AstraZeneca shares have slipped this morning after the firm revealed that regulators in the USA are not ready to approve its asthma blockbuster Symbicort for children.

The US Food and Drug Administration has issued a complete response letter on Symbicort (budesonide/formoterol) for the long-term maintenance treatment of asthma in paediatric patients aged between six and 11. The letter says that AstraZeneca did not provide adequate data to establish the appropriate dose of the two components of the drug in children.

The Anglo-Swedish drugmaker said it is evaluating the FDA’s letter and will provide a response to the FDA “in due course”. Symbicort, which had sales of $514 million in the fourth quarter, up 29%, is approved for asthma in patients over 12 years old and for chronic obstructive pulmonary disease.

FDA staff concerns about Seroquel XR
The Symbicort setback comes just as briefing documents released ahead of an FDA advisory panel meeting on Wednesday show that AstraZeneca's antipsychotic blockbuster Seroquel XR (quetiapine) is effective at treating generalised anxiety disorder and major depressive disorder. However, agency staff said there is “accumulating evidence" that the drug may have "substantial metabolic risk".

In the documents, released on the FDA’s website, agency staff also noted that while tardive dyskinesia is considered an acceptable risk in Seroquel XR's currently-approved indications of schizophrenia and bipolar disorder, that risk becomes "even more important with the possibility of broader use." They also expressed concern that the drug may be associated with sudden cardiac death.

Despite these concerns, most analysts believe that the FDA’s Psychopharmacologic Drugs Advisory Committee will recommend expanded approval of Seroquel XR. Getting the green light for MDD and GAD will significantly boost sales of the compound.

OTC sale to GSK approved
Meantime, AstraZeneca also noted that the sale of a portfolio of over-the-counter products to GlaxoSmithKline has been cleared by Swedish competition authorities.

The brands, which are predominantly sold in Sweden, include analgesics Alvedon and Reliv, Nezeril/Nasin for decongestion, Minifom for gastrointestinal disorders and Duroferon for the treatment of iron deficiency. AstraZeneca will receive around $220 million from the sale.