Concerns about the safety of a class of drugs used to treat anaemia have triggered a federal alert in the United States. The alert comes after recent studies reported a higher incidence of fatal cancers and cardiovascular events among patients who were treated with drugs known as erythropoiesis stimulating agents when the drugs were used to raise haemoglobin concentrations to more than 120 g/l.

The US Food and Drug Administration issued the alert on 16 February, urging doctors “not to [give doses] to exceed haemoglobin levels of 12 g/dl” when treating patients with anaemia resulting from chronic renal failure, cancer or cancer chemotherapy, or HIV or AIDS.

The agency has scheduled an advisory committee meeting for 10 May to assess the risks of the drugs, which include epoetin alfa (made by Ortho Biotech and sold in the US under the brand name …