Dr. Fahar Merchant reports

MEDICENNA PRESENTS PROMISING PRECLINICAL DATA FROM ITS FIRST-IN-CLASS TUMOR TARGETED AND CONDITIONALLY ACTIVATED ANTI-PD-1-IL-2 BIFUNCTIONAL SUPERKINE AT THE ANNUAL 2025 AACR MEETING

Medicenna Therapeutics Corp. has presented new preclinical data from MDNA113, its first candidate from the BiSKIT (bifunctional superkine immunotherapies) platform, at the 2025 annual meeting of the American Association for Cancer Research in Chicago, Ill.

"Our MDNA113 program continues to generate encouraging preclinical data that underscores its potential as a first-in-class immunotherapy for immunologically cold tumours," said Fahar Merchant, PhD, president and chief executive officer of Medicenna. "MDNA113 is uniquely differentiated against competing anti-PD-1-IL-2 therapies, with an optimized safety and efficacy profile that leverages its clinically validated pharmacology and novel IL-13 targeting approach. Not only are we observing compelling anti-tumour activity in IL-13Ra2 positive tumours but also signs of enhanced memory that may support durable responses. Commercial interest for bispecific anti-PD-1 therapies is gaining momentum, with several recent transactions validating this emerging class of immunotherapies with the potential to offer new hope to millions of cancer patients worldwide."

MDNA113 is based on the company's IL-2 and IL-13 superkine platforms, the former being used to develop MDNA11, a long-acting IL-2 super agonist, which has demonstrated durable single agent anti-tumour activity in the continuing phase 1/2 Ability-1 study of patients with advanced solid tumours.

Key highlights from the presentation are:

• Cis-binding maximizes synergy between immune checkpoint blockade and IL-2R activation on the same CD8+ T effector cells for optimal tumour cytotoxicity;
• MDNA113 retains PD-1/PDL-1 blockade while exhibiting attenuated IL-2R signalling that is restored upon cleavage by tumour-specific proteases in the tumour microenvironment;
• Preferential tumour localization and retention of MDNA113 in the TME for at least 72 hours in mice implanted with tumours;
• IL-13SK masking of IL-2SK in MDNA113 enhances tolerability and attenuates IL-2SK induced peripheral lymphocyte expansion in mice;
• MDNA113 inhibits MC38/IL-13Ra2 tumour growth in mice and promotes memory response against tumour rechallenge with 100-per-cent protection observed with complete responders;
• MDNA113 enhances infiltration of functionally active CD8+ T cells over NK cells and tregs in different tumour models;
• The combination of MDNA113's tumour targeting and conditional activation represents a uniquely differentiated and potentially superior alternative to other anti-PD-1-IL-2 bispecifics currently in development.

A copy of the poster and related slide deck are available on the scientific presentations page of Medicenna's website.

About MDNA113

MDNA113 is a novel, first-in-class tumour-targeted and tumour-activated bifunctional anti-PD1-IL-2 superkine with exceptionally high affinity for IL-13Ra2 without binding to the functional IL-13Ra1. IL-13Ra2 is overexpressed in a wide range of solid tumours, including cold tumours with minimal to no expression in normal tissues. IL-13Ra2 expressing tumours also have abundant matrix metalloprotease in the tumour microenvironment that may efficiently activate MDNA113. IL-13Ra2 expression is associated with poor clinical outcome in multiple tumour types including prostate cancer, pancreatic cancer, ovarian cancer, liver cancer, breast cancer and brain cancer, with an annual worldwide incidence of over two million.

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 affinity toward CD122 (IL-2 receptor beta) and no CD25 (IL-2 receptor alpha) binding, 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 enrolling over 130 patients, 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 high-affinity IL-2b biased IL-2/IL-15 superantagonists, from its MDNA209 platform, are being evaluated as potential therapies for autoimmune and graft versus host diseases. Medicenna's early-stage BiSKITs (bifunctional superkine immunotherapies) and the T-Mask (targeted metalloprotease activated superkine) programs are designed to enhance the ability of superkines to treat immunologically cold tumours.

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