Lilly's Forteo gets backing for treatment of osteoporosis in USA

Eli Lilly's recombinant parathyroid hormone drug Forteo (teriparatide)has been recommended for approval as a treatment for osteoporosis in post-menopausal women by a US Food and Drug Administration advisory committee. However, although the panel voted unanimously in favor of the female indication, it was split five to five on whether Lilly had demonstrated the efficacy of the drug in building bone mass in men with the disease.

In addition, the committee had some concerns about animal data showing that Forteo had increased the risk of a type of bone cancer, osteosarcoma, in rats. Lilly representatives told the panel meeting that primate studies had not replicated these findings, and argued that key inter-species differences meant the findings in rats were unlikely to predict an increased risk in humans. For example, the rats studied by Lilly had received the drug for their entire lifespan, while the firm recommends that Forteo be used for a maximum of two years. Opinion was split on whether Forteo should be reserved for second-line use or was suitable as a first-line treatment option. Suggestions made by the panel included additional long-term studies of the drug, as well as the setting up of a registry to monitor patients who receive it, according to a Reuters report.

Analysts see Forteo as a significant new product for Lilly as the firm weathers the loss of patent protection for its antidepressant Prozac (fluoxetine; Marketletters passim), with some estimating that peak sales for the drug could reach around $700 million a year. If approved, Forteo will bolster Lilly's franchise in osteoporosis, currently headed by the selective estrogen-receptor modulator Evista (raloxifene) which achieved sales of $167 million in the second quarter (Marketletter July 30). The company has also just initiated a clinical trial comparing Evista with the market-leading osteoporosis drug on the USA, Merck & Co's Fosamax (alendronate), which saw its second-quarter sales leap by more than 50% to $490 million.