The National Institutes of Health (NIH) has initiated a clinical investigation of fostamatinib, developed by Rigel Pharmaceuticals, as a potential therapeutic option for patients with sickle cell disease (SCD). The study aims to explore a novel approach to managing this challenging genetic condition that affects over 100,000 Americans and millions worldwide.
Mechanism of Action and Preclinical Promise
Preclinical research has revealed promising mechanisms through which fostamatinib, specifically its active metabolite R406, may benefit SCD patients. The drug works by inhibiting the production of neutrophil extracellular traps (NETs) and affecting platelet function. In laboratory studies using a humanized SCD mouse model, R406 demonstrated significant reduction in platelet ATP secretion and aggregation responses to collagen, without compromising bleeding time.
The drug's mechanism offers a unique advantage by targeting the SYK pathway, which plays a crucial role in red blood cell membrane stability. Dr. David Chertow, a researcher involved in previous fostamatinib studies, noted that the drug's ability to impact the phosphorylation of RBC Band 3 protein could potentially enhance red blood cell membrane stability and reduce sickling.
Addressing an Unmet Medical Need
Sickle cell disease, characterized by rigid, crescent-shaped red blood cells, leads to severe complications including strokes, infections, and vaso-occlusive crises. Current treatment options are limited, making the search for new therapeutic approaches crucial.
"The investigation of fostamatinib represents a potentially important advancement in SCD treatment," states the research team. "The drug's dual action on both platelet function and red blood cell stability could address multiple aspects of the disease's pathophysiology."
Safety Profile and Current Applications
Fostamatinib is already FDA-approved under the brand name TAVALISSE® for treating chronic immune thrombocytopenia in adults. The drug's established safety profile includes manageable side effects such as hypertension, elevated liver function tests, and diarrhea, which are regularly monitored in current clinical applications.
Research Implications
This NIH-led investigation marks a significant step in exploring new therapeutic options for SCD. If successful, fostamatinib could offer a novel treatment approach that addresses both the prothrombotic state and red blood cell abnormalities characteristic of sickle cell disease, potentially providing a much-needed additional treatment option for patients.
