New Anti-Tau trial with blood-based screening

[Beaker]

thank you
Melissa 4/4

[Beaker]

Thanks Nancy !!!

[JimInSYR]

Hi, I just joined this board today, and I also just learned today that I didn’t qualify for this study due to tau levels below the study threshold (best news I’ve had in some time!).

I was wondering whether someone could provide some more explanation of the following observation up thread:

“ As I understand it, the threshold for the study is based solely on the regions of the brain with tau and an overall level above 1.1.”

What are the units for the “1.1” figure? And what should I take from the fact that apparently I am below that threshold?

Thanks!

[NF52]

Hi, I just joined this board today, and I also just learned today that I didn’t qualify for this study due to tau levels below the study threshold (best news I’ve had in some time!).

I was wondering whether someone could provide some more explanation of the following observation up thread:

“ As I understand it, the threshold for the study is based solely on the regions of the brain with tau and an overall level above 1.1.”

What are the units for the “1.1” figure? And what should I take from the fact that apparently I am below that threshold?

Thanks!

Welcome! We're glad you have joined today. I'm the author of that earlier post, and I am thrilled when people are willing to be screened for a trial. [I'm nearing the end of the third year in AHEAD-45, a trial studying lecanemab as an anti-amyloid drug, vs. placebo, in people with normal cognition and elevated amyloid. ]

People like you are who "screen fail" provide valuable information on what are typical levels of tau are at various ages, in various races, ethnicities and genders and in ApoE 4 carriers and non-carriers. It's rapidly expanding the necessary research into the decades- long "preclinical" stage when amyloid and tau may be slowly developing. This is when eventual prevention treatments may be most useful.

I think you can take from your result that you are not in the group of people who may be at higher risk of MCI in some foreseeable future. It's frustrating when you don't get specific results, but I think that's because this field is so new and until they look at 100's or 1000's of PET scans like yours, they won't be able to say just what it means it someone has tau in some earlier, low-risk area for their personal risk profile.

I apologize for not trying to provide more context in my earlier post, though I have no neuro-radiology expertise beyond getting PET scans and MRIs! Here's the source for that figure from one ReTAIN study description: https://globaltrialfinder.janssen.com/t ... 56ALZ2001

The reference is from a term called SUVR, for Standardized Uptake Value Ratio, or a ratio of how much of a radioactive tracer is taken up by a particular "region of interest" compared to how much is taken up overall. Here's my very basic understanding:

• if some of the tau PET tracer is taken up in entorhinal cortex and none is in the Medial Temporal Lobe, the person would be at Braak Stage 1, with an SUVR that might be above or below 1.1.

• If the tau tracer was a 1.1 SUVR in the medial temporal lobe (MTL) that would assume they were at that level or higher in regions for Stages 1 and 2. This trial wants both ≥ 1.1 SUVR and that level in the medial temporal lobe (MTL).

The MTL has a big role in the skills that are first noticed in early cognitive impairment:

The temporal lobe of your brain is a pair of areas on your brain’s left and right sides. These areas, which are inside your skull near your temples and ears, play a role in managing your emotions, processing information from your senses, storing and retrieving memories, and understanding language.

https://my.clevelandclinic.org/health/b ... poral-lobe

Here's how Wikipedia defines SUVR:

The SUV is the ratio of the image-derived radioactivity concentration cimg and the whole body concentration of the injected radioactivity

https://en.wikipedia.org/wiki/Standardized_uptake_value Here's a brief explanation of why SUVR ratios in specific regions seem to be more predictive of cognitive changes that MAY occur, rather than a centiloid score that is used in amyloid PET scans regardless of where the amyloid is: Location matters is tau and it seems to change in a relatively consistent pattern; total amount matters in amyloid and it too seems to correlate with risk of cognitive changes.

Baseline global tau-PET SUVRs explained more variance (partial R2) in future cognitive decline than Centiloid across all cognitive tests (Cohen’s d ~ 2, all tests p < 0.001) and diagnostic groups.

https://alzres.biomedcentral.com/articl ... 21-00880-x

Bottom line: It is great news for you!! Hope you are open to other studies

Nancy

[JimInSYR]

Thanks for such a thoughtful and thorough reply! I actually only had a blood test result (presumably for pTau217?), and the number in your post was an order of magnitude higher than what I understand to be typical results expressed as pg/mL for the blood test. I see now you were referring to a different test result. And I should have clarified that the test result I was referring to was a blood test, not PET. My bad. Bottom line, I am pleased with the results of my test and look forward to engaging here in the future!

[NF52]

Thanks for such a thoughtful and thorough reply! I actually only had a blood test result (presumably for pTau217?), and the number in your post was an order of magnitude higher than what I understand to be typical results expressed as pg/mL for the blood test. I see now you were referring to a different test result. And I should have clarified that the test result I was referring to was a blood test, not PET. My bad. Bottom line, I am pleased with the results of my test and look forward to engaging here in the future!

No apologies needed! Even better for you, since a blood test that didn't predict a significant level of p-tau may also mean that you don't have a significant level of amyloid either. Amyloid rises earlier than tau, so a positive p-tau test above a certain level generally means a positive amyloid PET scan, a negative p-tau screening blood test may well mean a low risk of amyloid.

Enjoy a two-for-one win!

Nancy

[rdpchef]

Hi, I just joined this board today, and I also just learned today that I didn’t qualify for this study due to tau levels below the study threshold (best news I’ve had in some time!).

I was wondering whether someone could provide some more explanation of the following observation up thread:

“ As I understand it, the threshold for the study is based solely on the regions of the brain with tau and an overall level above 1.1.”

What are the units for the “1.1” figure? And what should I take from the fact that apparently I am below that threshold?

Thanks!

Hi JimInSYR,

I'm one of the forum interns and want to welcome you to our site. I see you have already been conversing with one of our experts. Congratulations on not qualifying for the study, it seems like you are in a good place.

Please feel free to introduce yourself further. I have a long family history of Alzheimer's and Lewy Body Dementia. I am personally Apoe4 homozygous. You'll find many other people here who share the same story and are doing very well.

If you haven't already, it would be a great idea to first take a look at our Primer. It is an incredible resource of information about the biochemistry of ApoE4. It offers researched-based prevention strategies and was written by a practicing M.D. with ApoE4. Do not become overwhelmed with all the information. Sometimes it is best to slowly read through it, decide which section resonates with you, and focus on that area first. Remember that small changes can make a big difference to brain health.

The How-To Guide will help you learn how to navigate this site. It includes topics such as navigating the forum, private messaging, and searching.

You can find other members' experiences in Our Stories. Sometimes reading the stories of others helps us realize that we are not alone.

I'm so glad you have joined us on this site. Please feel free to reach out anytime with questions or if you just need support.

Take care,
Patty