should be applied to involved pelvic lymph nodes. Our study aims to assess if pelvic EBRT boost would reduce recurrence, benefit survival, and affect associated toxicities. Methods We conducted a retrospective review of locally advanced cervical cancer cases treated with definitive treatment at our institution. Involvement of pelvic lymph nodes were assessed on CT, MRI (> 10 mm or suspicious features) or PET scan (SUVmax > 2.5). EBRT dose ranged from 45 to 50.4 Gy with nodal boost ranging from 3.6–19.8 Gy. Results Between 2008 to 2015, 139 patients with locally advanced cervical cancer underwent treatment. Sixty-seven patients had positive pelvic lymph nodes, of which 53.7% received a nodal boost. Five-year recurrence free survival was 48.6% with vs. 64.5% without nodal boost (P = 0.169) and 5-year overall survival in those with positive pelvic lymph nodes was 74.3% with vs. 80.6% without nodal boost (P = 0.143). There was no significant difference in toxicity with nodal boost. Conclusions EBRT boost to pelvic lymph nodes does not reduce recurrence or improve survival in locally advanced cervical cancer with lymph node involvement at diagnosis.