The FDA’s guidance on developing Alzheimer’s drugs is overly rigid when it comes to enrollment of patients in clinical trials, drugmakers said in public comments.
In its comments, AstraZeneca noted that the guidance calls for eligibility in efficacy trial enrollment to be based on “current consensus diagnostic criteria,” but said future guidance should acknowledge possible contradictions between such diagnostic classifications and the guidance. “As AD is recognized as a continuum, some flexibility is required, particularly for ongoing clinical trials,” the comment states. “Further dialogue is encouraged on the relationship between different classifications and the term ‘Early Alzheimer’s Disease’.”
Eli Lilly, meanwhile, called for the agency to clarify “the requirement for a cognitive effect for approval of a drug expected to have its primary effect on function.” The agency should include patients with stage 4, or mild Alzheimer’s, in the scope of its guidance, the company said. There is considerable overlap in cognitive and functional measures between trial subjects meeting entry criteria for stage 4 AD versus mild cognitive impairment.