Oxipurinol: alloxanthine, Oxyprim, oxypurinol

Oxipurinol [alloxanthine, Oxyprim, oxypurinol] is the active metabolite of the only commercially available xanthine oxidase inhibitor, allopurinol. Oxipurinol is also a xanthine oxidase inhibitor. Oxipurinol is currently being developed by Cardiome Pharma. It is waiting for approval in the US for the treatment of allopurinol-intolerant hyperuricaemia (gout) and is in phase III trials for the treatment of congestive heart failure. Allopurinol is indicated for the treatment of symptomatic hyperuricaemia, or gout. Approximately 3-5% of patients receiving allopurinol develop intolerance to the drug. Oxipurinol was originally developed by Burroughs Wellcome (later GlaxoSmithKline), and has been available on a compassionate-use basis since 1967 for use in allopurinol-intolerant patients. The licensee company ILEX Oncology has stated that oxipurinol does not have patent protection. Oxipurinol's potential for treatment of congestive heart failure is based on the possibility that xanthine oxidase inhibitors may improve myocardial work efficiency by sensitising cardiac muscle cells to calcium ions, which are a key determinant of cardiac muscle function. This results in more efficient contraction of cardiac muscle cells, without the same increase in oxygen demand. At the second annual BioPartnering North America conference (BPN-2004) [February 2004, Vancouver, Canada], Cardiome Pharma stated that it was seeking a commercialisation partner to market and distribute oxipurinol in the US for the treatment of allopurinol-intolerant hyperuricaemia. In 1995, ILEX Oncology obtained an exclusive licence to oxipurinol from Burroughs Wellcome. Burroughs Wellcome later became part of Glaxo Wellcome, which merged with SmithKline Beecham in December 2000 to form GlaxoSmithKline. ILEX's licence agreement is now with GlaxoSmithKline and The Wellcome Foundation. In December 2001, ILEX granted Paralex, a privately held New York-based company, an exclusive sublicence to all of ILEX's rights to oxipurinol for the treatment of hyperuricaemia in allopurinol-intolerant patients. Paralex additionally gained the right to develop and commercialise oxipurinol in all fields, under data and technology owned by ILEX. Furthermore, Paralex had licensed certain intellectual property rights from The John Hopkins University relating to cardiovascular applications of xanthine oxidase inhibitors. Paralex was acquired by Cardiome Pharma in March 2002. Cardiome Pharma announced early in May 2002 that it had exercised its option to acquire from ILEX Oncology Inc. rights to clinical trial data for oxypurinol for the treatment of gout in allopurinol-intolerant patients. ILEX completed its open-label phase II clinical study of Oxyprim in allopurinol-intolerant gout patients, and the trial data were transferred to Cardiome. Cardiome stated in May 2002 that it intended to commence a further phase II trial of oxypurinol in gout. Phase III trials were in progress in 2003 in this indication. In 1995, ILEX Oncology continued the compassionate use distribution of oxipurinol while establishing a US FDA-approved registration plan for the agent. In November 1998, ILEX received Orphan Drug status for the use of oxipurinol in patients with symptomatic hyperuricaemia. ILEX Oncology's Development Pipeline for 1998 stated that oxipurinol had entered phase II clinical trials for the treatment of hyperuricaemia. In 2001, the clinical trials listing service CenterWatch stated that oxipurinol was in a phase II clinical trial with ILEX Oncology for the treatment of symptomatic hyperuricaemia in patients who are intolerant to allopurinol. The trial appeared to be taking place in the US, and was a multicentre, open-label, 14-week study in 90 patients. In February 2003, Cardiome confirmed beginning patient enrollment in three smaller phase II studies, with the first trial (EXOTIC) now completed. These three smaller proof-of-concept studies will observe surrogate endpoints such as cardiac output and exercise tolerance. The second proof-of-concept study in patients with CHF of ischemic aetiology (IV), known as EXOTIC-EF (Evaluation of XanThine Oxidase Inhibition on Cardiac Ejection Fraction), will assess the effects of oxypurinol on left ventricular performance. The EXOTIC-EF trial will start in the first quarter of 2004 and be completed by the second quarter of 2004. The third, LA PLATA, proof-of-concept study will explore the effects of 1 month of oral oxypurinol therapy on exercise capacity and left ventricular performance. It is projected that the LA PLATA study will start in the first quarter of 2004 and be completed by the third quarter of 2004. During the Heart Failure Society of America's meeting on 21 September 2003, Cardiome presented clinical data from its first proof-of-concept EXOTIC (European Xanthine Oxidase Inhibitors Trial In Cardiac Disease) study. Cardiome intends to conduct a second trial, at the Eppendorf Clinic at the University of Hamburg, to determine the effect of oxypurinol on left ventricular performance in patients with CHF of ischaemic aetiology. This study will be an extension of the original proof-of-concept study. According to the 1st Annual BioPartnering conference held in Vancouver, Canada, in February 2003, Cardiome is seeking co-development partners for oxipurinol in the treatment of congestive heart failure. In July 2003, the US Patent and Trademark Office issued a new patent providing additional protection to Cardiome's programme focused on treatment of congestive heart failure with oxypurinol. The patent, No. 6,569,862, was the second issued to the Johns Hopkins University (JHU) in this field. The key claims in the new patent cover use of the entire family of drugs known as xanthine oxidase inhibitors applied to contractile disorders of the heart, including congestive heart failure. An earlier patent issued to JHU contained provisions relating to a specific mechanism of action and to specific forms of heart disease. Both patents and related intellectual property are licensed exclusively to Cardiome.