BTG announces data presentation on Voraxaze® (glucarpidase) at the American Society of Clinical Oncology Annual Meeting

WEST CONSHOHOCKEN, Pa., June 4, 2012 /PRNewswire/ -- BTG International Inc., the specialist healthcare company, today announces the presentation of data on Voraxaze^® (glucarpidase) at the American Society of Clinical Oncology (ASCO) Annual Meeting on June 1-5, 2012 in Chicago, Illinois.

BTG received US regulatory approval for Voraxaze^® on 17 January 2012, and the data presented formed a key part of the Biologics License Application (BLA) submission.

Clinical data on the compassionate use of Voraxaze^® for methotrexate toxicity were presented at the Leukemia, Myelodysplasia, and Transplantation poster session (abstract #6530) on Friday June 1, 2012 from 1 - 5pm.   A poster discussion session, presented by Dr. Brigitte Widemann from the National Cancer Institute (NCI), occurred at 4.30pm on the same day.

In the study, 492 patients experiencing renal toxicity and delayed elimination of methotrexate were treated with Voraxaze^® (50 U/kg intravenously) in compassionate use trials conducted in the United States and Europe from November 1993 to June 2009.  The median age of the patients in the study was 18 years (range: 5 weeks to 85 years).  63% were male.  41% had NHL, 30% had osteogenic sarcoma, 23% ALL, and 7% other malignancies.  The median pre-Voraxaze^® methotrexate concentration was 17 micromoles/litre.  76% of patients received a single dose Voraxaze^®, 22% received 2 doses, and 2% received 3 doses.  The first dose of Voraxaze^® was given at a median of 3 days after methotrexate administration.  156 patients had methotrexate concentrations determined by high performance liquid chromatography (HPLC) assay.  At the first measurement (median 15 minutes post-Voraxaze^®) serum methotrexate was reduced by a median of 99% relative to the pre- Voraxaze^® baseline.  At the last measurement (median 40 hours post-Voraxaze^®) median serum methotrexate reduction remained at 99% compared with baseline.  Among 410 patients with pre-Voraxaze^® renal impairment (measured as common terminology criteria for adverse events (CTCAE) Grade 2 or higher), 64% recovered to Grade 0 or 1 after a median of 12.5 days post-Voraxaze^®.

Voraxaze^® was well-tolerated overall; adverse events included paresthesia (2.0%), flushing (1.8%) and headache (1.0%).  8% of patients died within 30 days of Voraxaze^® administration of causes unrelated to Voraxaze^®, as judged by the treating physician.  Voraxaze^® reliably reduced serum methotrexate concentrations by 99% within 15 minutes of administration in patients with impaired renal clearance of methotrexate.

Dr. Brigitte Widemann, MD with the NCI, said: "These data demonstrate that in patients receiving high-dose methotrexate chemotherapy, early recognition of renal dysfunction may warrant intervention with Voraxaze^® to reduce serum methotrexate concentrations. Voraxaze^® is unique in addressing an unmet medical need in the area of methotrexate-treated cancers."

Guenter R. Janhofer MD, PhD, BTG's Chief Medical Officer and Head of Development commented: "BTG is committed to acute care therapies in oncology, as demonstrated in these data presented at ASCO.  This is the first time our comprehensive data, supporting the use of Voraxaze^® in adults and children, were presented in a public forum.  Voraxaze^®, a newly approved therapy, provides a rapid and sustained reduction in plasma methotrexate concentration, helping physicians treat this rare but potentially life-threatening toxicity among patients receiving high-dose methotrexate cancer therapy." 

Indication

Voraxaze^® (glucarpidase) is indicated for the treatment of toxic plasma methotrexate concentrations (>1 micromole per liter) in patients with delayed methotrexate clearance due to impaired renal function. Voraxaze^® is not indicated for use in patients who exhibit the expected clearance of methotrexate or those with normal or mildly impaired renal function because of the potential risk of subtherapeutic exposure to methotrexate.

Safety Information

Serious allergic reactions, including anaphylactic reactions, may occur.  In clinical trials the most common adverse reactions (incidence >/= 1%) were paresthesias, flushing, nausea and/or vomiting, hypotension and headache.

Healthcare providers should note that:

• Methotrexate concentrations within 48 hours following glucarpidase administration can only be reliably measured by a chromatographic method due to interference from metabolites [4-deoxy-4-amino-N10-methylpteroic acid (DAMPA)]. Measurement of methotrexate concentrations within 48 hours of glucarpidase administration using immunoassays can overestimate the methotrexate concentration.
• Leucovorin should not be administered within 2 hours before or after a glucarpidase dose because leucovorin is a substrate for glucarpidase.¹

Reference

1. Voraxaze^® (glucarpidase) prescribing information January 2012

About BTG

BTG is an international specialist healthcare company that is developing and commercialising products targeting critical care, cancer and other disorders. The Group is seeking to acquire new products to develop and market to specialist physicians, and is building a sustainable business financed by revenues from sales of its own marketed products and from royalties and milestone payments on partnered products. For further information about BTG please visit our website at www.btgplc.com.

SOURCE BTG International Inc.