The characteristics and outcomes of patients with multiple myeloma dual refractory or intolerant to bortezomib and lenalidomide in the era of carfilzomib and pomalidomide

Expression analysis of two SLAM family receptors, SLAMF2 and SLAMF7, in patients with multiple myeloma

Monoclonal antibodies against surface antigens on MM cells, such as anti-SLAMF7 and anti-CD38 antibodies, represent an attractive therapeutic modality for the eradication of multiple myeloma (MM) cells. However, further exploration of target molecules is urgently needed for the development of more effective therapies. In the present study, we studied the expression of CD48 in a total of 74 primary MM samples derived from patients to evaluate SLAMF2 (CD48) as a candidate in mAb therapy for MM. Of 74 samples, 39 were subjected to SLAMF7 analysis. Most of the MM cells, defined as CD38 and CD138 double-positive cells, showed strong expression of CD48 or SLAMF7 independent of disease stage or treatment history. In these 39 samples, most MM cells showed expression of both SLAMF7 and CD48; however, several samples showed expression of either only CD48 or only SLAMF7, including seven cases that were only highly positive for SLAMF7, and five that were only highly positive for CD48. Our study demonstrates that the immune receptor CD48 is overexpressed on MM cells together with SLAMF7, and that CD48 may be considered as an alternative target for treatment of MM in cases showing weak expression of SLAMF7.

Allogeneic Hematopoietic Cell Transplantation in Multiple Myeloma: Focus on Longitudinal Assessment of Donor Chimerism, Extramedullary Disease, and High-Risk Cytogenetic Features

Although generally not applied as first-line treatment of multiple myeloma, allogeneic hematopoietic cell transplantation (allo-SCT) can still be chosen as ultimate escalation approach in high-risk patients, preferentially within the framework of clinical trials. In this study, we investigated whether decreasing donor chimerism (DC) is predictive for relapse. In addition, we comprehensively determined the impact of several other disease- and treatment-related factors on outcome. One hundred fifty-five multiple myeloma patients whose DC status was followed serially by the short tandem repeat-based techniques at a single lab were included in this retrospective study. Outcome variables were studied in univariate and multivariable analyses. Available were 2.324 DC samples (median, 12 per patient). Loss of full DC was associated with shorter progression-free survival (PFS) (HR, 1.7; 95% CI, 1.1 to 2.6) but did not impact overall survival. Two-thirds of patients with International Myeloma Working Group-defined relapses still displayed a full DC in peripheral blood or bone marrow. Extramedullary manifestations were observed in 33% of patients, accounting for the discrepancy between DC analysis and the actual disease status. In multivariable analysis, the 2 most relevant variables for an unfavorable PFS were progressive disease before allo-SCT (HR, 3.0; 95% CI, 1.5 to 5.9) and allo-SCT at least the second relapse (HR, 2.8; 95% CI, 1.5 to 4.9), whereas for overall survival progressive disease or partial response before allo-SCT had the strongest negative effects (HR, 4.2; 95% CI, 1.9 to 9, and HR, 2.0; 95% CI, 1.0 to 3.8, respectively). Adverse cytogenetics such as del17p, t(4,14) or amp(1q21) were not associated with shorter survival after allo-SCT. Extensive DC sampling beyond robust engraftment does not appear to provide additional information helpful for disease management in most patients and is challenged by a significant incidence of extramedullary disease. In our series, allo-SCT overcame unfavorable cytogenetics.

A multicenter phase 2 study of pomalidomide plus dexamethasone in patients with relapsed and refractory multiple myeloma: the Japanese MM-011 trial

Background

The immunomodulatory agent pomalidomide in combination with low-dose dexamethasone has demonstrated efficacy and safety for the treatment of relapsed and refractory multiple myeloma (RRMM) in phase 2 and 3 trials. However, these trials enrolled very few Asian patients.

Methods

This phase 2 study investigated pomalidomide plus low-dose dexamethasone in 36 Japanese patients with RRMM after ≥2 prior therapies.

Results

Patients enrolled in the study had a relatively high disease burden (81 % Durie–Salmon stage II or III) and were heavily pretreated (median, 6.5 prior antimyeloma regimens). The overall response rate was 42 % (1 patient with complete response and 14 with partial response), with an additional 44 % (16 patients) achieving stable disease (SD). Response rates in patients aged ≤65 years and >65 years were 47 and 35 %, respectively. None of the five patients with extramedullary disease achieved a response, with three of them maintaining SD of short duration. Median progression-free survival was 10.1 months after a 7.7-month median follow-up, and the median overall survival was not reached. The most frequent grade ≥3 adverse events (AEs) were neutropenia (64 %), anemia (42 %), and thrombocytopenia (31 %). The most frequent nonhematologic grade ≥3 AEs were pneumonia and decreased appetite (8 % each). Adverse events in patients aged >65 years were similar to those in patients aged ≤65 years, except for a higher rate of grade ≥3 pneumonia.

Conclusions

Collectively, the results of this study demonstrate that pomalidomide plus low-dose dexamethasone is an effective and safe treatment for Japanese patients with RRMM, although careful attention needs to be paid to serious infections.

Trial registration: Clinicaltrials.gov NCT02011113

Safety and tolerability of pomalidomide-based regimens (pomalidomide-carfilzomib-dexamethasone with or without cyclophosphamide) in relapsed/refractory multiple myeloma and severe renal dysfunction: a case series

Renal dysfunction negatively impacts outcomes in patients with multiple myeloma (MM). Few treatment options are currently available for patients with MM and comorbid renal dysfunction, and as they are generally excluded from clinical trials, data on the use of immunomodulatory drugs in this population are scarce. In this paper, we describe a case series of five women with MM and severe renal dysfunction or dialysis dependency who were refractory to both bortezomib and either lenalidomide or thalidomide and were treated with full-dose (4 mg) pomalidomide. As part of their treatment regimen, these patients also received carfilzomib and dexamethasone with or without cyclophosphamide. All five patients achieved at least a partial response to pomalidomide-based therapy, which was relatively well tolerated. Our findings suggest that pomalidomide may represent a valuable and tolerable treatment option for MM patients with severe renal impairment. The fact that pomalidomide is extensively metabolized prior to urinary excretion may explain the improved tolerability of pomalidomide versus lenalidomide in such patients. Copyright © 2016 John Wiley & Sons, Ltd.

Ex Vivo and In Vivo Evaluation of Overexpressed VLA-4 in Multiple Myeloma Using LLP2A Imaging Agents

Very-late-antigen-4 (VLA-4, α4β1 integrin, CD49d/CD29) is a transmembrane adhesion receptor that plays an important role in cancer and immune responses. Enhanced VLA-4 expression has been observed in multiple myeloma (MM) cells and surrounding stroma. VLA-4 conformational activation has been associated with MM pathogenesis. VLA-4 is a promising MM imaging and therapeutic biomarker.

METHODS

Specificity of (64)Cu-LLP2A ((64)Cu-CB-TE1A1P-PEG4-LLP2A), a high-affinity VLA-4 peptidomimetic-based radiopharmaceutical, was evaluated in α4 knock-out mice and by competitive blocking in wild-type tumor-bearing mice. (64)Cu-LLP2A PET/CT (static and dynamic) imaging was conducted in C57BL6/KaLwRij mice bearing murine 5TGM1-GFP syngeneic tumors generated after intravenous injection via the tail. Blood samples were collected for serum protein electrophoresis. Bone marrow and splenic cells extracted from tumor-bearing and control mice (n= 3/group) were coincubated with the optical analog LLP2A-Cy5 and mouse B220, CD4, Gr1, and Mac1 antibodies and analyzed by fluorescence-activated cell sorting. Human radiation dose estimates for (64)Cu-LLP2A were extrapolated from mouse biodistribution data (6 time points, 0.78 MBq/animal, n= 4/group). Ten formalin-fixed paraffin-embedded bone marrow samples from deceased MM patients were stained with LLP2A-Cy5.

RESULTS

(64)Cu-LLP2A and LLP2A-Cy5 demonstrated high specificity for VLA-4-positive mouse 5TGM1-GFP myeloma and nonmalignant inflammatory host cells such as T cells and myeloid/monocytic cells. Ex vivo flow cytometric analysis supported a direct effect of myeloma on increased VLA-4 expression in host hematopoietic microenvironmental elements. SUVs and the number of medullar lesions detected by (64)Cu-LLP2A PET corresponded with increased monoclonal (M) protein (g/dL) in tumor-bearing mice over time (3.29 ± 0.58 at week 0 and 9.97 ± 1.52 at week 3). Dynamic PET with (64)Cu-LLP2A and (18)F-FDG demonstrated comparable SUV in the prominent lesions in the femur. Human radiation dose estimates indicated urinary bladder wall as the dose-limiting organ (0.200 mGy/MBq), whereas the dose to the red marrow was 0.006 mGy/MBq. The effective dose was estimated to be 0.017 mSv/MBq. Seven of the ten human samples displayed a high proportion of cells intensely labeled with LLP2A-Cy5 probe.

CONCLUSION

(64)Cu-LLP2A and LLP2A-Cy5 demonstrated binding specificity for VLA-4 in an immune-competent murine MM model. (64)Cu-LLP2A displayed favorable dosimetry for human studies and is a potential imaging candidate for overexpressed VLA-4.

New Approaches to Molecular Imaging of Multiple Myeloma

Molecular imaging plays an important role in detection and staging of hematologic malignancies. Multiple myeloma (MM) is an age-related hematologic malignancy of clonal bone marrow plasma cells characterized by destructive bone lesions and is fatal in most patients. Traditional skeletal survey and bone scans have sensitivity limitations for osteolytic lesions manifested in MM. Progressive biomedical imaging technologies such as low-dose CT, molecularly targeted PET, MRI, and the functional-anatomic hybrid versions (PET/CT and PET/MRI) provide incremental advancements in imaging MM. Imaging with PET and MRI using molecularly targeted probes is a promising precision medicine platform that might successfully address the clinical ambiguities of myeloma spectrum diseases. The intent of this focus article is to provide a concise review of the present status and promising developments on the horizon, such as the new molecular imaging biomarkers under investigation that can either complement or potentially supersede existing standards.