Carboxyl Terminal Peptide (CTP) is a naturally-occurring human peptide evolved to provide the Human Chorionic Gonadotropin (hCG) with the longevity required for maintaining pregnancy. hCG has a long half-life due to a unique CTP comprised of 28 amino acids and four potential O-linked oligosaccharides. These O-linked oligosaccharides add flexibility to the fused protein and decrease its hydrophobicity, enabling lower renal and hepatic clearance and increased circulatory half-life.
Preclinical and Clinical studies show that the CTP technology appears to be safe and effective in extending the serum half-life of all proteins tested to date. The safety and efficacy of CTP have also been validated by the marketing approval of Merck’s long-acting fertility drug Elonva® (FSH-CTP) in 2010 for the European market and the recently approved OPKO Biologics long-acting hGH, NGENLA,for the treatment of children and adolescents. Both drugs replace daily injections with a single weekly treatment, improving patients’ quality of life and compliance.
CTP was discovered by researchers at Washington University in St. Louis and is exclusively licensed to OPKO Biologics for all proteins and peptides, except for four endocrine hormones that are licensed to Merck & Co. OPKO applies this technology to successfully extend protein half-life, and to reduce the frequency of biotherapeutic injections.