Switching to Bisremi

[Izzys-Mum]

Hi Everyone, Could do with your thoughts, I'm usually on Pegasys 65mcg every 5 weeks (I'm ET Jak2) and my numbers are all good.

Due to shortage of Pegasys (in UK) I've been given Bisremi and told to continue with 65mcg every 5 weeks, which from what I've seen on here seems unusual to carry on same amount/frequency as Pegasys. Anyone have any experience of this?

[hunter5582]

Besremi and Pegasys are different formulations with different half-lifes. Besremi has a longer half life, usually requiring a lower combined monthly dose to achieve the same effect. The attached slide has the standard conversion formula when moving from weekly Pegasys to bi-weekly Besremi. Switching from Pegasys every 5 weeks to Besremi every 5 weeks would need to use a different formula for an equivalent dosing regimen.

It is very reasonable for you to question this dosing recommendation. It is worth noting that 65mcg every 5 weeks is still a very low dose. Suggest that you seek a second opinion on the dosing from a MPN Specialist or consult with a specialty pharmacist about your concerns. I would also suggest more frequent monitoring of CBC/CMP during the transition period. You will want to carefully monitor your response to the change and titrate the dose as needed.

This will be new territory for many people. Please let us know what you learn and how you get on with the change.

PEG to BES conversion

[Izzys-Mum in reply to hunter5582]

Thanks Hunter as you say new territory, I'll seek a second opinion for dosing.