US orphan drug designation aims to encourage the development of drugs involved in the diagnosis, prevention or treatment of a medical condition affecting fewer than 200,000 people in the country. Among other things, the designation grants US market exclusivity to a drug for a particular indication for a seven-year period if the sponsor complies with certain FDA specifications.
In 2004, investigators reported that in a phase II single agent study, 43% of patients treated with Nexavar (sorafenib) experienced stable disease for at least four months and an additional 9% of patients experienced tumor shrinkage. The toxicity profile of Nexavar was similar to previously reported safety analysis in patients with renal cell carcinoma.
A phase III trial of Nexavar administered as a single agent is ongoing. It is designed to measure differences in overall survival, time-to-symptom progression and time-to-tumor progression of Nexavar versus placebo in liver cancer patients.
A randomized phase II trial for liver cancer patients to evaluate the efficacy of Nexavar in combination with the chemotherapeutic agent doxorubicin is also ongoing.