17 January 2023

Avacta Group plc

("Avacta" or "the Group" or "the Company")

Avacta Announces Successful Completion of Fourth Dose Escalation in AVA6000 Phase 1 Clinical Study

Positive safety profile of AVA6000 continues in the fourth cohort

Analysis of six tumour biopsies confirms the tumour targeting potential of pre|CISION^TM technology

Avacta Group plc (AIM: AVCT), a life sciences company developing innovative, targeted oncology drugs and powerful diagnostics announces that AVA6000 continues to show a very favourable safety profile in the fourth dose cohort of the ALS-6000-101 dose escalation phase 1 clinical trial. Additionally, analysis of tumour biopsies obtained from six patients across several cohorts indicates that doxorubicin is being released within the tumour tissue confirming the tumour targeting potential of the pre|CISION^TM technology.

AVA6000 continues to be well tolerated by patients in cohort 4 with a marked reduction in the incidence and severity of the typical toxicities associated with the standard doxorubicin chemotherapy administration. Typical toxicities include alopecia, myelosuppression, nausea, vomiting, mucositis and cardiotoxicity. Importantly, even at the highest dosing levels in cohort 4, equivalent to more than double the normal dose of doxorubicin, the typical drug-related cardiotoxicity of doxorubicin was not observed.

A number of tumour biopsies obtained from patients in different cohorts have also been analysed in order to confirm the release of the active chemotherapy, doxorubicin, in the tumour tissue. This analysis shows that AVA6000 targets the release of doxorubicin to the tumour tissue at therapeutic levels which are much higher than the levels being detected in the bloodstream at the same timepoint.

19 patients with a range of advanced and/or metastatic solid tumours enrolled across four cohorts, have been administered AVA6000 to date. On the basis of the very favourable safety profile of AVA6000 in the study to date, the Safety Data Monitoring Committee (SDMC) has recommended continuation to higher dose cohorts with the aim of identifying a maximum tolerated dose (MTD) necessary to inform the dosing levels for the phase 1b and future studies. The Company expects that it will complete these additional cohorts during the first half of 2023.

Dr Alastair Smith, Chief Executive Officer of Avacta Group plc commented:

"We're delighted with the very positive data emerging from the dose escalation study of our lead pre|CISION^TM tumour targeted therapy AVA6000. The very significant reduction in the usual toxicities, plus the observed release of doxorubicin at significant levels in the tumour tissue, show that the pre|CISION^TM platform has the potential to significantly improve the safety and tolerability of chemotherapies, and other drugs, by targeting their release to the tumour.

"This is extremely encouraging as we work towards realising our vision of "chemotherapy without side effects" to make a meaningful difference to cancer patients' lives.

"We are now in a position to proceed beyond the fourth cohort in the dose escalation study to even higher doses than originally anticipated, which is an unexpected and very positive development. The data being generated in the ALS-6000-101 study are providing detailed insights into the pre|CISION^TM platform which add significant value to the technology and confirm the potential of the pre|CISION^TM platform."

-Ends-

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 ('MAR'). Upon the publication of this announcement via a Regulatory Information Service ('RIS'), this inside information is now considered to be in the public domain.

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About Avacta Group plc - https://www.avacta.com

Avacta Group plc is a life sciences company working to improve people's health and well-being through innovative oncology drugs and powerful diagnostics. Operating through two divisions, Diagnostics and Therapeutics, the Group's mission is to provide professionals and consumers with solutions that improve healthcare, fitness and well-being.

Avacta's Therapeutics Division, a clinical stage oncology drug innovator, is building a wholly owned pipeline of novel Affimer^® immunotherapies and pre||CISION™ tumour targeted chemotherapies. This approach is designed to address the lack of a durable response to current cancer immunotherapies experienced by most patients and reduce the severe systemic toxicities caused by chemotherapies. There are five programmes in the pipeline as well as several global research collaborations and licensing partnerships. Avacta's lead programme, AVA6000, is a preCISION™ tumour-targeted form of the established chemotherapy doxorubicin. AVA6000 is in Phase I clinical trials in patients with locally advanced or metastatic selected solid tumours.

The Affimer^® platform is an alternative to antibodies that has been designed to address many of the drawbacks of antibodies which, despite their shortcomings, currently dominate the immuno-diagnostics and immuno-therapeutics markets.

The pre|CISION™ tumour targeting platform can be used to modify a chemotherapy in order to selectively release the active drug in tumour tissue thereby reducing the systemic exposure that causes damage to healthy tissues. pre|CISION™ modified chemotherapies are designed to reduce the side effects and improve the overall safety and therapeutic potential of these powerful anti-cancer treatments.

Avacta's Diagnostics Division develops and supplies a broad range of in-vitro diagnostic (IVD) solutions. The Division is growing rapidly through an M&A strategy to deliver a global scale IVD business providing market leading solutions for healthcare professionals and consumers to inform treatment and monitor health and well-being. In October 2022, Avacta acquired Launch Diagnostics which serves the hospital pathology laboratory market in the UK and Europe. Avacta Diagnostic's research and development centre in Wetherby, UK uses its proprietary Affimer^® platform to differentiate immunodiagnostic products to provide marketing leading performance.

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About AVA6000

AVA6000 is a novel form of doxorubicin that has been modified with Avacta's pre|CISION™ FAP-activated delivery platform to improve its safety and therapeutic index. AVA6000 has been designed to limit cell penetration of the drug- and therefore its cell killing effect- until it is specifically activated by fibroblast activation protein α (FAP) which is in high concentration in many solid tumours compared with healthy tissues. The resulting reduced exposure of healthy tissues to free doxorubicin has the potential to significantly increase its therapeutic index by reducing the incidence of adverse effects, including cardiotoxicity and myelosuppression.

Anthracyclines such as doxorubicin, a generic chemotherapeutic agent, with a market size that is expected to grow to $1.38bn by 2024[1], are widely used as part of standard of care in several tumour types, but its use is limited by cumulative dose toxicity associated with cardiomyopathy.