Has anyone gone from Pegasys to Besremi?

[ET625]

Hi all,

I am a 65 year old woman in the US with ET. My hematologist has had me on Pegasys for 2 years now, starting with 45 mcg, then 90 mcg injected once a week. Originally my platelets were in the high 400's and have crept up even with the injections and are now at 610. He had me go up to 135 mcg January 1st but the first time I did it I felt terrible for a week- flu symptoms, migraines and anxiety. We are now trying " in the middle" at 112 mcg. which I have been handling well and I am going to have my blood draw next week to see if that is helping to lower the count. Otherwise, my blood is in good shape with everything in the normal range.

First question, has anyone had this "sluggish" result with Peg? I see and know so many people who have had great results, even at lower doses. I am 5'8" and 160 lbs.

I have complete confidence with my doctor. He is at Weill Cornell in NYC and one of the top MPN doctor's there.

My last visit he informed me that Weill Cornell is doing a trial putting Pegasys patients onto Besremi (it is not approved in the US for treatment of ET and they are trying to get it approved). One of the (great) benefits is that if I participate in the trial the treatment will be free for me. I am an excellent candidate for this trial given all the above. The starting dose would be 250mcg I believe every two weeks.

I went online and googled Besremi and was very alarmed at the potential side effects- of course I know the potential side effects of Pegasys and have had some along the way, particularly anxiety as I am already an anxious person and have been on Zoloft 50 mg. for 20 years. Besremi looked even more intense and I am scared of what could potentially happen to me.

Sorry for this long post! So, has anyone been on Pegasys and then been switched to Besremi? What was that like?

And what is it like to go on Besremi and were people started at that dose? My doctor explained to me the difference in the two medicines doses but starting at 250mcg sounded high but that dose is the initial trial dose.

Thank you ahead of time and again sorry for the long post!

Deirdre

[EPguy]

I agree 250 is high since, at least for PV, much lower doses are effective for many, I've posted on members' early dosing.nnYou have access to the top institution, they should have good advice on your Peg experience vs any risks of the planned Bes dose.

A good thing is you have not experienced obvious autoimmune effects on IFN which are a rare worst case for which I am the top example.

You're probably referring to the ExceedET trial. If so this is the plan:

"Ropeginterferon alfa-2b-njft will be administered subcutaneously every 2 weeks at the starting dose of 250 mcg (Week 0), 350 mcg (Week 2), and target dose of 500 mcg (Week 4) and remain fixed for the 12-month treatment period."

ascopubs.org/doi/abs/10.120...

So it titrates to a very high dose, "the whole bottle" by week 4. Did they mention the titration plans in your case? Is there an option to raise it more slowly? At 500 it is at least equivalent to 135 of Peg, but the mfr is suggesting this is ok for Bes.

[monarch5000]

I have PV, am 70 yrs old, and was on Pegasys at 90 mcg every week for 6 years until January 2023. Then out of curiosity, I tried Besremi for two months at doses ranging from 125-175 mcg.

I did not like Besremi at all. Super dry eyes, mouth and skin. Joint and bone pains that made me walk slow like a much older man. I was anxious to get back on Pegasys so I could feel back to normal again.

Not everyone has the bad experience I had with Besremi. Some tolerate huge 500 mcg bi-weekly doses of it. But on various MPN forums I've noticed quite a few Pegasys users that switched to Besremi have ended up going back to Pegasys.

In sum, it can't hurt to try Besremi, but be sure you have the option to return to Pegasys if the side effects turn out to be worse.

[KLCTJC]

I agree with EP guy 250mcg is high without doing any intro dose. You maybe fine because you are “kind of” used to it being on peg already. I have been on Besremi for almost a year and we went slow. There are different approaches but I like low slow. Can always go up! I am on 225mcg, but it took 9 mos to get there. I go today for labs 🙏 But I feel good. Not sure if that would have been true if they started high, would have been like a shock to the system. My last two sets of labs October and end of November were great. So hoping for better or no change today. But I love this drug. Will stick with it til something better rolls around. Talk to your doctor and express your concerns and see what he says then decide. Good luck!

[WRLM]

I am in the Exceed ET trial, but was not on Pegasys (or anything else except aspirin) prior to starting.

I’ve had my 250mcg & 350mcg doses so far. Will proceed to 500mcg on Thursday if my labs look good.

I’ve had pretty minimal side effects so far; mostly sleep issues, burning/irritation at the injection site and fatigue (unsure if the fatigue is an actual side effect of the drug or the result of my interrupted sleep/insomnia, or a combo of the two)

I had a pretty substantial drop in my platelets after the first injection, but my Dr said not to be concerned if they bounce back a bit. I’m interested to see my lab results this week!

I have seen a few other patients in the same study in passing, and they’ve reported similar, minimal side effects, even with the high starting dose.

Feel free to reach out if you have any questions. 😊

[hunter5582 in reply to WRLM]

I did switch from Pegasys to Besremi. I found no difference in the side effects at all. I do think it correct that adverse effects are dose dependant.

The dose equivalent PEG>BES conversion for a starting Besremi dose provided by Dr. Ruben Mesa is Σ monthly doses x .7/2. 112mcg X 4 = 448 x .7 = 313.6 /2 = 156.8mcg every two weeks. It would appear that you would be starting at a higher than equivalent dose of Besremi, then escalating rapidly.

The study that is recruiting looking at Besremi for ET is the EXCEED ET clinical trial. clinicaltrials.gov/study/NC...

You can look for more clinical trials here. clinicaltrials.gov/

We all react differently to each of the meds. Some find no difference in adverse effects at an equivalent dose of Besremni or Pegasys. Some respond differently to one that the other. While you response to Pegasys might predict your response to Besremi, it also may not.

It would be best to talk review this all again with your MPN Specialist. That will be your best source for case-specific considerations.