First patient dosed in SCIB1 Phase 2 trial

19 November 2021

Scancell Holdings plc

("Scancell" or the "Company")

First patient dosed in SCIB1 Phase 2 clinical trial

Phase 2 clinical trial of SCIB1 in patients with metastatic melanoma also receiving the checkpoint inhibitor pembrolizumab (Keytruda^®)

Scancell Holdings plc (AIM: SCLP), the developer of novel immunotherapies for the treatment of cancer and infectious disease, today announces the enrolment and treatment of the first patient in its multicentre SCIB1 Phase 2 clinical trial at the Churchill Hospital, Oxford University Hospitals Trust, UK. The Phase 2 study is designed to assess whether the addition of SCIB1 to pembrolizumab (Keytruda^®) will result in an improvement in the tumour response rate, progression-free survival and overall survival in patients with advanced melanoma, who are also eligible for treatment with pembrolizumab.

As a result of the COVID-19 pandemic, screening and recruitment into the study was paused due to the prioritisation of COVID-19 patients in UK hospitals. Patient screening has now been re-initiated in the UK, with Professor Poulam Patel, Professor of Clinical Oncology at the University of Nottingham as the Chief Investigator. The Nottingham site, along with the Oxford centre, Velindre Hospital and Mount Vernon Hospital are actively screening subjects, with additional centres due to come online in the coming months.

SCIB1 is the lead product from the Company's ImmunoBody^® immunotherapy platform, which uses the body's immune system to identify, attack and destroy tumours. This is achieved by delivering a DNA plasmid using Ichor's TriGrid^® 2.0 electroporation delivery device to enhance the uptake and presentation of cancer antigens to harness high avidity T cell responses. In a Phase 1/2 clinical trial, survival following SCIB1 monotherapy was superior to historical survival rates, with 14 of 16 resected patients surviving for more than five years. Although pembrolizumab is an approved therapy for advanced melanoma, response to treatment is limited to only a subset of patients (circa 30%). The Phase 2 study is therefore designed to assess whether the addition of SCIB1 treatment to pembrolizumab will result in an improvement in patient outcomes.

Further information relating to the clinical trial can be found on the Company's website at www.scancell.co.uk and at https://clinicaltrials.gov.

Professor Lindy Durrant, Chief Executive Officer, Scancell, commented: "We are delighted to have started our SCIB1 Phase 2 trial in the UK as we believe that SCIB1 administration in combination with an immune checkpoint inhibitor such as pembrolizumab has the potential to offer greater efficacy than when either agent is used alone."

Professor Poulam Patel, Chief Investigator, commented: "As the Chief Investigator for this combination study, I am delighted to be working with Scancell again to determine if the addition of SCIB1 to current, standard treatment with pembrolizumab improves response rates."

Dr Miranda Payne, Principal Investigator, Oxford University Hospitals commented: "Although checkpoint inhibitor combinations have improved outcomes for patients with melanoma, there remains a need to develop combinations with other investigational agents such as SCIB1, which have the potential to improve response rates without increasing toxicity. We are therefore very pleased to have recruited the first patient into this Phase 2 study."

This announcement contains inside information for the purposes of Article 7 of Regulation (EU) 596/2014 (MAR).

About Scancell

Scancell is developing novel immunotherapies for the treatment of cancer based on its technology platforms, ImmunoBody^®, Moditope^® and AvidiMab^TM, with four products in multiple cancer indications, development of a vaccine for COVID-19 and a growing portfolio of novel anti-TaG monoclonal antibodies.

ImmunoBody^® vaccines target dendritic cells and stimulate both CD4 and CD8 T cells with the ability to identify, target and eliminate cancer cells. These cancer vaccines have the potential to be used as monotherapy or in combination with checkpoint inhibitors and other agents. The Directors believe that this platform has the potential to enhance tumour destruction, prevent disease recurrence and extend survival.

DNA vaccine against COVID-19: As research data emerges, it is becoming increasingly clear that the induction of potent and activated T cells may play a critical role in the development of long-term immunity and clearance of virus-infected cells. Initial research is underway and Scancell initiated a Phase 1 clinical trial known as COVIDITY in October 2021.

Moditope^® represents a completely new class of potent and selective immunotherapy agents based on stress-induced post-translational modifications (siPTM). Examples of such modifications are citrullination, an enzyme-based conversion of arginine to citrulline, and homocitrullination (or carbamylation), in which lysine residues are converted to homocitrulline. Expression of peptides containing these modifications have been demonstrated to induce potent CD4 cytotoxic T cells to eliminate cancer. The Directors believe that this platform has the potential to eradicate hard to treat solid tumours.

AvidiMab™ has broad potential to increase the avidity or potency of any therapeutic monoclonal antibody (mAb) including those being developed for autoimmune diseases, as well as cancer. Scancell's development pipeline includes mAbs against specific tumour-associated glycans (TaGs) with superior affinity and selectivity profiles, that have now been further engineered using the Company's AvidiMab™ technology; this confers the Scancell anti-TaG mAbs with the ability to directly kill tumour cells. The mAbs targeting TaGs can also be used to deliver a cytotoxic payload to cancer cells or to redirect T cells.