The treatment strategies in patients with partial response to high-dose chemotherapy and ASCT

Abstract

FH Campus Vienna, University of Applied Sciences, Vienna, Austria; Department of Laboratory Medicine, Wilhelminenhospital, Vienna; Wilhelminen Cancer Research Institute, c/o Department of Medicine I, Center of Oncology, Hematology with Outpatient Department and Palliative Care, Wilheminenhospital, Vienna, Austria Background: Up to 10% of newly diagnosed multiple myeloma (MM) patients present with oligosecretory disease. In these instances serum free light chain (FLC) measurements are recommended for monitoring M-Ig changes; provided FLC ratio is abnormal and involved FLC (iFLC) >100 mg/L at presentation. Novel immunoassays have become available that measure immunoglobulin heavy/light chain (HLC) subsets and may offer a sensitive method of monitoring oligosecretory patients. Patients and Methods: FLC and and HLC Ig’ and Ig’ were quantified turbidimetrically in sequential sera from 16 oligosecretory MM patients (6 IgG and 10 IgA) assessed at Wilhelminenspital, Vienna, Austria. Median age was 72 (53-90) years and median follow-up 992 (2533743) days. 9/16 patients were ISS stage 1, 3/16 were ISS stage 2 and 4/16 were ISS stage 3. HLC measurements were compared to serum protein electrophoresis (SPE) and nephelometric total Ig’ concentrations. Results: In 6/16 patients the M-Ig bands were nonquantifiable by SPEP and in the remaining 10/16 patients the M-Ig concentrations were 100 mg/L; and could be monitored by serum FLC measurements. For the remaining 8/16 patients none of the standard techniques provided information for monitoring M-Ig changes. All 8/8 patients had an abnormal HLC ratio and 5/8 had elevated involved HLC (iHLC) concentrations (IgA n1⁄43, HLC ratio: 6.7 (2.9-85.5), iHLC: 7.0 (3.1-8.6) g/L; IgA n1⁄42, HLC ratio: 0.08 and 0.05; iHLC: 5.9 and 5.0 g/L). In these 5 patients there was overall concordance between changes in HLC ratio /dHLC (involved-uninvolved HLC) and clinical assessment. Importantly in 2/3 patients an increasingly abnormal HLC ratio and dHLC preceded relapse; including 1 IgA patient where immunofixation remained negative and total IgA concentrations within the normal range for 12 months before progression. Conclusion: HLC immunoassays may offer a sensitive method of quantifying M-Ig concentrations in oligosecretory MM patients. Further studies on larger cohorts and comparison with clinical assessment are necessary to validate the assays for monitoring these patients.