UPDATE 2-U.S. Congress seeks information from FDA on approval of Biogen's Alzheimer's drug

(Adds Biogen response, background)

Sept 2 (Reuters) - U.S. lawmakers have requested data and documents from the Food and Drug Administration (FDA) related to its accelerated approval of Biogen Inc's new Alzheimer's drug, mounting further pressure on the agency that has come under fire for clearing the drug.

The chairs of the House Committee on Oversight and Reform and the Committee on Energy and Commerce have requested the FDA to disclose documents related to the interactions between Biogen and the agency's staff.

"We are concerned by apparent anomalies in FDA's processes surrounding its review of Aduhelm," chairs of the two committee wrote in a letter to the agency.

The committees had launched an investigation following the drug's approval on June 7 that had sparked controversy and concerns over the FDA's process, as a panel of its outside advisers had recommended against the approval.

The letter, dated Sept. 1, also requests for details on the agency's process for approving a therapy when there is a disagreement between the FDA staff and its panel of external advisers, known as the advisory committee.

Biogen said it was continuing to cooperate with the committees' investigation and had produced documents as and when requested.

An independent federal review was launched last month into the accelerated approval pathway used by the drug regulator to approve the treatment, on the request of the FDA's acting commissioner Janet Woodcock.

(Reporting by Manas Mishra and reporting from Amruta Khandekar in Bengaluru; Editing by Vinay Dwivedi)