Dr. Fahar Merchant reports

MEDICENNA ANNOUNCES FIRST PATIENT DOSED IN ABILITY-1 STUDY OF MDNA11 IN COMBINATION WITH KEYTRUDA(TM) (PEMBROLIZUMAB) IN PATIENTS WITH ADVANCED SOLID TUMORS

Medicenna Therapeutics Corp. has dosed the first patient in the combination arm of the phase 1/2 Ability (a beta-only IL-2 immunotherapy) study evaluating MDNA11, a long-acting, beta-enhanced not-alpha interleukin-2 (IL-2) superagonist, with Keytruda (pembrolizumab). The combination portion of the study is designed to evaluate the potential for a synergistic effect of MDNA11 with Keytruda in patients with advanced solid tumours.

"Dosing the first patient in the combination arm with MDNA11 and Keytruda is a significant milestone for Medicenna and are excited with the progress of our novel IL-2 superkine," said Dr. Fahar Merchant, PhD, president and chief executive officer of Medicenna. "By combining MDNA11 with Keytruda, we are building upon the promising data generated to date by MDNA11 as a single agent. Targeting the PD1/PD-L1 pathway in addition to MDNA11's differentiated mechanism of action is expected to further stimulate and restore the patient's immune system, which should result in improved anti-tumoral activity and patient outcomes. We are thrilled to enter this new phase of development of MDNA11 and further demonstrate its potential in combination with the world's bestselling drug."

Solid tumours represent 90 per cent of all cancers and although CPI therapies have shown promising advances in some types of immunosensitive cancers, more than 70 per cent of patients do not respond to or become resistant to such therapies. MDNA11, with its uniquely differentiating beta-enhanced not-alpha features, continues to be a potential best-in-class next-generation IL-2 superagonist for treatment of advanced solid tumours. Preclinical data published in JITC in 2022 demonstrated that mice receiving both MDNA11 and checkpoint inhibitors achieved complete and sustained tumour control even after multiple rechallenges, demonstrating the capacity for MDNA11 to sensitize solid tumours to checkpoint blockade.

The Ability-1 study is actively recruiting patients with different types of recurrent or metastatic solid tumours at multiple sites in the United States, Canada, Australia and South Korea and is expected to initiate patient enrolment in Europe. Preliminary results from both the monotherapy expansion and combination escalation and expansion arms of the Ability-1 study will be available in H1 and H2 2024.

About the Ability-1 study

The Ability-1 study (NCT05086692) is a global, multicentre, open-label study that assesses the safety, tolerability, pharmacokinetics, pharmacodynamics and anti-tumour activity of MDNA11 as monotherapy or in combination with pembrolizumab (Keytruda). In the combination dose escalation of the phase 2 study, approximately six to 12 patients are expected to be enrolled and administered ascending doses of MDNA11 intravenously once every two weeks in combination with Keytruda. This portion of the study includes patients with a wide range of solid tumours with the potential for susceptibility to immune modulating therapeutics. Upon identification of an appropriate dose regimen for combination, the study will proceed to a combination dose expansion cohort.

About MDNA11

MDNA11 is an extensively engineered long-acting recombinant IL-2 superkine fused with human albumin. MDNA11 has complete abrogation of IL-2 receptor alpha binding and is the only IL-2 therapy in clinical development with enhanced binding to the intermediate affinity receptor (beta-gamma). These changes enable effective expansion and activation of anti-tumour CD8+ effector and NK cells while avoiding excessive stimulation of immunoinhibitory Treg cells or side-effect-inducing endothelial cells, as well as ensuring retention in the tumour and tumour-draining lymph nodes. These changes vastly increase efficacy and therapeutic index over the predecessor drug aldesleukin. MDNA11 is currently being evaluated in the phase 1/2 Ability-1 study as both a monotherapy and in combination with the PD-1-blocking antibody pembrolizumab (Keytruda).

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 (glioblastoma), 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 (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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