HU wait time to take effect

[Jazzman7]

Hi good folks!

In your experiences, how long does one wait for the chemo (hydroxyurea) to significantly lower the platelets?

74 y/o male with ET/jac2. I started 500mg 2X/day 8 days ago. Had blood work done yesterday and down from 664 to 579. If the threshold is 430, then I have a long way to go. I realize everyone reacts differently.

Thanks so much for your thoughts.

Jazzman7

[Whitehair51]

My count dropped from 1.1 million to 534,000 in 2

[Bluetop]

I have PV and when this was diagnosed (aged 66) I first had two phlebotomies (2 weeks apart), these had only marginal impact on the bloods . I then had 500mg hydroxy/day for a fortnight, this again had marginal impact so the dose was increased to 500 x2 per day. This did the trick within a fortnight.

At diagnosis my haematocrit was 0.507 and came down to 0.411. Two weeks later it went to 0.25. As it settled, my hydroxy dose was tweaked and this continues to be the case (after 6 years).

I currently take 6.000mg/week, with a haematocrit of around 3.9. Ofcourse everyone is different. This just gives you my experience. Good luck. Good that you have been diagnosed and your bloods can now be managed.

[Jazzman7 in reply to Bluetop]

Bluetop

Thanks so much for sharing your information with me. Helpful. Hopefully, the 500 2/day will kick in soon.

All the best

[Cokopops]

Hi. Like you say, everyone react differently. I started hydro two years ago but stopped because of bad side effects. After a couple of months I was given the choice to retry hydro or try something else. Looked at the side effects of anagrelide and for me that looked worse. So went back to hydro. Side effects controlled and platelets down from 700 to 469 . Slow but haematologist happy. Good luck!

[Jazzman7 in reply to Cokopops]

Kokopops

So appreciate your response! This process is daunting on the front end isn’t it? Sticking with the regimen and trusting for good results.

Appreciate your information so much!

[Meatloaf9]

Hi, when I first started on HU, 2 per day, my Platelets went from about 650 to about 300 in about 3 weeks. I now have PV 73 yo and have so far settled on 9 HU per week. Best to you.

[nightshadow]

Hi Jazzman,

All in all, it took about 9 months for my platelets to stabilize at a good level.

I was diagnosed at age 60 with ET/Jak2 almost two years ago and started on HU 1/day 500 mg. At the start my platelet count was somewhere high 600's. My platelet count began dropping immediately, then plateaued after a couple of months. I was put on 2x/day and they started dropping again, very rapidly. I was not having a good reaction to HU at that dosage and we went to 1/day for 5 days and 2/day for 2 days. This was a good compromise for me, I could tolerate the drug well at that dosage and the platelets continued to drop, finally stabilizing around 300-325. My platelet level has been very stable since.

I had had the same question when I started and the timelines were pretty widespread, anywhere from a month to almost a year. Fortunately, I started to see improvement in the symptoms of ET in only a few months, far before the platelets reached the goal level.

[Minify]

Hi Jazzman, You and I are sorta on the same timeline. I was just diagnosed one month ago (ET JAK-2), and today is my 30th day on Hydroxyurea 500 once daily. My hematologist told me it may take 3 months to get a stabilizing dose. She wrote me a standing order for CBC every two weeks (for one year) so we can monitor and tweak the dosage.. and check in via telemedicine monthly.

Start - Hct 49, Platelets 697K, WBC 9.06

2wk. -Hct 46, Platelets 518K, WBC 8.73

4 wk - Hct 46, Platelets 480K, WBC 7.33

Hematologist said the numbers they monitor to gauge impact and adjust dose are Hgb, Platelets, and WBC. I’m expecting my dose will be moved up a bit, as the recommended dose is 15mg/kg/day, which would be about 900 for me. I’m glad she started me off low, and I haven’t had any side effects.

I’m in the high risk group (age, previous stroke), so also take a statin and aspirin and do all the other healthy lifestyle cardiovascular measures.

Lauren- 70yo ET-JAK-2, Hydroxurea 500 daily, ASA 81mg day.

[hunter5582]

You are correct that we all respond differently to HU and the other meds used to treat MPNs. Response to HU ends to be faster than the other first-line treatment option (Pegasys) but everyone has a different rate of response.

It is also worth noting that it is normal for platelet levels to cycle by as much as 100 in a single day. When I was not using cytoreductive treatment, my platelets would routinely cycle between the 500s and 700s. It is always the trend that matters, not any single lab read.

A common protocol for initiation of HU calls for a CBC every two weeks until you reach goal and remain stable. this is the protocol my doc used. More frequent CMPs are also called for during initiation of HU to monitor for kidney and liver toxicity. Once goal is reached and tolerance is established, CBCs and CMPs are less frequent.

Many people start on 500mg/day and monitor for a month or two to see how they respond. If a more rapid response needed, some dose at 500mg/2x-day. I think it is common for it to take several months to reach goal.

Suggest you circle back to your MPN care team for input on how rapidly they expect you to reach goal. Hopefully, your care team includes a MPN Specialist rather than a regular hematologist. This helps to ensure optimal MPN care.

Meanwhile, here is some information you may find helpful.

drugs.com/monograph/hydroxy...

online.epocrates.com/drugs/...

oralchemoedsheets.com/sheet...