Additional Advances in Hemophilia Research and Clinical Trials With Robert F. Sidonio, Jr., MD, MSc

In the rapidly evolving treatment landscape of hemophilia, real-world experience and careful patient selection are continuing to shape day-to-day practice. Robert Sidonio, Jr., MD, MSc, Professor of Pediatrics and the Medical Director of Hemophilia at the Georgia Center for Bleeding and Clotting Disorders, Children’s Healthcare of Atlanta, recently served as co-chair of i3 Health’s symposium and online activity, Raising the Bar for Hemophilia Management. In this interview, he sits down again to share how continual guidance is impacting hemophilia management and outcomes.

Updates in Treatment Implementation

While there haven’t been any significant updates in hemophilia treatment over the last six months, Dr. Sidonio notes that clinicians continue to gain new knowledge and experience about how to optimize use of current treatments.  “The field is constantly evolving, and we want to continue to learn from things and not just be static,” he says. He also underscores a key reassurance for clinicians following the newer wave of therapies: “What’s important is that we haven’t seen any concerns with any of these novel medications.” 

Where the field is sharpening, he explains, is implementation—particularly for rebalancing approaches. “What we have learned is that it’s important that there are certain guardrails in how you manage patients, particularly with the rebalancing agents, and what dosing to use for those rebalancing agents.” Looking ahead, he remains optimistic about near-term progress: “Certainly, we’re hopeful that 2026 will bring approval for at least one more new medication for hemophilia.”

Inhibitors: Challenges and Emerging Mitigation Strategies 

Inhibitor development remains one of the most pressing challenges in hemophilia, with a limited toolset available to proactively reduce inhibitors. Dr. Sidonio highlights a recently completed study of rurioctocog alfa, a pegylated version of a recombinant factor VIII product, that may help to expand the toolbox. Patients experienced a potentially meaningful reduction in inhibitor rates, particularly among very young patients. Dr. Sidonio explains, “When you look at the number of young children or babies who developed inhibitors, it was a low rate of 11%, which is below the typical baseline of around 20% to 30%.” For clinicians, that signal, if reproduced and contextualized, could matter in early-life FVIII exposure decisions. 

The Atlanta Protocol

For patients who develop inhibitors, Dr. Sidonio discusses ongoing work evaluating an institutional approach called the Atlanta Protocol. “You take a non-factor therapy, emicizumab, and you combine it with factor VIII to induce tolerance,” he explains, with a typical regimen of approximately 100 units per kilo, three times a week. 

Importantly, he previews a dosing insight that may influence immune tolerance induction (ITI) thinking within this approach: “One thing that we learned about the Atlanta Protocol is that low doses of factor VIII are not as good as higher doses in inducing tolerance or getting rid of the inhibitor. He cautions on timelines familiar to anyone running trials: “we should have some interim analysis published soon, but like in most clinical trials, there’s still a few years left before we can complete the trial.”

Personalizing Therapy in a “Golden Age” of Options 

With multiple mechanisms and delivery models available, Dr. Sidonio frames current practice as unusually flexible: “Patients with hemophilia have so many options now. It’s sort of a golden age of hemophilia care and therapy.” He lists the breadth that clinicians now juggle: “Whether it’s using a bispecific antibody, extended ultra-long half-life factor VII product, or one of the many new rebalancing agents, anti–tissue factor pathway inhibitor (TFPI) agents, or small interfering RNA products, there are plenty of options available for patients.” 

That abundance, he argues, enables meaningful preference-sensitive care: “It allows people to have their therapy tailored and to have a little bit of choice in their treatment.” He also emphasizes the practical value of alternatives when first-line choices fail: “It’s nice to have a few different options, because sometimes you do need those options, and it’s nice to have backup plans if the typical gold-standard treatment isn’t working for you.”

On gene therapy, he describes an uneven trajectory: “We saw the version 1 for hemophilia B, and it looks really good. For hemophilia A, it’s been a little disappointing that we haven’t seen the uptake.” He returns to a patient-centered north star: “It’s important that if patients want something, they’ll have it prescribed to them and they’ll use it,” and he hopes that future products track toward the considerations that patients seek. 

Bleeding Disorders Awareness Month

During Bleeding Disorders Awareness Month, Dr. Sidonio urges the community to modernize its mental model of risk. He observes that awareness efforts often spotlight the most severe phenotype but notes that many patients with severe disease are now considered non-severe. As a result, he notes the importance of reframing the models to drive attention to all levels of severity. He underscores the inclusion of gender-based equity in that expanded focus, highlighting a focus on the smaller populations of women and girls with hemophilia.

Importance of Education 

Reflecting on the value of educational opportunities, Dr. Sidonio notes that the i3 Health activity distills an immense amount of scientific effort: “We’re doing this presentation in 60 minutes, but it encompasses 10 years and millions of dollars of efforts and time.” He believes the activity serves as a vital benchmark for how far the field has come: “I think it’s nice for us to be able to summarize all the great work that’s been done in our community, show the riches that we have, and explore the armamentarium that we have in caring for patients with hemophilia.”

Key Takeaways

• Even without major headline changes, clinical practice is tightening around guardrails for newer therapeutic approaches.

• Inhibitor mitigation remains a central challenge; a completed trial cited a low rate of inhibitors in young children.

• For inhibitor eradication strategies like the Atlanta Protocol, interim data suggest that low doses of factor VIII are less effective than higher doses for inducing tolerance.

• Therapeutic choice is expanding rapidly as the field enters a golden age of hemophilia care and therapy, enabling tailoring, patient preference alignment, and backup strategies.

• Awareness efforts should broaden beyond severe male phenotypes to include moderate and mild phenotypes and females with hemophilia.

About Dr. Sidonio

Robert F. Sidonio, Jr., MD, MSc, is a Professor of Pediatrics and the Medical Director of Hemophilia at the Georgia Center for Bleeding and Clotting Disorders, Children’s Healthcare of Atlanta. Dr. Sidonio specializes in the treatment of adolescent girls and women with bleeding disorders, and his research focuses on conducting clinical trials in hemophilia A with and without inhibitors.