Impact of pretransplant minimal residual disease in patients with multiple myeloma and a very good partial response or better receiving autologous hematopoietic stem cell transplantation

BACKGROUND

The prognostic significance of minimal residual disease (MRD) status before autologous hematopoietic stem cell transplantation (autoHCT) in patients with multiple myeloma (MM) has not been clearly elucidated.

METHODS

Retrospective single-center study of adult MM patients who achieved ≥very good partial response (VGPR) after induction therapy from 2015 to 2021 received upfront autoHCT and had available pretransplant MRD status by next-generation flow cytometry. The cohort was divided into pretransplant MRD-negative (MRDneg) and MRD-positive (MRDpos) groups.

RESULTS

A total of 733 patients were included in our analysis; 425 were MRDneg and 308 MRDpos at autoHCT. In the MRDpos group, more patients had high-risk cytogenetic abnormalities (48% vs. 38%, respectively; p = .025), whereas fewer patients achieved ≥CR before autoHCT (14% vs. 40%; p < .001). At day 100 after autoHCT, 37% of the MRDpos versus 71% of the MRDneg achieved ≥CR, and at best posttransplant response 65% versus 88% achieved ≥CR, respectively. After a median follow-up of 27.6 months (range, 0.7-82.3), the median PFS was significantly shorter for patients in the MRDpos group compared to the MRDneg group: 48.2 months (95% confidence interval [CI], 0.3-80.5) versus 80.1 months (95% CI, 0.5-80.1), respectively (p < .001). There was no significant difference in overall survival between the two groups (p = .41). Pretransplant MRDpos status was predictive of shorter PFS in multivariate analysis (hazard ratio, 1.80; 95% CI, 1.31-2.46; p < .001). The impact of pretransplant MRD status was retained in most of the examined subgroups.

CONCLUSIONS

In patients achieving ≥VGPR to induction, pretransplant MRDpos status was associated with a lower CR rate after autoHCT and a shorter PFS.

Eltrombopag improves platelet engraftment after haploidentical bone marrow transplantation: Results of a Phase II study

Slow platelet recovery frequently occurs after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with bone marrow graft and post-transplant cyclophosphamide (PCy)-based graft-versus-host disease (GVHD) prophylaxis. Improved platelet recovery may reduce the need for transfusions and improve outcomes. We investigated the safety and efficacy of eltrombopag, a thrombopoietin receptor agonist, at enhancing platelet recovery post-haplo-HSCT. The prospective study included patients ≥18 years of age who received haplo-HSCT with bone marrow graft and PCy. Patients received eltrombopag 300 mg/day starting on Day +5. The primary objective was to estimate platelet engraftment (>50 000/μL by Day 60). In a post hoc analysis, they were compared to a contemporary matched control group who did not receive eltrombopag. One hundred ten patients were included in the analysis (30 eltrombopag and 80 control). Seventy-three percent and 50% of patients in the eltrombopag group and control group, respectively, attained >50 000/μL platelet count by Day 60 (p = .043). No eltrombopag-related grade ≥4 adverse events were observed. Median time to platelet recovery (>20 000/μL) was 29 days with eltrombopag and 31 days for controls (p = .022), while its cumulative incidence was 90% (95% confidence interval [CI]: 78%-100%) with eltrombopag versus 67.5% (95% CI: 57%-78%) for controls (p = .014). Number of platelet transfusions received, overall survival, progression-free survival, GVHD rate, relapse rate, and non-relapse mortality were similar between groups. Overall, eltrombopag is safe and improves platelet recovery in patients undergoing haplo-HSCT with bone marrow graft and PCy.

Impact of revised International Staging System 2 risk stratification on outcomes of patients with multiple myeloma receiving autologous haematopoietic stem cell transplantation

The second revision of the International Staging System (R2-ISS) is a simple tool to risk-stratify newly diagnosed multiple myeloma (NDMM) patients. Here, we completed a retrospective analysis to evaluate the utility of R2-ISS in NDMM patients who underwent up-front autologous haematopoietic stem cell transplantation (auto-HCT). A total of 1291 patients were included, with a median age of 62 years (range 29-83). The distribution of R2-ISS stages was: 123 (10%) stage I, 471 (36%) stage II, 566 (44%) stage III and 131 (10%) stage IV. With a median follow-up of 42.2 months (range 0.3-181.0), the median PFS was 73.0, 65.2, 44.0 and 24.8 months, (p < 0.001) and the median OS was 130.8, 128.5, 94.2 and 61.4 months (p < 0.001) for patients with R2-ISS stages I, II, III and IV respectively. On multivariable analysis (MVA) for PFS, using R2-ISS stage I as reference, R2-ISS stages III (hazard ratio [95% confidence interval], 1.55 [1.05-2.29]; p = 0.028) and IV (2.04 [1.24-3.36]; p = 0.005) were associated with significantly inferior PFS. In the MVA of OS, using R2-ISS stage I as reference, only R2-ISS stage IV was associated with significantly inferior OS (2.43 [1.18-5.01]; p = 0.017). Overall, we found that R2-ISS is a reliable prognostic tool for NDMM patients undergoing up-front auto-HCT.

Safety, efficacy and determinants of response of allogeneic CD19-specific CAR-NK cells in CD19+ B cell tumors: a phase 1/2 trial

There is a pressing need for allogeneic chimeric antigen receptor (CAR)-immune cell therapies that are safe, effective and affordable. We conducted a phase 1/2 trial of cord blood-derived natural killer (NK) cells expressing anti-CD19 chimeric antigen receptor and interleukin-15 (CAR19/IL-15) in 37 patients with CD19+ B cell malignancies. The primary objectives were safety and efficacy, defined as day 30 overall response (OR). Secondary objectives included day 100 response, progression-free survival, overall survival and CAR19/IL-15 NK cell persistence. No notable toxicities such as cytokine release syndrome, neurotoxicity or graft-versus-host disease were observed. The day 30 and day 100 OR rates were 48.6% for both. The 1-year overall survival and progression-free survival were 68% and 32%, respectively. Patients who achieved OR had higher levels and longer persistence of CAR-NK cells. Receiving CAR-NK cells from a cord blood unit (CBU) with nucleated red blood cells ≤ 8 × 107 and a collection-to-cryopreservation time ≤ 24 h was the most significant predictor for superior outcome. NK cells from these optimal CBUs were highly functional and enriched in effector-related genes. In contrast, NK cells from suboptimal CBUs had upregulation of inflammation, hypoxia and cellular stress programs. Finally, using multiple mouse models, we confirmed the superior antitumor activity of CAR/IL-15 NK cells from optimal CBUs in vivo. These findings uncover new features of CAR-NK cell biology and underscore the importance of donor selection for allogeneic cell therapies. ClinicalTrials.gov identifier: NCT03056339 .

Characteristics and Outcomes of Patients With Multiple Myeloma Who Developed Therapy-Related Acute Myeloid Leukemia and Myelodysplastic Syndrome After Autologous Cell Transplantation

Patients with multiple myeloma (MM) who undergo high-dose chemotherapy and autologous hematopoietic cell transplantation (Auto-HCT) have an increased risk of developing therapy-related myelodysplastic syndrome and acute myeloid leukemia (t-MDS/AML). We retrospectively reviewed the medical records of all MM patients who underwent an Auto-HCT at our institution between 1 January and 31 December 2018 and later developed t-MDS/AML. Among the 2982 patients who underwent at least 1 Auto-HCT, 55 (2%) developed t-MDS/AML (MDS, n = 52; AML, n = 3). The median age at t-MDS/AML diagnosis was 66 years (range 43-83 years), and the median time from Auto-HCT to t-MDS/AML diagnosis was 58.5 months (range 6-206 months). At diagnosis, all 3 patients with tAML and 65% of those with therapy-related myelodysplastic syndrome (tMDS) had high-risk disease, per 2022 European LeukemiaNet and R-IPSS, respectively, and 62% had TP53 gene mutations. Patients who developed tMDS/AML were older at MM diagnosis (median 61 versus 59 years; P = .06), more often were male (73% versus 58%; P = .029), received more than 2 years of lenalidomide maintenance (57% versus 39%; P = .014), and experienced complete remission more frequently after Auto-HCT compared to those who did not develop t-MDS/AML (56% versus 40%; P = .012). In a multivariable model, male gender, advanced age at MM diagnosis, experiencing complete remission after Auto-HCT, and lenalidomide maintenance were independent predictors of developing t-MDS/AML. Among the patients who developed t-MDS/AML, 14 (25%) underwent allogeneic hematopoietic stem transplantation (Allo-HCT). After a median follow-up of 9.9 months from t-MDS/AML diagnosis, the median overall survival (OS) after t-MDS/AML diagnosis was 11.8 months for all patients, and 18.2 months versus 11.1 months for Allo-HCT recipients versus nonrecipients, respectively (P = .25). On univariate analysis, receiving an alkylator as induction for MM (hazard ratio [95% confidence interval]: 2.9 [1.3-6.3]; P = .009), age > 60 years (3.1 [1.2-8.2]; P = .025), and higher-risk R-IPSS (2.7 [1.3-6.0]; P=0.011) predicted worse OS after t-MDS/AML diagnosis. None of these retained significance in the multivariable analysis. T-MDS/AML after Auto-HCT for MM is associated with aggressive disease characteristics, including high-risk cytogenetics and TP53 mutations. The outcomes of patients remain poor, even with Allo-HCT. A better understanding of disease biology and novel therapeutic approaches is warranted.

Impact of Visceral Obesity on Clinical Outcome and Quality of Life for Patients with Multiple Myeloma: A Secondary Data Analysis of STaMINA (BMT CTN 0702) Trial

Obesity is a common health problem among multiple myeloma (MM) patients, and it has been linked to poor clinical outcomes and quality of life (QOL). We conducted a secondary analysis of the BMT CTN 0702, a randomized, controlled trial comparing outcomes of three treatment interventions after a single hematopoietic cell transplant (HCT) (N = 758), to investigate the impact of visceral obesity, as measured by waist-to-hip ratio (WHR), on clinical outcomes and QOL in MM patients. A total of 549 MM patients, median age 55.5 years, were enrolled in the study. The majority of patients received triple-drug antimyeloma initial therapy before enrollment, and 29% had high- risk disease according to cytogenetic assessment. The median follow-up time was 6 years. There was no significant association between WHR and progression-free survival (PFS) or overall survival (OS) in MM patients undergoing HCT. Similarly, body mass index (BMI) did not significantly predict PFS or OS. Furthermore, there was no significant correlation between WHR and QOL measures. In conclusion, this study suggests that visceral obesity, as measured by WHR, may not have a significant impact on clinical outcomes in MM patients undergoing HCT. These findings add to the existing literature on the topic and provide valuable information for healthcare professionals and MM patients. Further studies are needed to confirm these results and to investigate other potential factors that may affect clinical outcomes and QOL in this patient population using modern imaging technologies to assess visceral obesity.

Outcomes of patients with multiple myeloma and 1q gain/amplification receiving autologous hematopoietic stem cell transplant: the MD Anderson cancer center experience

The prognostic impact of additional copies of chromosome 1q (1q + ) on outcomes of newly-diagnosed multiple myeloma (NDMM) patients undergoing autologous transplantation (autoSCT) is unclear. We conducted a retrospective single-center analysis of NDMM patients with 1q21 gain/amplification (3 or ≥4 copies of 1q, respectively) that received autoSCT between 2008-2018. 213 patients were included (79% 1q gain; 21% 1q amplification). The most commonly used induction regimen was bortezomib, lenalidomide, and dexamethasone (41%). At day100 post-autoSCT and at best post-transplant response, 78% and 87% of patients achieved ≥VGPR, and 38% and 50% achieved MRD-negative ≥VGPR, respectively. Median PFS and OS for the entire cohort were 35.5 months and 81.4 months, respectively. On multivariable assessment for PFS, MRD negative ≥VGPR before autoSCT (HR 0.52, p = 0.013) was associated with superior PFS, whereas 1q amplification was associated with inferior PFS (2.03, p = 0.003). On multivariate analysis for OS, achieving MRD negative ≥VGPR at best post-transplant response was associated with superior survival (0.29, p < 0.001), whereas R-ISS III and concomitant del17p or t(4:14) were associated with inferior survival (6.95, p = 0.030, 2.33, p = 0.023 and 3.00, p = 0.047, respectively). In conclusion, patients with 1q+ NDMM, especially 1q amplification, have inferior survival outcomes compared to standard-risk disease after upfront autoSCT, though outcomes are better than other high-risk cytogenetic abnormalities.

Transplantation Outcomes of Myelofibrosis with Busulfan and Fludarabine Myeloablative Conditioning

Outcomes of myelofibrosis (MF) with allogeneic stem cell transplantation (allo-SCT) have improved over the past decade, related in part to advances in supportive treatments and conditioning regimens. Several factors are known to predict transplantation outcomes. However, most studies lack homogeneity in conditioning regimens used, limiting their ability to assess prognostic factors on transplantation outcomes. We aimed to identify the risk factors that predict transplantation outcomes in patients with MF who underwent matched or mismatched allo-SCT using a uniform myeloablative conditioning regimen consisting of busulfan and fludarabine with tacrolimus and methotrexate-based graft-versus-host disease prophylaxis. This single-center study included patients with MF who underwent allo-SCT with a matched unrelated donor (MUD), matched related donor (MRD), or mismatched unrelated donor (MMUD) and received busulfan and fludarabine conditioning with methotrexate/tacrolimus-based GVHD prophylaxis. Sixty-five patients with MF met the study criteria and were included in our analysis. At a median follow-up of 35.6 months, the 3-year cumulative incidence of relapse (CIR), nonrelapse mortality (NRM), and overall survival (OS) for all study patients were 27%, 20%, and 65%, respectively. In a multivariable analysis for CIR, prior use of JAK inhibitors was significantly associated with a decreased risk of relapse (hazard ratio [HR], .33; 95% confidence interval [CI], .11 to .99; P = .048). For NRM, Hematopoietic Cell Transplantation Comorbidity Index (≥3 versus <3; HR, 10.09; 95% CI, 2.09 to 48.76; P = .004) and donor type (MUD versus MRD: HR, 5.38; 95% CI, 1.14 to 25.30; P = .033; MMUD versus MRD: HR, 10.73; 95% CI, 1.05 to 109.4; P = .045) were associated with an increased risk of mortality. Likewise for OS, HCT-CI (≥3 versus <3; HR, 3.31; 95% CI, 1.22 to 8.99; P = .019) and donor type (MMUD versus MRD: HR, 5.20; 95% CI, 1.35 to 19.98; P = .016) were significantly associated with inferior survival. Longer time from diagnosis to allo-SCT seemed to confer worse survival, but the difference did not reach statistical significance (>12 months versus ≤12 months: NRM: HR, 7.20; 95% CI, .96 to 53.94; P = .055; OS: HR, 2.60; 95% CI, .95 to 7.14; P = .06). In a homogenous cohort of MF patients uniformly treated with busulfan/fludarabine myeloablative conditioning and methotrexate-based GVHD prophylaxis, we show that donor choice and HCT-CI are the 2 strongest predictors for improved survival after allo-SCT.

Outcomes of Autologous Stem Cell Transplantation in Patients with Ultra-High-Risk Multiple Myeloma

Multiple myeloma (MM) patients with high-risk cytogenetic abnormalities have inferior survival outcomes and are underrepresented in clinical trials. There is scarce data on MM patients with more than one high-risk cytogenetic aberration (ie, ultra- high-risk MM). This study was conducted to evaluate outcomes of newly diagnosed MM patients with ultra-high-risk MM who underwent autologous hematopoietic stem cell transplantation (autoHCT). We conducted a retrospective single-center chart review analysis of adult patients with ultra-high-risk MM who underwent autoHCT between 2008 and 2018 at MD Anderson Cancer Center. High-risk cytogenetics were defined as del(17p), t(4;14), t(14;16), or 1q21 gain or amplification (1q+) by fluorescence in situ hybridization. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Seventy-nine patients with two or more high-risk cytogenetic abnormalities were included in our analysis. The median age of 61 years (range, 33.5 to 76.5 years), and 57% were female. Sixty-seven patients had two high-risk cytogenetic abnormalities, and 12 patients had three high-risk cytogenetic abnormalities. The most common combinations of high-risk abnormalities were [1q+, t(4:14)] (n = 25; 32%) and [1q+, del17p] (n = 21; 27%). The majority of patients received either bortezomib, lenalidomide, and dexamethasone (48%) or carfilzomib, lenalidomide, and dexamethasone (16%) as induction therapy. Prior to autoHCT, 52 patients (66%) achieved a very good partial response or better (≥VGPR), whereas 23 patients (29%) achieved minimal residual disease (MRD)-negative ≥VGPR. Fifty-six patients (71%) received post-transplantation maintenance therapy. Thirty-six patients (46%) achieved MRD-negative ≥VGPR at day +100 after autoHCT, and 40 patients (51%) did so at best post-transplantation response. With a median follow-up in surviving patients of 38.3 months (range, 11.9 to 104.8 months), the median PFS and OS in the entire cohort were 22.9 months and 71.5 months, respectively. For the subset of patients with three HR abnormalities, the median PFS was 15.6 months and median OS was 28.0 months. In multivariate analysis, achieving MRD-negative ≥VGPR prior to autoHCT was associated with improved PFS (hazard ratio [HR], .42; P = .045), whereas male sex (HR, .15; P = .009) and achieving MRD-negative ≥VGPR post-autoHCT (HR, .27; P = .026) were associated with improved OS. In conclusion, patients with ultra-high-risk MM have a median PFS of <24 months with the current standard of care that includes consolidation with autoHCT. These patients may benefit from earlier use of newer treatment modalities, such as chimeric antigen receptor T cell therapy and bispecific antibodies.

Personalized Medicine's Coming of Age: One Drug, One Patient

A dendritic cell/myeloma fusion vaccine, given with lenalidomide and GM-CSF, did not result in a statistically significant increase in CR rates at 1 year posttransplant but was associated with a significant increase in circulating multiple myeloma-reactive lymphocytes indicative of tumor-specific immunity. See related article by Chung et al., p. 4784.

Myeloablative fractionated busulfan for allogeneic stem cell transplant in older patients or patients with comorbidities

Traditional conditioning regimens for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) provide suboptimal outcomes, especially for older patients and those with comorbidities. We hypothesized that a fractionated myeloablative busulfan dose delivered over an extended period would reduce nonrelapse mortality (NRM) while retaining antileukemic effects. Here, we performed a phase 2 trial for adults with hematological malignancies receiving matched related or unrelated allo-HCT. Participants received busulfan 80 mg/m2 as outpatients on days -20 and -13 before transplant. Fludarabine 40 mg/m2 was administered on days -6 to -3, followed by busulfan dosed to achieve a target area under the curve of 20 000 mol/min for the whole course. The primary end point was day-100 NRM. Seventy-eight patients were included, with a median age of 61 years (range, 39-70 years), who received transplantation for acute leukemia (24%), myelodysplastic syndrome (27%), or myeloproliferative disease/chronic myeloid leukemia (44%). HCT-specific comorbidity index (HCT-CI) was ≥3 in 34 (44%). With a median follow-up of 36.4 months (range, 2.9-51.5), the 100-day, 1-year, and 3-year NRM rates were 3.8%, 8%, and 9.3%, respectively, without a significant difference in age or HCT-CI score. The 1-year and 3-year relapse incidence was 10% and 18%, respectively. The 3-year overall survival was 80%, without a significant difference in age or HCT-CI score and was similar for patients aged >60 years and those aged <60 years as well as for those with HCT-CI ≥3 and HCT-CI <3. Overall, a myeloablative fractionated busulfan regimen has low NRM without an increase in relapse rate, resulting in promising survival, even in older patients or in patients with comorbidities. This trial was registered at www.clinicaltrials.gov as #NCT02861417.

Single-agent lenalidomide maintenance after upfront autologous stem cell transplant for newly diagnosed multiple myeloma: The MD Anderson experience

The optimal duration of lenalidomide (Len) maintenance for patients with multiple myeloma (MM) after autologous stem cell transplantation (autoHCT) is unknown. We conducted a retrospective single-center analysis of adult MM patients that received upfront autoHCT between 2005 and 2021, followed by single-agent Len maintenance. A total of 1167 patients were included with a median age of 61.4 (range 25.4-82.3) years, and high-risk chromosomal abnormalities in 19%. Median duration of maintenance was 22.3 (range 0.03-139.6) months. After a median follow-up of 47.9 (range 2.9-171.7) months, median PFS and OS for the entire cohort were 56.6 (95% CI 48.2-61.4) months and 111.3 (95% CI 101.7-121.5) months, respectively. In MVA, high-risk cytogenetics was associated with a worse PFS (HR 1.91) and OS (HR 1.73) (p < .001 for both). Use of KRD induction and achievement of MRD-negative ≥ VGPR before autoHCT were associated with an improved PFS (HR 0.53 and HR 0.57, respectively; p < .001 for both). Longer maintenance duration, even with a 5-year cutoff, was associated with superior PFS and OS (HR 0.17 and 0.12, respectively; p < .001 for both). A total of 106 patients (9%) developed a second primary malignancy (SPM), mostly solid tumors (39%) and myeloid malignancies (30%). Longer maintenance duration was associated with a higher risk of SPM, reaching statistical significance after >2 years (odds ratio 2.25; p < .001). In conclusion, outcomes with Len maintenance were comparable to those reported in large clinical trials. Longer duration of maintenance, even beyond 5 years, was associated with improved survival.

Outcomes of young adults (aged ≤ 40 years) with newly diagnosed multiple myeloma after up-front autologous stem cell transplant

Multiple myeloma (MM) primarily affects older patients. There are scarce data on the outcomes of young adults undergoing autologous transplantation (auto-HCT). In this single-centre analysis, we included 117 younger patients, with a median age of 37 years (range 22-40) at transplant. Seventeen (15%) patients had high-risk cytogenetics. Before transplant, 10% of patients achieved ≥CR and 44% achieved ≥VGPR. At best post-transplant response, 56% and 77% of patients achieved ≥CR and ≥VGPR respectively. With a median follow-up for survivors of 72.6 months (range 0.9-238.0), median PFS and OS were 43.1 months (95% CI 31.2-65.0) and 146.6 months (95% CI 100.0-208.1) respectively. Patients who underwent auto-HCT after 2010 had better median PFS (84.9 months vs. 28.2 months, p < 0.001) and OS (NR vs. 91.8 months, p < 0.001) compared with those transplanted earlier. In multi-variate analysis, achieving ≥CR as best post-transplant response was associated with improved PFS (HR [95% CI] 0.55 [0.32-0.95], p = 0.032), while achieving ≥VGPR was predictive of superior OS (0.32 [0.16-0.62], p < 0.001). Three patients (3%) developed a second primary malignancy. Younger MM patients had durable survival after auto-HCT, which further improved after the availability of novel anti-myeloma drugs in recent years. Depth of response following transplant remains a key predictor of survival.

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.

Impact of second primary malignancy post-autologous transplantation on outcomes of multiple myeloma: a CIBMTR analysis

The overall survival (OS) has improved significantly in multiple myeloma (MM) over the last decade with the use of proteasome inhibitor and immunomodulatory drug-based combinations, followed by high-dose melphalan and autologous hematopoietic stem cell transplantation (auto-HSCT) and subsequent maintenance therapies in eligible newly diagnosed patients. However, clinical trials using auto-HSCT followed by lenalidomide maintenance have shown an increased risk of second primary malignancies (SPM), including second hematological malignancies (SHM). We evaluated the impact of SPM and SHM on progression-free survival (PFS) and OS in patients with MM after auto-HSCT using CIBMTR registry data. Adult patients with MM who underwent first auto-HSCT in the United States with melphalan conditioning regimen from 2011 to 2018 and received maintenance therapy were included (n = 3948). At a median follow-up of 37 months, 175 (4%) patients developed SPM, including 112 (64%) solid, 36 (20%) myeloid, 24 (14%) SHM, not otherwise specified, and 3 (2%) lymphoid malignancies. Multivariate analysis demonstrated that SPM and SHM were associated with an inferior PFS (hazard ratio [HR] 2.62, P < .001 and HR 5.01, P < .001, respectively) and OS (HR 3.85, P < .001 and HR 8.13, P < .001, respectively). In patients who developed SPM and SHM, MM remained the most frequent primary cause of death (42% vs 30% and 53% vs 18%, respectively). We conclude the development of SPM and SHM leads to a poor survival in patients with MM and is an important survivorship challenge. Given the median survival for MM continues to improve, continued vigilance is needed to assess the risks of SPM and SHM with maintenance therapy post-auto-HSCT.

Clinicopathologic Features of Therapy-Related Myeloid Neoplasms in Patients with Myeloma in the Era of Novel Therapies

The development of therapy-related myeloid neoplasms (t-MN) is a rare complication that can occur in myeloma patients treated primarily with novel therapies. To better understand t-MNs in this context, we reviewed 66 such patients and compared them with a control group of patients who developed t-MN after cytotoxic therapies for other malignancies. The study group included 50 men and 16 women, with a median age of 68 years (range, 48-86 years). Therapies included proteasome inhibitors, immunomodulatory agents, and high-dose melphalan-based autologous stem cell transplantation (HDM-ASCT) in 64 (97%), 65 (98.5%), and 64 (97%) patients, respectively; 29 (43.9%) patients were exposed to other cytotoxic drugs besides HDM. The latency interval from therapy to t-MN was 4.9 years (range, 0.6-21.9 years). Patients who received HDM-ASCT in addition to other cytotoxic therapies had a longer latency period to t-MN compared with patients who only received HDM-ASCT (6.1 vs 4.7 years, P = .009). Notably, 11 patients developed t-MN within 2 years. Therapy-related myelodysplastic syndrome was the most common type of neoplasm (n = 60), followed by therapy-related acute myeloid leukemia (n = 4) and myelodysplastic syndrome/myeloproliferative neoplasm (n = 2). The most common cytogenetic aberrations included complex karyotypes (48.5%), del7q/-7 (43.9%), and/or del5q/-5 (40.9%). The most frequent molecular alteration was TP53 mutation, in 43 (67.2%) patients and the sole mutation in 20 patients. Other mutations included DNMT3A, 26.6%; TET2, 14.1%; RUNX1, 10.9%; ASXL1, 7.8%; and U2AF1, 7.8%. Other mutations in less than 5% of cases included SRSF2, EZH2, STAG2, NRAS, SETBP, SF3B1, SF3A1, and ASXL2. After a median follow-up of 15.3 months, 18 patients were alive and 48 died. The median overall survival after the diagnosis of t-MN in the study group was 18.4 months. Although the overall features are comparable to the control group, the short interval to t-MN (<2 years) underscores the unique vulnerable status of myeloma patients.

Impact of clonal plasma cells in autografts on outcomes in high-risk multiple myeloma patients

Most patients with multiple myeloma (MM) undergoing autologous hematopoietic stem cell transplantation (autoHCT) eventually relapse, perhaps due to the presence of clonal plasma cells (CPC) in the autograft. We conducted a retrospective analysis to evaluate the impact of CPC in the autograft on the outcomes of high-risk chromosomal abnormalities (HRMM) patients undergoing autoHCT between 2008 and 2018. Patients were divided into CPC+ or CPC- in the autograft by next-generation flow cytometry (NGF). There were 75 CPC + autografts (18%) and 341 CPC- (82%). The CPC + group was less likely to achieve MRD-negative complete remission post-transplant (11% vs. 42%; p < 0.001). Median progression free survival (PFS) and overall survival (OS) were (12.8 vs. 32.1 months) and (36.4 vs. 81.2 months) in the CPC + and CPC- groups, respectively (both p < 0.001). Also in the subset of patients with MRD-negative ≥VGPR prior to autoHCT, those with CPC + autografts had inferior PFS (HR 4.21, p = 0.006) and OS (HR 7.04, p = 0.002) compared to CPC-. In multivariable analysis, the degree of CPC positivity in the autograft was independently predictive of worse PFS (HR 1.50, p = 0.001) and OS (HR 1.37, p = 0.001). In conclusion, both the presence and degree of CPC in the autograft were highly predictive of inferior PFS and OS.

Motixafortide and G-CSF to mobilize hematopoietic stem cells for autologous transplantation in multiple myeloma: a randomized phase 3 trial

Autologous hematopoietic stem cell transplantation (ASCT) improves survival in multiple myeloma (MM). However, many individuals are unable to collect optimal CD34+ hematopoietic stem and progenitor cell (HSPC) numbers with granulocyte colony-stimulating factor (G-CSF) mobilization. Motixafortide is a novel cyclic-peptide CXCR4 inhibitor with extended in vivo activity. The GENESIS trial was a prospective, phase 3, double-blind, placebo-controlled, multicenter study with the objective of assessing the superiority of motixafortide + G-CSF over placebo + G-CSF to mobilize HSPCs for ASCT in MM. The primary endpoint was the proportion of patients collecting ≥6 × 106 CD34+ cells kg-1 within two apheresis procedures; the secondary endpoint was to achieve this goal in one apheresis. A total of 122 adult patients with MM undergoing ASCT were enrolled at 18 sites across five countries and randomized (2:1) to motixafortide + G-CSF or placebo + G-CSF for HSPC mobilization. Motixafortide + G-CSF enabled 92.5% to successfully meet the primary endpoint versus 26.2% with placebo + G-CSF (odds ratio (OR) 53.3, 95% confidence interval (CI) 14.12-201.33, P < 0.0001). Motixafortide + G-CSF also enabled 88.8% to meet the secondary endpoint versus 9.5% with placebo + G-CSF (OR 118.0, 95% CI 25.36-549.35, P < 0.0001). Motixafortide + G-CSF was safe and well tolerated, with the most common treatment-emergent adverse events observed being transient, grade 1/2 injection site reactions (pain, 50%; erythema, 27.5%; pruritis, 21.3%). In conclusion, motixafortide + G-CSF mobilized significantly greater CD34+ HSPC numbers within two apheresis procedures versus placebo + G-CSF while preferentially mobilizing increased numbers of immunophenotypically and transcriptionally primitive HSPCs. Trial Registration: ClinicalTrials.gov , NCT03246529.

Autologous Stem Cell Transplantation for Patients with Multiple Myeloma with Translocation (4;14): The MD Anderson Cancer Center Experience

Translocation between chromosomes 4 and 14, t(4;14), has been reported in 15% of patients with multiple myeloma (MM) and is considered a high-risk cytogenetic abnormality associated with inferior outcomes. Autologous hematopoietic stem cell transplantation (auto-HCT) is standard of care for patients with high-risk MM, yet there are scarce data on post-transplantation outcomes of patients with t(4;14) MM. The aim of the present study was to evaluate outcomes of MM patients with t(4;14) who underwent auto-HCT and received contemporary anti-myeloma agents for induction and post-transplantation maintenance. We conducted a retrospective analysis of MM patients with t(4;14), detected by fluorescence in situ hybridization (FISH), who underwent auto-HCT between 2008 and 2018 at MD Anderson Cancer Center. Primary endpoints were progression-free survival (PFS) and overall survival (OS), and secondary endpoints were hematologic response and minimal residual disease (MRD) status after auto-HCT. MRD status in the bone marrow biopsy was evaluated using 8-color next-generation flow cytometry with a sensitivity of 1/10-5 cells. Seventy-nine patients were included (52% male), with a median age of 60 years (range, 32 to 78 years). Forty-four patients (56%) had an additional high-risk cytogenetic abnormality. Fifty patients (63%) achieved at least a very good partial response (≥VGPR) prior to auto-HCT and 20 (25%) had MRD-negative ≥VGPR. At the best post-transplantation evaluation, 90% had ≥VGPR and 63% had MRD-negative ≥VGPR. The median follow-up for survivors was 35.7 months (range, 7.7 to 111.6 months). For the entire cohort, median PFS and OS were 22.9 months and 60.4 months, respectively. Patients with MRD-negative ≥VGPR prior to transplantation had improved PFS and OS on both univariate analysis (UVA) and multivariate analysis (MVA) (hazard ratio [HR], .35 [95% confidence interval (CI), .16 to .76; P = .008] and .12 [95% CI, .03 to .44; P = .002], respectively). The presence of additional high-risk cytogenetic abnormalities was not associated with inferior PFS (P = .57) or OS (P = .70). Post-transplantation lenalidomide-based combinations were associated with improved OS in both UVA and MVA (HR, .14; 95% CI, .04 to .45; P = .001), while their impact on PFS was not statistically significant (P = .37). Our results consolidate t(4;14) as a high-risk abnormality associated with poor outcomes despite novel agent induction, auto-HCT, and post-transplantation maintenance. Despite some inherent study design limitations, including a relatively small cohort and heterogeneity in treatment, we observed that deeper pretransplantation response and post-transplantation maintenance with lenalidomide-based combination were associated with improved outcomes. Novel immune and cellular therapies are needed to improve the outcomes in patients with t(4;14).

Long-Term Outcomes of Allogeneic Hematopoietic Cell Transplantation in Patients with Newly Diagnosed Multiple Myeloma

Despite remarkable progress in survival with the availability of novel agents, an overwhelming majority of patients with multiple myeloma (MM) have disease that relapses. Allogeneic (allo-) hematopoietic cell transplantation (HCT) is a potentially curative option for a subgroup of patients with high-risk MM. This study assessed the long-term outcome of MM patients who underwent allo-HCT while in first remission as consolidation treatment. Thirty-three patients with newly diagnosed MM who underwent allo-HCT as part of consolidation therapy between 1994 and 2016 were reviewed retrospectively. Of these patients, 70% underwent autologous HCT before allo-HCT. All patients were chemosensitive and achieved at least partial response before proceeding to allo-HCT. Most received nonmyeloablative/reduced-intensity conditioning (88%) and a matched sibling donor graft (85%). Acute graft-versus-host disease (GVHD) and chronic GVHD occurred in 30% and 61% of patients, respectively. The median duration of follow-up was 64.1 months (range, 1.4 to 199.2 months) for all patients and 164.4 months (range, 56.0 to 199.2 months) for survivors. The median progression-free survival (PFS) was 36 months (95% confidence interval (CI), 8.6 to 73.0 months). The median time from treatment to progression was 73.0 months (95% CI, 30.6 months to not reached). The median overall survival (OS) was 131.9 months (95% CI, 38.4 months to not reached). Of all patients, 39% were alive for more than 10 years, with 46% (n = 6) without progression or relapse. The cumulative incidence of relapse was 18% at 1 year, 39% at 5 years, and 46% at 10 years post-allo-HCT. The cumulative incidence of nonrelapse mortality was 3% at 100 days, 18% at 1 year, 21% at 3 years, and 24% at 5 year post-allo-HCT. On multivariable analysis, high-risk cytogenetics were associated with a shorter PFS (hazard ratio [HR], 2.7; 95% CI, 1.01 to 7.21; P = .047) and OS (HR, 4.91; 95% CI, 1.48 to 16.27; P = .009). Achieving complete remission after allo-HCT also was associated with longer PFS (HR, 0.24; 95% CI, 0.09 to 0.64; P = .004) and OS (HR, .23; 95% CI, .07 to .72; P = .012). Allo-HCT may confer a survival advantage in a selected population of MM patients when performed early in the disease course; additional data on identifying the patients who will benefit the most are needed.

Enhanced Recovery Stem-Cell Transplantation: Multidisciplinary Efforts to Improve Outcomes in Older Adults Undergoing Hematopoietic Stem-Cell Transplant

PURPOSE

Older adults have unique risk factors for poor outcomes after hematopoietic stem-cell transplant (HSCT). We sought to determine the impact of our multidisciplinary supportive care program, Enhanced Recovery after stem-cell transplant (ER-SCT), on survival outcomes in patients age 65 years and older who underwent HSCT.

PATIENTS AND METHODS

In this retrospective study, clinicodemographic data, nonrelapse mortality (NRM), overall survival (OS), and relapse were compared between 64 patients age 65 years and older who underwent allogeneic stem-cell transplant during ER-SCT program's first year, October 2017 through September 2018, and 140 historical controls age 65 years and older who underwent allogeneic HSCT, January 2015 through September 2017.

RESULTS

In the ER-SCT cohort, 41% (26 of 64) of patients were women, and the median (range) age was 68 (65-74) years; in the control cohort, 38% (53 of 140) of patients were women, and the median (range) age was 67 (65-79) years. Hematopoietic cell transplant comorbidity index and donor type/cell source were similar between cohorts. The ER-SCT cohort had a lower 1-year NRM rate (13% v 26%, P = .03) and higher 1-year OS rate (74% v 53%, P = .007). Relapse rate did not differ significantly between cohorts. In multivariate analyses, ER-SCT was associated with improved 1-year NRM (hazard ratio, 0.4; 95% CI, 0.2 to 0.9; P = .02) and improved 1-year OS (hazard ratio, 0.5; 95% CI, 0.3 to 0.9; P = .03).

CONCLUSION

A multidisciplinary supportive care program may improve NRM and OS in older patients undergoing allogeneic HSCT. Randomized studies are warranted to confirm this benefit and explore which program components most contribute to the improved outcomes.

HLA Factors versus Non-HLA Factors for Haploidentical Donor Selection

When multiple haploidentical donors are available for transplantation, those of younger generations are generally selected over those of older generations. However, it is unclear who is the optimal donor when selecting candidates from within a generation, such as father versus mother, son versus daughter, or brother versus sister. Although traditionally male donors are favored over female donors, particularly for male recipients, and significant associations of individual HLA mis(matches) on outcomes are being increasingly recognized, the hierarchy of factors for donor selection is indeterminate. To assess whether HLA factors take precedence over non-HLA factors and to isolate the influence of specific characteristics on outcomes, we analyzed 412 patients stratified by donor relationship: child donor (son [n = 202] versus daughter [n = 96]), parent (father [n = 28] versus mother [n = 29]), and sibling (noninherited maternal [NIMA; n = 29] versus paternal [NIPA; n = 28] mismatched). Among siblings, NIMA mismatch was associated with a lower risk of acute graft-versus-host disease (aGVHD); B-leader mismatch was associated with high nonrelapse mortality (NRM), poor progression-free survival, and a trend toward poor overall survival (OS), whereas A-mismatch was associated with lower aGVHD. Among parent donors, the relationship did not impact any outcome; B-leader mismatch was associated with higher NRM and a trend toward poor OS, whereas A-mismatch was associated with lower NRM and improved progression-free survival and OS. Among child donors, no individual HLA mismatch was predictive of any outcome, and daughter donors were not associated with any adverse outcomes in multivariate analyses. Our data suggest that certain HLA factors may be more significant in some cases and should be given priority over simply selecting a donor based on relationship/sex.

Trajectories of quality of life recovery and symptom burden after autologous hematopoietic cell transplantation in multiple myeloma

Early autologous hematopoietic cell transplantation (AHCT) with post-transplant maintenance therapy is standard of care in multiple myeloma (MM). While short-term quality of life (QOL) deterioration after AHCT is known, the long-term trajectories and symptom burden after transplantation are largely unknown. Toward this goal, a secondary analysis of QOL data of the BMT CTN 0702, a randomized controlled trial comparing outcomes of three treatment interventions after a single AHCT (N = 758), was conducted. FACT-BMT scores up to 4 years post-AHCT were analyzed. Symptom burden was studied using responses to 17 individual symptoms dichotomized as 'none/mild' for scores 0-2 and 'moderate/severe' for scores of 3 or 4. Patients with no moderate/severe symptom ratings were considered to have low symptom burden at 1-year. Mean age at enrollment was 55.5 years with 17% African Americans. Median follow-up was 6 years (range, 0.4-8.5 years). FACT-BMT scores improved between enrollment and 1-year and remained stable thereafter. Low symptom burden was reported by 27% of patients at baseline, 38% at 1-year, and 32% at 4 years post-AHCT. Predictors of low symptom burden at 1-year included low symptom burden at baseline: OR 2.7 (1.8-4.1), p < 0.0001; older age: OR 2.1 (1.3-3.2), p = 0.0007; and was related to being employed: OR 2.1 (1.4-3.2), p = 0.0004). We conclude that MM survivors who achieve disease control after AHCT have excellent recovery of FACT-BMT and subscale scores to population norms by 1-year post-transplant, though many patients continue to report moderate to severe severity in some symptoms at 1-year and beyond.

Radiation Therapy Can Be Safely Incorporated into Pretransplantation Treatment Regimens for Patients with Multiple Myeloma

Primary treatment of multiple myeloma (MM) often involves systemic induction therapy (SIT) followed by autologous stem cell transplantation (ASCT). Radiation therapy (RT) is sometimes used for palliation; however, many practitioners avoid RT out of concern that future peripheral blood progenitor cell (PBPC) collection required for ASCT may be compromised. In this study, we retrospectively examined the possible effect of RT on PBPC collection. We reviewed the charts of 732 patients with MM treated with RT at our institution from 1999 to 2017, including patients who received RT prior to PBPC collection for planned ASCT. RT plans (both MM and non-MM RT) were reviewed to estimate the percentage of bone marrow (BM) treated using published estimates of skeletal BM distribution. Statistics were performed using Pearson correlation and the t-test. The 732 MM patients included 485 planned for ASCT; of these, 223 received RT prior to PBPC collection and were included in the final cohort. The median age at PBPC collection was 59 years (range, 33 to 80 years). For SIT, patients received combination regimens including the following agents: bortezomib (142 patients; 64%), lenalidomide (111 patients; 50%), and alkylators (46 patients; 21%). Nine patients (4%) received dexamethasone alone. The median cumulative %BM treated per patient was 6.7 (range .0 to 47.4). The median RT dose was 24 Gy (range, 10.0 to 75.6 Gy). Mobilization was performed using granulocyte-colony stimulating factor (G-CSF) alone (189 patients; 85%), G-CSF with plerixafor (15 patients; 7%), or chemotherapy (19 patients; 9%). A median of 7.8 × 106 CD34+/kg PBPCs (range, .5 to 54.8× 106 CD34+/kg) were collected in a median of 3 (range, 1 to 9) apheresis procedures. One hundred ninety-six patients (99%) collected ≥2.0 × 106 CD34+/kg PBPCs, and 166 (83%) collected >5.0 × 106 CD34+/kg PBPCs. The number of PBPCs collected was not associated with %BM treated (P = .15) or RT dose (P = .56). The number of apheresis procedures performed was not associated with %BM treated (P = .54) or RT dose (P = .85). The amount of PBPCs collected did not differ significantly between patients receiving RT to the pelvis/sacrum (P = .20) and those receiving RT to the spine (P = .13). The time to platelet engraftment was longer for patients with higher %BM treated (P = .02). Eleven patients did not undergo a confirmed ASCT, owing to patient preference (3 patients), trial therapy (1 patient), comorbidities (1 patient), election for hospice (1 patient), inadequate collection (4 patients), or inadequate follow-up (1 patient). In our study cohort, RT prior to ASCT did not impair successful ASCT. RT must be carefully planned and delivered to ensure safe incorporation into pre-ASCT treatment regimens.

Impact of second primary malignancy post-autologous hematopoietic stem cell transplantation on outcomes of multiple myeloma: A CIBMTR analysis

8057

Background: Following autologous hematopoietic stem cell transplant (auto HCT), maintenance therapies improve survival, reduce relapse risk in multiple myeloma (MM), and are the de facto standard-of-care. However, clinical trials have shown an increased risk of second primary malignancies (SPM) with maintenance therapy, including second hematological malignancies (SHM). We examined data from the Center for International Blood and Marrow Transplant Research (CIBMTR) registry to evaluate the impact of SPM on progression-free (PFS) and overall survival (OS) and the utilization of allogeneic HCT in patients with therapy-related myeloid neoplasms (t-MN). Methods: Adult patients (pts) with MM who underwent first auto HCT in the United States with a melphalan conditioning regimen from 2011-2018 and subsequently received maintenance therapy were included (N=3948). The primary endpoint of interest was the impact of SPM and SHM on OS. Multivariate analytic (MVA) modelling was applied, accounting for competing risks while integrating significant covariates to determine the impact of SPM on PFS and OS. Finally, we studied the utilization and survival following allogeneic HCT for SHM. Results: Baseline characteristics were similar between the two groups. Maintenance regimens used were lenalidomide (2836, 72%), bortezomib (370,9 %) or lenalidomide + bortezomib (372, 9%) based combinations. At a median follow up of 37 months, 175 (5%) pts developed SPM, including 112 (64%) solid 36 (21%) myeloid, and 27 (15%) lymphoid cancers. In MVA, the development of SPM and SHM was associated with an inferior PFS (HR 2.62, P<0.001 and HR 5.01, P<0.001, respectively) and OS (HR 3.85, P<0.001 and 8.13, P<0.001, respectively). The two commonest causes of death were MM (42%) and SPM (30%) for those developing SPM. Similarly, MM (53%) and SHM (18%) were the two commonest causes of death for those developing SHM. Nine (14%,5 t-MDS and 4 t-AML) of 63 patients with SHM underwent an allogeneic HCT. Patients undergoing allogeneic HCT were more likely to have Karnofsky score ≥90 (100% vs. 50%, P=0.02) compared to those who did not. One year survival from allo SCT was 66.7% (CI 34.6-92%). Conclusions: The three-year cumulative incidence of SPM was 3.3 (2.6-4)% in this large contemporaneous CIBMTR cohort. Disease relapse remains the primary cause of death in MM patients who develop SPM or SHM. Given the median OS for MM is now > 10 years, longer follow-up is needed to assess the SPM and SHM risks with maintenance therapy post-auto HCT.

Lenalidomide: Based maintenance after autologous hematopoietic stem cell transplant for patients with high-risk multiple myeloma

e20024

Background: Maintenance therapy with single-agent lenalidomide (Len) after autologous hematopoietic stem cell transplantation (autoHCT) for multiple myeloma (MM) is associated with improved progression-free survival (PFS). However, patients with high-risk chromosomal abnormalities may need a more intense regimen. We hypothesized that adding another anti-myeloma drug to Len would lead to improved outcomes. Methods: We conducted a retrospective single-center chart review of adult MM patients with high risk cytogenetic abnormalities that received autoHCT between 2008-2018, followed by Len-based maintenance therapy. High risk cytogenetics were defined as del17p, t(4;14), t(14;16), 1q21 gain or amplification by fluorescence in situ hybridization. We divided patients into those who received either single-agent Len maintenance (Len-only) or Len-based combinations (Len-combo). We compared PFS, overall survival (OS), non-relapse mortality (NRM), day 100 and best post-transplant responses, and minimal residual disease (MRD) status between groups. We performed sensitivity analyses using inverse probability weights to correct for potential bias due to nonrandomization of the two groups. Results: A total of 231 patients with HRMM were included in our analysis, with a median age of 62.4 (range 33.5-79.9) years, and 55% were male. There were 153 patients in the Len-only group and 78 in the Len-combo group. Len-combo regimens were either doublets (Len with dexamethasone [dex: n = 10], elotuzumab [n = 28] or ixazomib [n = 14]) or triplets (Len with bortezomib/dex [n = 10], ixazomib/dex [n = 10] or carfilzomib/dex [n = 6]). More patients in the Len-combo group had >2 high risk cytogenetic abnormalities compared to the Len-only group (32% vs. 12%: p < 0.001). Busulfan + melphalan (Bu-Mel) conditioning was used in 12% vs. 18% in Len-only vs. Len-combo groups (p = 0.32). The final best response post-transplant of sCR/CR was 50% in the Len-only group vs. 54% in the Len-combo group (p = 0.72). Median follow up was 40.7 and 35.3 months, with Len-only and Len-combo, respectively. Median PFS and OS for all patients were 25.5 and 82.6 months, respectively. There was no significant difference in PFS (HR: 1.01, CI: 0.71-1.44, p = 0.94) or OS (HR: 0.84, CI: 0.49-1.43, p = 0.52) between groups. Similarly, there was no difference in outcomes between the groups whether they received conditioning with melphalan-only or Bu-Mel. However, for patients with HR cytogenetic abnormalities other than 1q+ there was a trend towards better PFS with Len-combo (HR 0.59, CI 0.32-1.09, p = 0.09), without a difference in OS (HR: 0.79, CI: 0.37-1.65, p = 0.53). Conclusions: In this single center retrospective analysis, intensification of post-transplant Len maintenance did not show an improvement in outcomes for HRMM patients. However, there was a trend towards improved PFS in patients with HR abnormalities other than 1q+.

Phase II study of umbilical cord blood–derived natural killer (CB-NK) cells with elotuzumab, lenalidomide, and high-dose melphalan followed by autologous stem cell transplantation (ASCT) for patients with high-risk multiple myeloma (HRMM)

8009

Background: Despite the introduction of several novel agents over the past decade, patients with HRMM continue to have relatively poor outcomes. In a first-in-human study, we previously showed the feasibility of using CB-NK cells up to a dose of 1 x 108 cells/kg in MM patients undergoing high-dose melphalan (200 mg/m2; Mel200) plus lenalidomide and ASCT (NCT01729091). Lenalidomide enhances NK cell function and antibody-mediated cell toxicity against tumor targets. Our preclinical data showed that ex vivo expanded NK cells demonstrated higher elotuzumab-mediated cytotoxicity against myeloma targets than non-expanded cells, and the addition of elotuzumab to lenalidomide augmented the CB-NK cell ADCC against MM1.S myeloma targets. Hence, we aimed from this expansion part of the phase 2 clinical trial to determine the efficacy of CB-NK cells combined with elotuzumab/lenalidomide for HRMM undergoing ASCT. Methods: Patients with HRMM, ages 18-75 years, were eligible. HRMM defined as: disease relapse within 18 months of ASCT; fluorescence in situ hybridization (FISH) showing t(4:14), t(14:16), t(14:20), deletion (del) 17/17p or gain (amp) 1q; del(13) by conventional cytogenetic analysis; high-risk signatures as determined by the GEP-70 or EMC-92 gene expression profiles. With day 0 defined as day of stem cell infusion, treatment consisted of IV elotuzumab 10 mg/kg (days -15 and -8), oral lenalidomide 10 mg (days -8 to -2 prior to ASCT), Mel200 on day -7, and CB-NK cells on day -5. The primary endpoints were best response rate (≥VGPR) and minimal residual disease (MRD) at 3 months after ASCT, as defined per the IMWG criteria. MRD was tested by using 8-color multiparametric flow cytometry validated to a sensitivity level of 0.001% (1 cell in 100,000). Results: Thirty patients, with a median age of 63 (range, 40-72) years, were enrolled between 03/2018 and 01/2021. 97% had R-ISS stages 2/3, 40% had ≥2 high-risk genetic abnormalities, and 23% had del TP53. Most (80%) received induction therapy with bortezomib or carfilzomib + lenalidomide + dexamethasone, 1 patient had prior ASCT, and 4 received >1 prior line of therapy. Before ASCT, 73% had VGPR or better (40% in CR/sCR) and 40% had negative MRD. At 3 months after transplant, 97% achieved ≥VGPR (76%, CR/sCR) and 75% had negative MRD. At median follow-up of 26 (range, 12-44) months, only 4 patients progressed (3 had positive MRD after ASCT). The 2-year PFS and OS rates were 83% and 97%, respectively. No unexpected serious adverse effects attributable to NK cells were noted. Conclusions: CB-derived expanded NK cells plus elotuzumab/lenalidomide combined with Mel200 and ASCT results in excellent and durable hematologic and MRD responses in HRMM patients. Furthermore, PFS and OS rates compare favorably to published outcomes for HRMM patients. Clinical trial information: NCT01729091.

Mycophenolate Mofetil: A Friend or a Foe with PTCy and Tacrolimus Prophylaxis in HLA-Matched donors?

Adapted from the haploidentical literature, post-transplantation cyclophosphamide (PTCy) is increasingly being used with HLA-matched donors, generally with a calcineurin inhibitor, such as tacrolimus (Tac) with or without mycophenolate mofetil (MMF). Owing to its immunosuppressive, potentially antitumor, and antimicrobial properties, MMF is an attractive drug; however, it remains unclear how much benefit is gained when used with PTCy/Tac. To assess that, we compared PTCy/Tac (n=242) to PTCy/Tac/MMF (n= 144) in recipients of HLA-matched donors. In multivariate analysis, the PTCy/Tac/MMF group had a significantly higher risk of grade II-IV acute graft-versus-host disease (GVHD; hazard ratio (HR) 2.1, 95% confidence interval (CI) 1.6-2.8, p<0.001), and steroid-refractory/dependent acute GVHD (HR 4.8, 95% CI 2.4-9.6, p<0.001), yet a significantly lower risk of relapse (HR 0.5, 95% CI, 0.3-0.9, p=0.009) and better progression-free survival (PFS; HR 0.7, 95% CI 0.5-0.9, p=0.04). There was no difference in the risk of grade III-IV acute GVHD, chronic GVHD, non-relapse mortality, or overall survival. MMF was associated with prolonged neutrophil engraftment by 2 days, and a higher risk of bacterial infections. In an exploratory stool microbiome analysis (n=16), we noted a higher relative abundance of β-glucuronidase-producing bacteria in the MMF group, which may have a role in the pathogenesis of MMF-related GVHD. Our data suggest that the addition of MMF to PTCy/Tac for HLA-matched donor HCT does not provide any advantage for GVHD prevention. Further studies are needed to decipher this mechanism, and understand its role with PTCy-based prophylaxis.

Safety and Efficacy of Combination Maintenance Therapy with Ixazomib and Lenalidomide in Patients with Posttransplant Myeloma

PURPOSE

In this study, the addition of ixazomib to lenalidomide maintenance post-autologous stem cell transplant (ASCT) in 64 patients with newly diagnosed multiple myeloma was evaluated on the basis of the observed benefit of lenalidomide-only maintenance in prior studies.

PATIENTS AND METHODS

Patients were started on maintenance therapy with lenalidomide and ixazomib within 60-180 days of stem cell infusion.

RESULTS

Response rates deepened over time from baseline post-ASCT for 39 patients. The complete response (CR)/stringent CR rate was 43% and median overall survival was not reached with a median follow-up of 62 months (range, 25-82 months). Median PFS (mPFS) for all patients was 73 months and has not been reached for those with International Staging System (ISS) stage 1 disease. mPFS in 9 patients who had ISS stage 3 disease and 14 patients who had high-risk cytogenetics was 34 and 25 months, respectively. Twenty-two patients had progressive disease, while 19 patients continue to receive dual maintenance. The most common grade 3/4 adverse events included neutropenia, leukopenia, thrombocytopenia, lung infections, diarrhea, and maculopapular rash. Second primary malignancies occurred in 9 patients. Toxicity led to dose reductions in ixazomib and lenalidomide in 20 and 31 patients, respectively. Discontinuation of ixazomib due to toxicity occurred in 4 patients. Grade 1/2 neuropathy occurred in 22 patients and led to reduction or discontinuation of ixazomib in 2 patients.

CONCLUSIONS

The addition of ixazomib to lenalidomide maintenance demonstrated a better than expected PFS compared with historical data using lenalidomide alone and was safe and tolerable.