Dr. Fahar Merchant reports

MEDICENNA PRESENTS PRECLINICAL MDNA223 BISKIT DATA AT THE AACR SPECIAL CONFERENCE ON TUMOR IMMUNOLOGY AND IMMUNOTHERAPY

Medicenna Therapeutics Corp. has released new preclinical data characterizing MDNA223, an anti-PD1-IL-2 BiSKIT (bifunctional superkine for immunotherapy), at the 2023 AACR (American Association for Cancer Research) Special Conference in Cancer Research: Tumor Immunology and Immunotherapy held from Oct. 1 to 4, 2023, in Toronto, Canada.

"We are excited to demonstrate the versatility of our superkines and the potential of our next-generation BiSKITs platform, particularly in cold tumours that remain a therapeutic challenge for immunotherapy," said Dr. Fahar Merchant, PhD, president and chief executive officer of Medicenna. "We believe that our dual-functioning BiSKIT candidates, such as MDNA223, are more potent and selective and may have an increased capacity to induce superior CD8+ T-cell responses against tumour cells. These data demonstrate the potential of IL-2 BiSKITs either as monotherapy or in combination with other treatment modalities including cell-based therapies where better effector T-cells are a prerequisite for improving patient outcomes."

MDNA223 is a fusion of Medicenna's IL-2 superkine with an anti-PD1 antibody, designed to maximize anti-tumour response by concurrently facilitating IL-2R pathway stimulation and PD1 checkpoint blockade on the same effector immune cell. The poster presentation includes preclinical data demonstrating that the MDNA223 BiSKIT:

• Showed enhanced IL-2R selectivity and no binding to IL-2R, leading to preferential stimulation of CD8+ T-cells over Tregs in human PBMCs;
• Retained high affinity to PD-1, generating potent blockade of PD-1/PD-L1 mediated exhaustion of T-cells;
• Induced durable proliferation and expansion of CD8+ T-cells in the periphery, and enhanced tumour infiltration of functionally active CD8+ T-cells;
• Demonstrated superior efficacy and survival benefit in multiple syngeneic tumour models, including cold tumours compared with co-administration (combination) of anti-PD1 and IL-2 agonist;
• Synergized with agonist of the STING (stimulator of interferon genes) pathway to enhance tumour inhibition and promote an abscopal effect as demonstrated by shrinkage of the untreated tumour on opposite flank;
• Synergized with STING agonist and enhanced tumour inhibition by abscopal effect;
• Enhanced tumour response while being well tolerated in a step-up dosing setting.

The sum of encouraging preclinical data on MDNA223 highlights the potential of Medicenna's BiSKIT platform to broadly delivery effective therapy to otherwise challenging-to-treat cold tumours. Copies of the poster will be posted to the events and presentations page of Medicenna's website following the conclusion of the meeting.

About BiSKITs and MDNA223

BiSKITs are novel bifunctional superkines for immunotherapy designed to have dual functionality within a single molecule with the potential of improving patient outcomes where other immunotherapies have failed to be effective. One example is MDNA223, an IL-2 superkine fused to an anti-PD1 antibody. MDNA223 is a BiSKIT designed to activate cancer-killing immune cells via the IL-2 receptor while simultaneously preventing their exhaustion by blocking PD-1 signalling. Combining these two functions into a single molecule allows Medicenna to simultaneously modulate both pathways on the same immune cells, also known as cis-targeting.

About Medicenna Therapeutics Corp.

Medicenna is a clinical-stage immunotherapy company focused on developing novel, highly selective versions of IL-2, IL-4 and IL-13 superkines and first-in-class empowered superkines. Medicenna's long-acting IL-2 superkine, MDNA11, is a next-generation IL-2 with superior CD122 (IL-2 receptor beta) binding without CD25 (IL-2 receptor alpha) affinity thereby preferentially stimulating cancer-killing effector T-cells and NK cells. Medicenna's IL-4 empowered superkine, bizaxofusp (formerly MDNA55), has been studied in five clinical trials, including a phase 2b trial for recurrent GBM, the most common and uniformly fatal form of brain cancer. Bizaxofusp has obtained fast-track and orphan drug status from the Food and Drug Administration and FDA/European Medicines Agency, respectively. Medicenna's early-stage BiSKITs program (bifunctional superkine immunotherapies) is designed to enhance the ability of superkines to treat immunologically cold tumours.

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