As expected, regulators in the USA have approved new safety information on Amgen and Johnson’s anaemia drugs which now that the treatments impaired survival rates in certain groups of cancer patients.

The US Food and Drug Administration has updated the black-box warning on the class of anaemia drugs known as erythropoiesis-stimulating agents, notably Amgen’s Aranesp(darbepoetin alfa) and Epogen (epoetin alfa), plus J&J’s Procrit (also epoetin alfa). The new labelling states that ESAs shortened overall survival and/or time-to-tumor progression in clinical studies in patients with breast, non-small cell lung, head and neck, lymphoid and cervical cancers, when dosed to target a haemoglobin of greater than or equal to 12 g/dL.

Amgen also noted that the labelling now includes interim results of the Preoperative Epirubicin Paclitaxel Aranesp (PREPARE) study in neo-adjuvant breast cancer as well as follow-up data from the Gynecologic Oncology Group study in cervical cancer. It also contains data from other clinical studies with ESAs in the oncology setting, but the US biotechnology major is standing behind its products.

Specifically, Amgen said that “these results have not changed the benefit-risk profile significantly of ESAs in this setting from previously available data”, which was discussed at previous meetings (in 2004 and 2007) of the FDA’s Oncologic Drugs Advisory Committee meetings. ESAs have had a rough ride over the last year, most recently when a meta-analysis of 51 studies claimed that the use of agents such as Aranesp and Procrit increased the risk of blood clots and death among patients with cancer. The meta-analysis was dismissed by Amgen and J&J who said the study did not provide an accurate reflection of the safety profile of ESAs.

Most eyes are now turning towards the upcoming ODAC meeting on Thursday (March 13) where Amgen says it will “address the science and safety of ESAs in oncology”. The PREPARE findings and other data will be discussed and analysts fear that more restrictions will be put on the sales of ESAs, which would hurt Amgen especially, given its reliance on revenues from Aranesp and Epogen.

Michael King at Rodman & Renshaw recently issued a note to clients saying that there is a 30% possibility that the FDA committee will recommend ending the use of ESAs for breast cancer patients, and there is a 10% chance that the agency’s panel will advise doctors stop prescribing the drugs for all cancer patients.

The effect on Aranesp, Epogen and Procrit sales could be spectacular and more than the damage caused by the adverse publicity that has already been directed at the ESA class. In the fourth quarter, worldwide sales of Aranesp dropped 25% to $827 million and were down 40% in the USA, while global Epogen turnover fell 3% to $638 million.