PB2177 IMMUNOGLOBULIN D MULTIPLE MYELOMA IN THE ERA OF BORTEZOMIB‐BASED REGIMENS: A SINGLE CENTER EXPERIENCE
Authors: L. Ciuffreda, G. Palumbo, M. G. Franzese, V. Fesce, S. F. Capalbo
Journal: HemaSphere (2019)

Background: Immunoglobulin D (IgD) Multiple Myeloma (MM) is uncommon variant of myeloma affecting less than 2% of all myeloma patients. This subtype is characterized by a reversed light chain ratio and a very low M‐spike on SPEP. The clinical features are similar to those of the other isotypes, but there appears to be an increased incidence of extra osseous disease, renal failure and amyloidosis. The prevalence of extra osseous disease in IgD MM is around 19‐63% with usual sites being the chest wall, respiratory tract, gastrointestinal tract, skin, lymph nodes and paraspinal areas. Aims: We report clinical presentation, response to therapy with novel agents (bortezomib and thalidomide) and survival of six patients with IgD MM. Methods From December 2012 to December 2018 six patients with IgD MM were treated in our institution. Patient characteristics and laboratory findings are listed in Table 1. Diagnosis of MM was performed in according with International Myeloma Working Group (IMWG) and evaluation of response was based on the International Uniform Response Criteria. All pts had bone lesions documented by MRI and CT scan and four pts (67%) at onset presented extra osseous disease in paraspinal areas (3 pts) or in soft tissue of chest wall (1 pts). One patient showed extraosseous disease in paraspinal area at time of relapse. Results: All patients were treated with bortezomib based therapy; two pts received VTD combination (bortezomib‐thalidomide and dexamethasone), two VD (bortezomib and dexametasone), one patient PAD (bortezomib, doxorubicin and dexametasone and one VCD (bortezomib, cyclophosphamide and dexamethasone). The median number of cicles was 3 (range 2‐4)and the median time to response was 3 months; at evalutation after three‐four courses 2 pts (33%) achieved Complete Response (CR), one patient (17%) very good partial response (VGPR), and 3 pts (50%) had progressive disease (PD) and these last had a median overall survival of 6 months (range 4‐8 months). Four of six patients were transplant eligible, of them three showed at least VGPR after induction and underwent ASCT, while one patients was defined refractory and received second line treatment with lenalidomide plus dexamethasone. In transplant group the median progression free survival was 12 months (range 6‐42) and the median overall survival was 24 months (range 15‐46) Summary/Conclusion: In our case series IgD MM is characterized by aggressive clinical features and poor survival. The bortezomib–based regimen seems to be effective to achieving a response, but the duration of the response is very short. The approval of promising novel agents as new proteosome inhibitors (e.g. carlfizomib) and monoclonal antibodies (e.g. daratumumab), if used quikly at time of diagnosis, could be able to prevent the fast progression and appearance of extra‐osseous disease at the relapse in this subtype. More studies are needed to understand the biology of the IgD MM and to improve outcomes for our patients. image