Peripheral Neuropathy - Retuximab

This blog is now devoted to documenting the several disease processes that I have and serves two purposes: first to give me a permanent record of the course of these diseases and, secondly, to provide information to those searching online for information in these areas.

As a follow-up to my blog of 4/21/10, the neurology department at OHSU informed me that Medicare coverage for the IVIG treatment for my peripheral neuropathy would expire in 12/10. This would most likely not be renewed because of the expense involved: about $160,000 per year. So, I have been looking for alternate treatments.

In the April blog I outlined the possible treatment options available. Since then, I have done some research and, also, saw the hematologist who has been supervising my treatment, Dr. Deloughery. We agreed to follow what appears to be the best treatment available based on current research.

I tried Retuxmab in February 2009 at which time I noted no improvement in symptoms so we progressed to IVIG which did give me some symptomatic relief, indicating that it was effective in halting the damage to my nerves caused by the Gammopathy. However, in reading some of the recent literature it became apparent that Retuximab may not only improve symptoms but it may also halt progression of symptoms without showing any immediate improvement in symptoms. Markers have been evaluated to assess whether they can give a measure of the effectiveness of treatment. Benedetti (1)felt that IgM levels gave the best measure of improvement and hypothesized that there may be a critical level of IgM where disease would be triggered, and conversely, a reduction from an abnormal level where you would see improvement or stabilization. Anti-MAG titers were less clearly related to clinical changes.

It is pointed out by Ramchadren (2) that there is a distinction between the gammopathies associated with the M protein DADS-M (distal-acquired demyelinating sensory neuropathy) and those without the M protein, DADS. The latter characteristically have elevated levels of IgA/IgG. A distinction is that DADS-M occurs more in an older population and is predominantly a sensory neuropathy with mild distal weakness. Large fibers controlling vibration and proprioception are affected more than pain and temperature sensation, resulting in progressive balance problems. DADS presents a more variable picture; there is typically more weakness and less balance problems. Another distinction is that DADS-M responds more to Retuximab while DADS is more like the neuropathy seen with CIPD and is more likely to respond to treatments for this type of neuropathy.

My neuropathy appears consistent with DADS-M and, so, should more likely respond to Retuximab. I expect we will stop the IVIG therapy within a few months and switch to Retuximab. We will check markers and, in addition to checking IgM, we will also check the other markers that have been used, anti-MAG titer and level of B cells
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1 Benedetti L, Brian C. Grandis M, et al. Predictors of response to Retuximab in patients with neuropathy and antimyelin associated glycoprotein immunoglobulin M. J Peripher Nerv Syst 2007; 12: 102-107.
2 Ramchadren S, & Richard A. Lewis. Monoclonal gammopathy and neuropathy. Current Opinion in Neurology 2009; 22: 480-485.