Novartis and Astellas are facing more disappointment for the eczema creams, Elidel (pimecrolimus) and Protopic (tacrolimus), after the US Food and Drug Administration slapped black-box warnings on their labels highlighting the potential risk of skin cancer.

Last year, an advisory committee to the FDA recommended the labelling be updated and that patients and physicians be given a Medication Guide to ensure broad awareness of the concerns. Then, in March, the agency issued a public warning to advise doctors of the possible link, and intimated that it would request a boxed warning be added to the labelling.

However, the move met with ferocious opposition from dermatologists and Professor Johannes Ring, President of the European Academy of Dermatology and Venereology, and Dr Ramon Grimalt, General Secretary of the ESPD said the FDA's concerns about cancer were purely theoretical. "There is no clinical evidence whatsoever to support this warning. We think it is disproportionate and unjustified," said Professor Ring. "We are upset because we don't want this to limit access to the drugs or cause unnecessary anxiety to patients or their caregivers." Health authorities should not be swayed by theoretical risks, he added, but base decisions to allow prescribing on proper evidence-based risk/benefit reviews.

Ten months later, the FDA, in a statement, noted: “Although a causal link has not been established, rare reports of cancer (for example, skin and lymphoma) have been reported in patients who had been receiving these products.” As of October last year, some 78 cancer cases were reported for both products.

Novartis and Astellas have argued against a solid link between their drugs and the malignancies, but last year said they would conduct additional safety reviews and studies to investigate the possibility. In its results statement, Novartis said the FDA's decision was based on studies of Elidel in high doses and added that it agreed to change the labelling although it believes "this action is not substantiated by scientific or clinical evidence." The FDA’s move last March has already had a significant impact on sales, with full-year 2005 revenues for Elidel tumbling 23% to $270 million.