Allele >50% vs Thrombosis and Progression - MPN Voice

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Allele >50% vs Thrombosis and Progression

EPguy profile image
14 Replies

Came across this retrospective study that looked at AT vs VT vs allele.

ncbi.nlm.nih.gov/pmc/articl...

As usual I'm focused on the progression data that is sort of buried in here. See below this data for rough definitions of training vs validation cohorts.

Training cohort:

MF progression; n (%) All= 75 (13%) Jak2 <50%=16 (4.3%) Jak2 >50% = 59 (28.5%) P=<0.0001

AML progression: n (%) 12 (2.1) <50%+ 4 (1.1) >50%= 8 (3.9) P= 0.03

Validation cohort:

MF progression; n (%) 23 (7.9) <50%=4 (2.8) >50%=19 (13.0) P=0.0013

AML progression: n (%) 5 (1.7) 2 (1.4) 3 (2.1) P=0.67

For MF Jak2 allele more than 50% takes MF progression from 4.3% to 28.5% (training) and 2.8% to 13% (validation) for

**~5X more MF risk for allele > 50%.

For AML only the Training cohort has a signif P value. In this one allele >50% leads to

**3.5X higher AML risk.

It does not cover reducing allele, and that remains a question. But reducing (via INF for example) should be better than not reducing. INF over time usually can give reductions of the size needed to get under 50%.

Still need prospective studies clearly showing this direct benefit, but more circumstantial evidence that INF may be useful.

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Here is more on the main point of the study:

My focus was elsewhere but a few details some of us may like to know about that I learned:

1- Arterial Thrombosis concerns stroke or heart attack, Venous Thromb is

for <<deep vein thrombosis, DVT (has been called economy class syndrome) , and pulmonary embolism or

abdominal vein thrombosis>>

AT is a bigger deal in the reference below. I've not been clear on these before.

silvermpncenter.weill.corne...

2- In my very basic understanding; a Training cohort is the actual experimental group and the Validation cohort is where the lesson learned is applied to see if it holds. They used both which seems good.

Some misc thoughts on the ncbi study:

The main goal was <<we identified JAK2V617F VAF > 50% as an independent strong predictor of VT>> AT was less affected. They claim to have corrected for the other factors (which includes the way high HCTs in the >50% allele of ~HCT 54-56) I'd like to see more in here about that.

From the ref below and others, HU helps with AT but not much for VT. Maybe reducing allele to <50% can reduce VT as in the ncbi study at top here.

nature.com/articles/s41408-...

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EPguy
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14 Replies
Wewo01 profile image
Wewo01

Hi ETguy,Thanks for this information! I recently found out my allele burden on my first test was 12%. That was in 2016 (a test my dr did and never told me!). In 2020 per BMB, it was 15% and then up to 18% this past November. I have been on HU since October 2020. I’m 63, so I feel like I am at pretty low risk of it increasing very substantially. It does appear that HU is not going to keep the allele burden in check. Is that true?

EPguy profile image
EPguy in reply to Wewo01

Are your alleles all by BMB? I've read that blood based can give ~4 points lower. I fit that, 14 Blood vs 19 BMB. So you need to compare same methods.

You've likely seen these plots here made from the ContiPV data. The top one suggests HU may level allele but at a much higher level than INF.

The most complete study, contiPV shows average starting alleles closer to ~40%. But this recent press release points to an advantage for starting with lower allele. I think they have data details that are not public. The lower age part also points to us (I'm 62) getting moving on it.

aoporphan.com/global_en/our...

<<Achieving deep molecular response correlated statistically significant with lower age and lower allele burden at the start of treatment.>>

INF beneficial
Wewo01 profile image
Wewo01 in reply to EPguy

The test in 2016 was blood. The other 2 were BMB. Thanks for the info!

Bluetop profile image
Bluetop

Thanks for posting. A lot of very interesting material.I have never had my allele burden tested - (on the basis that it wouldn't affect my treatment). I shall certainly ask for this at my next appointment.

Mamab83 profile image
Mamab83

This is all so confusing to me. I’m considered triple negative… does that mean this doesn’t have anything to do with me? 🧐 this is for jak2?

EPguy profile image
EPguy in reply to Mamab83

Generally correct. But 3x neg may still have other non-driver mutations. Problem is they are still figuring out what those mean and you're right, this study did not look there.

Here is an example which shows how complex it is:

cap.org/member-resources/ar...

<<Recent studies have turned their attention to triple-negative MPNs and the search for other possible driver mutations using whole exome sequencing (WES)5, 6, 7. Both somatic and germline gain-of-function mutations in non-traditional exons of MPL and JAK2 were identified, as well as cases with no mutation that showed polyclonal hematopoiesis. About 10% of cases of triple-negative ET and PMF showed mutations in exons 3, 4, 5, 6, 12 of MPL and 10% showed germline mutations in exons 8, 13, and 15 of JAK2. WES methodology is limited, however, in that it can only detect mutation(s) in the coding exons of genes, and cannot detect mutations in coding sequences at low variant allele frequency6, >>

Mamab83 profile image
Mamab83 in reply to EPguy

I was checked for about 22 different mutations. All negative. I’m sure there’s one somewhere. Just something they haven’t found yet 🤨

EPguy profile image
EPguy in reply to Mamab83

I got 54 genes studied in the "next gen sequencing." Probably need to wait for the gen after that to really find them all... Most the ones in that mess above were not in my gene study.

patriciapugliese profile image
patriciapugliese

Just diagnosed in December 2021 ET with JAK2 positive my dr. did not know the meaning of the quantitative value. Is that the allele #? JAK2 V617F Mutation Quant

Rslt ⁰²

POSITIVE

The JAK2 V617F mutation is detected in the provided specimens of this individual.

Quantitative Value: ⁰² 10.82

%

EPguy profile image
EPguy in reply to patriciapugliese

The formatting in the post is broken up but it appears you have ~11% Jak2 allele. That is in a common range for ET. But the exact 10.82 number is surprising since it's not normally that precise.

If your Dr does not know about this subject you should find one who knows MPN at least for 2nd opinions. Allele is known as a basic part of the MPN condition for the last 15 years.

Did you get NGS (next generation Sequencing)? This looks for other mutations that you should have in your record for future reference along with Jak2.

patriciapugliese profile image
patriciapugliese in reply to EPguy

"Reflex to CALR Mutation Analysis, JAK2 Exon 12-15 Mutation Analysis,

and MPL Mutation Analysis is not indicated." I think that says negative?

EPguy profile image
EPguy in reply to patriciapugliese

From what I could find, reflex means they added the CALR test to the series. Not indicated suggests they saw no need to do MPL test.

Usually these three mutations are not seen together, but there are exceptions. No info I can see on yours whether they found the unlikely CALR.

ncbi.nlm.nih.gov/pmc/articl...

<<JAK2 and CALR mutations coexisted in 7 (4.2%) of 167 ET patients>>

Jak2 usually has exon 14, but the other exons can be found and they looked for it in your case. No info on which one (12-15) they found)

The wording on your results appears maybe from Lab Corp. If that is all the info, there was no NGS test.

It remains a good idea that you find an MPN specialist to discuss all this with. Problem is you might need to do a or another BMB to get NGS.

patriciapugliese profile image
patriciapugliese

What does NGS stand for? The soonest I could get to see a MPN specialist is in July. I am scheduled bi-weekly with a local hematologist. Yeah I'm not sure how to interpret it "not indicated" as in not tested or not there? Yup LabCorp

EPguy profile image
EPguy in reply to patriciapugliese

See earlier reply, "Did you get NGS (next generation Sequencing)"

Good idea to make that MPN specialist apportionment.

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