Medicenna's MDNA11 Data Signals a New Front in Cancer Immunotherapy

TORONTO, ON – December 10, 2025 – In the high-stakes world of oncology drug development, where billions in market value can be created or destroyed by a single clinical trial update, few events capture attention like a small biotech delivering data that punches well above its weight. Today, Medicenna Therapeutics Corp. did just that, presenting results for its lead drug candidate, MDNA11, that could reshape treatment paradigms for some of the most difficult-to-treat cancers.

The updated data from the Phase 1/2 ABILITY-1 study, unveiled at the prestigious European Society of Medical Oncology (ESMO) Immuno-Oncology Congress, is not just another incremental step forward. It represents a potential breakthrough for a large and growing population of cancer patients who have exhausted the benefits of today's frontline immunotherapies, positioning Medicenna at the forefront of the next wave of cancer treatment innovation.

A New Benchmark in a Crowded Field

At the heart of the announcement is MDNA11's performance in patients with advanced solid tumors who have already seen their disease progress despite treatment with powerful immune checkpoint inhibitors (ICIs) like KEYTRUDA. This patient group represents a critical unmet need and a major challenge for oncologists.

Medicenna reported that in patients who received MDNA11 as their very next treatment after failing an ICI, the drug achieved an objective response rate (ORR) of 42% and a disease control rate (DCR) of 83%. To put these numbers in perspective, standard second-line therapies for these resistant cancers often yield response rates in the single-digit to low double-digit percentages. For example, in the notoriously difficult-to-treat ICI-resistant melanoma cohort, MDNA11 monotherapy achieved a 38% ORR, a figure that significantly exceeds historical benchmarks.

Even more striking was the combination data. When paired with Merck’s blockbuster KEYTRUDA in patients with microsatellite stable (MSS) endometrial cancer—a group that typically responds poorly to immunotherapy—the combination achieved a 50% ORR. This result substantially surpasses the approximate 38% ORR of the current approved combination standard of care in a similar population, signaling MDNA11’s potential as a best-in-class combination agent.

“The most important message from today’s data is that they absolutely add to the differentiation of MDNA11’s mechanism relative to other next-generation IL-2s,” stated Fahar Merchant, Ph.D., President and CEO of Medicenna. This differentiation is key. MDNA11 is an engineered 'beta-enhanced not-alpha' Interleukin-2 (IL-2) Superkine. It's designed to selectively activate the cancer-killing CD8+ T cells and NK cells of the immune system while avoiding the stimulation of immunosuppressive cells and the severe toxicities, like vascular leak syndrome, that plagued first-generation IL-2 therapies.

De-Risking the Asset, Re-Rating the Company

For a clinical-stage company like Medicenna (TSX: MDNA, OTCQX: MDNAF), where every data release can dramatically alter its trajectory, these results represent a pivotal de-risking event. The strong efficacy, durable responses, and manageable safety profile—with over 90% of adverse events being mild and transient—provide powerful validation for its underlying scientific platform. Dr. Merchant's assertion that MDNA11 is “potentially a de-risked drug candidate” is more than just executive optimism; it's a signal to the market that the asset's biological hypothesis has been confirmed in a difficult human trial setting.

This success comes at a time when the field of next-generation IL-2s has seen both triumphs and high-profile failures. The struggles of competitors have cast a long shadow, making Medicenna’s positive and consistent data all the more significant. By demonstrating clear, durable anti-tumor activity where others have faltered, the company has carved out a compelling competitive position.

From a financial and strategic perspective, this data fundamentally changes Medicenna’s optionality. The company is now in a much stronger position to command favorable terms in potential partnership discussions with large pharmaceutical firms looking to bolster their oncology pipelines. Furthermore, the results significantly enhance its ability to raise capital for the expensive, late-stage pivotal trials required for regulatory approval. The significant improvement in median overall survival for patients who achieved disease control—a median of 120.2 weeks versus 28.6 weeks for those who did not in the monotherapy arm—provides a powerful argument for the drug's value proposition to both regulators and payers.

The Strategic Path to Market

With a manageable safety profile and compelling efficacy, the path forward for MDNA11 now comes into sharper focus. The immediate challenge for Medicenna's leadership is to capitalize on this momentum and design a pivotal trial strategy that is both efficient and robust. Based on the strength of the ABILITY-1 data, the company has clear potential registration pathways in ICI-resistant melanoma and in combination with KEYTRUDA for MSS endometrial cancer.

The impressive combination data with Merck’s KEYTRUDA is particularly strategic. It not only validates MDNA11 as a potent partner for the world’s leading checkpoint inhibitor but also opens the door to deeper collaborations. For a giant like Merck, finding effective agents to overcome resistance to its flagship product is a top strategic priority. Medicenna’s MDNA11 now stands out as a prime candidate.

Furthermore, the company is already thinking beyond late-stage cancer. The recently announced NEO-CYT trial, sponsored by an external group to study MDNA11 in pre-surgery melanoma patients, provides what Dr. Merchant calls “external validation of our approach.” This move into earlier lines of therapy, where patients have healthier immune systems, could dramatically expand the drug's ultimate market potential and clinical impact.

While the journey from a successful Phase 2 trial to a commercial product is long and fraught with risk, the data presented today provides Medicenna with significant leverage and a clear line of sight. For a patient population with few remaining options and for investors searching for the next meaningful advance in immunotherapy, the results from the ABILITY-1 study confirm that MDNA11 is an asset that can no longer be overlooked.