Management of post-autologous transplant relapse in patients with T-cell lymphomas.

Autologous hematopoietic cell transplantation (AHCT) is often used as a consolidation for patients with peripheral T-cell lymphomas (PTCLs) due to the poor prognosis associated with this heterogenous group of disorders. However, a significant number of patients will experience post-AHCT disease relapse. Here, we report a retrospective study of consecutive 124 patients with PTCLs who underwent AHCT from 2008 to 2020. With a median follow-up of 6.01 years following AHCT, 49 patients (40%) experienced disease relapse. As expected, more patients who were not in first complete remission experienced post-AHCT relapse. Following relapse, majority of the patients (70%) receiving systemic therapies intended as bridging to curative allogeneic HCT. However, only 18 (53%) patients eventually underwent allogeneic HCT. The estimated 3-year OS among patients proceeding to allogeneic HCT was 72% (95% CI 46%-87%). Our report details the pattern of post-AHCT relapse and the management of relapsed disease using different therapeutic modalities.

CAR19 monitoring by peripheral blood immunophenotyping reveals histology-specific expansion and toxicity.

Chimeric antigen receptor (CAR) T cells directed against CD19 (CAR19) are a revolutionary treatment for B-cell lymphomas. CAR19 cell expansion is necessary for CAR19 function but is also associated with toxicity. To define the impact of CAR19 expansion on patient outcomes, we prospectively followed a cohort of 236 patients treated with CAR19 (brexucabtagene autoleucel or axicabtagene ciloleucel) for mantle cell (MCL), follicular (FL), and large B-cell lymphoma (LBCL) over the course of five years and obtained CAR19 expansion data using peripheral blood immunophenotyping for 188 of these patients. CAR19 expansion was higher in patients with MCL compared to other lymphoma histologic subtypes. Notably, patients with MCL had increased toxicity and required four-fold higher cumulative steroid doses than patients with LBCL. CAR19 expansion was associated with the development of cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS), and the requirement for granulocyte colony stimulating factor (GCSF) after day 14 post-infusion. Younger patients and those with elevated lactate dehydrogenase (LDH) had significantly higher CAR19 expansion. In general, no association between CAR19 expansion and LBCL treatment response was observed. However, when controlling for tumor burden, we found that lower CAR19 expansion in conjunction with low LDH was associated with improved outcomes in LBCL. In sum, this study finds CAR19 expansion principally associates with CAR-related toxicity. Additionally, CAR19 expansion as measured by peripheral blood immunophenotyping may be dispensable to favorable outcomes in LBCL.

CD22 CAR T cells demonstrate high response rates and safety in pediatric and adult B-ALL: Phase 1b results.

Chimeric antigen receptor (CAR) T cells targeting CD22 (CD22-CAR) provide a therapeutic option for patients with CD22+ malignancies with progression after CD19-directed therapies. Using on-site, automated, closed-loop manufacturing, we conducted parallel Phase 1b clinical trials investigating a humanized CD22-CAR with 41BB costimulatory domain in children and adults with heavily treated, relapsed/refractory (r/r) B-ALL. Of 19 patients enrolled, 18 had successful CD22-CAR manufacturing, and 16 patients were infused. High grade (3-4) cytokine release syndrome (CRS) and immune effector-cell-associated neurotoxicity syndrome (ICANS) each occurred in only one patient; however, three patients experienced immune-effector-cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS). Twelve of 16 patients (75%) achieved CR with an overall 56% MRD-negative CR rate. Duration of response was overall limited (median 77 days), and CD22 expression was downregulated in 4/12 (33%) available samples at relapse. In summary, we demonstrate that closed-loop manufacturing of CD22-CAR T cells is feasible and is associated with a favorable safety profile and high CR rates in pediatric and adult r/r B-ALL, a cohort with limited CD22-CAR reporting.

Single-center randomized trial of T-reg graft alone vs T-reg graft plus tacrolimus for the prevention of acute GVHD.

ABSTRACT: Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for hematological malignancies for which graft-versus-host disease (GVHD) remains a major complication. The use of donor T-regulatory cells (Tregs) to prevent GVHD appears promising, including in our previous evaluation of an engineered graft product (T-reg graft) consisting of the timed, sequential infusion of CD34+ hematopoietic stem cells and high-purity Tregs followed by conventional T cells. However, whether immunosuppressive prophylaxis can be removed from this protocol remains unclear. We report the results of the first stage of an open-label single-center phase 2 study (NCT01660607) investigating T-reg graft in myeloablative HCT of HLA-matched and 9/10-matched recipients. Twenty-four patients were randomized to receive T-reg graft alone (n = 12) or T-reg graft plus single-agent GVHD prophylaxis (n = 12) to determine whether T-reg graft alone was noninferior in preventing acute GVHD. All patients developed full-donor myeloid chimerism. Patients with T-reg graft alone vs with prophylaxis had incidences of grade 3 to 4 acute GVHD of 58% vs 8% (P = .005) and grade 3 to 4 of 17% vs 0% (P = .149), respectively. The incidence of moderate-to-severe chronic GVHD was 28% in the T-reg graft alone arm vs 0% with prophylaxis (P = .056). Among patients with T-reg graft and prophylaxis, CD4+ T-cell-to-Treg ratios were reduced after transplantation, gene expression profiles showed reduced CD4+ proliferation, and the achievement of full-donor T-cell chimerism was delayed. This study indicates that T-reg graft with single-agent tacrolimus is preferred over T-reg graft alone for the prevention of acute GVHD. This trial was registered at www.clinicaltrials.gov as #NCT01660607.

Idecabtagene vicleucel chimeric antigen receptor T-cell therapy for relapsed/refractory multiple myeloma with renal impairment.

We evaluated patients with relapsed multiple myeloma with renal impairment (RI) treated with standard of care idecabtagene vicleucel (ide-cel), as outcomes with chimeric antigen receptor (CAR) T-cell therapy are unknown in this population. RI was defined as creatinine clearance (CrCl) <50 mL/min. CrCl of <30 mL/min or dialysis dependence were defined as severe RI. The study cohort included 214 patients, 28 (13%) patients with RI, including 11 patients severe RI (dialysis, N=1). Patients with RI were older, more likely to be female and had higher likelihood of having Revised International Staging System stage 3 disease. Rates and severity of cytokine release syndrome (89% vs. 84%, grade ≥3: 7% vs. 2%) and immune effector cell-associated neurotoxicity syndrome (23% vs. 20%) were similar in patients with and without RI, respectively. Patients with RI had higher incidence of short-term grade ≥3 cytopenias, although cytopenias were similar by 3 months following CAR T-cell therapy. Renal function did not worsen after CAR T-cell therapy in patients with RI. Response rates (93% vs. 82%) and survival outcomes (median progression-free survival: 9 vs. 8 months; P=0.26) were comparable in patients with and without RI, respectively. Treatment with ide-cel is feasible in patients with RI, with a comparable safety and efficacy profile as patients without RI, with notable exception of higher short-term high-grade cytopenias.

Racial and ethnic differences in clinical outcomes among patients with multiple myeloma treated with CAR T-cell therapy.

ABSTRACT: Idecabtagene vicleucel (ide-cel) was the first chimeric antigen receptor T-cell therapy to gain US Food and Drug Administration approval for patients with relapsed/refractory multiple myeloma (RRMM). The clinical outcomes of standard of care (SOC) ide-cel in racially and ethnically diverse populations have been understudied. This study pooled data from 207 patients with RRMM (28% patients of racial and ethnic minority groups) treated with SOC ide-cel across 11 institutions to examine racial and ethnic differences in the incidence of toxicities and adverse events, response to ide-cel, and survival. This study included 22 (11%) Hispanic, 36 (17%) non-Hispanic Black, and 149 (72%) non-Hispanic White patients with RRMM. Compared with Hispanic and non-Hispanic White patients, non-Hispanic Black patients had higher median levels of C-reactive protein (1.0, 0.8, and 3.5 mg/dL, respectively; P = .02) and baseline ferritin (362.0 vs 307.0 vs 680.5, respectively; P = .08) and were more likely to develop cytokine release syndrome (77%, 85%, and 97%, respectively; P = .04). Although best overall response rate was lower among Hispanic patients (59%) than among non-Hispanic Black (86%) and White patients (86%; P = .01), there were no racial and ethnic differences in progression-free or overall survival. We provide, to our knowledge, the first and largest investigation of clinical outcomes of SOC ide-cel by race and ethnicity. Despite differences in safety and response to ide-cel, our findings encourage the use of ide-cel in all patients with RRMM. These findings should be confirmed in larger samples of diverse patients with RRMM, with longer follow-up time.

Chimeric Antigen Receptor T Cell Therapy for Myeloma: Where Are We Now and What Is Needed to Move Chimeric Antigen Receptor T Cells Forward to Earlier Lines of Therapy? Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy.

Since 2021, 2 B cell maturation antigen (BCMA)-directed chimeric antigen receptor T cell (CAR-T) therapies-idecabtagene vicleucel (ide-cel), and ciltacabtagene autoleucel (cilta-cel)-have been approved by the US Food and Drug Administration (FDA) for treating relapsed or refractory multiple myeloma (RRMM) after 4 or more prior lines of therapy, including an immunomodulatory drug, a proteasome inhibitor, and an anti-CD38 antibody. The 2 products have shown unprecedented activity in RRMM, but relapses remain common, and access to and safety of CAR-T therapy in patients with rapidly progressing advanced disease are not ideal. Sequencing CAR-T therapy with other options, including the 2 recently approved BCMA-directed T cell-engaging bispecific antibodies teclistamab and elranatamab, has become increasingly challenging owing to data showing inferior outcomes from CAR-T therapy after prior BCMA-directed therapy. This has led to the consideration of CAR-T therapy earlier in the course of disease for myeloma, when T cells are potentially healthier and the myeloma is less aggressive. To address the question of earlier use of CAR-T therapy, several trials are either ongoing or planned, and results have recently been reported for 2 randomized trials of CAR-T therapy showing improved progression-free survival compared to standard of care therapy in second-line (CARTITUDE-4) or third-line therapy (KarMMA-3). With the anticipation of the FDA possibly expanding approval of CAR-T to earlier lines of myeloma therapy, the American Society for Transplantation and Cellular Therapy convened a group of experts to provide a comprehensive review of the studies that led to the approval of CAR-T therapy in late-line therapy for myeloma, discuss the recently reported and ongoing studies designed to move CAR-T therapy to earlier lines of therapy, and share insights and considerations for sequencing therapy and optimization of patient selection for BCMA-directed therapies in current practice.

Managing side effects: guidance for use of immunotherapies in multiple myeloma.

Chimeric antigen receptor T-cell therapy and bispecific T-cell recruiting antibodies have transformed the treatment landscape for relapsed/refractory multiple myeloma, with B-cell maturation antigen being the most common target and other targets in clinical development. However, these therapies are associated with unique and severe toxicities, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), delayed neurotoxicity, cytopenias, and infection. In addition, immune effector cell-associated hemophagocytic lymphohistiocytosis (HLH)-like syndrome (IEC-HS), which exhibits overlap between CRS and HLH, can be challenging to diagnose and treat. In this review, we provide an overview of toxicities associated with novel immunotherapies for treatment of multiple myeloma and describe management recommendations. The pathophysiology and risk factors behind these toxicities are not yet comprehensively understood. Based on consensus recommendations, treatment for CRS consists of tocilizumab and steroids, while treatment for ICANS includes steroids and anakinra in severe cases. Management of cytopenias and infection is similar to post-hematopoietic cell transplantation principles with antimicrobial prophylaxis, growth factor support, immunoglobulin replacement, and vaccinations. In contrast, effective treatments for delayed neurotoxicity and IEC-HS are lacking, although steroids and anakinra are commonly used. Management of all these toxicities should include a broad differential and multidisciplinary collaboration with infectious diseases, neurology, and/or critical care providers.

Integrating Immune Therapies for the Treatment of Multiple Myeloma.

Patients with relapsed or refractory multiple myeloma (RRMM) that is refractory to a proteasome inhibitor, an immunomodulatory drug (IMiD), and an anti-CD38 antibody (triple-class refractory MM) have poor outcomes. Recently, 2 classes of T-cell engaging therapies-CAR T-cell therapy and bispecific T-cell engaging antibodies (BsAbs)-have resulted in unprecedented response rates and survival outcomes in these heavily pretreated patients. The most common targets are BCMA and GPRC5D, with other targets in development. The main classes of adverse effects include cytokine release syndrome, neurotoxicity, infections, and cytopenias, as well as adverse effects unique to specific products. As of September 2023, 2 BCMA-targeting CAR-T cell products, 2 BCMA-targeting BsAbs, and 1 GPRC5D-targeting BsAb, are FDA-approved for standard-of-care use in patients with RRMM who received at least 4 prior lines of therapy, including prior treatment with a proteasome inhibitor, an IMiD, and an anti-CD38 antibody. Earlier-line use is under investigation and has shown promising results. Several other investigational CAR-T constructs and bispecific antibodies are in clinical development. As these therapies become more widely used, including in earlier-line setting, efforts to understand optimal sequencing and mitigate toxicities remain critical.

Factors associated with refractoriness or early progression after idecabtagene vicleucel in patients with relapsed/refractory multiple myeloma: U.S. Myeloma Immunotherapy Consortium real world experience.

While response rates and survival outcomes have been very promising for idecabtagene vicleucel (ide-cel), a proportion of patients do not respond or relapse early after this B-cell maturation antigen (BCMA) targeted CAR T-cell therapy. Understanding the characteristics of these patients is important for patient selection and development of novel strategies to improve outcomes. We evaluated factors associated with early progression (progression or death due to myeloma ≤ 3 months after CAR T infusion) in patients treated with standard of care ide-cel at 11 US academic centers. Among 211 patients that received ide-cel, 43 patients had a progressive event ≤ 3 months of infusion. Patients with a history of extramedullary disease, prior BCMA targeted therapy, elevated ferritin at lymphodepletion, use of bridging therapy, Hispanic ethnicity, plasma cell leukemia and t(4;14) were more likely to progress ≤ 3 months of infusion (p < 0.05). Of these risk factors for early progression identified in univariate analyses, history of extramedullary disease, prior BCMA targeted therapy, elevated ferritin at lymphodepletion, plasma cell leukemia, and t(4;14) were associated with worse progression-free survival (PFS) in multivariable analysis. Presence of three or more of these factors had a significant negative impact on PFS (p < 0.001; median PFS for ≥ 3 factors, 3.2 months vs. 0 factors, 14.1 months). This study helps identify patients at high risk of early progression after CAR T who may benefit from specific interventions pre and post CAR T to improve outcomes.

Using a Modified Delphi Panel to Estimate Health Service Utilization for Patients with Advanced and Non-Advanced Systemic Light Chain Amyloidosis.

Purpose: Patients with diagnosed with systemic light chain (AL) amyloidosis at advanced Mayo stages have greater morbidity and mortality than those diagnosed at non-advanced stages. Estimating service use by severity is difficult because Mayo stage is not available in many secondary databases. We used an expert panel to estimate healthcare utilization among advanced and non-advanced AL amyloidosis patients. Patients and Methods: Using the RAND/UCLA modified Delphi method, expert panelists completed 180 healthcare utilization estimates, consisting of inpatient and outpatient visits, testing, chemotherapy, and procedures by disease severity and organ involvement during two treatment phases (the 1 year after starting first line [1L] therapy and 1 year following treatment [post-1L]). Estimates were also provided for post-1L by hematologic treatment response (complete or very good partial response [CR/VGPR], partial, no response or relapse [PR/NR/R]). Areas of disagreement were discussed during a meeting, after which ratings were completed a second time. Results: During 1L therapy, 55% of advanced patients had ≥1 hospitalization and 38% had ≥2 admissions. Rates of hematopoietic stem cell transplant (HSCT) in advanced patients were 5%, while pacemaker or implantable cardioverter defibrillator (ICD) placement were 15%. During post-1L therapy, rates of hospitalization in advanced patients remained high (≥1 hospitalization: 20-43%, ≥2 hospitalizations: 10-20%), and up to 10% of advanced patients had a HSCT. Ten percent of these patients underwent pacemaker/ICD placement. Conclusion: Experts estimated advanced patients, who would not be good candidates for HSCT, would have high rates of hospitalization (traditionally the most expensive type of healthcare utilization) and other health service use. The development of new treatment options that can facilitate organ recovery and improve function may lead to decreased utilization.

Real-world experience of patients with multiple myeloma receiving ide-cel after a prior BCMA-targeted therapy.

Most patients with multiple myeloma experience disease relapse after treatment with a B-cell maturation antigen-targeted therapy (BCMA-TT), and data describing outcomes for patients treated with sequential BCMA-TT are limited. We analyzed clinical outcomes for patients infused with standard-of-care idecabtagene vicleucel, an anti-BCMA chimeric antigen receptor (CAR) T-cell therapy, at 11 US medical centers. A total of 50 patients with prior BCMA-TT exposure (38 antibody-drug conjugate, 7 bispecific, 5 CAR T) and 153 patients with no prior BCMA-TT were infused with ide-cel, with a median follow-up duration of 4.5 and 6.0 months, respectively. Safety outcomes between cohorts were comparable. The prior BCMA-TT cohort had a lower overall response rate (74% versus 88%; p = 0.021), median duration of response (7.4 versus 9.6 months; p = 0.03), and median progression-free survival (3.2 months versus 9.0 months; p = 0.0002) compared to the cohort without prior BCMA-TT. All five patients who received a prior anti-BCMA CAR T responded to ide-cel, and survival outcomes were best for this subgroup. In conclusion, treatment with ide-cel yielded meaningful clinical responses in real-world patients exposed to a prior BCMA-TT, though response rates and durability were suboptimal compared to those not treated with a prior BCMA-TT.

Embracing Myeloma Chimeric Antigen Receptor-T: From Scientific Design to Clinical Impact.

Despite recent advancement of treatment strategies in multiple myeloma (MM), patients with relapsed/refractory MM disease, particularly after triple-class refractoriness, continue to have poor prognosis. Chimeric antigen receptor (CAR-T) cells were developed and applied to improve outcomes in this setting, and two products, idecabtagene vicleucel and ciltacabtagene autoleucel, both targeting B-cell maturation antigen, have been approved by the Food and Drug Administration in the United States and European Medicines Agency in Europe. Both have shown unprecedented clinical outcomes with high response rate and prolonged progression-free survival and overall survival in this patient population with grim prognosis. Currently, further investigations are ongoing for CAR-T targeting different tumor antigens such as G protein-coupled receptor, class C, group 5, member D or with different combinations of intracellular signaling domains, as well as fourth-generation CAR-T with antigen-unrestricted inducible cytokines. Although CAR-T therapies hold hopes and enthusiasm from the myeloma community, several hurdles remain before these treatments become available for all patients in need. These barriers include CAR-T-cell manufacturing availability, access to administering centers, financial cost, caregivers' availability, and socioeconomic and racial disparities. Expanding clinical trial eligibility criteria and real-world data collection and analysis is crucial to understand the efficacy and safety of CAR-T in the patient cohort who tends to be excluded from current trials.

Cilta-cel or Standard Care in Lenalidomide-Refractory Multiple Myeloma.

BACKGROUND: Ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen (BCMA)-directed CAR T-cell therapy, is effective in heavily pretreated patients with relapsed or refractory multiple myeloma. We investigated cilta-cel in earlier treatment lines in patients with lenalidomide-refractory disease. METHODS: In this phase 3, randomized, open-label trial, we assigned patients with lenalidomide-refractory multiple myeloma to receive cilta-cel or the physician's choice of effective standard care. All the patients had received one to three previous lines of treatment. The primary outcome was progression-free survival. RESULTS: A total of 419 patients underwent randomization (208 to receive cilta-cel and 211 to receive standard care). At a median follow-up of 15.9 months (range, 0.1 to 27.3), the median progression-free survival was not reached in the cilta-cel group and was 11.8 months in the standard-care group (hazard ratio, 0.26; 95% confidence interval [CI], 0.18 to 0.38; P<0.001). Progression-free survival at 12 months was 75.9% (95% CI, 69.4 to 81.1) in the cilta-cel group and 48.6% (95% CI, 41.5 to 55.3) in the standard-care group. More patients in the cilta-cel group than in the standard-care group had an overall response (84.6% vs. 67.3%), a complete response or better (73.1% vs. 21.8%), and an absence of minimal residual disease (60.6% vs. 15.6%). Death from any cause was reported in 39 patients and 46 patients, respectively (hazard ratio, 0.78; 95% CI, 0.5 to 1.2). Most patients reported grade 3 or 4 adverse events during treatment. Among the 176 patients who received cilta-cel in the as-treated population, 134 (76.1%) had cytokine release syndrome (grade 3 or 4, 1.1%; no grade 5), 8 (4.5%) had immune effector cell-associated neurotoxicity syndrome (all grade 1 or 2), 1 had movement and neurocognitive symptoms (grade 1), 16 (9.1%) had cranial nerve palsy (grade 2, 8.0%; grade 3, 1.1%), and 5 (2.8%) had CAR-T-related peripheral neuropathy (grade 1 or 2, 2.3%; grade 3, 0.6%). CONCLUSIONS: A single cilta-cel infusion resulted in a lower risk of disease progression or death than standard care in lenalidomide-refractory patients with multiple myeloma who had received one to three previous therapies. (Funded by Janssen and Legend Biotech; CARTITUDE-4 ClinicalTrials.gov number, NCT04181827.).

Plain language summary of the MajesTEC-1 study of teclistamab for the treatment of people with relapsed or refractory multiple myeloma.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of a phase 1-2 clinical trial called MajesTEC-1. This trial tested the cancer drug teclistamab in people with relapsed or refractory multiple myeloma, a cancer that forms in a certain type of white blood cells known as plasma cells. Most participants who took part in the study had at least 3 prior treatments for multiple myeloma before their cancer came back. HOW WAS THE STUDY IN THIS SUMMARY CONDUCTED?: A total of 165 participants from 9 countries were included in this study. All participants were given teclistamab once per week and monitored for side effects. Once participants started taking teclistamab, they were checked regularly to monitor if their cancer had no change, improved (responded to treatment), or worsened or spread (known as disease progression). WHAT WERE THE RESULTS OF THE STUDY?: After approximately 14.1 months of follow-up (from 2020 to 2021), 63% of participants who were given teclistamab had a decrease in myeloma burden, meaning that they responded to treatment with teclistamab. Participants who responded to teclistamab lived without their myeloma coming back for approximately 18.4 months. The most common side effects were infections, cytokine release syndrome, abnormally low white and red blood cell counts (neutropenia, lymphopenia, and anemia), and low platelet cell counts (thrombocytopenia). Approximately 65% of participants experienced serious side effects. WHAT DO THE RESULTS OF THIS STUDY MEAN?: Overall, more than half of the participants (63%) in the MajesTEC-1 study responded to treatment with teclistamab despite previous myeloma treatment failures. Clinical Trial Registration: NCT03145181, NCT04557098 (ClinicalTrials.gov).

Impact of bortezomib-based versus lenalidomide maintenance therapy on outcomes of patients with high-risk multiple myeloma.

BACKGROUND: Lenalidomide maintenance after autologous stem cell transplant (ASCT) in multiple myeloma (MM) results in superior progression-free survival and overall survival. However, patients with high-risk multiple myeloma (HRMM) do not derive the same survival benefit from lenalidomide maintenance compared with standard-risk patients. The authors sought to determine the outcomes of bortezomib-based maintenance compared with lenalidomide maintenance in patients with HRMM undergoing ASCT. METHODS: In total, the authors identified 503 patients with HRMM who were undergoing ASCT within 12 months of diagnosis from January 2013 to December 2018 after receiving triplet novel-agent induction in the Center for International Blood and Marrow Transplant Research database. HRMM was defined as deletion 17p, t(14;16), t(4;14), t(14;20), or chromosome 1q gain. RESULTS: Three hundred fifty-seven patients (67%) received lenalidomide alone, and 146 (33%) received bortezomib-based maintenance (with bortezomib alone in 58%). Patients in the bortezomib-based maintenance group were more likely to harbor two or more high-risk abnormalities and International Staging System stage III disease (30% vs. 22%; p = .01) compared with the lenalidomide group (24% vs. 15%; p < .01). Patients who were receiving lenalidomide maintenance had superior progression-free survival at 2 years compared with those who were receiving either bortezomib monotherapy or combination therapy (75% vs. 63%; p = .009). Overall survival at 2 years was also superior in the lenalidomide group (93% vs. 84%; p = .001). CONCLUSIONS: No superior outcomes were observed in patients with HRMM who received bortezomib monotherapy or (to a lesser extent) in those who received bortezomib in combination as maintenance compared with lenalidomide alone. Until prospective data from randomized clinical trials are available, post-transplant therapy should be tailored to each patient with consideration for treating patients in clinical trials that target novel therapeutic strategies for HRMM, and lenalidomide should remain a cornerstone of treatment.