Outcome of Patients With Nonsecretory Multiple Myeloma After Autologous Hematopoietic Stem Cell Transplantation

Comparison of clinical and laboratory characteristics of nonsecretory multiple myeloma and secretory multiple myeloma in a tertiary care hospital

INTRODUCTION

Nonsecretory multiple myeloma (NSM) is a rare variant of multiple myeloma, accounting for approximately 1%-5% of all reported cases. We compared the characteristics of NSM and secretory multiple myeloma (SM).

METHODS

We examined clinical and laboratory characteristics of 17 patients diagnosed with NSM and 40 patients diagnosed with SM. NSM was diagnosed based on findings of bone marrow (BM) examination, serum-free light chain (sFLC) assay, flow cytometric (FCM) immunophenotyping, chromosomal analysis, and imaging studies.

RESULTS

No patient with NSM had hypercalcemia or renal insufficiency at diagnosis. Patients with NSM were less anemic (p < .05) but had higher lactate dehydrogenase levels (p < .05) than patients with SM. In addition, patients with NSM had a lower percentage of plasma cells in the BM, confirmed by manual differential count (p < .05) and FCM immunophenotyping (p < .05). The sFLC ratio in patients with NSM was abnormal (15/17, 88.2%) and was lower than that in patients with SM (p < .05). Risk stratification in Revised International Staging System revealed a low-risk tendency in patients with NSM (p = .235).

CONCLUSION

NSM patients showed different clinical and laboratory characteristics from SM patients. FCM immunophenotyping and sFLC assay particularly had differences between NSM patients and SM patients. Thus, they are essential for diagnosing NSM.

IgD Subtype But Not IgM or Non-Secretory Is a Prognostic Marker for Poor Survival Following Autologous Hematopoietic Cell Transplantation in Multiple Myeloma. Results From the EBMT CALM (Collaboration to Collect Autologous Transplant Outcomes in Lymphomas and Myeloma) Study

BACKGROUND

The Collaboration to Collect Autologous Transplant Outcomes in Lymphoma and Myeloma (CALM) study has provided an opportunity to evaluate the real-world outcomes of patients with myeloma. The aim of this study was to compare the outcome according to the different subtypes of myeloma using CALM data.

PATIENTS

This study compared overall survival (OS), progression-free survival (PFS), and complete remission (CR) and the impact of novel versus non-novel drug containing induction regimens prior to autologous hematopoietic cell transplantation (HCT) of 2802 patients with "usual" and "rare" myelomas.

RESULTS

Our data suggest that IgM and non-secretory myeloma have superior PFS and OS compared with IgD myeloma and outcomes comparable to those for usual myeloma. Patients who received novel agent induction had higher rates of CR prior to transplant. Non-novel induction regimens were associated with inferior PFS but no difference in OS. Although not the primary focus of this study, we show that poor mobilization status is associated with reduced PFS and OS, but these differences disappear in multivariate analysis suggesting that poor mobilization status is a surrogate for other indicators of poor prognosis.

CONCLUSION

We confirm that IgD myeloma is associated with the worst prognosis and inferior outcomes compared with the other isotypes.

Nonsecretory and Light Chain Escape in Patients With Multiple Myeloma

BACKGROUND

Multiple myeloma (MM) is characterized by the secretion of monoclonal protein by malignant plasma cells in the vast majority of cases. We identified and analyzed patterns of disease relapse and progression associated with disappearance of the paraprotein ("nonsecretory [NS] escape"), or conversion from production of intact Ig molecule to its associated light chain ("LC escape").

PATIENTS AND METHODS

We retrospectively reviewed medical records and a database of 791 consecutive patients with symptomatic MM.

RESULTS

Twenty-eight (3.5%) patients had disease evolution associated with either NS (n = 13) or LC (n = 15) escape. The event occurred at a median of 37 months (range, 3-156 months) after the diagnosis of MM, and after a median of 3 chemotherapy regimens (range, 1-8 regimens). Presence of extramedullary disease at progression was detected in 8 (29%) patients. Sensitivity to chemotherapy before and after escape was present in 21 (75%) and 14 (50%) patients, respectively. After a median follow-up of 55 months, 19 (68%) patients died, and progressive MM was the cause of death in 18 patients. The median overall survival after escape was 20 months (95% confidence interval, 9-25 months), and no significant difference was found between the NS and LC groups (P = .44). The median overall survival after diagnosis of MM was worse in patients with NS/LC escape than in those without escape (52 vs. 94 months; P = .018).

CONCLUSIONS

Our study describes the largest series of NS and LC escape in MM to date. The development of this phenomenon is associated with more aggressive clinical features, frequent resistance to chemotherapy, and worse clinical outcome.

Lenalidomide vs bortezomib maintenance choice post-autologous hematopoietic cell transplantation for multiple myeloma

Maintenance therapy post-autologous hematopoietic cell transplantation (AHCT) with either lenalidomide or bortezomib for multiple myeloma (MM) have separately been shown to improve progression-free survival (PFS), but have never been directly compared. We performed a retrospective study to investigate progression-free and overall survival outcomes and toxicities of lenalidomide maintenance therapy compared with bortezomib maintenance in MM patients post-AHCT. This study included 156 patients who received post-AHCT lenalidomide or bortezomib maintenance therapy for MM. The primary outcome was PFS. Ninety-two patients received lenalidomide maintenance and 64 received bortezomib maintenance post-AHCT. By multivariable analysis, maintenance therapy choice and cytogenetics risk did not impact PFS or OS. Staging by International Staging System and pre-maintenance disease response were the greatest predictors for PFS. Treatment-related toxicities were as anticipated with 5.4% of patients receiving maintenance lenalidomide experiencing secondary primary malignancies (SPMs) compared with 3% for bortezomib. These findings suggest there were no differences in PFS or OS between lenalidomide and bortezomib maintenance therapy options for post-transplantation MM patients. These data should be validated in a larger, prospective cohort to determine if maintenance choice should be guided by side effect profile and patient anticipated tolerance rather than by disease biology alone.

Non-secretory multiple myeloma: from biology to clinical management

Multiple myeloma (MM) is the second most common hematologic malignancy in the US. It is typically characterized by production of large amounts of defective immunoglobulin (Ig). Diagnosing MM and monitoring treatment response, including eventual relapse, are largely based on sequential measurements of Ig. However, a small subset of MM called non-secretory multiple myeloma (NSMM) produces no detectable Ig. This subset of true NSMM has become even smaller over time, as the advent of the serum free light chain assay has resulted in the majority of NSMM patients being recategorized as light-chain MM – that is, MM cells that produce only the light-chain component of Ig. True forms of NSMM, meaning MM that secretes no monoclonal proteins whatsoever, constitute a distinct entity that is reviewed; definition of NSMM using current detection methods, discuss the biology underpinning NSMM development, and share recommendations for how NSMM should be managed clinically with respect to detection, treatment, and monitoring.