ALRN-5281

ALRN-5281 is a proprietary, long-acting synthetic peptide and a member of the stapled peptide class. It acts as an agonist of the growth hormone-releasing hormone receptor (GHRHR), thereby stimulating endogenous pulsatile secretion of growth hormone. This mechanism aims to provide a more physiological alternative to direct growth hormone replacement, potentially reducing safety and tolerability issues associated with chronic GH therapy. The drug was originally developed by Aileron Therapeutics (now Rein Therapeutics) using their Stapled Peptide technology platform, which locks peptides into their biologically active conformation for improved stability and pharmacokinetics. ALRN-5281 has been investigated primarily for orphan endocrine disorders such as adult growth hormone deficiency and HIV-associated lipodystrophy, as well as broader metabolic/endocrine conditions. Clinical development reached Phase 1 trials in healthy volunteers but has not advanced further[1][2][3][4][5][7].