Oxford GlycoSciences Plc has submitted an amendment to its New Drug Application (NDA) for Zavesca to the U.S. Food and Drug Administration (FDA).

The FDA stated that the original NDA, submitted in August 2001, might only be approved if a number of issues were addressed and further clinical studies were conducted to provide sufficient support for the safety and efficacy of Zavesca. Following an End-of-Review meeting in September 2002, the FDA indicated that it believed that management of benefit/risk ratio could be achieved through restricted use of the drug.

OGS believes that the amendment to the NDA addresses the FDA's comments. It includes data that were gathered after the original NDA submission and that were part of the submission to the European regulatory authorities. The FDA has informed OGS that it considers this submission a Complete Response to the Action Letter received in June 2002 and that a further review cycle has begun.

David Ebsworth, Chief Executive Officer of OGS said, "We are committed to gaining regulatory approval in the US. We are confident that the information now supplied provides evidence that a positive benefit/risk ratio can be achieved for Zavesca. We look forward to a response from the FDA on this latest submission."

Zavesca received EU marketing approval in November 2002 for the treatment of patients with mild to moderate type 1 Gaucher disease for whom enzyme replacement therapy is unsuitable. The product was launched in the UK on 3 March by Actelion Ltd. under the terms of a worldwide licensing agreement (with the exception of Israel). A named-patient program is also in place, which allows commercial access to the drug through an international pharmacy, if so permitted by local regulations. Actelion expects to begin making Zavesca available throughout the European Union in the coming months.