Design, synthesis and evaluation of trofinetide prodrug based on diketopiperazine strategy

Trofinetide is the only drug approved worldwide for the treatment of Rett syndrome, a rare pediatric disease. However, its extremely short half-life, large oral dose, high incidence of gastrointestinal adverse reactions, and consequently high treatment costs pose formidable clinical and economic challenges. To address these issues, we employed a diketopiperazine strategy to design a novel class of trofinetide prodrugs, aiming to alter the administration route and optimize its pharmacokinetic properties. Through the determination of solubility and in vitro conversion half-life, and based on the established screening criteria, TFD 10 was selected from the series of qualified compounds as a representative for pharmacokinetic evaluation. TFD 10 exhibited efficient conversion to trofinetide both in vitro and in vivo. Compared to oral administration of trofinetide, subcutaneous injection of TFD 10 markedly prolonged the half-life (6-fold) and substantially increased systemic exposure (40-fold), successfully achieving the design objectives. This study validates the feasibility of this strategy, and TFD 10, as a proof-of-concept lead compound, demonstrates significant potential for further development.