Immune checkpoint inhibitors (ICI), monoclonal antibodies enhancing T cell responses against tumour cells, have revolutionised the treatment of cancers such as advanced melanoma, leading to enhanced survival. Their action, however, is not tumour-specific, and patients can develop multisystem immune related adverse events (irAE). Neurological irAEs have been reported in 1–14% of patients, depending upon the ICI used, and can affect any part of the neuro-axis. A recent case series from the Royal Marsden Hospital (RMH) identified 10 patients with neurotoxicity following ICI for advanced melanoma between 2010–15, specifically neuropathy (6), plexopathy (1) and aseptic meningitis (3). Exactly how neurological injury occurs, whether cell-, cytokine- or antibody-mediated, is unknown. We present early data from a newly established collaboration with RMH, aiming to clinically characterize these patients, and identify the cause of neurological injury. To date, we have advised on patients (age range 53–80) with myositis, Guillain-Barré (GBS)-like neuropathy, plexopathy, aseptic meningitis, and encephalitis following ICI (ipilimumab and/or nivolumab) for advanced melanoma. Features common to these patients include their subacute onset, time from ICI administration, and steroid responsiveness (including in GBS-like cases). The incidence of neurological irAEs following ICI will rise with increasing use, and is therefore of concern to practicing neurologists.

Abstract Background Multiple genomic and transciptomic biomarkers have been associated with response to immune checkpoint inhibitor (CPI) therapy. Emerging evidence suggests that each solid tumour type has a unique mix of factors determining CPI response, reflecting the subtle differences in antigen repertoire and immune microenvironment across histologies. Compiling large-scale sequencing datasets of patients treated with CPI therapy, from a range of solid tumour types, allows detailed comparison of the contrasting immune drivers per histology. Understanding these differences enhances our understanding of the pathways influencing CPI response, which may be of utility for therapeutic and biomarker development. Methods We compiled data from 13 CPI treated cohorts, across 6 solid tumour types, encompassing 1,453 patients (n = 1,453 with exome data, n = 674 with RNAseq data). All raw data was accessed, and reprocessed through a standardised state of the art bioinformatics pipeline. A comphrehensive range of genomic & transcriptomic biomarker metrics were derived across the cohort. A combined predictive model was constructred encompassing all biomarkers, & the importance weighting was calculated for each biomarker, in each tumour type. Results TMB was found to be a universal predictor of response across all tumour types, except for renal cell carcinoma (RCC). Instead CPI response in RCC appears to be strongly driven by expression of human endogeneuos retroviruses (hERV). In malignant melanoma, while TMB (nsSNVs) was associated with CPI response, the number of expressed indel mutations was found to be a stronger predictor. Shared antigen expression also demonstrated tumour specific predictive patterns. A signature of high immune inflitatation was found to be another universal predictor of response across multiple tumour types, however differences in the varying importance of immune cell subsets across histologies was observed. The rate of HLA LOH, and other immune evasion mechanisms also varied dramatically by cancer type. Conclusions The determinants of immunotherapy response vary across solid tumour types, offering unique insight into both tumour intrinsic and extrinsic drivers of immunogenicity. Legal entity responsible for the study The Francis Crick Institute. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Abstract Background Intratumour heterogeneity is recognised across different tumour types and has implications for therapeutic resistance. At present, clinical practice often relies upon molecular information derived from a single biopsy of a primary or metastatic tumour. This information guides treatment choice but may not be representative of the diversity of the tumour. It is currently difficult to evaluate how effectively a single region guides treatment decisions because the formalin-fixed residual surgical sample that is not paraffin embedded for diagnostic purposes is typically thrown away. Retention and homogenisation – ‘blending’- of this residual formalin-fixed leftover tumour tissue creates a more representative sample for analysis. DNA may be extracted from this sample for sequencing. Pilot data in kidney cancer has demonstrated the potential of this methodology for robust mutational calling, accurate determination of cancer cell fraction and the ability to discern clonal from subclonal variants. Such information may be clinically relevant; for example, discerning resistant subclones prior to treatment, or identifying clonal neoantigens worth targeting with immunotherapy. Trial design In order to establish the feasibility of homogenization as a potential companion diagnostic tool, our study aims to 1) identify the proportion of primary tumour cases that have left over tissue amenable to homogenization across multiple tumour types and 2) pilot homogenization across multiple tumour types. The molecular profile of the homogenate will be compared to that obtained from the diagnostic specimen using next generation sequencing techniques. This is a prospective non-interventional study (NCT03832062). Patients undergoing surgical intervention at The Royal Marsden Hospital (NHS Foundation Trust) with leftover tumour tissue from primary breast, colorectal, gastric, pancreatic, ovarian, renal cancer and sarcoma surgeries, as well as melanoma lymph node dissections will be included in the feasibility assessment. We plan to homogenise 500 cases across different tumour types. The study opened in September 2018 and is expected to run for 2 years. Clinical trial identification NCT03832062; Release date: February 2019. Legal entity responsible for the study Royal Marsden NHS Foundation Trust. Funding Ventana Medical Systems (a subsidiary of Roche). Disclosure L. Gallegos: Full / Part-time employment: Roche. S. Hill: Full / Part-time employment: Roche. A. Barhoumi: Full / Part-time employment: Roche. S. Stanislaw: Full / Part-time employment: Roche. M. Mendoza: Full / Part-time employment: Roche. J.M.G. Larkin: Research grant / Funding (institution): Roche; Advisory / Consultancy: Roche. N. Alexander: Full / Part-time employment: Roche; Shareholder / Stockholder / Stock options: Roche. S. Turajlic: Research grant / Funding (institution): Ventana Medical Systems (subsidiary of Roche). All other authors have declared no conflicts of interest.

Abstract Background ADATPeR is the first prospective study evaluating the role of anti-PD1 agents in the neoadjuvant setting prior to cytoreductive nephrectomy in treatment-naive patients with metastatic clear cell renal cell carcinoma (mccRCC). We performed multi-omic analyses to resolve spatial heterogeneity and temporal dynamics in putative biomarkers of response to anti-PD1 blockade. Methods In a single center study, patients received nivolumab (3mg/kg every 2 weeks) pre- and post-operatively until progressive disease (PD). Primary endpoint was safety, secondary endpoints were response evaluation and exploratory biomarker analysis. Multiregion tumour biopsies were obtained at baseline, on-treatment (week 9) and at PD. Whole-exome sequencing was performed to infer somatic mutations and predict candidate neoantigens (NAs). Tumour immune microenvironment was evaluated using a RNA-seq-derived immune signature and by stromal and intraepithelial tumour infiltrating lymphocytes (TILs) assessments. Results 15 patients were treated. At median follow-up of 12.5 months(m), nivolumab had an acceptable side-effect profile. Overall response rate was 37%. Preliminary transcriptome analyses of pre-treatment biopsies (33 samples from 14 patients; up to 4 regions per case) revealed enrichment for primary-resistance (defined as PD within 2m; n = 4) with immune ‘cold’ tumours, distinct from ’hot’ tumours. Histologic TILs scoring showed concordant immune phenotypic clusters. Primary-resistant cases demonstrated 0% on-treatment stromal- and IE-TILs (2 evaluable patients). In contrast, we observed heavy on-treatment stromal TILs (70-90%) and intraepithelial TILs (30-90%) across 7 regions at nephrectomy in an exceptional responder receiving ongoing treatment (>24 cycles). Conclusions ADATPeR is the first neoadjuvant immune checkpoint inhibitor study pre-cytoreductive nephrectomy, and incorporated multi-omic analyses of putative biomarkers. Baseline immune gene expression signature is distinct in responders compared with non-responders. On-treatment intraepithelial TILs were prominent in those deriving durable clinical benefit. Integrative analyses are ongoing. Clinical trial identification NCT02446860. Legal entity responsible for the study The authors. Funding Bristol-Myers Squibb; The National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research; Cancer Research UK (CRUK). Disclosure All authors have declared no conflicts of interest.

Abstract Background In 2017 a new PN led clinic was established for immunotherapy patients. At the 1-year mark to ensure patients were satisfied with the service provision, a patient experience survey was conducted. The survey explored if patients felt comfortable in discussing side effects with the PN and if they felt part of their treatment related decisions. Importantly patients were asked if they had confidence and trust in the PN. Methods The survey was provided to all patients whom attended the PN led clinic from May 2017 to May 2018. The survey consisted of 10 closed questions using the Likert scale, with spaces provided for personal comments. Data collection period was 1.06.18 to 29.06.18. Estimated number of patients was 10. Results Questionnaires were provided to a total of 10 patients. Three questionnaires could not be provided to 3 patients whom attended the PN led clinic as they had died. Two patients did not respond back. 6/8 patients strongly agreed (SAg) to feeling comfortable in discussing treatment related side effects and 2/8 patients agreed (Ag). This same result was found when patients were asked if they felt involved in the decisions related to their care e.g. stopping immunotherapy treatment at 2 yrs. With respect to having confidence and trust with the advice and care provided by the PN, 7 patients SAg and 1 Ag. All patients felt that they were being listened to and had the opportunity to ask questions during their consultations (7 patients SAg and 1 Ag). Reassuringly all 8 patients said that they would recommend this service to their friends and family (7 patients SAg and 1 Ag). Conclusions This survey was to ensure patients were satisfied with being reviewed by a PN and as the service was new to the melanoma unit in 2017; it was vital that the patients had the opportunity to evaluate the service provision. With this positive feedback the clinic was expanded from September 2018 and to date 36 patients have now been seen within the PN led immunotherapy clinic and another patient experience survey is due. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Neurological adverse events from immune checkpoint inhibition are increasingly recognised, especially with combination anti-cytotoxic T-lymphocyte antigen 4 (CTLA4) and anti-programmed death receptor 1 (anti-PD-1) therapies. Their presenting symptoms and signs are often subacute and highly variable, reflecting the numerous components of the nervous system. Given the risk of substantial morbidity and mortality, it is important to inform patients of symptoms that may be of concern, and to assess any suspected toxicity promptly. As with other immune-related adverse events, the cornerstone of management is administration of corticosteroids. Specialist neurology input is vital in this group of patients to guide appropriate investigations and tailor treatment strategies.