The Aducanumab Drama Continues...

As I write, The12th Clinical Trials Conference on Alzheimer's Disease is in progress in San Diego, and it's in the news.  It's in the news because everyone wants to know what's going on with aducanumab, and Biogen was there to talk about it.  The PowerPoint for their presentation is here.

As we discussed previously, back in March Biogen suspended trials of aducanumab when a futility study found that the results were not sufficiently promising to justify continuing.  But in October, they did an about face, saying they would be applying to the FDA for approval after all.  They had reassessed the data and found the the treatment was actually working for some people.

What happened?  When I originally auditioned for the trial, the researchers disclosed that earlier trials found that aducanumab was causing brain inflammation and micro-hemorrhages in some subjects.  At the time (early-mid 2016) these were not believed to be life threatening, and the researchers monitored test subjects with relatively frequent MRIs.  Nevertheless, dose levels appeared to be a risk factor, and they cut back the dose in the study populations receiving the higher dose in the middle of the trial.  (Two different doses were administered to different populations.)  Review of the data found that subjects on the higher dose were improving while they were on the higher dose.  But this effect was diluted in the data after their dose was reduced.  (Subjects on the lower dose had marginal improvement.)

So what does this mean?  Obviously the idea that removing beta amyloid from the brain can slow cognitive decline is exciting, and it encourages further exploration of this path.  It had looked very much like a dead end.  But, so far, aducanumab has neither reversed nor stopped the advance of Alzheimer's disease.  By some interpretations of the data, it has slowed the advance by an average of 30%.  A lot better than nothing, but some are observing that insurance companies and others will be asking if that's enough to justify the (so far unknown) cost of the treatments.

And it won't just be the insurance companies.  The researchers found that not everyone was willing to be persistent in showing up for the monthly, hour-long infusions.  Regular MRIs will undoubtedly be a feature of the treatment process, and this could be a further inhibition to encouraging people to receive the treatment.  Aducanumab won't be a pill you can take at bedtime.

Should the FDA approve aducanumab as a treatment for Alzheimer's disease?  Depends on who you ask.  Some say yes, others say it needs another trial that applies what we learned in the previous three trials.

Here is Biogen's aducanumab web page.