Novo Nordisk Unveils Positive Phase 3b Results for Mim8 in Hemophilia A: Seamless Switch from Emicizumab Shows Safety, Efficacy, and High Patient Satisfaction
Novo Nordisk presented new findings from its pivotal phase 3b FRONTIER5 clinical trial at the 2025 International Society on Thrombosis and Haemostasis (ISTH) Congress, revealing that patients with haemophilia A—both with and without inhibitors—can be safely and effectively transitioned from emicizumab to the investigational therapy Mim8 (denecimig) without a washout period or loading dose. The study marks a significant step forward in the treatment landscape for haemophilia A, demonstrating not only clinical safety and pharmacokinetic stability, but also strong patient preference for the Mim8 pen-injector delivery system.
Seamless Transition without Safety Compromise
The FRONTIER5 study enrolled 61 adult and adolescent participants aged 12 years and older with haemophilia A, all of whom had previously been receiving emicizumab prophylaxis. In the trial, participants were directly switched to Mim8 without a washout period. The first dose of Mim8 was administered on the same day as their next scheduled emicizumab dose, ensuring continuous prophylactic coverage.
Participants could choose between once-weekly, once every two weeks, or once-monthly Mim8 dosing regimens, regardless of their prior emicizumab dosing schedule. This flexibility in dosing frequencies was designed to reflect real-world patient needs and preferences.
By week 16, steady-state concentrations of Mim8 were reached, and by week 26, the clearance of emicizumab from the body was complete. Importantly, the switch to Mim8 was associated with a sustained increase in thrombin peak levels—indicative of improved clotting potential—without triggering excessive thrombin generation, which could pose safety risks.
According to Dr. Allison P. Wheeler of the Washington Center for Bleeding Disorders in Seattle, “Continuous prophylactic coverage is critical to avoiding breakthrough bleeds in people living with haemophilia. With new non-factor therapeutic options, many patients may feel uncertain about switching treatments. These data are important because they show a switch to Mim8 from emicizumab can be accomplished safely and without a washout period—helping maintain uninterrupted protection against bleeds.”
Strong Safety Profile Reinforces Mim8’s Potential
Mim8’s safety profile was a central focus of the FRONTIER5 trial. Throughout the 26-week study period, the investigational therapy was well-tolerated. There were no thromboembolic events, hypersensitivity reactions, or treatment-emergent adverse events (TEAEs) that led to discontinuation. Additionally, no participants developed neutralizing antibodies to Mim8—a key concern with biological therapies that could undermine long-term efficacy.
These findings are particularly promising for the haemophilia community, where the balance between effective prophylaxis and safety is critical. The absence of major adverse events and the maintenance of steady therapeutic levels throughout the treatment period position Mim8 as a compelling option for both new and experienced patients transitioning from other therapies.
Patient-Centric Delivery: Mim8 Pen-Injector Favored Over Emicizumab System
In addition to clinical efficacy and safety, Novo Nordisk emphasized the importance of the patient experience with Mim8. Results from a Patient-Reported Outcomes (PROs) sub-study of FRONTIER5 indicated a strong user preference for the Mim8 pen-injector over the emicizumab injection system.
Of the 59 participants who completed the PRO assessment, 97% reported a “very strong” or “fairly strong” preference for the Mim8 device. The ease of use was particularly notable—98% found the pen-injector “very easy” or “easy” to use, and 95% said it was “much easier” or “easier” compared to their previous method of administration. Furthermore, all participants (100%) expressed “extreme” or “high” confidence in their ability to correctly use the Mim8 device, and 83% found the injection process itself to be “very easy.”
These findings reflect the growing importance of patient-friendly delivery systems in chronic treatment regimens. Minimizing the burden of administration and increasing patient autonomy can lead to improved adherence, better quality of life, and ultimately, better health outcomes.
Stephanie Seremetis, Chief Medical Officer and Corporate Vice President for Haemophilia at Novo Nordisk, highlighted the broader implications of these findings: “The FRONTIER5 safety and patient-reported outcomes data support Mim8 as a potential future treatment option for people living with haemophilia A and demonstrate our continued commitment to developing innovative, patient-centered therapies. These results provide valuable insight into real-world haemophilia management and confirm that a direct switch from emicizumab is not only clinically feasible but also preferred by patients.”
Broader Clinical Program and Regulatory Pathway
Mim8, a next-generation investigational bispecific antibody, is currently being evaluated across multiple studies within Novo Nordisk’s comprehensive FRONTIER clinical development program. These include trials assessing Mim8’s efficacy and safety in both previously treated and treatment-naïve individuals with haemophilia A, with or without inhibitors.
Novo Nordisk has stated its intention to submit Mim8 for regulatory approval in 2025, contingent on data from the broader FRONTIER program. Additional trial results are expected to be presented at upcoming medical conferences and published in peer-reviewed journals throughout 2025 and 2026.
The clinical development of Mim8 comes at a time of significant innovation in haemophilia care. While traditional factor replacement therapies have been the mainstay of treatment for decades, newer non-factor options like emicizumab—and potentially Mim8—offer improved pharmacokinetics, less frequent dosing, and subcutaneous delivery. Mim8 aims to build on these advances by offering extended dosing intervals with a favorable safety and efficacy profile, thereby addressing unmet needs within the haemophilia A population.
Addressing the Evolving Needs of the Haemophilia Community
With approximately 1 in 5,000 male births affected by haemophilia A globally, the development of therapies that provide consistent bleeding protection, ease of use, and patient satisfaction is paramount. The data presented at ISTH 2025 indicate that Mim8 could become a transformative addition to the treatment landscape, especially for patients looking to simplify their prophylactic regimen without compromising safety or efficacy.
Beyond clinical metrics, Novo Nordisk’s focus on patient-reported outcomes highlights a broader shift in therapeutic development—one that values not only how a drug performs in the lab, but also how it fits into the lives of those who depend on it.
As regulatory submissions move forward in 2025, the haemophilia community—and clinicians alike—will be watching closely. If approved, Mim8 could become a new standard for long-acting, convenient, and patient-preferred prophylaxis in haemophilia A care.
