Adrenocorticotropic hormone 1-24 (ACTH[1-24]) has a similar effect as endogenous ACTH(1-39) to generate cortisol by targeting the MC2R receptor on the adrenal gland. A new investigational ACTH receptor antagonist drug is being developed to treat diseases of ACTH excess (e.g., Cushing's disease) by binding to the MC2R receptor. Administration of ACTH(1-24) was used in a Phase I clinical study to assess the ability of this drug candidate to suppress the cortisol response to ACTH stimulation. A hybrid immunoaffinity-LCMS assay measuring ACTH(1-24) with a concentration range of 10 to 400 pg/ml was developed to support the study. Consistent and acceptable A&P results were achieved. The assay development and qualification will be discussed.
Keywords: ACTH(1–24); ACTH(1–39); bead conjugation; cosyntropin-stimulation test (CST); fit-for-purpose; hybrid IA-LC-MS.
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