Biogen stacks the deck but the path forward is no clearer in Alzheimer’s

The presentation of Biogen’s hugely complex aducanumab pivotal programme confirms that the US regulator is destined to make another polarising decision.

After scrapping and then resuscitating its Alzheimer’s project aducanumab, Biogen needed to make a very strong case for pushing on. That attempt came yesterday at a medical conference, CTAD, and it seems that the hugely complex presentation failed to substantially shift opinions in either the medical or financial communities, many of which were firmly entrenched either way.

Biogen has insisted that it will file for approval next year, setting the FDA up to make a decision that, inevitably, many will disagree with. And yesterday’s presentation will not have made life easier for the regulator. By allowing a company employee to present the data – highly irregular for a medical conference – and having no real dissenting voices among the reviewers, Biogen has remained in control of the message. 

That message is clear: aducanumab is an effective drug, dosed high enough and for long enough, and represents a real step forward for Alzheimer’s disease. This almost puts a moral obligation on the FDA to grant approval. It will also make running any sort of confirmatory trial incredibly hard, because if physicians and patients believe this interpretation, enrolling a trial in which subjects might receive a placebo becomes almost impossible.

Biogen has said it is preparing to re-dose patients who were originally enrolled in the Engage and Emerge studies. The company presumably hopes that this endeavour will be sufficient to clear up any remaining questions that regulators may have.

But this would be a deeply imperfect way of rigorously examining aducanumab, and there are a lot of unanswered questions here, as well as unseen data. Even if one stands by the way that Biogen has re-analysed the results, the clinical relevance of the efficacy signal teased out remains a subject of debate. And this is before safety is considered – something that must not be easily dismissed with an agent that will be dosed chronically.

The advisory committee hearing that will inevitably be convened next year will provide the FDA’s first thoughts on all this, and will be a hugely pivotal moment for the biopharma sector. A green light will be interpreted as Sarepta 2.0, and a further demise in standards of evidenced-based medicine. Roadblocks will be criticised for delaying patients’ access to potentially life-changing therapies.

History suggests that Biogen will prevail here. Either way, Alzheimer’s is now set to be one of the big stories of 2020.

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