Abstract Background: Conventional IgG-based antibody-drug conjugates (ADCs) face major limitations, including heterogeneous drug-to-antibody ratios (DAR), variable pharmacokinetics, limited tumor penetration, and linker instability that can lead to off-target toxicity. To overcome these challenges, Sonnet has developed a non-IgG peptide drug conjugate (PDC) platform that enables precise drug loading and improved distribution. SON-5010 is the first proof-of-concept PDC generated using this approa