Pegasys --> Besremi and HCT

[Swede99]

Hi,

What a great forum - thanks to you all for contributing.

I'm a 37 year old male - diagnosed with PV 3 years ago. I recently made the jump from Pegasys to Besremi. I was on 135ug every 9 days without need of supporting venesection (at least for the last 8 months or so). Since switching medication 9 months ago, I've gradually increased Besremi dosage to 400ug biweekly but have trouble with keeping HCT below 0.45 (3 venesections since the switch). Anyone had a similar challenge or have ideas on what to do and if to consider going back to Pegasys? I've also found that some of the side effects (fatigue, mood) that came with pegasus but that subsided with time are back again with Besremi, hopefully they will subside again with time...

Thanks!

[hunter5582]

It is hard to say exactly what is going on. Whether this is a function of a different response to the Besremi vs Pegasys or a change in your PV status is hard to say. You were on the higher side for the Pegasys dose for PV. It is not surprising that you would need a higher dose of Besremi as well.

We are too new to the switch from Pegasys to Besremi to have adequate data. Others have reported a difference with at least some responding better to Pegasys. I would predict that what we will find is that it is like most other options for treating PV. We are all different in how we respond. At this point, there is no way to predict. We just have to try different approaches until we find one that works.

Suggest going back to your MPN Specialist to review your PV status. At a minimum, I would recheck the Variant Allele Frequency to see if there has been any change in the JAK2 allele burden. I might consider a comprehensive NGS MPN panel to see if there are any non-driver mutations involved. The MPN Specialist will likely have other ideas of what should be checked to determine your current status.

This may be simply a difference in how your body responds to Pegasys vs Besremi. It is very reasonable to thinks that some people will respond differently. The only way to find out would be to switch back. It would also be an option to increase the Besremi dose and see if you are able to tolerate it.

Please do let us know how you get on and what you learn. Everyone can benefit from your experience and knowledge.