Tesaglitazar, a dual PPAR-α/γ agonist, hamster carcinogenicity, investigative animal and clinical studies

Area of Science:

• Pharmacology
• Toxicology
• Carcinogenicity Studies

Background:

• Tesaglitazar is a dual peroxisome proliferator-activated receptor (PPARα/γ) agonist.
• Initial hamster studies suggested potential links between tesaglitazar and liver hemangiomas/hemangiosarcomas.

Purpose of the Study:

• To investigate the potential carcinogenicity of tesaglitazar in hamsters.
• To elucidate the mechanisms behind observed neoplastic findings in liver tissues.

Main Methods:

• A two-year carcinogenicity study in hamsters with interim necropsies.
• In vivo and in vitro endothelial cell (EC) proliferation assays.
• Immunohistochemistry and gene expression analyses for cellular stress and VEGF.
• Assessment of circulating vascular endothelial growth factor (VEGF) levels.

Main Results:

• Tesaglitazar treatment caused hepatocellular hypertrophy and carcinoma, typical of exaggerated PPARα activity in rodents.
• No increased hemangiosarcoma frequency was observed.
• Increased sinusoidal dilatation and hemangiomas occurred at the highest dose.
• No increased EC proliferation was detected; however, increased cellular stress and VEGF expression were noted in the liver.
• Circulating VEGF increased in hamsters but not in patients.

Conclusions:

• Tesaglitazar does not induce hemangiosarcomas in hamsters.
• Observed vascular changes in the liver are likely due to exaggerated PPARα pharmacology and cellular stress, not direct tumor promotion.
• Findings support the safety of tesaglitazar regarding hemangiosarcoma risk in clinical applications.