Senator Ron Johnson, Republican of Wisconsin, launched an investigation into the Food and Drug Administration's (FDA) denials of drugs for rare diseases.[1][2][3] It requests complete responses to submissions (complete response letters) that the FDA sent to drug manufacturers for diseases such as ataxia, Sanfilippo syndrome, Huntington's disease and Duchenne muscular dystrophy.[3][4] Johnson plans to write letters to the agency questioning the reasons for the denials and is considering hearing senior FDA officials, including Commissioner Marty Makary, before the Senate Permanent Subcommittee on Investigations, which he chairs.[1][2][3] He said he spoke with Commissioner Makary about the FDA's handling of rare disease treatments.[3] Johnson called some of the FDA's requirements, such as the sham surgery-controlled phase 3 trial of uniQure's gene therapy for Huntington's disease, bureaucratic stupidity.[2] He is a longtime advocate of expanding access to experimental therapies for patients with rare or terminal diseases.[2][5] He expressed dissatisfaction with the rejection of Biohaven's troriluzole for spinocerebellar ataxia and the withdrawal of PTC Therapeutics' ataluren (Translarna) application for DMD.[4]