Sanofi’s Rilzabrutinib Gets FDA Orphan Drug Status for Rare Diseases

The US Food and Drug Administration (FDA) has granted orphan drug designation to rilzabrutinib, an investigational, novel, advanced, oral, reversible Bruton’s tyrosine kinase (BTK) inhibitor, for two rare diseases, warm autoimmune haemolytic anaemia (wAIHA) and IgG4-related disease (IgG4-RD). There is still a significant unmet medical need for these two rare diseases, and neither have any currently approved medicine. FDA grants orphan drug designation to investigational therapies addressing rare medical diseases or conditions that affect fewer than 200,000 people in the US.

Karin Knobe, MD, PhD, global head of development, rare diseases, said “Orphan drug designation for these two rare, immune-mediated conditions validates our ongoing commitment to pursuing potential first- and best-in-class medicines for diseases that affect small populations but persist with unmet medical need. Our continued exploration of rilzabrutinib across multiple indications speaks to our belief in its potential for multi-immune modulation, as well as our belief in supporting treatment options, no matter how rare a condition.”

Rilzabrutinib is currently under regulatory review in the US, the EU, and China for its potential use in immune thrombocytopenia (ITP). The target action date for the FDA regulatory decision for ITP, which was granted fast track designation, is August 29, 2025. Rilzabrutinib also received orphan drug designation for ITP in the US, EU, and Japan.

Results from a phase 2b study on wAIHA presented at ASH 2024 (clinical study identifier: NCT05002777) demonstrated that treatment with rilzabrutinib showed clinically meaningful outcomes on response rate and disease markers.

In IgG4-RD patients, results from a phase 2a study (clinical study identifier: NCT04520451) showed treatment with rilzabrutinib for 52 weeks led to reduction in disease flare, other disease markers, and glucocorticoid sparing. More detailed results will be shared at a forthcoming medical meeting.

The safety profile of rilzabrutinib in both studies was consistent with previous studies.

Rilzabrutinib is an investigational, oral, reversible, BTK inhibitor that has the potential to be a first- and best-in-class treatment of several immune-mediated diseases. BTK, expressed in B cells, macrophages, and other innate immune cells, plays a critical role in inflammatory pathways and multiple immune-mediated disease processes. With the application of Sanofi’s Tailored Covalency technology, rilzabrutinib can selectively inhibit the BTK target while potentially reducing the risk of off-target side effects. Based on its ability to drive multi-immune modulation, rilzabrutinib holds great promise in the treatment of multiple clinical indications.

Affecting one to three people out of 100,000 in the US each year, wAIHA is a rare, potentially life-threatening, autoimmune disorder where autoantibodies lead to the premature destruction of the body’s own red blood cells (haemolysis). People living with wAIHA may experience debilitating fatigue, thromboembolism, dizziness, palpitations, and shortness of breath as the rate of production of new red blood cells in their bone marrow cannot compensate quickly enough for premature destruction of red blood cells.

IgG4-RD affects approximatively eight out of 100,000 adult patients in the US each year and is a rare, progressive, relapsing, chronic fibro-inflammatory condition which can manifest in almost every organ and can lead to organ damage and irreversible dysfunction with a sometimes-fatal outcome.

ITP is a rare, complex autoimmune disorder characterized by low platelet counts (less than 100,000/µL) resulting from both increased platelet destruction and decreased platelet production. Beyond bruising and bleeding, which can include potentially life-threatening episodes like intracranial haemorrhage, people living with ITP may experience arterial or venous thrombosis, which can result from the ITP itself, from other medical comorbidities, or may also be associated with the use of certain other ITP treatments. Additionally, people living with ITP often experience easily overlooked symptoms that can significantly impair their quality of life, such as unexplained fatigue, anxiety or depression, and cognitive impairment.

Optimize Your trial insights with Clival Database.

Are you exhausted from the uncertainty of trial insights pricing? Clival Database ensures the clarity in the midst of the global scenario for clinical trials to you.

Clival Database is one of the best databases that offers an outstanding number of clinical trial data in terms of 50,000+ molecules and from primary regulatory markets as well as new entrants like Indian and Chinese markets.

With Clival, you get accurate positioning of historical sales data, patent database, company profiling, safety & efficacy, and prediction of launch of new innovative molecules helping you to align your research and driving down the cost.

To add value, we further break down our analytics for you so that improving your operational effectiveness; optimizing your clinical trials; and offering you accurate and high-quality data at lowest possible prices becomes possible.

Elevate your trial success rate with the cutting-edge insights from Clival database.

Check it out today and make more informed sourcing decisions! Learn More!