Rituximab Round Four

[Sangye]

I got some info from the JHU infusion clinic nurses today about the dosing and administration of rtx. The clinic is very conservative about how they administer rtx so they have a low rate of allergic reactions.

The 2-infusion protocol: 1,000mg of rtx each infusion for every patient (ie, not based on height/ weight).
The 4-infusion protocol: Dose is 375mg/m2 per infusion, so the actual dose you receive is calculated based on your height and weight.

I'm pretty fat, so on the 4-infusion protocol I get 900mg of rtx each infusion (total 3,600mg). That's a lot more rtx than I got on the 2-infusion protocol (2,000mg) and is probably why it didn't work for me. It makes me wonder if "larger" people need the 4-infusions but smaller people do okay with 2. A smaller person would receive similar doses using either protocol. I'll definitely ask Dr Seo if he's seen that trend.

The nurses also told me:
--The rtx (at any dose) should be given in a 500 ml bag of saline. Some infusion centers are using 250ml to speed up the infusion, but this is too fast and makes it more likely to have a reaction to the rtx. The nurses said the studies used 500 ml of saline.

-- Appropriate "pre-meds" need to be given to all patients--solumedrol and Benadryl. I get 100mg solumedrol. Some of their patients even get 150mg. They now give the solumedrol and Benadryl and wait 30 min before starting the rtx. This has decreased allergic reactions.

Rtx is a genetically-engineered antibody. The pre-meds work by sort of hiding the rtx from your immune system so it can go in unnoticed. You don't want to form antibodies to those antibodies or you'll be unable to take more rtx.