Anavex Life Sciences Corp (AVXL)

[Doc328]

Blood diagnostics continue to improve but are not quite as sensitive as PET or CSF biomarkers. No single biomarker passes muster at this time but panels are rather good My current go to test is the Labcorp ATN panel (https://www.labcorp.com/providers/neurology/atn/primary-care). It measures amyloid 42/40 ratio, pTau 181 and neurofilament light. Many patients follow a pattern (1) reduced AB42/40 ratio (corresponding to FDA Stage 1 and 2 and beyond) followed by (2) elevated pTau (stage 2 to 3 and beyond) and finally (3) elevated NfL (stage 3/4 and beyond). AB 42/40 decrease and pTau increase correlates with PET amyloid pathology >90% of the time. If AB42/40 only, a PET may be necessary to more definitely diagnose (and always required by insurance if a MAb is being considered). Studies show primary care diagnostic opinion only correlates with PET 60-70% of the time and neurology 70-80% so this easy relatively inexpensive test is easy. Other companies have panels using pTau217 instead of pTau181 and they are likely similar

So preclinically or minimally symptomatic (performing normally on screening tests like MMSE (Stage 1 and 2)), the blood test will often show the AB42/40 reduction and sometimes both AB42/40 ratio reduction and pTau elevation (inspiring more confidence in the diagnosis)

If blarcamesine ever gets approval (which I believe would take another trial) or other oral safe med like simufilam is approved, then a test like this every 2-3 years after age 65 would be a great screen. The tests are getting better and there could be >95% agreement with PET in another 2-3 years.