Protherics PLC, the international biopharmaceutical company focused on critical care and cancer, announces that it has commenced the submission of a rolling Biologics License Application (BLA) for Voraxaze with the Food and Drug Administration (FDA) in the US. This marketing application is being made for the interventional use of Voraxaze for the rapid and sustained reduction of methotrexate (MTX) in patients who have toxic MTX levels due to impaired renal function.

Voraxaze contains an enzyme that breaks down MTX, a commonly used cancer drug. It is an investigational new drug that is available in the US under a Treatment Protocol for patients receiving high dose MTX (? 1g/m2) who are experiencing, or at risk of, MTX toxicity. High dose MTX is used to treat or prevent the recurrence of certain types of cancer. Patients are considered at risk of MTX toxicity if they have impaired renal function, which can lead to a delay in MTX elimination, or have evidence of delayed elimination based on MTX levels. Voraxaze is also available in Europe and elsewhere outside the US on a named patient basis.

The development program for interventional use of Voraxaze has been granted Fast Track designation by the FDA, enabling the submission of the licensing application in sections rather than all components simultaneously. The Voraxaze rolling BLA commenced today with the submission of a pre-clinical data module. The remaining two modules containing the CMC (chemistry, manufacturing and control) and clinical data are scheduled for submission within the next 12 months, as stipulated by the FDA. Protherics intends to seek a Priority Review, reducing the time for the BLA review from 10 to 6 months from submission of the final part of the application. This would allow a potential marketing approval in US in 2010. Protherics estimates that the global market potential for Voraxaze, for interventional use, is approximately $25-50m per annum.

Andrew Heath, chief executive of Protherics, commented, "The initiation of the Voraxaze BLA submission represents a significant milestone towards enhancing our portfolio of niche, specialty pharmaceutical products. Approval by the FDA would provide an excellent opportunity for us to promote and sell this important product in the US, alongside CroFab and DigiFab when their US marketing rights are returned to us in 2010."

Protherics is a leading international biopharmaceutical company focused on specialist products for critical care and cancer.

Methotrexate is a widely used anti-cancer drug which is often used in high-doses (>1g/m2) in certain types of cancer.