Cardiome Pharma Corp announced that the U.S. Patent and Trademark Office has issued a new patent providing additional protection to Cardiome's program 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. The invention underlying both patents, originally described by Dr. Eduardo Marban of JHU, involves the novel observation that these agents appear to increase cardiac work output without increasing cardiac oxygen consumption.

"Cardiome's ongoing clinical studies on the use of oxypurinol may open a major new option in the treatment of patients," said Dr. Alan Ezrin, Cardiome's Chief Scientific Officer. "This broader patent coverage can only increase the commercial value of our potential breakthrough approach to congestive heart failure therapy."

Congestive heart failure (CHF) is a disease characterised by an inability of the heart to pump blood at a rate sufficient to support the needs of the body.

Cardiome is currently conducting four clinical studies utilizing oxypurinol to treat patients with CHF. The key clinical study, OPT-CHF, is a Phase II/III oral study enrolling 400 patients to measure clinical endpoints such as mortality and rehospitalization. Three smaller proof-of-concept studies will observe surrogate endpoints such as cardiac output and exercise tolerance.

CHF is a common disease whose incidence and severity increase with age, and is a significant cause of death in the developed world. CHF is also an important risk factor for serious disorders of the cardiac rhythm, and is associated with a 6 to 9 fold increase in the risk of sudden cardiac death. The condition also significantly reduces the quality of life in those who suffer from the disease. Approximately 4.7 million persons in the U.S. suffer from CHF, while the developed world total is estimated at approximately 10 million.

Although some of the existing drugs used to treat CHF can provide a short-term increase in the heart's ability to pump blood, they do so at the cost of exacerbating the underlying disease. Such drugs increase contractile energy at the expense of increasing the heart's utilization of oxygen and energy.

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. These calcium-sensitized cardiac cells contract more efficiently without the same increase in oxygen demand.