The head of the Food and Drug Administration is calling for an inquiry into her own agency’s approval of a controversial drug to treat Alzheimer’s disease. Dr. Janet Woodcock, the acting commissioner, published a letter to Health and Human Services Inspector General Christi Grimm on Twitter Friday urging an independent probe into potentially improper contacts between Biogen, the developer of the drug, and FDA regulators during the approval process. A probe will “determine whether any interactions that occurred between the manufacturer and the agency’s review staff were inconsistent with FDA’s policies and procedures,” Woodcock wrote.

Stat News reported last month a number of unusual meetings between Biogen and FDA reps, including an undisclosed meeting between a Biogen exec and the FDA regulator in charge of Alzheimer’s drugs. The drug Aduhelm, which costs $56,000 a year and requires monthly IVs, has come under scrutiny over whether it actually works. The FDA said Thursday it should only be prescribed to people with early-stage or mild disease, reversing a prior recommendation.