A question which comes up not infrequently during nephrology fellowship is whether or not to perform pheresis on patients with multiple myeloma. Once very much in vogue, the results of a fairly recent (Annals of Internal Medicine, 2005) randomized control trial cast doubt on the efficacy of plasma exchange in this group of patients, and it is not used with as much enthusaism (though I have certainly seen it done).
The trial was done on over 100 patients with newly-diagnosed myeloma and acute kidney injury who were randomly assigned to conventional therapy alone versus conventional therapy plus pheresis (5-7 treatments over 10 days). The end-point was a combination of death, dialysis-dependence, or GFR<30 at 6 months. The two groups did not show any significant difference though there was a slight “trend” (58% versus 69%) towards benefit in the pheresis group. Limitations of study were that there was no renal Bx performed and the numbers were small.
I myself am not in favor of pheresis for patients with myeloma. If I were to use it, I would do so only in conjunction with chemotherapy (the clearance of light chains by pheresis, which is actually pretty inefficient, provides a temporary effect only), and in patients with relatively high concentrations of serum & urine light chains. I would imagine that this treatment, like many in nephrology, would be much more effective early on in the course of renal involvement, and may have little effect on patients with advanced renal failure or those already on dialysis.