C-terminal telopeptide of type II collagen (CTX-II) (CTX-II)

C-terminal telopeptide of type II collagen (CTX-II) is a specific peptide fragment released into systemic circulation and urine during the proteolytic degradation of type II collagen, the primary structural component of articular cartilage (PubMed: 11132144). It is generated by the action of various proteases, including matrix metalloproteinases (MMPs) and cathepsin K, which break down the extracellular matrix in response to mechanical stress or inflammatory signaling (PubMed: 15593144). While CTX-II is not a therapeutic target that drugs bind to for clinical effect, it is widely recognized as one of the most sensitive biochemical markers for monitoring cartilage turnover and joint destruction (PubMed: 20183118). In clinical research, CTX-II levels are used to assess the progression of osteoarthritis and rheumatoid arthritis, as well as to evaluate the efficacy of chondroprotective agents and anti-inflammatory drugs (PubMed: 24553461). Elevated concentrations of CTX-II in urine or serum are strongly associated with the risk of joint space narrowing and the development of osteophytes seen on radiographs. As a result, it serves as a vital tool for patient stratification in clinical trials and for monitoring the biological response to therapies aimed at preserving joint integrity.

Other names

CTX-IIType II collagen C-telopeptideCross-linked C-telopeptide of type II collagenCartilaps

Not applicable as CTX-II is a degradation product and biomarker rather than a therapeutic target.