LONDON (AP) — Drug maker AstraZeneca PLC faces a delay in marketing its asthma treatment Symbicort for young children in the United States after regulators on Monday requested more information about the drug. The use of Symbicort for the long-term maintenance treatment of asthma is already approved for patients aged 12 and over in the United States and the company has applied to sell it for the same purpose for children aged six to 11. AstraZeneca revealed Monday that the U.S. Food and Drug Administration said the company had not provided adequate data to establish the appropriate dosage for the drug's two components — budesonide and formoterol — in the younger group. The company said it was evaluating the letter it had received from the FDA and would provide a response to the agency "in due course." AstraZeneca had submitted a supplemental new drug application to the FDA in late February. It needs the approval to better compete with GlaxoSmithKline PLC's Advair medicine, which is already cleared for use in children as young as four. Both drugs are approved for adult use relating to chronic obstructive pulmonary disease, or COPD, the condition commonly known as "smokers cough." Symbicort has registered sales of more $50 million in the United States since it was launched last June. Total Symbicort sales were almost $2 billion last year, well below sales of $6.9 billion for Advair and its international versions. In a separate statement on Monday, AstraZeneca said that Swedish competition authorities had approved its sale of a portfolio of over-the-counter products to GlaxoSmithKline. Under the deal, first announced in November, AstraZeneca will receive around $220 million to offload analgesics Alvedon and Reliv, Nezeril/Nasin for decongestion, Minifom for gastrointestinal disorder and Duroferon for treatment of iron deficiency. The company said that the sale will be recorded as a gain in its second quarter accounts.