Pomalidomide-dexamethasone for treatment of soft-tissue plasmacytomas in patients with relapsed / refractory multiple myeloma

Multiple Myeloma in 2023 Ways: From Trials to Real Life

Multiple myeloma is a chronic hematologic malignancy that obstinately tends to relapse. Basic research has made giant strides in better characterizing the molecular mechanisms of the disease. The results have led to the manufacturing of new, revolutionary drugs which have been widely tested in clinical trials. These drugs have been approved and are now part of the therapeutic armamentarium. As a consequence, it is essential to combine what we know from clinical trials with real-world data in order to improve therapeutic strategies. Starting with this premise, our review aims to describe the currently employed regimens in multiple myeloma and compare clinical trials with real-life experiences. We also intend to put a spotlight on promising therapies such as T-cell engagers and chimeric antigen receptor T-cells (CAR-T) which are proving to be effective in changing the course of advanced-stage disease.

Liquid extramedullary disease in multiple myeloma strongly predicts a poor prognosis and is associated with bortezomib resistance gene upregulation

BACKGROUND-AIM

Patients with multiple myeloma (MM) relapse with extramedullary disease (EMD) exhibits an aggressive disease course and poor prognostic features. Myelomatous effusion (ME) is a rare subtype of EMD.

METHODS

In this retrospective study, we analyzed the baseline characteristics and therapies of 14 EMD patients relapse with ME and 21 EMD patients relapse without ME.

RESULTS

Patients with ME relapse demonstrated higher concentrations of serum lactate dehydrogenase, a higher fraction in the International Staging System stage III, and poorer event-free survival (EFS) (9.3 vs. 36.57 months; P = 0.0013) and overall survival (OS) (12.06 vs. 42.64 months; P < 0.001). The multivariate analysis showed that the presence of ME (hazard ratio [HR] 12.57; P = 0.003) and lack of autologous hematopoietic stem cell transplantation therapy (HR 4.382; P = 0.014) were predictive factors for poor OS. Using single-cell RNA sequencing, we discovered several bortezomib resistance genes were highly expressed in extramedullary malignant plasma cells.

CONCLUSIONS

The presence of ME strongly predicts a poor prognosis in patients with MM relapse with EMD, and bortezomib resistance genes are highly expressed in extramedullary malignant plasma cells.

Evaluation of isatuximab in patients with soft-tissue plasmacytomas: An analysis from ICARIA-MM and IKEMA

The Phase 3 ICARIA-MM (NCT02990338) and IKEMA (NCT03275285) studies demonstrated that isatuximab (Isa) plus pomalidomide (P) and dexamethasone (d; Isa-Pd) or carfilzomib (K) and d (Isa-Kd) improved progression-free survival (PFS) versus Pd or Kd in patients with relapsed and/or refractory multiple myeloma. In this post hoc analysis of patients with soft-tissue plasmacytomas, we evaluated Isa-Pd/Isa-Kd efficacy using central radiology and central laboratory assessments. Given the low incidence of soft-tissue plasmacytomas (7.8 %, ICARIA-MM; 6.3 %, IKEMA), efficacy data were pooled across the two studies. PFS (HR, 0.47; 95 % CI, 0.21-1.08), overall response rate (50.0 % vs 17.7 %), and very good partial response or better rate (26.9 % vs 11.8 %) were improved with Isa-Pd/Isa-Kd versus Pd/Kd, with consistent improvements within individual studies. Patients with soft-tissue plasmacytomas who received Isa-Pd/Isa-Kd had similar median PFS compared with those without soft-tissue plasmacytomas and received Pd/Kd. Safety is reported individually per study. Longer median treatment duration and more Grade ≥ 3 treatment-emergent adverse events occurred in the Isa versus control arms in ICARIA-MM (36.9 vs 8.4 weeks; 85.7 % vs 70.0 %) and IKEMA (41.9 vs 29.9 weeks; 100.0 % vs 57.1 %); however, Isa did not increase the percentage of patients with fatal events or drug discontinuation. Isa-Pd or Isa-Kd is a potential new treatment option and partially overcomes the poor prognosis associated with soft-tissue plasmacytomas in relapsed and/or refractory multiple myeloma.

Real-World Evidence of Daratumumab Monotherapy in Relapsed/Refractory Multiple Myeloma Patients and Efficacy on Soft-Tissue Plasmacytomas

INTRODUCTION

Daratumumab is an anti-CD38 agent that was first investigated as single agent in GEN501 and SIRIUS trials in patients with advanced multiple myeloma (MM). Overall response rate (ORR) was 30% with positive impact on progression-free survival (PFS). However, there is a lack of information regarding plasmacytoma response.

MATERIALS AND METHODS

Here, we described a heavily pretreated group of 43 patients who received daratumumab monotherapy after EMA approval and focused on plasmacytoma response.

RESULTS

After a median follow-up of 26 months, median time to best response was 2.9 months (range 0.8-13.1), median PFS was 5.2 months (95% CI 2.5 - 8.8) and median OS was 11.2 months (95% CI 6.3 - 17.0). Patients who achieved at least partial response had longer median PFS and OS (12.8 and 20.2 months, respectively) than those who achieved minimal response or stable disease (5.3 and 11.2 months, respectively). Ten patients (23%) had plasmacytomas (70% paraskeletal, 30% extramedullary). The clinical benefit for patients with and without plasmacytomas was 20% versus 42%. A dissociation between serological and plasmacytoma response was observed in 40% of the patients. Thus, 50% of the patients with plasmacytomas achieved at least serological minimal response but only 20% had plasmacytoma response.

CONCLUSION

This is the first real-world study of daratumumab monotherapy that focuses on efficacy data regarding soft-tissue plasmacytomas in patients with relapsed/refractory mieloma, showing a limited benefit in this patient population.

Advances in the treatment of extramedullary disease in multiple myeloma

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Extramedullary multiple myeloma results in an adverse prognosis.

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Novel agents such as bortezomib, lenalidomide, pomalidomide, isatuximab and selinexor showed efficacy and were recommended to treat EMD.

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For EMD at special sites, marizomib has advantages in the treatment of CNS-MM; Daratumumab combining with intrapleural bortezomib administration is active in treating myelomatous pleural effusion.

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Based on treatment experience of EMD in our department, we summarized treatment approach for EMD.

Extramedullary disease (EMD) is characterized by plasma cells outside of bone marrow in multiple myeloma (MM) patients, which results in an adverse prognosis. The cornerstone of treatment consists of combination therapy including proteasome inhibitors, immunomodulatory agents, steroids, followed by consolidative autologous hematopoietic stem cell transplantation in eligible patients. This review summarized the recent advances in the treatment of EMD. Bortezomib based therapy showed efficacy and was recommended to treat EMD. Marizomib had advantages in the treatment of central nervous system-multiple myeloma (CNS-MM) because of its good central nervous system penetrability. Immunomodulatory drugs such as lenalidomide and pomalidomide have been reported to be effective. Isatuximab and selinexor were also active. Based on the treatment experience of EMD in our department, we summarized treatment approach for EMD. However, the benefits of patients with EMD from the new era of novel drugs were limited. Novel drugs combination, monoclonal antibody, molecular targeted therapy, cellular immunotherapy and autologous stem cell transplantation (ASCT) are under investigation. Therapeutic studies and clinical trials specifically target EMD should be conducted. Hopefully, these treatment options for EMD will be demonstrated efficacy in the future.

Research progress on treatment of extramedullary multiple myeloma

ABSTRACTObjectives: Extramedullary multiple myeloma (EMM) is a relatively less frequent subentity of multiple myeloma (MM) and is generally considered to be a poor prognostic factor. Novel agents and hematopoietic stem cell transplantation (HSCT) have led to a significant improvement in the progression-free survival and overall survival of patients with MM, but outcomes of EMM remain dismal. Little is known regarding the role of novel therapies in this setting. This review summarizes the current available data regarding the roles of proteasome inhibitors, immunomodulators, monoclonal antibodies, chimeric antigen receptor (CAR)-T cell therapy and HSCT in EMM.Methods: A systematic literature review through PubMed was conducted to summarize the published evidence on the therapeutic developments of novel agents and HSCT in EMM. Literature sources published in English were searched, using the terms multiple myeloma, extramedullary and treatment.Results: Long-term outcomes of EMM patients remain dismal despite the utilization of novel agents and HSCT. The standard therapy of EMM has not been established. EMM should be managed as high-risk disease and treated accordingly.Discussion and conclusion: This review will provide an insight on the current and emerging treatment strategies as well as their efficacy in EMM. Further subgroup analyses in large prospective trials focusing on EMM is needed to help optimize the therapy.

Single organ microenvironment and the common features of tumors of leukemia, lymphoma, and myeloma cells growing there: A literature review

OBJECTIVE

To explore whether the growth and treatment resistance of lymphoma and myeloma tumors is similar to that previously observed in leukemic and solid tumors growing in the same organ microenvironment.

METHODS

All published cases of 3 primary hematologic malignancies in breast, without systemic involvement, were identified, with follow-ups solicited from authors. Treatment approaches were analyzed to highlight the most effective.

RESULTS

Similar histologic features and biology among primary tumors of leukemia, lymphoma, plasmacytoma, and solid breast cancer was revealed. Review of treatments: tumor-directed, chemotherapy, or combination showed the benefit of tumor removal, and use of systemic agents in adjunct, not primary, treatment. Optimal assessment is limited by few cases of PET/CT verifying limited tumor extent. The common biology observed and cases of long survival after tumor/stroma eradication point to the complicity of organ microenvironment in the chemoresistance and treatment failure commonly observed in patients.

CONCLUSIONS

The interaction of an organ microenvironment, particularly its adipocytes, with malignant cells, results in similar histologic changes, metastatic potential, and chemoresistance in 3 hematologic malignancies and solid cancers. Improved survival in hematologic malignancies could result from adopting PET/CT to find tumor and its extent, eradicating tumor, and elucidating common therapeutic targets.

Identification of patients at high risk of secondary extramedullary multiple myeloma development

Multiple myeloma (MM) is characterized by malignant plasma cell infiltration of the bone marrow. In extramedullary multiple myeloma (EMD), a subclone of these cells migrates out of the bone marrow. Out of 4 985 MM patients diagnosed between 2005 and 2017 in the Czech Republic, we analyzed 234 secondary EMD patients to clarify risk factors of secondary EMD development. We found younger age [<65 years; odds ratio (OR) 4·38, 95% confidence interval (CI): 2·46–7·80, P < 0·0001], high lactate dehydrogenase (LDH) levels (>5 μkat/l; OR 2·07, 95% CI: 1·51–2·84, P < 0·0001), extensive osteolytic activity (OR 2·21, 95% CI: 1·54–3·15, P < 0·001), and immunoglobulin A (IgA; OR 1·53, 95% CI: 1·11–2·11, P = 0·009) or the non‐secretory type of MM (OR 2·83; 95% CI: 1·32–6·04, P = 0·007) at the time of MM diagnosis to be the main risk factors for secondary EMD development. Newly diagnosed MM (NDMM) patients with subsequent EMD had inferior median progression‐free (PFS) and overall (OS) survival when compared to NDMM patients without future EMD [mPFS: 13·8 months (95% CI: 11·4–16·3) vs 18·8 months (95% CI: 17·7–19·9), P = 0·006; mOS: 26·7 months (95% CI: 18·1–35·4) vs 58·7 months (95% CI: 54·8–62·6), P < 0·001]. We found that NDMM patients with specific risk factors associated with secondary EMD development have a more aggressive disease course before secondary EMD develops.

Outcomes of VDPACE with an immunomodulatory agent as a salvage therapy in relapsed/refractory multiple myeloma with extramedullary disease

Extramedullary disease (EMD) is an aggressive form of multiple myeloma (MM). Confirming the presence of plasma cells outside the bone marrow makes the diagnosis of EMD. There is no clear consensus on the management of EMD in MM, and this entity continues to remain an unmet need. Rapidly controlling EMD to prevent end-organ damage is a priority. Retrospectively, we reviewed our database for patients with EMD that received treatment with bortezomib, dexamethasone, cisplatin, doxorubicin, cyclophosphamide, etoposide (VDPACE) plus an immune modulator (IMiD) regimen. We identified 21 patients with a median age of 61 years. Ten patients received a VDPACE based regimen as a bridge to autologus stem cell transplant (ASCT). After a median follow-up of 51.4 months, the median overall survival (OS) and progression-free survival were 14.9 months (95% CI: 7.8-NA) and 5.5 months (95% CI: 3.9-NA), respectively. The overall response rate was 76%, with a manageable safety profile. Interestingly, these results were similar regardless of the presence of high-risk cytogenetics. The safety profile was acceptable. In conclusion, a salvage VDPACE-based regimen plus an IMiD remains an effective and safe bridging therapy to future ASCT and immunotherapy in relapsed/refractory multiple myeloma patients with EMD.

Extramedullary Plasmacytoma Causing Myelopathy Resulting in Gait Imbalance

Plasmacytomas are neoplasms of plasma cells that can involve the bone marrow, the bone itself, or soft tissue without bone marrow involvement. Extramedullary plasmacytomas are most commonly found in the upper respiratory tract in a total of 80% of all cases. Extramedullary plasmacytomas have also been documented in locations such as the central nervous system. This form of plasmacytoma may be seen as a solitary entity or in patients with multiple myeloma. We present a case of a 66-year-old female with a history of multiple myeloma on maintenance therapy with lenalidomide who has been experiencing gait imbalance for the past two months. The patient had a thoracic MRI done that revealed a mass at T7-8 with associated cord compression. She was taken for surgical intervention by neurosurgery. Pathology revealed trabecular bone and cartilage infiltrated by sheets of plasma cells highlighted by immunostaining CD138, monoclonal lambda light chains, consistent with a plasma cell neoplasm (plasmacytoma). The patient’s hospital course was complicated by hypotension resulting in transient ischemic myelopathy that was addressed in the neuro-intensive care unit. The patient was then discharged to an inpatient rehabilitation center. She would follow up with her primary oncologist for localized radiation therapy.

Successful Treatment of Relapsed/Refractory Extramedullary Multiple Myeloma With Anti-BCMA CAR-T Cell Therapy Followed by Haploidentical Hematopoietic Stem Cell Transplantation: A Case Report and a Review of the Contemporary Literature

Extramedullary multiple myeloma (EMM) is an aggressive sub-entity of multiple myeloma (MM). Despite an excellent improvement in survival for most patients with MM over recent decades, the overall survival (OS) of patients with EMM was usually not longer than 3 years. Standard treatment for patients with EMM has not been established, and their management is particularly challenging. We presented a heavily pretreated young patient with relapsed EMM and refractoriness to a proteasome inhibitor (PI; bortezomib), a next-generation PI (ixazomib), immunomodulatory drugs (IMiDs; lenalidomide), autologous hematopoietic stem cell transplantation (ASCT), and monoclonal antibody (directed against CD38: daratumumab) and indicated that myeloablative haploidentical hematopoietic stem cell transplantation (haploidentical-HSCT) as a salvage treatment of relapse after a chimeric antigen receptor (CAR)-T cell therapy that targeted B-cell maturation antigen (BCMA) (NCT04650724) is feasible. Taken together of the contemporary literature, the promising results on the effect of anti-BCMA CAR-T cell therapy and allogeneic HSCT might present a proof-of-principle for patients with EMM, and therefore, patients with the disease need to be included in future studies.

Role of D(T)PACE-based regimens as treatment of multiple myeloma with extramedullary relapse or refractory disease

In multiple myeloma, atypical forms with extramedullary involvement exhibit poor survival. The poly-chemotherapeutic regimen D(T)-PACE has shown high activity in relapsed or refractory multiple myeloma. In this large monocentric retrospective study, we addressed the activity of D(T)-PACE-based regimens in 43 heavily pretreated patients with relapsed/refractory multiple myeloma and extramedullary disease.Median age at initiation was 57 years. Four patients had a t(4;14) translocation, 3 had a t(11;14) translocation and 7 had a del(17p). Extramedullary sites were mostly the skin (15 patients), central nervous system (10 patients), and thorax or abdomen (10 patients each). Overall response was achieved in 25 (58%) patients, including 6 (14%) with a complete response. Median progression-free survival was 5.0 months. Median overall survival was 9.0 months. Fourteen patients subsequently underwent stem-cell transplantation. Cytogenetics had no impact on response rate, overall survival and progression-free survival.In the era of several new immunotherapies, D(T)-PACE-based regimens still remain a useful treatment option for a selected group of heavily pretreated myeloma patients.

Expert review on soft-tissue plasmacytomas in multiple myeloma: definition, disease assessment and treatment considerations

In this review, two types of soft-tissue involvement in multiple myeloma are defined: (i) extramedullary (EMD) with haematogenous spread involving only soft tissues and (ii) paraskeletal (PS) with tumour masses arising from skeletal lesions. The incidence of EMD and PS plasmacytomas at diagnosis ranges from 1·7% to 4·5% and 7% to 34·4% respectively. EMD disease is often associated with high-risk cytogenetics, resistance to therapy and worse prognosis than in PS involvement. In patients with PS involvement a proteasome inhibitor-based regimen may be the best option followed by autologous stem cell transplantation (ASCT) in transplant eligible patients. In patients with EMD disease who are not eligible for ASCT, a proteasome inhibitor-based regimen such as lenalidomide-bortezomib-dexamethasone (RVD) may be the best option, while for those eligible for high-dose therapy a myeloma/lymphoma-like regimen such as bortezomib, thalidomide and dexamethasone (VTD)-RVD/cisplatin, doxorubicin, cyclophosphamide and etoposide (PACE) followed by SCT should be considered. In both EMD and PS disease at relapse many strategies have been tried, but this remains a high-unmet need population.

Management of patients with difficult-to-treat multiple myeloma

Newer treatments for multiple myeloma (MM) have improved response rates and survival for many patients. However, MM remains challenging to treat due to the propensity for multiple relapses, cumulative and emergent toxicities from prior therapies and increasing genomic complexity that arises due to clonal evolution. In particular, patients with relapsed/refractory MM often require increased complexity of treatment, yet still experience poorer outcomes compared with patients who are newly diagnosed. Additionally, several patient subgroups, including those with extramedullary disease and patients who are frail and/or have multiple comorbidities, have an unfavorable prognosis and remain undertreated. This review (based on an Updates-in-Hematology session at the 25th European Hematology Association Annual Congress 2020) discusses the management of these difficult-to-treat patients with MM.

Melflufen and Dexamethasone in Heavily Pretreated Relapsed and Refractory Multiple Myeloma

PURPOSE

Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate that targets aminopeptidases and rapidly and selectively releases alkylating agents into tumor cells. The phase II HORIZON trial evaluated the efficacy of melflufen plus dexamethasone in relapsed and refractory multiple myeloma (RRMM), a population with an important unmet medical need.

PATIENTS AND METHODS

Patients with RRMM refractory to pomalidomide and/or an anti-CD38 monoclonal antibody received melflufen 40 mg intravenously on day 1 of each 28-day cycle plus once weekly oral dexamethasone at a dose of 40 mg (20 mg in patients older than 75 years). The primary end point was overall response rate (partial response or better) assessed by the investigator and confirmed by independent review. Secondary end points included duration of response, progression-free survival, overall survival, and safety. The primary analysis is complete with long-term follow-up ongoing.

RESULTS

Of 157 patients (median age 65 years; median five prior lines of therapy) enrolled and treated, 119 patients (76%) had triple-class-refractory disease, 55 (35%) had extramedullary disease, and 92 (59%) were refractory to previous alkylator therapy. The overall response rate was 29% in the all-treated population, with 26% in the triple-class-refractory population. In the all-treated population, median duration of response was 5.5 months, median progression-free survival was 4.2 months, and median overall survival was 11.6 months at a median follow-up of 14 months. Grade ≥ 3 treatment-emergent adverse events occurred in 96% of patients, most commonly neutropenia (79%), thrombocytopenia (76%), and anemia (43%). Pneumonia (10%) was the most common grade 3/4 nonhematologic event. Thrombocytopenia and bleeding (both grade 3/4 but fully reversible) occurred concomitantly in four patients. GI events, reported in 97 patients (62%), were predominantly grade 1/2 (93%); none were grade 4.

CONCLUSION

Melflufen plus dexamethasone showed clinically meaningful efficacy and a manageable safety profile in patients with heavily pretreated RRMM, including those with triple-class-refractory and extramedullary disease.

Elotuzumab for the treatment of extramedullary myeloma: a retrospective analysis of clinical efficacy and SLAMF7 expression patterns

Extramedullary disease (EMD) represents a high-risk state of multiple myeloma (MM) associated with poor prognosis. While most anti-myeloma therapeutics demonstrate limited efficacy in this setting, some studies exploring the utility of chimeric antigen receptor (CAR)-modified T cells reported promising results. We have recently designed SLAMF7-directed CAR T cells for the treatment of MM. SLAMF7 is a transmembrane receptor expressed on myeloma cells that plays a role in myeloma cell homing to the bone marrow. Currently, the only approved anti-SLAMF7 therapeutic is the monoclonal antibody elotuzumab, but its efficacy in EMD has not been investigated thoroughly. Thus, we retrospectively analyzed the efficacy of elotuzumab-based combination therapy in a cohort of 15 patients with EMD. Moreover, since the presence of the target antigen is an indispensable prerequisite for effective targeted therapy, we investigated the SLAMF7 expression on extramedullary located tumor cells before and after treatment. We observed limited efficacy of elotuzumab-based combination therapies, with an overall response rate of 40% and a progression-free and overall survival of 3.8 and 12.9 months, respectively. Before treatment initiation, all available EMD tissue specimens (n = 3) demonstrated a strong and consistent SLAMF7 surface expression by immunohistochemistry. Furthermore, to investigate a potential antigen reduction under therapeutic selection pressure, we analyzed samples of de novo EMD (n = 3) outgrown during elotuzumab treatment. Again, immunohistochemistry documented strong and consistent SLAMF7 expression in all samples. In aggregate, our data point towards a retained expression of SLAMF7 in EMD and encourage the development of more potent SLAMF7-directed immunotherapies, such as CAR T cells.

Development of CAR-T cell therapies for multiple myeloma

Currently available data on chimeric antigen receptor (CAR)-T cell therapy has demonstrated efficacy and manageable toxicity in heavily pretreated multiple myeloma (MM) patients. The CAR-T field in MM is rapidly evolving with >50 currently ongoing clinical trials across all phases, different CAR-T design, or targets. Most of the CAR-T trials are performed in China and the United States, while European centers organize or participate in only a small fraction of current clinical investigations. Autologous CAR-T cell therapy against B cell maturation antigen shows the best evidence of efficacy so far but main issues remain to be addressed: duration of response, longer follow-up, prolonged cytopenia, patients who may benefit the most such as those with extramedullary disease, outcome prediction, and the integration of CAR-T cell therapy within the MM treatment paradigm. Other promising targets are, i.a.,: CD38, SLAMF7/CS1, or GPRC5D. Although no product has been approved to date, cost and production time for autologous products are expected to be the main obstacles for broad use, for which reason allogeneic CAR-T cells are currently explored. However, the inherent risk of graft-versus-host disease requires additional modification which still need to be validated. This review aims to present the current status of CAR-T cell therapy in MM with an overview on current targets, designs, and stages of CAR-T cell development. Main challenges to CAR-T cell therapy will be highlighted as well as strategies to structurally improve the CAR-T cell product, and thereby its efficacy and safety. The need for comparability of the most promising therapies will be emphasized to balance risks and benefits in an evidence-based but personalized approach to further improve outcome of patients with MM.

Hematogenous extramedullary relapse in multiple myeloma - a multicenter retrospective study in 127 patients

The current study assesses the characteristics and outcomes of multiple myeloma (MM) patients, treated with novel agents for hematogenous extramedullary (HEMM) relapse. Consecutive patients diagnosed with HEMM between 2010-2018 were included. Patients' characteristics at diagnosis and at HEMM presentation, response to treatment, survival and factors predicting survival were recorded and analyzed. A group of 127 patients, all diagnosed with HEMM by imaging (87.3%) and/or biopsy (79%), were included. Of those, 44% were initially diagnosed with ISS3, 57% presented with plasmacytomas, and 30% had high-risk cytogenetics. Median time to HEMM was 32 months. In multivariate analysis, ISS3 and bone plasmacytoma predicted shorter time to HEMM (P = .005 and P = .008, respectively). Upfront autograft was associated with longer time to HEMM (P = .002). At HEMM, 32% of patients had no BM plasmacytosis, 20% had non-secretory disease and 43% had light-chain disease. Multiple HEMM sites were reported in 52% of patients, mostly involving soft tissue, skin (29%), and pleura/lung (25%). First treatment for HEMM included proteasome inhibitors (50%), immunomodulatory drugs (IMiDs) (39%), monoclonal antibodies (10%), and chemotherapy (53%). Overall response rate (ORR) was 57%. IMiDs were associated with higher ORR (HR 2.2, 95% CI 1.02-4.7, P = .04). Median survival from HEMM was 6 months (CI 95% 4.8-7.2). Failure to achieve ≥VGPR was the only significant factor for worse OS in multivariate analyses (HR = 9.87, CI 95% 2.35 - 39, P = .001). In conclusion, HEMM occurs within 3 years of initial myeloma diagnosis and is associated with dismal outcome. The IMiDs might provide a higher response rate, and achievement of ≥VGPR predicts longer survival.

Pomalidomide-Responsive Extramedullary Myeloma Relapsed after Allogeneic Hematopoietic Transplant and Refractory to Multiple Lines of Chemotherapy

Patients who experience extramedullary relapses (EMR) of multiple myeloma (MM) have an adverse prognosis, also in this era of novel agents like proteasome inhibitors and immunomodulatory drugs. We describe the case of an MM patient with EMR at 2 different sites after allogeneic stem cell transplantation. EMR was refractory to bortezomib, anthracycline, and bendamustine, but the patient achieved long-term complete remission (4 years) with pomalidomide and dexamethasone. This supports the hypothesis that this could be due to the graft-versus-myeloma effect during therapy enhanced by pomalidomide.