Paris, August 14, 2025 – The European Medicines Agency (EMA) has granted orphan drug designation to Sanofi’s rilzabrutinib, a reversible covalent Bruton’s tyrosine kinase (BTK) inhibitor, for the treatment of IgG4-related disease (IgG4-RD). This recognition follows positive Phase 2 study results presented at the EULAR 2025 Congress, where rilzabrutinib demonstrated significant clinical benefit in reducing disease flares and supporting glucocorticoid sparing.

Science Significance

Rilzabrutinib employs TAILORED COVALENCY® technology to selectively inhibit BTK while minimizing off-target effects, a mechanism that may restore immune balance across multiple pathways. In the 52-week Phase 2 trial, patients experienced durable reductions in disease activity, marking a potential new frontier in treating complex, immune-mediated disorders like IgG4-RD.

Regulatory Significance

The EMA’s orphan designation provides incentives including regulatory fee reductions, protocol assistance, and potential market exclusivity upon approval. With rilzabrutinib already holding multiple orphan and fast track designations worldwide, this latest recognition strengthens its regulatory momentum as the drug undergoes parallel reviews in the US, EU, and China for immune thrombocytopenia (ITP).

Business Significance

For Sanofi, this milestone underscores its commitment to immune-mediated rare diseases, strategically aligning its R&D pipeline toward high-impact therapies in underserved markets. Orphan designation enhances the commercial profile of rilzabrutinib, potentially accelerating time-to-market while securing a competitive position in the rare disease drug space..

Patients’ Significance

IgG4-RD is a progressive, relapsing, and organ-damaging condition with limited therapeutic options. By reducing disease flares and lowering dependency on long-term glucocorticoid use, rilzabrutinib could significantly improve quality of life and long-term health outcomes for patients, addressing an urgent unmet medical need.

Policy Significance

This designation aligns with the EU’s policy commitment to support innovation in rare disease therapeutics by incentivizing pharmaceutical companies to advance treatments for conditions that affect fewer than five in 10,000 people. Rilzabrutinib’s recognition reinforces the broader public health priority of fostering equitable access to life-saving therapies for rare patient populations

Transaction Highlights

As rilzabrutinib moves closer to regulatory decisions across multiple regions, Sanofi continues to position itself at the forefront of rare disease innovation. The EMA’s orphan designation for IgG4-RD not only validates the therapy’s scientific promise but also strengthens global efforts to deliver transformative treatments for patients living with devastating, underserved diseases.

Source: Sanofi Press Release