Jak2 now "Undetectable"

[WindyGale]

Hi

I was diagnosed with Jak2 positive PV back in May 2019, after months of venesections I was put on Peginterferon in Nov 2019. The first year I was 0n 45mg which worked well, without the need for any venesections. Then my HCT started to creep up again. Over the coarse of 9-10 months they gradually increased my dose to 135mg, which I have been on since sept 2021.

Over the last 12-18 months, I have had to have a venesection every 3-4 months. They have been suggesting that maybe another increase in my Peg was needed. Now after my latest blood test my HCT was 0.493, but out of the blue they are now saying that my Jak2 is now "undetectable" and are suggesting a reduction in my Peg even though my HCT is still rising.

I am so confused!! Has this happened to anyone else, where your Jak2 positive effectively becomes negative?

[ainslie]

I think I would be a bit sceptical about that. Number one is keep Hct below 45 , it seems very odd that on such a high dose of Peg your Hct is 49 and at the same No Jak2 detectable, even more concerning is the advice to reduce Peg dose while Hct rising. One simple thing to do is retest for Jak 2. If it’s still allegedly undetectable I would be getting a second opinion from a MPN expert. First thing to do is venisect until Hct is under 45.

[WindyGale in reply to ainslie]

I was hoping for a venesection, as the fatigue is getting to me atm ☹️

[Manouche]

Hi WindyGale,

Do you know what your jak2 level was at diagnosis ?

[WindyGale in reply to Manouche]

Unfortunately , I don’t think I was ever given a figure, just told that it was positive

[hunter5582]

I would agree with ainslie that retesting is indicated to be sure that there was not a lab error. If it confirms that the JAK2 mutation is no longer detectable, congratulations. This means you have achieved a molecular remission. The interferons are capable of inducing this response in some people. While everyone is very hopeful about what this means, it is unclear what all of the implications are. This issue is currently being studied.

It is worth noting that the Upper Limit of Normal HCT for males is 50/51%. The goal for males with PV is HCT<45% since this is associated with a reduced risk of thrombosis. Some MPN care teams are more comfortable with patients going above this target based on their MPN profile. SUggest that you consult with your MPN care team to see exactly what they are thinking and why. Is the plan to continue to use HCT<45% as your treatment goal? Will you reduce the PEG and continue to use venesections? What do they think the implications of a molecular remission are if it is conformed?

Please do let us know what you learn and how you get on.

[WindyGale in reply to hunter5582]

I have a face to face appointment scheduled for two weeks time, was just trying to get my head around it all before the appointment and go armed with a list of questions 😊

[Ben2022]

Hi I'd like to know if you have other so-called non-driven mutations besides the driven jak2? Sometimes the dirvens disappear becuz the new non-driven appears. But hope you just KO the driven jak2.

[Hopetohelp]

Not sure about the Haematocrit except to say drink plenty of water which I am sure you already know, but news on jak2 burden sounds very encouraging

[Limitpusher]

Did they do a bone marrow or new genetic test? how could Jak2 be undetectible if the didn't test for it? I go to Texas Oncology at Baylor in Dallas Texas and I am told that there is no way that a gene can unmutate once it has mutated. this sounds very fishy to me.

[Minify]

I’m very interested in hearing the outcome of your next doctor visit. I wish there was more information on the implications of the quantitative JAK2 (allele burden). One would think it’s related to disease severity/progression, but apparently that has not been proven. Please keep us updated. Thank you!