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Gemcitabina; Cáncer avanzado Gemcitabina; Càncer avançat Gemcitabine; Advanced cancer Purpose: This was a Phase I/II trial of the novel checkpoint kinase 1 (Chk1) inhibitor SRA737 given in combination with gemcitabine. Its objectives were to establish the safety profile, recommended Phase 2 dose (RP2D), pharmacokinetics profile, and clinical activity of SRA737. Patients and Methods: Patients with advanced solid tumors were enrolled into dose-escalation cohorts and treated in 28-day cycles with oral SRA737 on days 2, 3, 9, 10, 16, and 17, and intravenous gemcitabine on days 1, 8, and 15. Treatment was continued until progression. Each expansion cohort included up to 20 patients with specific genetically defined tumors. Results: The RP2D was determined to be 500 mg SRA737 combined with low-dose (250 mg/m2) gemcitabine. Of 143 enrolled patients, 77 were treated at doses of at least 500 mg SRA737 combined with 250 mg/m2 gemcitabine. Common toxicities of nausea, vomiting, fatigue, and diarrhea were primarily mild to moderate, and rarely led to treatment discontinuation. Anemia, neutropenia, and thrombocytopenia were grade ≥3 in 11.7%, 16.7%, and 10% of patients treated at the RP2D, respectively. The objective response rate (ORR) was 10.8% overall and notably the ORR in anogenital cancer was 25%. Partial tumor responses were observed in anogenital cancer, cervical cancer, high-grade serous ovarian cancer, rectal cancer, and small cell lung cancer. Conclusions: SRA737 in combination with low-dose gemcitabine was well tolerated with lower myelotoxicity than has been seen at standard doses of gemcitabine or with other combinations of Chk1 inhibitors with gemcitabine. Tumor responses were observed in anogenital and other solid tumors. The trial was sponsored by Sierra Oncology, Inc. Medical writing support was provided by Tina Ippolito, an independent consultant funded by Sierra Oncology. Andrew Dye, an employee of Sierra Oncology, also provided medical writing support and data curation. Bryan Strouse, an employee of Sierra Oncology, also contributed to data curation for this report. UK clinical trial sites acknowledge infrastructural funding from the Experimental Cancer Medical Center and National Institute of Health and Care Research Biomedical Research Centers. The ICR/RMH in addition acknowledges Cancer Research UK funding to Cancer Centre Funding and funding to the Cancer Therapeutics Unit. U. Banerji is a recipient of the NIHR RP-2016–07–028. The publication costs of this article were defrayed in part by the payment of publication fees. Therefore, and solely to indicate this fact, this article is hereby marked “advertisement” in accordance with 18 USC section 1734.

Ovarian carcinosarcoma (OCS) is an aggressive and rare tumor type with limited treatment options. OCS is hypothesized to develop via the combination theory, with a single progenitor resulting in carcinomatous and sarcomatous components, or alternatively via the conversion theory, with the sarcomatous component developing from the carcinomatous component through epithelial-to-mesenchymal transition (EMT). In this study, we analyzed DNA variants from isolated carcinoma and sarcoma components to show that OCS from 18 women is monoclonal. RNA sequencing indicated that the carcinoma components were more mesenchymal when compared with pure epithelial ovarian carcinomas, supporting the conversion theory and suggesting that EMT is important in the formation of these tumors. Preclinical OCS models were used to test the efficacy of microtubule-targeting drugs, including eribulin, which has previously been shown to reverse EMT characteristics in breast cancers and induce differentiation in sarcomas. Vinorelbine and eribulin more effectively inhibited OCS growth than standard-of-care platinum-based chemotherapy, and treatment with eribulin reduced mesenchymal characteristics and N-MYC expression in OCS patient-derived xenografts. Eribulin treatment resulted in an accumulation of intracellular cholesterol in OCS cells, which triggered a downregulation of the mevalonate pathway and prevented further cholesterol biosynthesis. Finally, eribulin increased expression of genes related to immune activation and increased the intratumoral accumulation of CD8+ T cells, supporting exploration of immunotherapy combinations in the clinic. Together, these data indicate that EMT plays a key role in OCS tumorigenesis and support the conversion theory for OCS histogenesis. Targeting EMT using eribulin could help improve OCS patient outcomes. Significance: Genomic analyses and preclinical models of ovarian carcinosarcoma support the conversion theory for disease development and indicate that microtubule inhibitors could be used to suppress EMT and stimulate antitumor immunity.

Supplementary Figure from Dual G9A/EZH2 Inhibition Stimulates Antitumor Immune Response in Ovarian High-Grade Serous Carcinoma

Supplementary Table from Dual G9A/EZH2 Inhibition Stimulates Antitumor Immune Response in Ovarian High-Grade Serous Carcinoma

Supplementary Data from Dual G9A/EZH2 Inhibition Stimulates Antitumor Immune Response in Ovarian High-Grade Serous Carcinoma

Ovarian high-grade serous carcinoma (HGSC) prognosis correlates directly with presence of intratumoral lymphocytes. However, cancer immunotherapy has yet to achieve meaningful survival benefit in patients with HGSC. Epigenetic silencing of immunostimulatory genes is implicated in immune evasion in HGSC and re-expression of these genes could promote tumor immune clearance. We discovered that simultaneous inhibition of the histone methyltransferases G9A and EZH2 activates the CXCL10–CXCR3 axis and increases homing of intratumoral effector lymphocytes and natural killer cells while suppressing tumor-promoting FoxP3+ CD4 T cells. The dual G9A/EZH2 inhibitor HKMTI-1–005 induced chromatin changes that resulted in the transcriptional activation of immunostimulatory gene networks, including the re-expression of elements of the ERV-K endogenous retroviral family. Importantly, treatment with HKMTI-1–005 improved the survival of mice bearing Trp53−/− null ID8 ovarian tumors and resulted in tumor burden reduction. These results indicate that inhibiting G9A and EZH2 in ovarian cancer alters the immune microenvironment and reduces tumor growth and therefore positions dual inhibition of G9A/EZH2 as a strategy for clinical development.

Contains fulltext : 283536.pdf (Publisher’s version ) (Closed access) The Gynecologic Cancer InterGroup (GCIG) sixth Ovarian Cancer Conference on Clinical Research was held virtually in October, 2021, following published consensus guidelines. The goal of the consensus meeting was to achieve harmonisation on the design elements of upcoming trials in ovarian cancer, to select important questions for future study, and to identify unmet needs. All 33 GCIG member groups participated in the development, refinement, and adoption of 20 statements within four topic groups on clinical research in ovarian cancer including first line treatment, recurrent disease, disease subgroups, and future trials. Unanimous consensus was obtained for 14 of 20 statements, with greater than 90% concordance in the remaining six statements. The high acceptance rate following active deliberation among the GCIG groups confirmed that a consensus process could be applied in a virtual setting. Together with detailed categorisation of unmet needs, these consensus statements will promote the harmonisation of international clinical research in ovarian cancer.

SV loads in non-BRCA1/2 HR genes per sample by SV type

Supplementary Data from Multiomic Characterization of High-Grade Serous Ovarian Carcinoma Enables High-Resolution Patient Stratification

Supplementary methods and figures

Ovarian carcinosarcoma (OCS) is an aggressive and rare tumor type with limited treatment options. OCS is hypothesized to develop via the combination theory, with a single progenitor resulting in carcinomatous and sarcomatous components, or alternatively via the conversion theory, with the sarcomatous component developing from the carcinomatous component through epithelial-to-mesenchymal transition (EMT). In this study, we analyzed DNA variants from isolated carcinoma and sarcoma components to show that OCS from 18 women is monoclonal. RNA sequencing indicated that the carcinoma components were more mesenchymal when compared with pure epithelial ovarian carcinomas, supporting the conversion theory and suggesting that EMT is important in the formation of these tumors. Preclinical OCS models were used to test the efficacy of microtubule-targeting drugs, including eribulin, which has previously been shown to reverse EMT characteristics in breast cancers and induce differentiation in sarcomas. Vinorelbine and eribulin more effectively inhibited OCS growth than standard-of-care platinum-based chemotherapy, and treatment with eribulin reduced mesenchymal characteristics and N-MYC expression in OCS patient-derived xenografts. Eribulin treatment resulted in an accumulation of intracellular cholesterol in OCS cells, which triggered a downregulation of the mevalonate pathway and prevented further cholesterol biosynthesis. Finally, eribulin increased expression of genes related to immune activation and increased the intratumoral accumulation of CD8+ T cells, supporting exploration of immunotherapy combinations in the clinic. Together, these data indicate that EMT plays a key role in OCS tumorigenesis and support the conversion theory for OCS histogenesis. Targeting EMT using eribulin could help improve OCS patient outcomes.Significance:Genomic analyses and preclinical models of ovarian carcinosarcoma support the conversion theory for disease development and indicate that microtubule inhibitors could be used to suppress EMT and stimulate antitumor immunity.

Purpose:The abundance and effects of structural variation at BRCA1/2 in tumors are not well understood. In particular, the impact of these events on homologous recombination repair deficiency (HRD) has yet to be demonstrated.Experimental Design:Exploiting a large collection of whole-genome sequencing data from high-grade serous ovarian carcinoma (N = 205) together with matched RNA sequencing for the majority of tumors (N = 150), we have comprehensively characterized mutation and expression at BRCA1/2.Results:In addition to the known spectrum of short somatic mutations (SSM), we discovered that multi-megabase structural variants (SV) were a frequent, unappreciated source of BRCA1/2 disruption in these tumors, and we found a genome-wide enrichment for large deletions at the BRCA1/2 loci across the cohort. These SVs independently affected a substantial proportion of patients (16%) in addition to those affected by SSMs (24%), conferring HRD and impacting patient survival. We also detail compound deficiencies involving SSMs and SVs at both loci, demonstrating that the strongest risk of HRD emerges from combined SVs at both BRCA1 and BRCA2 in the absence of SSMs. Furthermore, these SVs are abundant and disruptive in other cancer types.Conclusions:These results extend our understanding of the mutational landscape underlying HRD, increase the number of patients predicted to benefit from therapies exploiting HRD, and suggest there is currently untapped potential in SV detection for patient stratification.

Supplementary methods and supplementary figures

Niraparib, an inhibitor of poly(adenosine diphosphate [ADP]-ribose) 1 and 2, has been shown to improve progression free survival in patients when used as maintenance treatment after first-line platinum-based chemotherapy in advanced stage (III to IV) high-grade ovarian cancer, and after platinum-based chemotherapy for relapsed disease. For grades greater than III, commonly reported side effects include bone marrow suppression (thrombocytopenia, neutropenia, and anemia) and hypertension. However, grade ≥ III pneumonitis was not reported in phase III trials (PRIMA or NOVA). We present a case of life-threatening niraparib-induced pneumonitis. With recent approval for use of first-line maintenance niraparib in the United States and Europe, knowledge of the side effects and how to manage them is vital.

OBJECTIVE: Studies on low-grade serous ovarian cancer (LGSC) are limited by a low number of cases. The aim of this study was to define the prognostic significance of age, stage, and CA-125 levels on survival in a multi-institutional cohort of women with pathologically confirmed LGSC. METHODS: Women with LGSC were identified from the collaborative Ovarian Cancer Association Consortium (OCAC). Cases of newly diagnosed primary LGSC were included if peri-operative CA-125 levels were available. Age at diagnosis, FIGO stage, pre- and post-treatment CA-125 levels, residual disease, adjuvant chemotherapy, disease recurrence, and vital status were collected by the participating institutions. Progression-free (PFS) and overall survival (OS) were calculated. Multivariable (MVA) Cox proportional hazard models were used and hazard ratios (HR) calculated. RESULTS: A total of 176 women with LGSC were included in this study; 82% had stage III/IV disease. The median PFS was 2.3 years and the median OS was 6.4 years. Age at diagnosis was not significantly associated with worse PFS (p = 0.23) or OS (p = 0.3) (HR per year: 0.99; 95%CI, 0.96-1.01 and 0.98; 95%CI 0.95-1.01). FIGO stage III/IV was independently associated with PFS (HR 4.26, 95%CI 1.43-12.73) and OS (HR 1.69, 95%CI 0.56-5.05). Elevated CA-125 (≥35 U/mL) at diagnosis was not significantly associated with worse PFS (p = 0.87) or OS (p = 0.78) in MVA. Elevated CA-125 (≥35 U/mL) after completion of primary treatment was independently associated with worse PFS (HR 2.81, 95%CI 1.36-5.81) and OS (HR 6.62, 95%CI 2.45-17.92). In the MVA, residual disease was independently associated with PFS (0.022), but not OS (0.85). CONCLUSION: Advanced LGSC was associated with poor long-term prognosis. FIGO stage and abnormal post-treatment CA-125 level are key prognostic factors inversely associated with PFS and OS. HIGHLIGHTS: 1. Through a multi-center collaborative effort, data from 176 women with low-grade serous ovarian cancer were analyzed. 2. Although low-grade serous ovarian cancer is often considered indolent, the progression-free and overall survival are poor. 3. Elevated post-treatment CA-125 levels are independently associated with poor survival. ispartof: CANCERS vol:14 issue:8 ispartof: location:Switzerland status: published

Purpose To support future dosing recommendations, the effect of food on the pharmacokinetics of adavosertib, a first-in-class, small-molecule reversible inhibitor of WEE1 kinase, was assessed in patients with advanced solid tumors. Methods In this Phase I, open-label, randomized, two-period, two-sequence crossover study, the pharmacokinetics of a single 300 mg adavosertib dose were investigated in fed versus fasted states. Results Compared with the fasted state, a high-fat, high-calorie meal (fed state) decreased adavosertib maximum plasma concentration (Cmax) by 16% and systemic exposure (area under the plasma concentration–time curve [AUC]) by 6%; AUC0–t decreased by 7% and time to maximum plasma concentration was delayed by 1.97 h (P = 0.0009). The 90% confidence interval of the geometric least-squares mean treatment ratio for AUC and AUC0–t was contained within the no-effect limits (0.8–1.25), while that of Cmax crossed the lower bound of the no-effect limits. Adverse events (AEs) related to adavosertib treatment were reported by 20 (64.5%) of the 31 patients treated in this study. Grade ≥ 3 AEs were reported by four (12.9%) patients (one in the fed state, three in the fasted state); two of these AEs were considered treatment-related by the investigator. Three serious AEs were reported in three (9.7%) patients; these were not considered treatment-related. No patients discontinued because of treatment-related AEs, and no new safety signals were reported. Conclusion A high-fat meal did not have a clinically relevant effect on the systemic exposure of adavosertib, suggesting that adavosertib can be administered without regard to meals.

BackgroundHigh grade serous ovarian carcinoma (HGSOC) is the most common type of ovarian cancer; most patients experience disease recurrence which accumulates chemoresistance, leading to treatment failure. Previous investigations have characterised HGSOC at the genomic and transcriptomic level, identifying subtypes of patients with differential outcome and treatment response. However, the relationship between molecular events identified at the gene sequence, gene copy number and gene expression levels remains poorly defined.MethodsWe perform multi-layer molecular characterisation of a large retrospective HGSOC cohort (n=362) with detailed clinical annotation to interrogate the relationship between patient groups defined by gene mutation, copy number events, gene expression patterns and infiltrating immune cell burden. We construct a high resolution picture of the molecular landscape in HGSOC and identify features of tumours associated with distinct clinical behaviour in patients.ResultsBRCA2-mutant (BRCA2m) andEMSY-overexpressing cases demonstrated prolonged survival (multivariable hazard ratio 0.40 and 0.53) and higher chemotherapy response rates at first- and second-line treatment.CCNE1-gained (CCNE1g) cases demonstrated shorter survival (multivariable hazard ratio 1.52, 95% CI 1.10-2.10), under-representation of FIGO stage IV cases (P=0.017) and no significant difference in treatment response. We demonstrate marked overlap between the TCGA- and derived subtypes: the TCGA DIF, IMR, PRO and MES subtypes correlated with the Tothill C4, C2, C5 and C1 subtypes (PBRCA1/2m frequency (25.5% and 32.5%) and significantly greater infiltration of immune cells (PCCNE1g rate (23.9% and 22.2%) and were uniformly low in immune cell infiltration. The survival benefit for cases with aberrations in homologous recombination repair (HRR) genes was apparent across all transcriptomic subtypes (hazard ratio range 0.48-0.68). There was significant co-occurrence of RB loss and HRR gene aberrations (P=0.005); RB loss was further associated with favourable survival within cases harbouring HRR aberrations (multivariable hazard ratio 0.50, 95% CI 0.30-0.84).ConclusionsThese data paint a high resolution picture of the molecular landscape in HGSOC, better defining patients who may benefit most from specific molecular therapeutics and highlighting those for whom novel treatment strategies are needed to improve outcomes.

Data Availability Statement: Data will be available upon reasonable request. Copyright © 2023 by the authors. Background: The incidence of brain metastases (BM) in patients with epithelial ovarian cancer (EOC) is low: 0.3–11%. The onset of BM has been regarded as a late event with limited treatment options and poor prognosis. This retrospective case series aims to explore the current management strategies with particular emphasis on the use of PARP inhibitors and outcomes, as well as identification of other prognostic indicators. Methods: A total of 39 ovarian cancer patients with brain metastases were identified from eight cancer centres in the UK. Clinical characteristics, details of management, and survival data were collected. Results: A total of 14/39 had BM as their first site of relapse. The majority (29 patients) received systemic treatments in addition to local radiotherapy (RT)/surgery. Nineteen patients had BRCA mutations (one somatic), one had a RAD51C mutation, and eighteen were BRCA wild type; one was unknown. A total of 14/39 patients received maintenance PARP inhibitors. As is well known, patients who received PARPi had consistently better outcomes. This was no different for those who received PARPi as part of the management of their BM. Platinum sensitivity and receiving more than one modality of therapy (e.g., radiation +/− chemotherapy and PARPi) for BM were also good prognostic indicators. Median PFS/OS for those treated with chemotherapy and either RT or surgery, then PARP inhibitor maintenance, have not been reached after a median of 33 months follow up. Conclusions: As with abdominal relapse, maintenance treatment with PARP inhibitors also has a valuable role in managing BMs in EOC patients. This research received no extra funding.

Ovarian high-grade serous carcinoma (HGSC) prognosis correlates directly with presence of intratumoral lymphocytes. However, cancer immunotherapy has yet to achieve meaningful survival benefit in patients with HGSC. Epigenetic silencing of immunostimulatory genes is implicated in immune evasion in HGSC and re-expression of these genes could promote tumour immune clearance. We discovered that simultaneous inhibition of the histone methyltransferases G9A and EZH2 activates the CXCL10-CXCR3 axis and increases homing of intratumoral effector lymphocytes and natural killer cells whilst suppressing tumour-promoting FoxP3+ CD4 T cells. The dual G9A/EZH2 inhibitor HKMTI-1-005 induced chromatin changes that resulted in the transcriptional activation of immunostimulatory gene networks, including the re-expression of elements of the ERV-K endogenous retroviral family. Importantly, treatment with HKMTI-1-005 improved the survival of mice bearing Trp53-/-null ID8 ovarian tumours and resulted in tumour burden reduction.These results indicate that inhibiting G9A and EZH2 in ovarian cancer alters the immune microenvironment and reduces tumour growth and therefore positions dual inhibition of G9A/EZH2 as a strategy for clinical development.Abstract Figure

ObjectivesTo describe the clinical activity of metronomic cyclophosphamide in a population of patients with recurrent ovarian cancer, and to identify predictors of clinical response.MethodsWe retrospectively reviewed all patients treated at our institution with oral metronomic cyclophosphamide for relapsed ovarian cancer between January 2012 and December 2016. These were identified from electronic chemotherapy prescription records. The primary endpoint was response rate by combined Gynecologic Cancer InterGroup (GCIG) criteria. Data on patient demographics, previous therapies, platinum resistance, germline BRCA1/2 (gBRCA1/2) status, disease response by radiological or cancer antigen 125 (CA125) criteria alone, adverse events secondary to metronomic cyclophosphamide treatment, progression-free survival, and overall survival were also evaluated.Results50 out of 68 patients treated with oral metronomic cyclophosphamide were evaluable for disease response. By combination criteria (radiological plus CA125), complete response was 0%, partial response 32%, stable disease 16%, and progressive disease 52%. In the intention-to-treat population (n=68), progression-free survival and overall survival were 2.6 months and 6 months, respectively. Having a gBRCA1/2 mutation reduced the risk of disease progression by radiological criteria (OR 0.07, 95% CI 0.008 to 0.67, p=0.02), and patients with gBRCA1/2 mutations had improved progression-free survival (7.9 vs 2.5 months, HR 0.4, 95% CI 0.23 to 0.74, p=0.003) and overall survival (15.5 vs 6 months, HR 0.49, 95% CI 0.28 to 0.85, p=0.02) with metronomic cyclophosphamide when compared with patients without gBRCA1/2 mutations (or unknown gBRCA1/2 status).ConclusionOral metronomic cyclophosphamide showed a clinical benefit in 48% of patients with recurrent ovarian cancer. gBRCA1/2 status can be an independent predictor of response.

ADAPTeR is a prospective, phase II study of nivolumab (anti-PD-1) in 15 treatment-naive patients (115 multiregion tumor samples) with metastatic clear cell renal cell carcinoma (ccRCC) aiming to understand the mechanism underpinning therapeutic response. Genomic analyses show no correlation between tumor molecular features and response, whereas ccRCC-specific human endogenous retrovirus expression indirectly correlates with clinical response. T cell receptor (TCR) analysis reveals a significantly higher number of expanded TCR clones pre-treatment in responders suggesting pre-existing immunity. Maintenance of highly similar clusters of TCRs post-treatment predict response, suggesting ongoing antigen engagement and survival of families of T cells likely recognizing the same antigens. In responders, nivolumab-bound CD8+ T cells are expanded and express GZMK/B. Our data suggest nivolumab drives both maintenance and replacement of previously expanded T cell clones, but only maintenance correlates with response. We hypothesize that maintenance and boosting of a pre-existing response is a key element of anti-PD-1 mode of action.

Introduction/Background The PARP inhibitor (PARPi), niraparib, is EMA approved for maintenance treatment in platinum-sensitive recurrent ovarian cancer. The eligibility criteria set out in niraparib licence are less stringent than those in the NOVA trial, therefore outcomes may be different in the real-world to those observed in trial patients.1 The optimal management of patients after progression on PARPi is unknown and the relationship between platinum free interval and probability of response to platinum may be modified after PARPi therapy. To investigate this, we performed a retrospective analysis of real-world niraparib use and compared it to the NOVA trial. Methodology Data was collected retrospectively for all women receiving maintenance niraparib for BRCA wild-type, platinum sensitive relapsed ovarian cancer between June 2017 and September 2019. Response to prior platinum, median progression-free survival (mPFS) after 1st and subsequent platinum, number of cycles of PARPi, dose, haematological toxicities, and PFS2I (start of subsequent therapy to physician assessed progression or death) were obtained through electronic records. Results 37 patients received Niraparib in this timeframe. Median follow up was 16 months (range 5.7–37 months). Demographics were similar to previously published cohorts, however, only 11% (n=4) had a complete response (CR) to prior platinum therapy and 59% (n=22) had a partial response in comparison to 50% CR and 50% PR in the NOVA trial1. 35 (95%) of patients had progressed on niraparib at the time of data collection. The mPFS on niraparib was 4.4 months (95% CI 3.7 – 6.7 months) in comparison to 9.3 months in the NOVA study. Patients who met the NOVA trial radiological and serological response criteria, had a mPFS at 5.1 months (n = 19) compared to 3.9 months (n = 18). Dosing and toxicity data will be reported in full at the meeting. 31 patients received subsequent therapy, 19 (61%) were treated with paclitaxel, 9 (29%) were treated with platinum-based chemotherapy. Median PFS2I was 5.8 months for platinum sensitive disease and 3.5 months for platinum resistant disease. Conclusion The real-world outcomes for niraparib treatment are worse than observed in the NOVA trial. Patients who meet NOVA trial eligibility criteria have better outcomes, however, these results are still inferior to those reported in the trial. Post PARP outcomes are poorer than expected in both platinum sensitive and platinum resistant settings. Strategies to effectively treat PARPi resistant disease are urgently needed. Disclosures Dr R Glasspool: Grant funding for clinical trials from Boehringer Ingelheim, Lilly/Ignyta and Clovis. Consultancy fees, travel support and/or speaker fees for AstraZeneca, GSK/Tesaro, Clovis, Immunogen and Sotio. Site PI for studies sponsored by AstraZeneca, GSK/Tesaro, Clovis, Immunogen, Lilly and Pfizer. Reference Mirza MR, et al. Niraparib Maintenance Therapy in Platinum-Sensitive, Recurrent Ovarian Cancer. N Engl J Med 2016;375:2154–64.

Ovarian carcinosarcoma (OCS) is an aggressive and rare tumour type with limited treatment options. OCS is hypothesised to develop via the combination theory from a single progenitor, resulting in carcinomatous and sarcomatous components, or alternatively via the conversion theory, with the sarcomatous component developing from the carcinomatous component through epithelial-to-mesenchymal transition (EMT). We show OCS from 18 women to be monoclonal through analysis of DNA variants from isolated carcinoma and sarcoma components. RNA sequencing indicated the carcinoma components were more mesenchymal when compared with pure ovarian carcinomas, supporting the conversion theory. We used pre-clinical OCS models to test the efficacy of microtubule-targeting drugs, including eribulin, which has been shown to reverse EMT characteristics. We demonstrated that microtubule inhibitors, vinorelbine and eribulin, were more effective than standard-of-care platinum-based chemotherapy. Eribulin reduced mesenchymal characteristics, N-MYC expression and cholesterol biosynthesis. Finally, eribulin induced a strong immune response, supporting immunotherapy combinations in the clinic.

Background Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) and CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment may lead to stronger anti-tumor responses in combination with pembrolizumab than observed with pembrolizumab alone. We report results from stage 1 of all parts of the study (NCT03625323). Methods Patients (pts) with unselected PD-L1 expression were recruited into 3 cohorts: part A; 1st line, immunotherapy naive NSCLC; part B; 2nd line, immunotherapy refractory NSCLC and part C; 2nd line immunotherapy naive HNSCC. The study uses a Simon’s 2-stage design, with objective response rate (ORR) by iRECIST as the primary endpoint (EP). Secondary EPs include tolerability, disease control rate (DCR), progression free survival (PFS), overall survival (OS), PK, PD and immunogenicity. Fifty-eight (58) pts were recruited into stage 1. Up to additional 51 pts will be recruited if a pre-specified ORR threshold is met for the respective part. Efti is administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles; pembrolizumab is administered at 200 mg intravenous infusion every 3 wks for up to 2 yrs. The study was approved by ethic committees and institutional review boards. Results Between Mar 2019 and Jul 2020 88 pts were enrolled. The median age was 67 yrs (range 53-84) and 70% were male. ECOG PS 0:1 was 42% and 58% respectively. Pts from all PD-L1 tumor expression subgroups were recruited. Pts received a median of 4 (1-25) pembrolizumab and 5.5 (1-22) efti administrations. The most common (≥ 15%) treatment emergent adverse events (TEAEs) were asthenia (28%), cough (27%), decreased appetite (22%), dyspnea (21%), fatigue (18%) and diarrhea (15%). Three (3) pts discontinued due to treatment related AEs. The ORR (acc. to iRECIST) of the 58 patients enrolled into stage 1 is shown in (table1). PK profiles after the first or repeated efti dosing were in line with previous studies, with a mean Cmax at7 ng/ml reached ≤ 24h. Circulating TH1 biomarkers 2 weeks after the last efti administration were increased (3 months vs. baseline) by a mean 61% and 209% for CXCL10 (Student paired t-test, p=0.02, n=31) and IFN-γ(p= 0.02, n=19), respectively. Conclusions Efti plus pembrolizumab is safe and shows encouraging antitumor responses in NSCLC and HNSCC patients Trial Registration NCT03625323 Ethics Approval The study was approved by relevant ethic committees and institutional review boards.

PURPOSE: The abundance and effects of structural variation at BRCA1/2 in tumours are not well understood. In particular, the impact of these events on homologous recombination repair deficiency (HRD) has yet to be demonstrated. EXPERIMENTAL DESIGN: Exploiting a large collection of whole genome sequencing data from high grade serous ovarian carcinoma (N=205) together with matched RNA-seq for the majority of tumours (N=150), we have comprehensively characterised mutation and expression at BRCA1/2. RESULTS: In addition to the known spectrum of short somatic mutations (SSMs), we discover that multi-megabase structural variants (SVs) are a frequent, unappreciated source of BRCA1/2 disruption in these tumours, and we find a genome wide enrichment for large deletions at the BRCA1/2 loci across the cohort. These SVs independently affect a substantial proportion of patients (16%) in addition to those affected by SSMs (24%), conferring homologous recombination repair deficiency (HRD) and impacting patient survival. We also detail compound deficiencies involving SSMs and SVs at both loci, demonstrating that the strongest risk of HRD emerges from combined SVs at both BRCA1 and BRCA2 in the absence of SSMs. Further, these SVs are abundant and disruptive in other cancer types. CONCLUSIONS: These results extend our understanding of the mutational landscape underlying HRD, increase the number of patients predicted to benefit from therapies exploiting HRD, and suggest there is currently untapped potential in SV detection for patient stratification.

International audience; Although thousands of solid tumors have been sequenced to date, a fundamental under-sampling bias isinherent in current methodologies. This is caused by a tissue sample input of fixed dimensions (e.g., 6 mmbiopsy), which becomes grossly under-powered as tumor volume scales. Here, we demonstrate representative sequencing (Rep-Seq) as a new method to achieve unbiased tumor tissue sampling. Rep-Seq uses fixed residual tumor material, which is homogenized and subjected to next-generation sequencing. Analysis of intratumor tumor mutation burden (TMB) variability shows a high level of misclassification using current single-biopsy methods, with 20% of lung and 52% of bladder tumors having at least one biopsy with high TMB butlow clonal TMB overall. Misclassification rates by contrast are reduced to 2% (lung) and 4% (bladder) when a more representative sampling methodology is used. Rep-Seq offers an improved sampling protocol for tumor profiling, with significant potential for improved clinical utility and more accurate deconvolution of clonal structure.

BackgroundEftilagimod alpha (efti) is a soluble LAG-3 protein targeting a subset of MHC class II, thus mediating antigen presenting cell (APC) and CD8 T-cell activation. Such stimulation of the dendritic cell network and resulting T cell recruitment by efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. We hereby report results of the 2nd line metastatic head and neck squamous cell carcinoma (HNSCC) cohort (part C) of the TACTI-002 phase II trial (NCT03625323).MethodsEligible patients (pts) with HNSCC, unselected for PD-L1 expression with disease progression on or after 1st line platinum-based therapy, received 30 mg subcutaneous efti Q2W for 24 weeks and 200 mg pembrolizumab Q3W for up to 2 years or until disease progression. The study used a Simon’s 2-stage design with objective response rate (ORR) as the primary endpoint (EP). Secondary EPs included tolerability, progression free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics, and immunogenicity. Tumor response was assessed Q9W. PD-L1 was assessed centrally (22C3 clone). The study was approved by ethic committees and institutional review boards.ResultsBetween Mar 2019 and Jan 2021, 39 pts were enrolled (cut-off Apr 2021). The median age was 62 yrs (range 37–84) with 90% male pts. ECOG was 0 and 1 in 33% and 67%, respectively. Primary tumor location at diagnosis was oropharynx (36%), oral cavity (31%), hypopharynx (18%) and larynx (15%) with all PD-L1 subgroups (CPS< 1, ≥1 to ≤19; ≥20) being represented. All pts were pre-treated with platinum-based chemotherapy. Thirty-seven (37) pts were evaluated for response with ORR (iRECIST) of 30% (95% CI 16–47%) with 5 (14%) CRs; 6 (16%) PRs; 3 (8%) SDs; 17 (46%) PDs and 6 (16%) pts not evaluable. Median PFS was 2.1 months and 30+% were progression-free at 6 months. One patient (3%) discontinued due to pembro-related adverse event. The most common (>10%) treatment emergent adverse events were hypothyroidism (21%), cough (18%), asthenia (15%), fatigue (13%), anemia (13%), diarrhea (13%) and weight decreased (13%).ConclusionsEfti in combination with pembrolizumab is safe, showing encouraging antitumor activity in platinum pre-treated, 2nd line HNSCC patients. For further investigation of this combination, a 1st line HNSCC trial (NCT04811027) has been initiated.Trial RegistrationNCT03625323Ethics ApprovalThe study was approved by relevant ethic committees and institutional review boards

BACKGROUND: This study evaluated safety, pharmacokinetics, and clinical activity of intravenous and oral rucaparib, a poly(ADP-ribose) polymerase inhibitor, combined with chemotherapy in patients with advanced solid tumours.METHODS: Initially, patients received escalating doses of intravenous rucaparib combined with carboplatin, carboplatin/paclitaxel, cisplatin/pemetrexed, or epirubicin/cyclophosphamide. Subsequently, the study was amended to focus on oral rucaparib (once daily, days 1-14) combined with carboplatin (day 1) in 21-day cycles. Dose-limiting toxicities (DLTs) were assessed in cycle 1 and safety in all cycles.RESULTS: Eighty-five patients were enrolled (22 breast, 15 ovarian/peritoneal, and 48 other primary cancers), with a median of three prior therapies (range, 1-7). Neutropenia (27.1%) and thrombocytopenia (18.8%) were the most common grade ⩾3 toxicities across combinations and were DLTs with the oral rucaparib/carboplatin combination. Maximum tolerated dose for the combination was 240 mg per day oral rucaparib and carboplatin area under the curve 5 mg ml(-1) min(-1). Oral rucaparib demonstrated dose-proportional kinetics, a long half-life (≈17 h), and good bioavailability (36%). Pharmacokinetics were unchanged by carboplatin coadministration. The rucaparib/carboplatin combination had radiologic antitumour activity, primarily in BRCA1- or BRCA2-mutated breast and ovarian/peritoneal cancers.CONCLUSIONS: Oral rucaparib can be safely combined with a clinically relevant dose of carboplatin in patients with advanced solid tumours (Trial registration ID: NCT01009190).British Journal of Cancer advance online publication 21 February 2017; doi:10.1038/bjc.2017.36 www.bjcancer.com.

6028 Background: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses in combination than observed with pembrolizumab alone. We hereby report results of the 2nd line metastatic squamous head and neck carcinoma (HNSCC) cohort (part C) of phase II trial (NCT03625323). Methods: Patients (pts) with HNSCC progressed on or after 1st line platinum-based therapy and unselected for PD-L1 expression were recruited into part C. The study used a Simon's 2-stage design (18 pts planned for stage 1 and 19 for stage 2), with objective response rate (ORR) by iRECIST as the primary endpoint (EP). Secondary EPs include tolerability, disease control rate (DCR), progression free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics and immunogenicity. Efti was administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles with pembrolizumab (200 mg intravenous infusion every 3 wks for up to 2 yrs). Imaging was performed every 8 weeks. PD-L1 was assessed centrally (22C3 clone). The study was approved by ethics committees and institutional review boards. Results: In total 38 pts were enrolled. The median age was 62 yrs (range 37-84) and 89 % were male. The ECOG PS was 0 and 1 in 34% and 66%, respectively. Primary location at diagnosis was the oral cavity (29%), oropharynx (37%), hypopharynx (18%) and the larynx (16%). All PD-L1 subgroups (CPS < 1 %, ≥ 1 to ≤19; ≥20) were included. All pts were pre-treated with platinum-based chemotherapy. Pts received a median of 3.0 (range 1 – 21) pembrolizumab and 5.0 (range 1-31) efti administrations. Thirty-five (35) pts were evaluated for response (cut-off Jan 2021) with 4 (11 %) pts showing CR, 7 (20 %) pts PR, 3 (9 %) pts SD, 16 (46 %) pts PD with 5 (14 %) pts being not evaluable as per iRECIST. ORR was reported with 31.4 % (95 % CI 16.9 % - 49.3 %) and DCR 40 %Median PFS was 2.1 months and 35 % were progression free at 6 months. Median OS (46 % events) was 12.6 months. There were no adverse reactions leading to treatment discontinuation. The most common ( > 10 %) treatment emergent adverse events were cough (18 %), asthenia (16 %), dyspnea (11 %), fatigue (13 %), diarrhea (11 %), hypothyroidism (11%), upper respiratory tract infection (11%) and back pain (11%). Conclusions: Efti in combination with pembrolizumab is safe and shows encouraging antitumor activity in platinum pre-treated 2nd line HNSCC patients. Clinical trial information: NCT03625323.

Purpose: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and then CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. Combining an APC activator with an immune checkpoint inhibitor aims to increase efficacy without additional toxicity. We hereby report initial results of a phase II trial (NCT03625323). Methods: A predefined number of patients (pts) are recruited into this umbrella trial irrespective of PD-L1 expression. In part A: 1st line, PD-X naïve NSCLC; in part B: 2nd line, PD-X refractory NSCLC and in part C: 2nd line PD-X naive HNSCC. The study has a Simon's 2-stage design, with objective response rate (ORR) as primary endpoint. Secondary endpoints include progression free and overall survival, PK, PD and immunogenicity. Additional pts (N2) will be recruited for each part if the pre-specified threshold for ORR is met. Up to 109 pts will be enrolled. Efti is administered as 30 mg subcutaneous injection every 2 weeks for 8 cycles and then every 3 weeks for 9 cycles. Pembrolizumab is administered at a standard dose (200 mg intravenous infusion every 3 weeks for up to 2 years). The study was approved by ethic committees and institutional review boards. Results: Between 04 Mar 19 and 17 Jan 2020, 46 pts were enrolled and evaluated for safety. The median age was 66 years (range 48-84) and 74 % were male. The ECOG was 0 in 52 % and 1 in 48 % of the pts, respectively. Pts received a median of 5 (7) pembrolizumab (efti) administrations until data cut-off in Jan 2020. The most common (≥ 10%) adverse events (AEs) being cough (28 %), asthenia (24 %), dyspnea (17 %), decreased appetite (17 %), fatigue (15 %), diarrhea (15 %), non-cardiac chest pain (11 %), neck pain (11 %) and hypothyroidism (11 %). Two pts discontinued any study treatment due to AEs. All pts part A (1st line NSCLC) stage 1 (n=17) are evaluable for efficacy. Eight pts (47 %) had a partial response (iPR) and six (35 %) had stable disease according to iRECIST leading to an ORR of 47 %. Ten (10; 59 %) pts are still under therapy (7+ months). In part C (2nd line HNSCC) stage 1 13/18 pts are evaluable and five (39 %) had an iPR so far. Conclusions: Efti s.c. administered every 2 weeks in combination with pembrolizumab is safe and shows encouraging antitumor activity in all comer PD-L1 1st line NSCLC and 2nd line HNSCC. Stage 2 for both parts has been opened and stage 1 for part B is still recruiting. Citation Format: Martin Forster, Enriqueta Felip, Bernhard Doger, Margarita Majem, Enric Carcereny, Julio Peguero, Pawan Bajaj, Tim Clay, Matthew Krebs, Patricia Roxburgh, Leora Horn, Frederic Triebel. Initial results from a phase II study (TACTI-002) in metastatic non-small cell lung or head and neck carcinoma patients receiving eftilagimod alpha (soluble lag-3 protein) and pembrolizumab [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT202.

3100 Background: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and then CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. We hereby report initial results of a phase II trial (NCT03625323). Methods: A predefined number of patients (pts) are recruited into this 3-cohort trial irrespective of PD-L1 expression; part A: 1st line, PD-X naïve NSCLC; part B: 2nd line, PD-X refractory NSCLC and part C: 2nd line PD-X naive HNSCC. The study has a Simon's 2-stage design, with objective response rate (ORR) as primary endpoint. Secondary endpoints include disease control rate, progression free and overall survival, PK, PD and immunogenicity. Additional pts (N2) will be recruited for each part if pre-specified thresholds for ORR are met. Up to 109 pts will be enrolled. Efti is administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles with pembrolizumab (200 mg intravenous infusion every 3 wks for up to 2 yrs). The study was approved by ethic committees and institutional review boards. Results: Between 04 Mar 19 and 31 Jan 2020, 48 pts were enrolled and evaluated for safety and exposure. The median age was 66 yrs (range 48-84) and 73 % were male. The ECOG was 0 in 50 % and 1 in 50 % of pts, respectively. Pts received a median of 5 (7) and in total 311 (413) pembrolizumab (efti) administrations, respectively. Three pts (6.3 %) discontinued study treatment due to AEs. The most common ( > 10%) adverse events (AEs) being cough (31 %), asthenia (23 %), decreased appetite (19 %), fatigue (19 %), dyspnea (17 %), diarrhea (15 %) and constipation 13 %). From part A all pts (n = 17) were evaluated. Eight pts (47 %) had a partial response (iPR) and six (35 %) had stable disease according to iRECIST representing an ORR (DCR) of 47 % (82 %). irPRs were observed in all different PD-L1 groups ( < 1%; ≥ 1 % ≤49 %; ≥ 50 %). Ten (10; 59 %) pts are still on therapy (8+ months). In part C stage 1 15/18 pts are evaluable and six (40 %) had an iPR to date. Conclusions: Efti in combination with pembrolizumab is safe and shows encouraging antitumor activity in all comer PD-L1 1st line NSCLC and 2nd line HNSCC. Stage 2 has opened for both parts. Clinical trial information: NCT03625323 .

e16643 Background: Isocitrate dehydrogenase 1 mutations (mIDH1) are present in a variety of solid tumors resulting in production and accumulation of (R)-2-hydroxyglutarate causing DNA hypermethylation and promoting tumorigenesis. Olutasidenib is an oral, potent and selective inhibitor of mutated IDH1 protein. We report preliminary results from the ongoing, first-in-human, Phase 1, open-label, single-arm study of olutasidenib in non-CNS solid tumors. Methods: Patients with advanced relapsed/refractory (R/R) mIDH1 solid tumors received olutasidenib 150 mg BID, orally. Following a dose confirmation cohort (Phase 1b), patients with intrahepatic cholangiocarcinoma (IHCC), chondrosarcoma (CS), or unspecified mIDH1 solid tumors (Other) were enrolled in a Phase 2 efficacy evaluation (NCT: 03684811). Results: As of 31-Oct-2019, 44 patients with relapsed or refractory mIDH1 solid tumors were treated with olutasidenib. Diagnosis included: IHCC (n = 26), CS (n = 13), and Other (n = 5). The median age was 58 years (range: 29-81) and 43% were male. Median number of prior treatments was 2 (1-10). mIDH1 status was locally determined (IHC, NGS or PCR): R132C (61%), R132G (7%), R132S (7%), R132H (2%), R132L (2%), Others (2%) & unspecified (18%). Fourteen patients discontinued treatment (disease progression [n = 6; 3 IHCC, 2 CS, 1 Other], AE [n = 4; 3 IHCC, 1 CS], PI decision [n = 3; IHCC] & withdraw consent [n = 1; IHCC]). Treatment emergent adverse events (all grades, regardless of attribution) that occurred in > 15% of pts were: nausea (43%), fatigue (25%), decreased appetite (22%), AST increase (18%), ALT increase (16%), and constipation (16%). No protocol-defined DLTs occurred. Best responses by tumor type are shown in the table. Conclusions: Single agent olutasidenib at 150 mg BID demonstrates acceptable safety and tolerability with preliminary clinical activity in patients with R/R mIDH1 solid tumors. Updated safety and clinical activity, as well as exploratory evaluations of PK/PD will be provided. Clinical trial information: 03684811 . [Table: see text]

TPS2610Background: Membrane type I matrix metalloproteinase (MT1-MMP) is a member of the matrix metalloproteinase (MMP) family which are involved in tissue remodelling through proteolysis of extrac...

Background Olaparib (Lynparza®) is a poly(ADP-ribose) polymerase (PARP) inhibitor approved as maintenance treatment of PSR OC. MEDIOLA assessed olaparib in combination with the anti-programmed cell death ligand1 antibody, durvalumab, in germline BRCA1 and/or BRCA2 mutated (gBRCAm) PSR OC (NCT02734004). The 12-week (wk) disease control rate (DCR) = complete response [CR] + partial response + stable disease) was presented at SGO 2018 (late-breaker abst. 4). Methods Pts had PSR OC, gBRCA1 or gBRCA2 mutation, and had received at least one prior line of platinum. Pts received olaparib 300mg PO BID for a 4-wk runin, then olaparib 300mg PO BID and durvalumab 1.5g IV q 4 wks until progressive disease. Tumours were assessed by RECIST 1.1 at baseline, 4 wks, then every 8 wks. Primary endpoints were 12wk DCR and safety. Secondary endpoints were 28-wk DCR, objective response rate (ORR), duration of response (DoR), progression-free survival (PFS), overall survival (OS), and biomarker analyses. Results Thirty-two/thirty-four pts treated were eligible. With the data cut-off on 1 Nov 2018, 28% pts were still on treatment. Most common ≥Grade 3 AEs were anaemia (17.6%), elevated lipase (11.8%), neutropenia (8.8%), and lymphopenia (8.8%). Five pts discontinued olaparib and three discontinued durvalumab due to an adverse event. The 28-wk DCR was 65.6% (90% CI: 49.6%, 79.4%). ORR was 71.9% (95% CI: 53.25%, 86.25%) with a total of seven CRs. Median PFS was 11.1 months (95% CI: 8.2, 15.9) with a median DoR of 10.2 months (25/75th percentile: 5.6, NC). Second-line pts (N=13, 40.6%) had not yet reached the medians for PFS or DoR. Median OS for all pts was not yet reached, with 87.0% of pts alive at 24 months (median follow up=20.4 months). Updated results will be presented. Conclusions The combination of olaparib and durvalumab was well tolerated and showed promising median PFS and DoR. Median PFS and DoR for pts with fewer prior lines of chemotherapy was not yet reached, suggesting that these pts may derive a greater benefit from the combination. The CR rate was higher than anticipated. This cohort has been expanded to further explore the durability of this chemotherapy-sparing combination. Clinical trial identification NCT02734004. Editorial acknowledgement Emma Robinson, Mudskipper Business, Ltd, funded by AstraZeneca. Legal entity responsible for the study AstraZeneca. Funding AstraZeneca. Disclosure Y. Drew: Advisory / Consultancy, Research grant / Funding (institution): Clovis Oncology; Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Advisory / Consultancy: Merck; Advisory / Consultancy, Research grant / Funding (institution): Tesaro ; Advisory / Consultancy: Genmab; Research grant / Funding (institution): Oncology; Research grant / Funding (institution): Veratsem. B. Kaufman: Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: Medison. S. Banerjee: Honoraria (self), Research grant / Funding (self): AstraZeneca; Honoraria (self): Tesaro; Honoraria (self): Clovis Oncology; Honoraria (self): Merck; Honoraria (self): PharmaMar; Honoraria (self): Roche; Honoraria (self): Seattle Genetics; Honoraria (self): Nucana. A. Lortholary: Honoraria (self): AstraZeneca; Honoraria (self): Tesaro. P. Roxburgh: Research grant / Funding (institution), Travel / Accommodation / Expenses: AstraZeneca; Research grant / Funding (institution), Travel / Accommodation / Expenses: Tesaro. R.H. Alvarez: Honoraria (self): Eisai; Honoraria (self): Puma; Leadership role: Cancer Treatment Center of America. S. Domchek: Honoraria (self), Research grant / Funding (institution): AstraZeneca; Honoraria (self), Research grant / Funding (institution): Clovis Oncology; Honoraria (self): Bristol-Myers Squibb; Research grant / Funding (institution): PharmaMar. C. Gresty: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. H.K. Angell: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. V. Rocher Ros: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. K. Meyer: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. M. Lanasa: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. P. Herbolsheimer: Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca. All other authors have declared no conflicts of interest.

Background Enadenotucirev (EnAd) is a tumor selective Ad11/Ad3 group B adenovirus that has demonstrated pre-clinical activity in a model of platinum-resistant ovarian cancer. Synergy has also been reported between oncolytic adenoviruses and microtubule manipulating drugs such as paclitaxel (Pxl). This study aims to establish the tolerability and preliminary efficacy of EnAd delivered in combination with Pxl. Here we present data from the intravenous (IV) dose expansion group. Methods Patients with platinum-resistant or refractory ovarian cancer received a minimum of two 28-days cycles of IV infusional EnAd (1x1012 viral particles) on days 1, 3 and 5, and IV Pxl (80mg/m2) on days 9, 16 and 23. Baseline and on-treatment biopsies were taken. Primary endpoint was safety and tolerability; additional endpoints included, response rate (RECISTv1.1/GCIG CA125 criteria) and duration of response. Results Twenty patients, median age 60.5 years (range 37-78) who had received a median of 4 prior lines of therapy (range 1-12) were enrolled. Adverse events reported from the combination of EnAd and Pxl were as previously described (for both agents individually), with ‘flu-like symptoms reported in the majority of patients following EnAd administration. Hematological changes including neutropenia, previously identified at higher doses of EnAd IV monotherapy, were reported at the dose level tested in this study population. Virus kinetics, cytokine and anti-virus antibody responses were consistent with previous results with EnAd. As of 03May19, Investigator-assessed ORR is 37.5% (6/16), with median DoR of 16 weeks (range 8-32). Reductions in CA125 broadly follow the pattern of tumor regression, with 36% (4/11) achieving response according to GCIG CA125 criteria. Disease control rate (RECIST CR, PR, SD) is 75% (12/16). To date, matched biopsies (N = 2) have been analysed for pharmacodynamic markers, providing preliminary evidence of increased CD8 T cell infiltration in on-treatment tumour biopsies. Conclusions The combination of EnAd and Pxl has manageable tolerability. Favorable disease control is noted in this recurrent platinum-resistant population, which is worthy of further investigation. Clinical trial identification 2013-001276-38. Legal entity responsible for the study PsiOxus Therapeutics Ltd. Funding PsiOxus Therapeutics Ltd. Disclosure R. Brown: Shareholder / Stockholder / Stock options, Full / Part-time employment: PsiOxus Therapeutics Ltds. D. Krige: Full / Part-time employment: PsiOxus Therapeutics Ltds. J. Bendall: Full / Part-time employment: PsiOxus Therapeutics Ltds. G. Di Genova: Full / Part-time employment: PsiOxus Therapeutics Ltds. H. McElwaine-Johnn: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: PsiOxus Therapeutics Ltds. All other authors have declared no conflicts of interest.

High grade serous ovarian carcinomas (HGSOCs) are molecularly and clinically heterogeneous malignancies. Currently, molecular stratification of patient care is limited to tumors rendered homologous recombination deficient (HRD) by BRCA1/2 mutation (BRCAm). Here we explore the overlap, interplay and clinical impact of molecular subgrouping layers in a cohort of 362 FFPE HGSOCs. We overlay genomic subgrouping and tumor-infiltrating lymphocyte (TIL) burden with the three transcriptionally-defined subtypes (Immune, Angio and AngioImmune) we have previously reported as associated with survival and bevacizumab sensitivity. The BRCAm group, the Immune subtype and those with high CD8+ TIL burden demonstrated prolonged overall survival (OS) as previously reported. The OS benefit of CD8+ TILs was abrogated in the context of gross residual disease following debulking [multivariable hazard ratio (mHR)=0.51 (0.34-0.78) vs 0.93 (0.76-1.52)]. BRCAwild-type patients demonstrating high expression of EMSY, encoding the BRCA2-binding protein EMSY, demonstrated prolonged OS [mHR=0.48 (0.29-0.79)]. BRCA2m and high-EMSY patients displayed greater chemosensitivity (first-line CA125-CR 94.4% and 81.3% vs 48.2%, P There was significant enrichment and depletion of BRCAm and CCNE1-gain (CCNE1g) in the Immune subtype (28.9% vs 6.3%, P=0.001 and 9.1% vs 17.4%, P=0.050). The Angio subtype harboured far fewer CD8+ TILs compared to the Immune and AngioImmune subtypes (P The clinical impact of CCNE1g was modulated by transcriptomic subtype: in the Immune group, CCNE1g was associated with poor OS [mHR=3.32 (1.49-7.41)], while in the Angio group CCNE1g cases had favourable outcome [PFS mHR=0.26 (0.10-0.68)]. CD8+ TIL burden was not associated with outcome in CCNE1g cases. Missense TP53 mutation was associated with better outcome versus TP53-null mutations in BRCAm patients [PFS mHR=0.43 (0.14-0.82)], but not in the context of HR proficiency [mHR=0.90 (0.67-1.22)]. Integrated classification using the consensus of favourable and unfavourable HR-centric (HRD favourable, HR-proficient unfavourable) and transcriptomic (Immune favourable, Angio/AngioImmune unfavourable) subgrouping yielded three groups with distinct OS [favourable vs unfavourable mHR=0.49 (0.34-0.74); favourable vs no-consensus mHR=0.64 (0.42-0.98); unfavourable vs no-consensus mHR=1.31 (1.00-1.70)]. Together, these data paint a more granular picture of the clinical impact of HGSOC subgroups and demonstrate novel candidate interactions between subgrouping layers. The poorest outcome groups represent those with most to gain from trials of novel treatment regimens. Citation Format: Robert L. Hollis, Alison M. Meynert, Michael Churchman, Tzyvia Rye, Patricia Roxburgh, Daniel Stetson, Athena Matakidou, Brian Dougherty, J. Carl Barrett, Ruth E. March, Colin A. Semple, C. Simon Herrington, Charlie Gourley. Multi-layer molecular characterization of high grade serous ovarian carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 749.

3095 Background: SRA737 is a potent, highly selective and orally-bioavailable inhibitor of checkpoint kinase 1 (Chk1). SRA737-02 was designed to investigate the safety, tolerability and preliminary activity of SRA737 in a novel combination with sub-therapeutic doses of gemcitabine (low dose gemcitabine; LDG) utilized to potentiate SRA737’s activity by induction of replication stress in subjects with advanced solid tumors. Methods: Phase 1 dose escalation investigated cohorts of 3 to 6 subjects receiving escalating doses of SRA737 for 2 days after LDG administration on days 1, 8, 15 of 28-day cycles. Phase 2 expansion cohorts explored the hypothesis that LDG strongly synergizes with SRA737 in subjects with genetically-defined tumors hypothesized to be sensitive to Chk1 inhibition: urothelial, high grade serous ovarian, small cell lung, soft tissue sarcoma, and cervical or anogenital cancers. Results: A total of 55 subjects received SRA737 in 13 dose escalation cohorts at doses of 40 to 600 mg SRA737 combined with LDG doses of 50 to 300 mg/m2. No protocol-defined dose limiting toxicities (DLTs) have been observed. The pharmacokinetic profile of SRA737 revealed an AUC0-24 and Cmax of 3550 ng∙h/mL and 548 ng/mL at 150 mg SRA737. At this dose, the Cmin (52 ng/mL) exceeded that determined in preclinical models to be effective. Enrollment into expansion cohorts was initiated at 500 mg SRA737 plus 100 mg/m2 LDG with intra-patient dose escalation permitted to 250 mg/m2 LDG. Approximately 80 subjects were planned and 82 have been treated. Median treatment duration was 51 days (range 1 to 358). The most common treatment-emergent adverse events were nausea (53%), vomiting (45%), fatigue (40%), diarrhea (38%), and anemia (28%); the majority were of mild to moderate severity. Proof-of-concept clinical activity has been seen in tumor types such as anal, cervical, and rectal. Conclusions: The combination of LDG and SRA737 has been well tolerated. This first-in-human clinical study provides proof-of-concept that sub-therapeutic LDG effectively potentiates SRA737. This novel replication stress-targeted therapy warrants further evaluation in genetically pre-defined solid tumors. Clinical trial information: NCT02797977.