My personal experience is that Pegasys Interferon works very well and few have any side effects.

Plateletpheresis is rarely used to treat thrombocytosis. It would temporarily reduce the number of platelets but the overproduction of platelets would continue unabated. It is similar to a whole blood donation but the platelets are separated out and other blood components are returned to the patient. It can be done with a single line, like a whole blood donation.

Therapeutic phlebotomy of whole blood is used to treat erythrocytosis. It does cause iron deficiency since it is removing the red blood cells where the iron is found.

While plateletpheresis might be used occasionally, it is not a part of routine care for ET. Your MPN care team can do the best job of explaining each of your treatment options on a case specific basis.

Plateletpheresis was only used on me for 18 months because the antibiotic ciprofloxacin damaged my p450 endocrine system and made all PV meds toxic to me. I could not even handle 1.25mg BID of Jakafi. It's pretty extreme. For the most part it doesn't hurt that much doing the treatment, but the surgeries to insert and remove the catheter do hurt. Takes about 4 hours. If you need to pee, you can get a urinal. Ironically, with my health care provider, it was a $0 copay, so it turned out to be cheaper than my med, other than the cost of the surgeries. The big drawback is that the IV can cause clots. I got clots in my jugular vein. They gave me blood thinners to fix it, which caused internal bleeding in my leg. You have to be vigilant on clots and bleeding. So, you're on this rollercoaster, bouncing between extremes. It's a decent stopgap if you can't handle any meds. Just like HU, it doesn't address the underlying issue. The anemia got bad enough that I needed iron infusions. Things were looking dire, but eventually, I was able to use medications again.

I've been on most of the meds, but the miracle was the combo of Jakafi/Pegasys that turned everything around.

After a few errors, and scarring, with venesections courtesy of an ancient GP, I now use an emla patch to numb the area of my vein where the needle will be inserted. Don’t feel a thing. Plus, I now have rare venesections done in the oncology ward of my private hospital, they really know what they’re doing!!!

There is huge variance in how insurance plans and Medicare Part D plans arrange the copays. Even internally to an insurance company like BC/BS , there is wide variance between plans. You would need to call your insurance plan to find out what copay you would be responsible for once a medication is approved. I think you can assume Pegasys, Besremi, and Jakafi would be higher tier medications with a higher copay. The better plans all have a cap on monthly out-of-pocket copays for any medication. The better plans also have an annual cap on out-of-pocket expenses.

The Medicare Part D plan I am enrolled in is managed by Cigna and sponsored by my former employer (a county government that I retired from on full benefits). This plan is structured to have maximum out-of-pocket caps on both a monthly basis per medication ($100) and on a yearly basis ($2,000) for all medications. The good news for people on Medicare Part D plans is that there will be a $2,000 yearly cap for everyone on all plans in 2025.

If you reach the point where you need to use cytoreduction for ET, then you will need to make a choice about which agent to use. The current NCCN guidelines include hydroxyurea and Pegasys as preferred choices for ET. Note that neither of these medications has a FDA indication for any MPN. They are both used off -label, but are in common use. Besremi and Jakafi have an indication for PV but not for ET. Both of these medications are in clinical trial for ET. Hopefully, they will receive FDA approval for ET in due time.

It is correct that there is data about Besremi/interferon and Jakafi reducing the JAK2 allele burden (Variant Allele Frequency). There is evidence that Besremi has the benefit of improved progression free survival for people with PV. While there is still debate about the role of allele burden in MPN status, the emerging consensus is that VAF does matter and is a valid biomarker for MPN status and treatment. In my own case, Treatment with the interferons (Pegasys/Besremi) has reduced the JAK2 VAF from 38% to 10%. The IFNs have kept the erythrocytosis and thrombocytosis well controlled on a low dose (175mcg Besremi). My quality of life has significantly improved compared to what I experienced when using hydroxyurea and phlebotomies.

By the time you need cytoreduction, you may find there are even more options. Bomedemstat is in clinical trial for ET and looks promising. There are other agents in research as well.

Wishing you all the best.