rituximab dosing schedule--Q. for Dr. Edwards

[jaybee00]

Dear Dr. Edwards or other knowledgeable people,

Someone I know met with a rheumatologist for rituximab treatment for CFS. The physician said that if the patient receives 1g at day zero and 1 g at week two, then there could be problems if 500 mg are administered at 3 months resulting from low immunoglobulins. He suggested 500 mg at day zero, week two and 3 months or 1 g day zero, 1 g day 15 and no treatment at 3 months and then 500 g at 6 months. Thoughts on this?

Also what about co-administration of rituximab with methotrexate? He also recommended this.

Thank you

 

[msf]

I think combining Rituximab with methotrexate or other immunosuppressives is risky, unless you are sure you don´t have any infections (and aren´t going to acquire any nasty ones in the next few years).

 

[deleder2k]

It sounds like this doctor has no clue. The point is to kill as many B-cells as possible, isn't it? From what @Jonathan Edwards has said earlier it doesn't sound like low IgG levels is a major concern(?).

 

[Jonathan Edwards]

Dear Dr. Edwards or other knowledgeable people,

Someone I know met with a rheumatologist for rituximab treatment for CFS. The physician said that if the patient receives 1g at day zero and 1 g at week two, then there could be problems if 500 mg are administered at 3 months resulting from low immunoglobulins. He suggested 500 mg at day zero, week two and 3 months or 1 g day zero, 1 g day 15 and no treatment at 3 months and then 500 g at 6 months. Thoughts on this?

Also what about co-administration of rituximab with methotrexate? He also recommended this.

Thank you

It sounds as if the rheumatologist does not have a good grasp of rituximab biology. It may be OK to use 500mg on day one and a week later (two weeks is a hang over from my very first pilot study that got into the license by mistake) but until we have a robust dose ranging study we keep to 1gm twice. There is no reason to think that giving 500mg at 3 months is a particular problem for low immunoglobulin levels - which probably reflect the total period of depletion if they occur. Leaving the second dose to 6 months is usually OK in RA but some patient's B cells are already coming back then and a bit earlier may be sensible. We do not know what is best in ME and only have the Norwegian experience to go on - which is to retreat early.

There is no good reason to give rituximab with methotrexate. This idea is based on the fact that the drug company got a license with methotrexate so that they could patent the idea (sadly for them the courts agreed that it was my idea not theirs and that the methotrexate mixture did not deserve a patent!).

Drs Fluge and Mella are not keen on people being treated outside trials until we know more about efficacy and I would certainly advise against this sort of do-it-yourself dosing approach.

 

[jaybee00]

Thanks much for the reply..I had been on holiday and didn't see the reply until now.

Regards.