75 WIRE: Window of Opportunity Clinical Trials Platform for Evaluation of Novel Treatments Strategies in Renal Cell Cancer

Abstract Background Despite the success of immunotherapy and VEGFR directed tyrosine kinase inhibitors (TKIs) for the treatment of renal cell carcinoma (RCC), a significant proportion of patients display primary or secondary resistance to systemic therapy. New treatment approaches are needed for these patients. Pre-surgical clinical trials allow us to study the effects of cancer treatment on the tumour microenvironment, comparing baseline biopsy with post-treatment nephrectomy in a ‘window of opportunity’ study. The results may give us insight into the mechanisms of new cancer therapies, that may be advanced into further clinical trials. Methods The WIRE trial (NCT03741426) is a phase II, multi-centre, multi-arm, non-randomised, neoadjuvant clinical trial platform. The overall aim of the trial is proof of mechanism for new RCC therapies. There are five investigational arms: 1. Cediranib (a VEGFR directed TKI), 2. Cediranib + Olaparib (a PARP inhibitor), 3. Olaparib, 4. Volrustomig (anti PD-1/CTLA-4 bispecific) and 5. Rilvegostomig (anti PD-1/TIGIT bispecific). The study uses a Bayesian adaptive design to optimise recruitment, with pre-specified criteria assessed at interim analyses to stop for futility, continue recruitment to that arm, or move to the next investigational arm. Eligible patients have cT1b+, cN0/1, cM0/1 clear cell RCC, planning to undergo surgery, without medical contraindication to trial therapy. Patients undergo baseline biopsy to confirm clear cell RCC and multiparametric dynamic contrast enhanced (DCE) MRI scan of the primary tumour. For tablet arms 1-3, patients receive at least 14 days of investigational medicinal product (IMP). For immunotherapy arms 4 & 5, patients receive one infusion of IMP. The tumour is re-evaluated by DCE-MRI immediately before surgery. At nephrectomy, multi-region tissue sampling from the tumour is performed both pre-arterial ligation and post resection. Serial translational blood and urine samples are collected before, during and after treatment. The primary endpoint for arms 1-3 is a ≥30% reduction in DCE-MRI assessed capillary permeability (Ktrans) compared to baseline. The primary endpoint for arms 4 & 5 is a ≥30% increase in IHC assessed CD8+ T cell density comparing the resected tumour to baseline biopsy. Secondary endpoints include RECIST v1.1 primary tumour response and adverse events. A comprehensive translational science programme accompanies the trial, which will assess the tumour microenvironment and peripheral blood response to therapy, using techniques including imaging mass cytometry and single cell RNA sequencing. This will allow us to gain a deep understanding of mechanisms of response in each investigational arm. To date, arms 1 & 2 have completed recruitment, and arm 3 is actively recruiting. Conclusions WIRE offers a unique opportunity to investigate the mechanisms of new therapies for RCC. Successful completion of these peri-surgical studies depends on co-ordination between many specialties, including surgery, oncology, radiology, and pathology. The adaptive design allows for efficient allocation of patients to treatment arms to generate optimal data for each IMP. WIRE may identify novel biomarkers of response and toxicity, to inform treatment selection for patients. The data generated will be a foundation for further trials of these IMPs in advanced disease.