And then there's donanemab

Say that three times fast.  And where do they get these names from, anyway?  

Actually there is a system.  For example, the "mab" at the end of aducanumab and donanemab stands for monoclonal antibody.  And so another "mAb" or "moAb" is in the news with some new promise.

The news (and it's good news) is that Eli Lilly is finding favorable results in their phase 2 trials of donanemab.  We recall that phase 2 still uses a relatively small number of subjects and so is not considered confirmatory.  Nevertheless, these trials can give us hope.  

The hope is based on Lilly's finding that test subjects experienced a reduction in beta amyloid plaques to levels associated with normal people and improved their cognition.  These improvements are among people with early stage Alzheimer's disease.  Lilly said, "Donanemab met the primary endpoint of change from baseline to 76 weeks in the Integrated Alzheimer's Disease Rating Scale, slowing decline by 32 percent relative to placebo, which was statistically significant."  In other words, a slowing of cognitive decline by a third after 18 months of treatment.  

Lilly began another 18 month phase 2 trial of donanemab in June 2020, although they have not completed the recruitment of test subjects.  This will be a larger study with less restrictive criteria.  For example, the first study excluded people with certain tau pathologies, but the second trial will not.  The hope is that both trials taken together will preclude the requirement for an extended phase 3 trial before the FDA approves the treatment.

Similar to aducanumab, the treatment does not "cure" Alzheimer's disease, but it does significantly slow it's progress.  Also, similar to aducanumab, it causes some level of edema in the brain, which is troubling.  But, so far, it's meeting its safety criteria.

Perhaps what's especially important about these test results is the evidence that removing amyloid plaques can play a role in interrupting and, perhaps someday, reversing progress of the disease.  It also associates removal of the plaques with improved cognition, an association we haven't seen in some of the new treatments.    You can read more about the trial here.