Chemoradiation With Enadenotucirev as a Radiosensitiser in Locally Advanced Rectal Cancer (CEDAR)

A Phase 1 Trial of the Safety, Tolerability and Biological Effects of Intravenous Enadenotucirev, a Novel Oncolytic Virus, in Combination With Chemoradiotherapy in Locally Advanced Rectal Cancer

The use of chemoradiotherapy (CRT), in combination with surgery is the standard of care in the treatment of locally advanced rectal cancer. However some patients don't respond well to radiation. More advanced radiotherapy techniques, that result in fewer toxicities, means that we are now able to combine new anti-cancer agents into standard treatment. Targeting the tumour early in this way has the potential to improve response rates. Enadenotucirev is a specific type of anti-cancer virus that only targets cancer cells. It acts in the same way as any virus and can only survive by replicating inside cancer cells and not normal, non-cancerous cells. This means that it can selectively target and destroy tumours, without directly affecting normal cells. It also has the ability to attract cells from the body's immune system to help fight the cancer. The addition of enadenotucirev to standard chemoradiotherapy treatment may have a combined effect on the cancer cells with potentially few, additional side effects. This trial aims to determine the optimal dose and frequency of the virus to give by gradually increasing the number of doses each successive patient receives, and then increasing the dose of the virus itself. Each patient will receive a minimum of 3 doses, up to a maximum of 6, spread over the course of their 5 week standard chemoradiotherapy treatment. Patients will be closely monitored at all times to ensure that with each dosing group, there aren't excessive side effects. Patients will then undergo surgery as part of their standard of care and be followed up for up to 4-6 weeks post-surgery. This trial aims to determine the optimal dose and frequency that can then be used in future studies with the possibility of exploring the addition of Enadenotucirev to other chemoradiotherapy treatments.

At present identifying novel radiosensitising agents in colorectal cancer is an area of high need for patients considering sphincter preserving surgery or needing down staging to facilitate surgery. Although the combination of Enadenotucirev with chemoradiation is novel, there is a wealth of evidence to support the rationale for combining this class of agent with radiation and chemotherapy. Enadenotucirev is a group B oncolytic virus under development for the systemic treatment of metastatic or advanced epithelial tumours. Enadenotucirev is a chimeric adenovirus type 11p (Adp/adenovirus type 3 (Ad3) virus, discovered through a process of bio-selection from a library of chimeric viruses produced from a pool of adenoviruses from seven different serotypes utilizing human HT-29 colorectal cancer (CRC) cells. Enadenotucirev shows selective and potent toxicity in humans carcinoma cells with only very limited or no toxicity to normal (non-cancerous) human cells. Other than humans, there is no known permissive species for Enadenotucirev. The principle advantage of oncolytic therapy is that the virus replicates only in diseased cells meaning that the concentration of drug is amplified at the site of pathology so that it is higher in the tumour than in healthy tissue. Virus particles spread from cell to cell within a tumour nodule until they reach non-permissive normal tissues, in principle destroying all viable tumour cells they encounter. While the overall understanding of the mechanism of action of Enadenotucirev in humans is still under investigation, it is now well established from non-clinical and clinical studies that the mechanism of anti-cancer efficacy of oncolytic viruses not only involves direct infection and lysis of tumour cells, but that immune responses stimulated via an increased release of tumour-associated antigens and immune-inflammatory activation signals play a key role. CEDAR is dual endpoint, dose escalation phase 1 trial using a time to event continual reassessment method (TiTECRM). Response and Toxicity endpoints will be combined in dose escalation models to identify the optimal dose schedule. Dose decisions are made using the statistical model instead of just using the data from that particular dose, as in the case of 3+3 model, meaning it uses all available data to make a dose decision. This primary objective is to determine the optimal dose and frequency of the virus by firstly gradually increasing the number of doses each successive patient receives, and then increasing the dose of the virus itself. All participants will receive 3 loading doses in weeks 1-2, prior to initiation of standard chemoradiotherapy. Further doses of Enadenotucirev will either be given after or during and after standard chemoradiotherapy and this is dependent on which of the 4 different dose groups they are assigned to. The dose given will vary between either 1x1012 Viral Particles (VP) or 3x1012vp. Each patient will receive a minimum of 3 doses, up to a maximum of 6, spread over the course of 9 weeks. Patients will be closely monitored at all times to ensure that with each dosing group, there aren't excessive side effects. Patients will then undergo surgery as part of their standard of care and be followed up for 4-6 weeks after surgery.

locally advanced, rectal cancer, Enadenotucirev, oncolytic virus, adenovirus, dose escalation, Time To Event Continual Reassessment Method, chemoradiotherapy, phase 1

Dosing Group 1: - Loading dose pre chemoradiation (CRT) - 1x10^12 viral particles (vp) Dosing Group 2: Loading dose pre CRT - 1x10^12 vp Maintenance dose post CRT - 1x10^12vp Dosing Group 3: Loading doses pre CRT - 3x10^12vp Maintenance dose post CRT - 3x10^12vp Dosing Group 4: Loading dose pre CRT - 3x10^12vp Concurrent doses on Week 1, Day 1 and Day 5 of CRT - 3x10^12vp Maintenance post CRT - 3x10^12vp

Enadenotucirev is a live replicating oncolytic adenovirus; it is considered a BioSafety Level 1 (BSL-1) infectious substance.

Capecitabine is a chemotherapy drug licensed for use in rectal cancer, it is a non-cytotoxic pre-cursor of the cytotoxic 5-fluorouracil. Due to Capecitabine not being taken on Enadenotucirev dosing days it is considered an investigational medicinal product within this trial.

Used to determine the optimal dose and frequency of enadenotucirev that can be administered with chemoradiation. Highest treatment schedule resulting in less than 30% dose limiting toxicity rate.

Used to determine the optimal dose and frequency of enadenotucirev that can be administered with chemoradiation. The MRI tumour regression grade uses the following scale and for the purposes of the trial analysis and dose escalation, scores of 1 or 2 will be classified as responders and scores of 3, 4 or 5 will be classified as non-responders: - No/minimal fibrosis visible (tiny linear scar) and no tumour signal - Dense fibrotic scar (low signal intensity) but no macroscopic tumour signal (indicates no or microscopic tumour) - Fibrosis predominates but obvious measurable areas of tumour signal visible - Tumour signal predominates with little/minimal fibrosis - Tumour signal only: no fibrosis, includes progression of tumour

Treatment tolerance measured by proportion of patients completing at least 80% of the intended Capecitabine dose and at least 20 fractions of radiotherapy.

To measure local response rate to combined therapy compared to pre-treatment status The MRI tumour regression grade uses the following scale and for the purposes of the trial analysis and dose escalation, scores of 1 or 2 will be classified as responders and scores of 3, 4 or 5 will be classified as non-responders: - No/minimal fibrosis visible (tiny linear scar) and no tumour signal - Dense fibrotic scar (low signal intensity) but no macroscopic tumour signal (indicates no or microscopic tumour) - Fibrosis predominates but obvious measurable areas of tumour signal visible - Tumour signal predominates with little/minimal fibrosis - Tumour signal only: no fibrosis, includes progression of tumour

To measure local response rate to combined therapy compared to pre-treatment status The Neoadjuvant Rectal (NAR) score ranges from 0-100 where a higher score equates to a worse prognosis.

Patients archival, week 4 biopsy and resection sample will be processed and stained for the presence of a hexon protein coat, viral gDNA. This will identify the virus and allow confirmatory analysis (yes/no) to be completed to determine if the virus is only present within the tumour cells or not.

Patients archival, week 4 biopsy and resection sample will be processed using RNA sequencing to analyse whole genome RNA expression and nanostring gene expression

Inclusion Criteria: Histologically confirmed invasive adenocarcinoma of the rectum Locally advance colorectal cancer as defined by pelvic MRI with a threatened circumferential resection margin (cT3mrf+ve), or inclusion of an adjacent organ, or low tumours at/below the level of the levators or enlarged pelvic side wall nodes or selected by the multidisciplinary team MDT for treatment with neoadjuvant (chemo)radiotherapy, regardless of TNM classification Patients with oligometastatic disease suitable for radical treatment are permitted provided that the site specific MDT deems them suitable for chemoradiation Male or female, Age ≥ 18 years ECOG performance score of 0 - 1 The patient is willing and able to comply with the protocol scheduled biopsy, follow-up visits and examinations for the duration of the trial. Written (signed and dated) informed consent Adequate renal function demonstrated by: Adequate ≤1.5 ULN and estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73m (measured creatinine clearance ≥60 mL/min) and Urine dipstick for proteinuria at screening and baseline negative or trace. Patients may be included with results of 1+ if they have a spot urinary albumin creatinine ratio (ACR) of either: (i) ≤3 mg/mmol or (ii) >3 mg/mmol with a 24 hour urinary protein <1.0 g/24 hours and Serum complement C3 and C4 within the normal range Haematological and Biochemical indices within the ranges shown below: Haemoglobin: ≥90 g/L Absolute neutrophil count: ≥1.5x10^9/L Platelet count: ≥100x10^9/L Bilirubin: < 1.5 upper limit of normal Aspartate transaminase and/or alanine transaminase: ≤3 x upper limit of normal INR: ≤1.5 aPTT: within laboratory normal range Exclusion Criteria: Pregnant or breast-feeding women, or women of childbearing potential unless effective methods of contraception are used. Pulmonary lymphangitis (if metastatic disease present) Past medical history: Known history or evidence of significant immunodeficiency due to underlying illness and/or medication (e.g. systemic corticosteroids, or other immunosuppressive medications including cyclosporine, azathioprine, interferons in the 4 weeks before the first dose of trial treatment) Splenectomy Prior allogeneic or autologous bone marrow or organ transplantation Patients with a history of, or active, known or suspected auto-immune disease or a syndrome that requires systemic or immunosuppressive agents; patients with vitiligo, type I diabetes mellitus, residual hypothyroidism due to autoimmune disease only requiring hormone replacement, psoriasis not requiring systemic treatment or conditions not expected to recur in the absence of an external trigger are permitted to enrol. History of idiopathic pulmonary fibrosis, drug-induced pneumonitis, or evidence of active pneumonia or pneumonitis on computed tomography scan Active viral disease or known positive serology for HIV, hepatitis B or hepatitis C Active infections requiring antibiotics, physician monitoring, or recurrent fevers >38.0°C associated with a clinical diagnosis of active infection Prior pelvic radiotherapy Any other active malignancy, with the exception of adequately treated cone-biopsied in situ carcinoma of the cervix uteri and non-melanoma skin lesions Uncontrolled cardiorespiratory comorbidity (e.g. severe pulmonary fibrosis, inadequately controlled angina or myocardial infarction in the last 6 months) Major disturbance in bowel function (e.g. severe incontinence, Crohn's disease, >6 loperamide/day), risk of bowel obstruction due to tumour - exception defunctioning colostomy performed Treatment with any COVID-19 vaccine in the 28 days before the first dose of enadenotucirev, unless the vaccine is known to not be based on an adenoviral vector (e.g. mRNA vaccines) Treatment with any vaccine (including known non-adenoviral COVID-19 vaccines) in the 7 days before first dose of enadenotucirev Use of the following anti-viral agents: ribavirin, adefovir, lamivudine or cidofovir within 7 days prior to the first dose of trial treatment Treatment with any other investigational agent, or participation in another interventional clinical trial within 28 days prior to enrolment. In follow up for an interventional trials and observational studies are allowed History of DVT or pulmonary embolus in the 12 months before the first dose of study of study treatment History of significant bleeding requiring hospitalisation in the 12 months before the first dose of study treatment Patients receiving therapeutic or prophylactic anticoagulation therapy Known dihydropyrimidine dehydrogenase (DPYD) deficiency Prior chemotherapy is allowed as long as >28 days since the last administration and any toxicity has resolved to NCI CTCAE grade 1 or less Other psychological, social or medical condition, physical examination finding or a laboratory abnormality that the investigator considers would make the patient a poor trial candidate or could interfere with protocol compliance or the interpretation of trials results

O'Cathail SM, Davis S, Holmes J, Brown R, Fisher K, Seymour L, Adams R, Good J, Sebag-Montefiore D, Maughan T, Hawkins MA. A phase 1 trial of the safety, tolerability and biological effects of intravenous Enadenotucirev, a novel oncolytic virus, in combination with chemoradiotherapy in locally advanced rectal cancer (CEDAR). Radiat Oncol. 2020 Jun 12;15(1):151. doi: 10.1186/s13014-020-01593-5.