ET Jak 2 Hydroxcarbamide Low WBC

[Cassandra61]

Morning everyone,

I have been on a daily 500 grm of Hydroxcarbamide for about a year and my platelets have stablised in the normal range. However, just had my 3 monthly check up and my counsultant says that my WBC is a bit low at 3.3. It has been up and down but never this low. He says to lower the dose of Hydroxcaramide and take care to avoid infections as far as possible. He will review in six weeks. Does anyone else have any experience of this? Any advice? I am 61 and really well otherwise; I do loads of exercise and eat well and I feel well so this was a bit unexpected and alarming. I know how lucky I am. I know I don't post very often here but I am so grateful to you all for all the advice and support and understanding: you have always been there when I needed you. Thanks so much and take care everyone.

[hunter5582]

Hydroxycarbamide works by inhibiting DNA activity in hematopoietic stem cells. It is myelosuppressive agent that affects all types of blood cells, platelets, WBCs, and RBCs. Leukopenia is an inherent risk of any myelosuppressive agent. At WBC=3.3, you are considered mildly leukopenic.

Understanding what this mean in terms of risk depends a bit on looking at which WBCs are being affected. Neutrophils (antibacterial) are the WBC the docs are most concerned with. Lymphocytes (antiviral) can also be a concern. The other types of WBCs can be a concern depending on the levels. The more nuanced understanding of what these numbers mean would be a good conversation to have with your MPN care team. particular focus on acceptable levels of suppression of WBCs relative to achieving your treatment goals.

I am also encountering mild leukopenia on Besremi. Mostly lymphopenia. Also experiencing mild neutropenia, fluttering just above and a bit below the reference range. We monitor these numbers with, accepting a degree of mild leukopenia to achieve my treatment goals. Acceptable = NEUT>1.0 and LYMPH>0.50. Providing I do not drop below the mild level of suppressed NEUT/LYMPH, it is considered acceptable.

Note that I feel fine and have not experienced any unusual infections. I weathered COVID about as well as anyone does. Suggest you have a detailed and specific conversation with your care team and set targets for what is or is not acceptable. You may also want to consider what the appropriate target for your platelets should be. many docs not longer use "normal" as the target. That would be another conversation to have with your MPN care team.

All the best.

[Cassandra61 in reply to hunter5582]

Thank you so much as ever for your detailed and thoughtful reply. I was in shock this morning as I feel well although I was walloped by Covid and had the rebound on Paxlovid. I really don't want to fully shield again but will take sensible precausions for the next six weeks until I see my consultant again. Thanks so much for getting back to me, I feel a bit calmer now . Stay well and take care yourself.

[Rem31]

I’ve been on HU for ET for 9 years and my blood counts dodge around from time to time. The MPN team treating me are mostly interested in trends over time and any unexpected dips are monitored with more frequent testing.

Up to now my unexplained WBC and Hb dips have always improved within a few weeks without adjusting HU. The main concern is usually around keeping my platelets within my target range.

It’s reassuring your haematologist is keeping a close watch and that’s to be expected.

[Cassandra61 in reply to Rem31]

Thanks so much for your reply. I was really shocked this morning to hear this news. I think I will take reasonable precautions for the next few weeks including giving up by beloved boxing training and see how it goes. You take care yourself and thanks for getting in touch.