In an open letter released Thursday, Biogen pushed back on mounting criticism over the FDA's recent approval of Aduhelm (aducanumab), as the company looks to counter worries about the Alzheimer's disease drug's effectiveness and $56,000 annual cost. The statement from R&D head Alfred Sandrock coincided with Biogen's second-quarter earnings  report, in which it said Aduhelm generated sales of $1.6 million in the few weeks since it won accelerated approval  from the FDA in early June.
According to Sandrock, the FDA decision – based on the idea that Aduhelm's effect at reducing beta amyloid in the brain is "reasonably likely" to predict clinical benefit – came after an "extensive development, testing and review process," but has since been marred by what he termed "extensive misinformation and misunderstanding." He said that while "it is normal for scientists and clinicians to discuss…to debate and to disagree on the interpretation of data," the controversy swirling around Aduhelm has taken "a turn outside the boundaries of legitimate scientific deliberation."
The executive took issue with claims that all previously studied anti-amyloid antibodies clear amyloid from the brain, but have failed as a class to demonstrate benefit, saying there is "no basis" for comparing these to Aduhelm. "First-generation anti-amyloid antibodies were not specific for aggregated forms of amyloid beta, or targeted soluble monomeric amyloid beta, or were deficient in effector function," he said, and "as a result, these antibodies do not clear amyloid from the brain."
Further, claims that all of Aduhelm's results were analysed through a post-hoc lens are also incorrect, according to Sandrock. He noted that the primary and secondary endpoints had been pre-specified in the Phase III trial protocols, and the drug's label shows the results on these endpoints, "based on data that had already been collected…by the time the trials were prematurely terminated " in early 2019 after a futility analysis.
There have also been worries that Aduhelm's approval could hold back other, potentially more effective Alzheimer's therapies by stifling research that attempts to look outside the so-called "amyloid theory" box. However, Biogen disputes that argument as well, with Sandrock noting the approval has "already renewed investment activity" in Alzheimer's R&D, and "we are optimistic that other innovative treatments will soon join Aduhelm."
Meanwhile, acting FDA Commissioner Janet Woodcock recently called for an inquiry by the Office of the Inspector General into possible interactions between agency staff and Biogen relating to Aduhelm that may have been "inconsistent" with FDA policy. Sandrock said "we welcome a formal review into the interactions between the FDA and Biogen on the path to the approval of [Aduhelm]," adding that "a better understanding of the facts is good for everyone involved to assure confidence in both the therapy and the process by which it was approved."
For related analysis, read ViewPoints: Roche plays it cool as Biogen heats up the room .