On the Interpretation of Rat Carcinogenicity Studies for Human PTH(1‐34) and Human PTH(1‐84)

Two drags have been approved for the treatment of osteoporosis that act by stimulating the formation of new bone--often referred to as bone anabolic agents. These drugs are recombinant human PTH(1-34) (teriparatide), approved in the Americas (Forteo) and in Europe (For-steo), and recombinant human PTH(1-84) [rhPTH(1-84)], approved in Europe (Preotact). Both of these therapeutic agents, which have shown fracture prevention efficacy in clinical trials, have been shown to produce osteosarcomas in long-term carcinogenicity studies in rats. Although the relevance, if any, of the animal findings to patients will not be known with certainty until extensive clinical experience has accrued, it is believed that the risk of osteosarcomas in treated patients is low and that the therapeutic benefits on bone health of these anabolic agents significantly outweigh the theoretical risk of osteosarcoma.