UK drug development company Protherics has been forced to withdraw its marketing application in the USA for Voraxaze, a drug to treat side effects caused by cancer chemotherapy, after the Food and Drug Administration asked for more information on manufacturing.

This is the second delay for one of Protherics pipeline drugs in as many weeks, coming after its partner for sepsis treatment CytoFab, AstraZeneca, that it will have to carry out another Phase II study which could delay the project by almost two years. Shares in the company fell nearly 14% this morning to 70 pence.

Voraxaze (carboxypeptidase G2) is Protherics’ first product that will be sold by an in-house sales team, and is intended for use alongside methotrexate, a chemotherapy drug with broad applications across a range of cancers. It prevents blood concentrations of the drug rising too high in patients who struggle to eliminate the drug, usually as a result of impaired renal function.

At present there is no such treatment available on the market, and Protherics estimates that Voraxaze could be pitching at a market of up to $200 million a year. The drug has been filed for approval in Europe too, and Protherics is hoping for approval there in the first half of 2007.

Protherics said that is hopeful of securing fast-track review from the FDA, which would mean that approval could be granted in the USA from the second half of 2008, rather than the second half of 2007 as originally forecast.