FDA grants orphan drug designation to Adherex Technologies' lead candidate, Eniluracil, which has been designed to improve the effectiveness of fluoropyrimidines or 5-FU in liver cancer chemotherapy. Eniluracil, inhibits the 5-FU breakdown, and thereby increase its effectiveness. Additionally, it reduces its side effects and makes it orally available. However there have been drawbacks identified, and Adherex plans to repeat clinical trials. according to an article at the Triangle Business Journal,

Durham-based Adherex announced in November that it had received approval from the FDA to begin clinical trials of the drug - just months after sealing a drug-exchange deal with GlaxoSmithKline for development rights.
Under the agreement, Glaxo could buy back the drug at a later date, in which case Adherex would be eligible to receive up to $120 million in development and sales milestone payments, plus royalties.

Read more from the Adherex press release, or more on liver cancer from Elsevier and from the National Cancer Institute.