[marijasgirl]

Can Darzalex cause M-protein to show up?

by marijasgirl on Wed May 17, 2017 2:00 pm

Hello everyone!

My mom recently had her second stem cell transplant after her multiple myeloma got very out of control very quickly.

Long story short, the stem cell transplant worked! Now 5 months out she is feeling the best she has felt in a couple years! We trust and expect this to stay consistent for years to come!

She was presenting with only kappa light chain multiple myeloma after her first relapse. With the stem cell transplant, the light chains have come to a normal range now.

However, at her last check up the M protein (M-spike) showed as " >1", so to me that means its more than 1.

Her oncologist said he wasn't concerned. He thinks that because she is now being treated with Darzalex, it can be detected as a monoclonal protein, and also because the myeloma was only detected in her light chains at relapse. My mom has not had a detectable M-protein value since she was diagnosed back in 2013.

Has anyone heard of this happening?

[Multibilly]

Re: Can Darzalex cause M-protein to show up?

by Multibilly on Wed May 17, 2017 6:44 pm

Hi Mairjasgirl,

This is actually a well-reported phenomenon. See this article and this press release.

"Interference with Determination of Complete Response - Daratumumab is a human IgG kappa mono­clonal anti­body that can be detected on both, the serum protein electro­phoresis (SPE) and immunofixation (IFE) assays used for the clinical monitoring of endogenous M-protein. This interference can impact the determination of complete response and of disease pro­gression in some patients with IgG kappa myeloma protein."

[marijasgirl]

Re: Can Darzalex cause M-protein to show up?

by marijasgirl on Thu May 18, 2017 10:46 am

Hi Multibilly!

I was hoping you would be one of the people to respond to my question! You always have great information as well as proof to back it up!

Thank you for providing the articles, it definitely puts my mind more at ease!

Thank you!
Una