Image from Graham Beards
Platelets (blue) surrounded by red blood cells
The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to PRN1008 for the treatment of patients with immune thrombocytopenia (ITP).
PRN1008 is an oral, reversible, covalent Bruton’s tyrosine kinase (BTK) inhibitor being developed by Principia Biopharma, Inc.
Principia is conducting a phase 1/2 trial (NCT03395210) to evaluate the safety and efficacy of PRN1008 in patients with ITP.
Results of preclinical research with PRN1008 in ITP were presented at the 2017 ASH Annual Meeting.
There, researchers reported that PRN1008 significantly reduced platelet loss in a mouse model of ITP.
The team found the BTK inhibitor could diminish platelet loss in two ways:
- By reducing platelet destruction via inhibition of autoantibody/FcγR signaling in splenic macrophages
- By reducing autoantibody generation through inhibition of B-cell activation and maturation.
The researchers also assessed the effects of PRN1008 and ibrutinib on platelet function in samples from healthy volunteers and ITP patients.
Samples were treated with one of the two BTK inhibitors, and platelet aggregation was induced by platelet agonists.
Unlike ibrutinib, PRN1008 did not impact platelet aggregation in healthy volunteer or ITP patient samples.
About orphan designation
The FDA grants orphan designation to products intended to treat, diagnose, or prevent diseases/disorders that affect fewer than 200,000 people in the United States.
The designation provides incentives for sponsors to develop products for rare diseases. This may include tax credits toward the cost of clinical trials, prescription drug user fee waivers, and 7 years of market exclusivity if the product is approved.