https://www.linkedin.com/pulse/comment-gates-30m-alzheimers-diagnostics-ronald-louie/
While Mr. Gates has a laudable concern for this arena, I posted a comment on his blog about his latest announcement [edited for Alzheimer GADFLY]:
I am all for investing in curative research, but sorry, the idea of better diagnostics for Alzheimer’s leads me to comment on an number of your assertions.
1. Early diagnosis does not equate to better outcomes, sometimes it’s just “lead-time bias,” or the “Will Rogers Effect”, even if one has an effective therapy, and the NIA-AA both say there is no really effective therapy. [There are studies (Wattmo, in Sweden) that show that current meds delay time to nursing home admission and death, but no one really gets better].
2. The first “molecular disease” was sickle cell disease in 1949. Even though a prenatal test (a “better” diagnostic) has been available for decades, and early infection prevention is important (shown in the 80’s), for sixty years we could only give opioids or other symptom therapies. Only recently do we have genetic therapy. Alzheimer’s genetics and diagnostics might be much more complex.
3. Validating a better diagnostic test might take decades, especially for pre-symptomatic disease. Every test has false positives and false negatives; in the meantime, that effort takes away from the admittedly more frustrating endeavor of trying to have an impact on established disease. All cancer therapy was initially considered palliative and futile by many. There are ways to do clinical trials on the sickest patients. However, Alzheimer researchers seem to be abandoning patients with established clinical symptoms to get those with early disease, but you’re right, they can’t even do that easily without better diagnostics.
4. To say that there is no market for Alzheimer diagnostics, with the potential and the concern out there, is baffling, since home DNA testing, some with a few Alzheimer related items, is said to become a $10B market by 2022.
5. Spinal taps and scans are some procedures that children with cancer endure at diagnosis, difficult for them, too, but of course, both cancer and Alzheimer’s can be fatal. Blood tests are getting better, but so far, they can’t tell the whole story. Advances in diagnostics would be great, but of course, those affected want the game-changer in therapy more than anything.