Outcome of Patients with Nonsecretory Multiple Myeloma after Autologous Hematopoietic Stem Cell Transplantation

Introduction Fewer than 5% of patients have nonsecretory multiple myeloma (NSM), which is characterized by the absence of monoclonal protein in immunofixation in serum and urine. There are limited data on the outcome of NSM after autologous hematopoietic stem cell transplantation (auto-HCT). Patients and Methods Between 1988 and December 2010, we identified 31 patients with NSM, and compared their outcome with 124 patients with secretory myeloma (SM) who were matched for age, disease stage, year of auto-HCT, and disease status and received auto-HCT at our institution. The primary end points were time to progression (TTP), progression-free survival (PFS), and overall survival (OS). Results Nonrelapse mortality at 4 years was 4% and 4% in the NSM and SM patients, respectively (P =.612). Median follow-up was 102 and 74 months for NSM and SM patients, respectively. Median PFS was 37 (95% confidence interval [CI], 12-62) and 22 (95% CI, 18-26) months for NSM and SM patients, respectively (P =.527). Median OS was 51 (95% CI, 7-95) and 73 (95% CI, 59-86) months for NSM and SM patients, respectively (P =.740). In multivariate analyses, age >55 years, and relapsed disease were associated with a shorter TTP. Similarly, age >55 years, and relapsed or refractory disease at the time of auto-HCT were associated with a shorter OS. Conclusion Auto-HCT is associated with durable remission in NSM. There was no significant difference in transplant-related mortality, TTP, and PFS in patients with NSM compared with patients with SM after high-dose therapy and auto-HCT.