I have been on Besremi since May 2023, now consistently at 500 mcg.
So far it has brought my platelets under control where they have remained 200-300 consistently.
I have continued to need phlebotomies roughly every 80 days on average, though it can vary quite a bit, so my HCT has not seen control yet and the frequency of the phlebotomies have not really become any less frequent. I have tracked this data since I started getting them in 2020.
There are many in this group in a similiar position. However, I recently plotted out my RBCs to see how they are trending. The theory is that RBCs should be an indicator for HCT. HCT is the percentage of RBCs in our blood. So if RBCs are declining then it should follow that perhaps the HCT would then be more controlled. Does this rationale make sense?
If true, then tracking RBCs might be an indication whether the HCT might be controlled at some point in the future. Here's my plot of my RBCs over time. Note again that I started Besremi May 2023 at 50 mcgs and it took me a while to ramp up. I increased even more slowly than the normal 50 mcg each dose.
Thoughts on whether this could be an indicator? For those that have HCT under control from Besremi and who are also experiencing a CHR whether they had a similar pattern of improved RBCs prior to HCT control?
All thoughts welcome!
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Luthorville
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HU has a large effect on MCV so a bias would be expected on HU. For any treatment, the trend in MCV would be important.
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Here is my actual plot of the two. Interestingly the two parameters correlate least on Bes, better on HU or Rux. On Bes a general rise in RBC with no change in HCT.
That low point on Bes was the same days as my weak warning of disaster to come.
Did you start Bes 2020 or 2023? I assume you mean 2023. If so the Bes seems to have no clear visible effect on the RBC trend in that time frame.
Here is my full history. HCT is in red. The dates I had a phlebotomy are in blue. Again I started Besremi in May 2023 and so far, it does not look like it has any impact. But what I'm questioning is whether the improvement I've seen in RBCs suggests that HCT might be better controlled soon. That also does correspond with the timelines we've seen for an improvement in HCT from Besremi where it seems to take 1-3 years.
EPguy, I don't recall you having a lot of phlebotomies. I think they were more rare for you, but looking at HCT alone probably isn't enough. My HCT is only as low as it is because of the phlebs.
Makes sense HCT is redundant when controlled by phlbs, as it is assured to be in range. Same for Hb since these two are directly proportional. So for a given RBC, HCT will be higher as MCV is rising. (assuming the equation above applies) .
My take is as your MCV normalizes upward it will take a steeper drop in RBC to get HCT in range. The RBC plot you have does show this getting steeper, but visually the Bes doesn't look like the reason since there is no visual change in the trend after starting Bes. Of course there is a lot more to it all than just these items.
I find large variations in reported CHR response rates and durability of it. I made this plot (see my 2nd reply here) years ago from one of the reports, it's likely in an old post with the reports it's from. Also all the drug treatments we use also have surprisingly large % that don't maintain CHR, One example at year 3 "Maintenance of complete hematologic response ...39%" I've seen similar for Rux ect. This seems to conflict with our experiences here.
This report has a good compilation of the Bes studies.
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Interesting that in my case MCV was lowest on Bes, as in this plot. You're right I never had a phlb, my 1st Dr planned it but my HCT normalized on its own a few weeks post Dx before that could happen. If one wants higher MCV HU is quite good at it, but this is not usually a goal in that context.
This is a plot I made for a post long ago, likely from text in a report at the time. It shows ~70% getting CHR on Bes starting year 1. There must be fresher cleaner versions of this info available, but it broadly matches what I recall learning.
I am glad to hear that you are able to tolerate the max dose of Besremi. It sounds like you need the higher dosing.
There is not a single erythrocyte number that tells the whole story of what is going on with your PV status. There are three ways to measure PV status, HCT, HGB and Red Cell Mass. Note that Red Cell Mass is not the same as the RBC count. You are correct that the RBC count would be related to HCT, but there are other parameters. One of these is plasma volume. There are other erythrocyte numbers that also matter so interpretation needs to be done in toto. Most people use HCT as a singular number as a natter of convenience.
My max tolerated dose is 175mcg. This is keeps the thrombocytosis and erythrocytosis under control with only one phlebotomy/year. I consider this to be a complete hematologic response. It has also dropped my JAK2 VAF from 38% to 10%. I am very pleased by my response.
The JAK2 VAF improvement to that degree is fabulous. Thrilled to hear that level of improvement. I have gone from roughly 15 to 14, so a smaller improvement in roughly 14-15 months.
My HGB has always been within the normal range, but at the slightly lower end of that. Do you mean the MCV (mean corpuscular volume) for the Red Cell Mass? The MCV does measure the average size of red blood cells. But the MCV is typically low when receiving phlebotomies because of the intended iron deficiency.
Nonetheless, my MCV has improved since I've started Besremi. Here's my full MCV history. I'm not sure if this is because of the Besremi or not. Looking at the timing, it would suggest that some of the increase is likely due to the Besremi. Still, with the frequency of phlebotomies that I receive, I think it is not surprising to see MCV remain low.
HCT is calculated based on the total mass of red blood cells. One condition that could occur in PV patients is enlargement of red blood cells. So HCT is related to RBC count but not a sufficient indicator.
RBC levels are high and you can see mine graphed on the very first graph posted. It peaked around when I started Besremi and has been slowly coming down. MCV was low, but normal and then fell rapidly as I received a lot of phlebs initially to get the HCT in line.
Since that time, my MCV has been climbing again since around July 2023. The timing is interesting because I started Besremi in May 2023. This suggests that the rebound I've seen in MCV along with the RBC is due to the Besremi. Hopefully it results in HCT control.
My point of posting this, is that this does suggest that tracking RBC and even MCV could be an indicator of whether HCT will be improved/controlled. I wanted to hear what others thought about that. But I've seen no data on this whatsoever.
I think your assumption is likely correct, ie reds coming down are a good indicator that Hct will follow. I am sure you know that Hct=RBCxMCV. Your MCV is improving since starting Bes, (but slowly because your still venisecting ) , reds are lowering but MCV rising equals Hct staying up but as reds fall (as Bes does it’s job more) and you slow/stop venisecting Hct should/could come in line. The interferons can take a while to control Hct without. Venisect, I’ve seen 2 years with some at max dose Peg.
I seriously learn something every time I read this group. This all makes sense. I have my quarterly meeting with the team in a couple of days, so will definitely discuss this-
For me, it took longer for the HCT to come under control, and it appears to have followed the RBC by a few months. I got to the max dose of Besremi (500) over the course of four months, and it took 11 months from start of treatment for the HCT to be controlled without supplemental phlebotomies. Good luck with your treatment!
Very, very interesting. You were on Besremi early, which is great. It sounds like your HCT was normal, you said roughly 11 months after you started Besremi, but you were on the max dose for 7 months by then. I only went onto the max dose 2 months ago and had been around 350-400 over the prior 6 months. My RBCs are coming down, but not as quickly as yours. Your HCT was controlled on the graph roughly around May 2023 then when the levels hit 5.0 RBC. My RBCs are now 5.77 and 5.99 last 2 readings, off of the peak of just under 7. But the rate of decline has accelerated at the higher dose of Besremi and the decent slope now looks more similar to yours over the past 3 months. I'm curious where others saw their HCT stabilize in terms of RBC counts.
While my HCT has not currently stabilized, I wonder if it will follow a pattern similar to yours. Did your need for phlebs slow and then stop or was the improvement more rapid?
I am also on Besremi but only since Feb 2024. My HCT is not yet controlled and required several phlebotomies. I have only been at 500mcg for six weeks. Dr Masrova at MDA told me that HCT is the last to respond to Besremi and that usually takes the high dose for a good response. The RBC fight back! She would not say how long to expect to stay on high dose, but told me I need to be patient. I am also on iron supplements which make the dance of iron vs phlebotomies an interesting balancing act.
Yeah, it has been discussed on this group quite a bit. It's typical to take 1-2 years, sometimes longer to see a response with HCT. But it only happens some of the time depending on the study, perhaps 40% of the time.
I'm on Besremi for PV. Since Dec 2023, my RDW CV has moved downward like this: 25.6, 22.9, 20.2, 17.2, 16.2. Similarly, my RDW SD has reduced like this: 72.9, 69.2, 63.4, 57.1, 53.3. My platelets started at 472, and moved mostly downward like this: 461,386, 375, 423. HCT on the other hand has floated around from 41.8 and 44.8. Similarly, my RBC numbers started a bit high and flowed up and down before normalizing. For quite a few months I have been on the tiniest dose of 50 mcg, since my numbers were pretty good but side effects plenty tho not earth shattering. My tiredness and lethargy is pretty bad this summer, even at the tiny dose, so is the Besremi not to blame?
Hard to know the cause of the exhaustion. The side effects seem to vary enormously from person to person and range widely. I've been on 500 mcg and my only side effect, from what I can tell, is itchiness, though my Hematologist says this is from the underlying condition. I'm skeptical due to the timing of when the itchiness began and also when it happens relative to when I take the Besremi dose. But perhaps it's both.
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