Medicenna Therapeutics Corp. announced initiation of enrollment in the combination arm of the Phase 1/2 ABILITY (ABeta-only IL-2 ImmunoTherapY) study evaluating MDNA11, a long-acting, beta-enhanced not-alpha interleukin-2 (IL-2) super-agonist, with Merck?s pembrolizumab (KEYTRUDA®). The combination portion of the study is being conducted as part of the previously announced Clinical Trial Supply and Collaboration Agreement between Medicenna and Merck (known as MSD outside the United States and Canada) and is designed to evaluate the potential for a synergistic effect of MDNA11 with KEYTRUDA® in patients with advanced solid tumors.

In the Phase 1 monotherapy dose escalation and dose evaluation portions of the study, MDNA11 was well tolerated with promising single-agent activity. As of the data cutoff date of October 26, 2023, responses included: one confirmed durable (> 1.5 years) and deep (100% resolution of target lesions) partial response in a heavily pretreated patient with metastatic pancreatic cancer and primary resistance to checkpoint inhibitor (CPI) therapy, one deep (70% resolution of target lesion) unconfirmed partial response in a patient with cutaneous melanoma with secondary resistance to CPI, both of whom continue on therapy and, multiple patients with extended stable disease and/or target lesion reductions. Solid tumors represent 90% of all cancers and although CPI therapies have shown promising advances in some types of immunosensitive cancers, more than 70% 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 super-agonist for treatment of advanced solid tumors. Pre-clinical data published in JITC in 2023 demonstrated that mice receiving both, MDNA11 and checkpoint inhibitors achieved complete tumor control even after multiple rechallenges when compared to either treatment alone, demonstrating the capacity for MDNA11 to sensitize solid tumors to checkpoint blockade. The ABILITY-1 Study is actively recruiting patients with different types of recurrent or metastatic solid tumors at multiple sites in the USA and Australia and is expected to initiate patient enrolment in Canada and South Korea.