The US Food and Drug Administration has ordered changes to the labels of anaemia drugs sold by Amgen and Johnson & Johnson, restricting their usage in cancer patients.

The move, which comes as no great surprise, follows a recommendation by the agency’s Oncologic Advisory Committee in March that erythropoiesis-stimulating agents, notably Amgen’s Aranesp (darbepoetin alfa) and Epogen (epoetin alfa), plus J&J’s Procrit (also epoetin alfa), that called for greater limits for using the drugs on cancer patients. However arguably the most interesting aspect of the FDA’s move is the manner in which the agency is demanding the changes.

It is the first time the FDA has invoked powers granted in 2007 to force a pharmaceutical company to change a label, rather than negotiate with the drugmaker. Both Amgen and J&J had disputed the need to act but the agency has clearly put its foot down.

The FDA said that Amgen submitted labelling supplements for Epogen and Procrit (which it supplies to J&J), plus Aranesp on May 22, and “while agreement was reached on the general concepts”, the two parties disagreed on specific wording on two points, including a warning statement that ESAs “are not intended for use in patients receiving myelosuppressive therapy when the expected outcome is cure and statements regarding when to initiate and to discontinue ESA dosing”.

Labelling discussions concluded on July 15 but Amgen has been ordered to make the additional changes under new powers granted to the agency in the FDA Amendments Act of 2007. The firm has five days to appeal or 15 days to submit a supplement containing the labelling changes.

Amgen would appear to be non-plussed and issued a somewhat terse statement saying that "this label is consistent with our expectations. We will soon be communicating the revised product labelling for ESAs to both physicians and patients." The firm added that “the potential impact of this revised label was factored into our updated guidance” announced at the beginning of the week.

Then, the firm announced that second-quarter sales of Aranesp fell 13% to $825 million, and down 26% in the USA to $427 million. The label changes could reduce that figure still further as they will state that treatment should not begin until a patient’s haemoglobin falls to 10 g/dL. Language is being removed that implies safe to continue treating patients until their haemoglobin level reaches 12 g/dL and this could have an effect on the level of reimbursement offered by Medicare.

However, on the postive side for Amgen, the new labels will not advise against use of ESAs for all patients with breast cancer or head and neck cancer, one of the recommendations made by the OAC in March.