Regulators in the USA have warned that Bristol-Myers Squibb's leukaemia drug Sprycel may increase the risk of pulmonary arterial hypertension.

The US Food and Drug Administration has issued a safety announcement noting that 12 cases of PAH (ie abnormally high blood pressure in the arteries of the lungs) from B-MS’s database were confirmed by right heart catheterisation. "Sprycel (dasatinib) was identified as the most likely cause," the agency added, pointing out that no fatalities have been reported.

The FDA noted that patients developed PAH after starting Sprycel, including after more than one year of treatment, though they were often taking other drugs at the same time or had other co-existing medical conditions. However, it says that if other causes have been ruled out, a diagnosis of Sprycel-associated PAH should be considered, and the condition may be reversible if treatment with the B-MS drug is discontinued.

The FDA went on to state that nearly 33,0003 patients worldwide have taken Sprycel for Philadelphia chromosome-positive chronic myeloid leukaemia or acute lymphoblastic leukaemia between June 2006 (when it was approved) and June this year.

B-MS said it is in discussions with health authorities worldwide "about how to appropriately update product information" and provide information "supporting the safe and appropriate use of Sprycel". Second-quarter sales of the drug leapt 46% to $193 million.