SPD535

SPD535 is an investigational small molecule developed by Shire as a second-generation platelet-lowering agent for the treatment of essential thrombocythemia (ET). It was designed as an analogue of anagrelide (Agrylin) with the intent of maintaining the efficacy of platelet reduction while potentially offering an improved safety profile. The drug's primary therapeutic effect is mediated through the inhibition of megakaryocyte maturation and polyploidization, which leads to a decrease in the production of platelets. Like its predecessor, SPD535 also functions as an inhibitor of phosphodiesterase 3 (PDE3), an activity associated with cardiovascular side effects such as tachycardia. Clinical development of SPD535 reached Phase 2, but the program was terminated by Shire in 2007 following a review of the clinical data and the drug's overall profile.

Other names

second-generation anagrelideanagrelide analogue