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BIVICTRIX THERAPEUTICS PLC

("BiVictriX" or the "Company" or the "Group")

BiVictriX announces positive data from preclinical study of BVX001

·    BVX001 reported to be well-tolerated and showed a favourable safety profile when compared with Mylotarg™ (gemtuzumab ozogamicin) in models evaluating the risk for neutropenia

·    Encouraging results further support plans to progress BVX001 into the clinic for patients with acute myeloid leukaemia (AML)

·    Data from study provides preclinical validation of the Company's wider Bi-Cygni® platform approach in improving cancer-specific targeting across a range of cancer indications

Alderley Park, 31 January 2023 - BiVictriX Therapeutics plc (AIM: BVX), an emerging biotechnology company applying a novel approach to develop next-generation cancer therapies with improved tolerability and anti-cancer activity, announces positive in vivo data from a toxicity evaluation study with BVX001, BiVictriX's lead programme, compared to gemtuzumab ozogamicin (GO). GO, marketed as Mylotarg™, is the only approved antibody drug conjugate (ADC) indicated for the treatment of acute myeloid leukaemia (AML). One of the significant toxicities of GO is the reduction in normal neutrophil counts in patients with AML. Neutrophils are a form of immune cell and a reduction in the number of these cells heightens the risk of developing potential fatal severe infections and sepsis, a major concern in patients with AML.

BVX001 was reported to be well-tolerated and showed a highly favourable safety profile across two doses of BVX001 (0.3 mg/kg and 3 mg/kg), compared with the reported maximum tolerated dose of GO¹ (0.3 mg/kg) in a CD34-boosted humanised murine model. The results showed that:

-      The proportion of healthy human CD33⁺ myeloid cells in the bone marrow was significantly lower with GO compared to BVX001 at both an equivalent dose to GO (0.3mg/kg) and a 10-fold higher dose (3mg/kg), at seven- and fourteen-days post-injection.

-      The total number of healthy neutrophils and total healthy leukocytes, types of specialised immune cells, were significantly lower with GO compared to the equivalent dose of BVX001, at fourteen days post-injection.

-      The total number of healthy human CD33⁺ cells was significantly lower with GO compared to the vehicle control seven days post-injection.

These results model commonly reported toxicities of GO in clinical practice.

Other observed effects with GO included a non-statistical lower level of healthy early bone marrow progenitor cells at day fourteen post injection, compared to both doses of BVX001. A non-statistical higher proportion of CD7⁺ cells among CD3⁺ T cells in blood at day three post injection was reported with GO, compared to BVX001 and the control vehicle.

Tiffany Thorn, Chief Executive Officer of BiVictriX Therapeutics plc, commented: "Receiving these positive preclinical safety results, soon after identifying a development lead for BVX001, reinforces the superior cancer selectivity of our Bi-Cygni® approach - designing drugs with reduced toxicity on normal cells.  These findings move us another step closer to the clinic and provide further evidence that our first-in-class platform offers the potential to deliver the next generation of highly selective, anti-cancer therapies. Generating data that demonstrates BVX001 was well-tolerated in this in vivo model and showed reduced off-target effects, when compared to the only approved ADC drug addressing AML, puts us in a strong position to break into the market with the goal to offer a novel, game-changing bispecific treatment with better efficacy and improved safety for patients."

This announcement follows the identification of a development lead for BiVictriX's BVX001 programme as announced on 7 December 2022, together with the Company's previously shared in vivo efficacy data for this programme. The Company is now focused on delivering additional in vivo efficacy data to further strengthen the preclinical data package for BVX001, as the Company looks to progress this molecule towards the clinic.

The results from this in vivo toxicity evaluation study will be submitted for publication and will be presented at an upcoming scientific conference.

Background

AML is the most common type of acute leukaemia in adults, for which more targeted, less toxic treatments are needed. Gemtuzumab ozogamicin (GO, brand name Mylotarg™) is an approved therapy in AML which targets CD33⁺ expressing cells, these include CD33⁺ AML cancer cells and CD33⁺ healthy immune cells, the recognised side effects of which include neutropenia, low blood count and infection - which can be fatal.

BiVictriX's bispecific Bi-Cygni® therapeutic approach bypasses this known limitation of targeting a single protein expressed on both healthy and cancer cells by selectively targeting "twin antigen fingerprints" which are uniquely expressed on cancer cells. The Company's proprietary library of "twin antigen fingerprints" enables the fingerprints to be selectively targeted while leaving healthy cells alone. Through the BVX001 programme, BiVictriX is selectively targeting the cancer specific twin antigen fingerprint, CD7⁺CD33⁺, which is found to be expressed on AML cancer cells, but largely absent from healthy cells throughout the body. 

Building on the initial promising in vivo efficacy data seen with BVX001 and presented within the Company's Admission Document, BiVictriX has now successfully demonstrated, in a head-to-head comparison with a commercially available ADC, that the Company's Bi-Cygni® ADC approach offers the potential to overcome some of the drug-induced life-threatening side effects linked to bone marrow toxicity that have been reported with ADCs in the clinic, such as GO.

Ends

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About BiVictriX Therapeutics plc

BiVictriX is a UK-based drug discovery and development company which is focused on leveraging clinical experience to develop a new class of highly selective, next generation cancer therapeutics which exhibit superior potency, whilst significantly reducing treatment-related harmful side effects.

The Company utilises a first-in-class approach to generate a proprietary pipeline of Bi-Cygni® therapeutics which are designed to selectively target cancer-specific antigen pairs, or "twin antigens fingerprints", on tumour cells, which are largely absent from healthy cells. Whereas this concept has been validated in a clinical diagnostic setting to support the diagnosis and monitoring of haematological cancers, it has not yet been widely used in a therapeutic setting, where it offers the opportunity to be a game-changing approach to cancer care.

BiVictriX has identified a diverse panel of novel cancer-specific "twin antigens fingerprints" across a broad range of cancer indications. The Company is using these novel twin antigens to develop more effective and safer therapeutics to target cancers that are expected to constitute orphan indications and areas of high unmet medical need.

Find out more about BiVictriX online at www.bivictrix.com.