Secondary malignancies following high dose therapy and autologous hematopoietic cell transplantation-systematic review and meta-analysis

Selective haematological cancer eradication with preserved haematopoiesis

Haematopoietic stem cell (HSC) transplantation (HSCT) is the only curative treatment for a broad range of haematological malignancies, but the standard of care relies on untargeted chemotherapies and limited possibilities to treat malignant cells after HSCT without affecting the transplanted healthy cells1. Antigen-specific cell-depleting therapies hold the promise of much more targeted elimination of diseased cells, as witnessed in the past decade by the revolution of clinical practice for B cell malignancies2. However, target selection is complex and limited to antigens expressed on subsets of haematopoietic cells, resulting in a fragmented therapy landscape with high development costs2-5. Here we demonstrate that an antibody-drug conjugate (ADC) targeting the pan-haematopoietic marker CD45 enables the antigen-specific depletion of the entire haematopoietic system, including HSCs. Pairing this ADC with the transplantation of human HSCs engineered to be shielded from the CD45-targeting ADC enables the selective eradication of leukaemic cells with preserved haematopoiesis. The combination of CD45-targeting ADCs and engineered HSCs creates an almost universal strategy to replace a diseased haematopoietic system, irrespective of disease aetiology or originating cell type. We propose that this approach could have broad implications beyond haematological malignancies.

Tandem High-Dose Chemotherapy Increases the Risk of Secondary Malignant Neoplasm in Pediatric Solid Tumors

PURPOSE

This study aimed to investigate the incidence and risk factors for secondary malignant neoplasms (SMN) in pediatric solid tumors, focusing on the effects of tandem high-dose chemotherapy (HDCT).

MATERIALS AND METHODS

Patients (aged < 19 years) diagnosed with or treated for pediatric solid tumors between 1994 and 2014 were retrospectively analyzed. The cumulative incidence of SMN was estimated using competing risk methods by considering death as a competing risk.

RESULTS

A total of 1,435 patients (413 with brain tumors and 1,022 with extracranial solid tumors) were enrolled. Seventy-one patients developed 74 SMNs, with a 10-year and 20-year cumulative incidence of 2.680±0.002% and 10.193±0.024%, respectively. The types of SMN included carcinoma in 28 (37.8%), sarcoma in 24 (32.4%), and hematologic malignancy in 15 (20.3%) cases. Osteosarcoma and thyroid carcinoma were the most frequently diagnosed tumors. Multivariate analysis showed that radiotherapy (RT) > 2, 340 cGy, and tandem HDCT were significant risk factors for SMN development. The SMN types varied according to the primary tumor type; carcinoma was the most frequent SMN in brain tumors and neuroblastoma, whereas hematologic malignancy and sarcomas developed more frequently in patients with sarcoma and retinoblastoma, respectively.

CONCLUSION

The cumulative incidence of SMN in pediatric patients with solid tumors was considerably high, especially in patients who underwent tandem HDCT or in those who received RT > 2,340 cGy. Therefore, the treatment intensity should be optimized based on individual risk assessment and the long-term follow-up of pediatric cancer survivors.

Prolonged haematologic toxicity in CAR-T-cell therapy: A review

Chimeric antigen receptor-T-cell (CAR-T-cell) therapy is a novel immunotherapy with encouraging results for treatment of relapsed/refractory haematologic malignancies. With increasing use, our understanding of immune-mediated side effects such as cytokine release syndrome and neurotoxicity has improved; nevertheless, prolonged haematologic toxicity (PHT), with a high incidence rate, remains underrecognized. Owing to heterogeneity in populations, the CAR-T cells used and diseases treated as well as differences in the definition of PHT, its rate, risk factors and management vary across studies. In this review, we provide a narrative of PHT occurring in patients following CAR-T-cell therapy; evidence of PHT treatment strategies is also presented, with the aim of contributing to systematic understanding of PHT.

Long-term effectiveness and safety of high dose chemotherapy followed by autologous stem cell transplantation in daily practice in patients with diffuse large B-cell lymphoma

We retrospectively evaluated long-term outcomes of high dose chemotherapy followed by autologous stem cell transplant (HDC/ASCT) in patients with diffuse large B-cell lymphoma (DLBCL). Between 2004 and 2020, 46 DLBCL patients received HDC/ASCT in our institution, including 12 patients (26.1%), who received as an upfront setting (UFS). At a median follow-up time of 69 months (range, 2-169 months), the 5-year progression-free survival (PFS) rates were 82.5% (95%CI, 46.1-95.3%) in the UFS, and 57.8% (95%CI, 38.1-73.2%) in the relapsed or refractory (R/R) patients (n=34), respectively. The 5-year PFS rates were 62.3% (95%CI, 34.0-81.3%) in primary resistant (n=13) or early relapsing (within 1 year from the initial diagnosis) patients (n=4), and 53.3% (95%CI, 25.9-74.6%) in those relapsing >1 year after the initial diagnosis (n=17), with no statistically significant difference (p=0.498). In R/R patients, multivariate analysis showed that the remission status before HDC/ASCT was an independent poor prognostic factor for progression-free survival (hazard ratio [HR], 17.0; 95%CI, 3.35-86.6; p=0.000630) and high-risk category in the international prognostic index for OS (HR, 9.39; 95%CI, 1.71-51.6; p=0.0100). The incidence of non-relapse mortality by 5 years, and 10 years were 12.2%, and 15.2%, respectively. Eleven patients (23.9%) developed second malignancies, which was the most frequent late complication after HDC/ASCT, with 5-year, and 10-year cumulative incidence of 16.9%, 22.5%, respectively. In conclusion, HDC/ASCT is effective for chemo-sensitive R/R DLBCL regardless of the timing and lines of therapy. However, careful observation is required, considering the long-term complications such as secondary malignancies.

High risk-myelodysplastic syndrome following CAR T-cell therapy in a patient with relapsed diffuse large B cell lymphoma: A case report and literature review

Background

Chimeric antigen receptor (CAR) T-cell therapy represents the most advanced immunotherapy against relapsed/refractory B cell malignancies. While cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome are distinctive, known CAR T-cell acute adverse events, hematological toxicity has been increasingly reported. Cytopenia following CAR T-cell treatment is attributed in most cases to lymphodepletion regimens, bridging chemotherapy, or radiotherapy. However, when cytopenia becomes prolonged, the development of myelodysplastic syndrome (MDS) should be considered.

Case presentation

We report a case of high risk (HR)-MDS following CAR T-cell therapy in a patient with relapsed diffuse large B cell lymphoma. Eight months after CAR T-cell infusion, the blood count showed progressive, worsening cytopenia and the bone marrow biopsy revealed multilineage dysplasia without excess of blasts associated with chromosome 7 deletion and RUNX1 mutation. Next generation sequencing analysis, retrospectively performed on stored samples, showed a germ line CSF3R mutation, CEBPA clonal hematopoiesis, but no RUNX1 lesion.

Conclusion

We describe a case of HR-MDS, with deletion of chromosome 7 and acquisition of RUNX1 mutation, developing after CAR T-cell therapy in a patient with clonal hematopoiesis (CH). Previous chemotherapy favored MDS onset; however, we could not exclude the fact that the impairment of immunosurveillance related to either lymphodepletion or CAR T-cell infusion may play a role in MDS development. Thus, we designed a multicenter prospective study (ClonHema-CAR-T-Study) to investigate if cytopenia after CAR T-cell treatment may be due to underling CH as well as the presence of secondary myeloid malignancies.

Allogeneic Transplantation to Treat Therapy-Related Myelodysplastic Syndrome and Acute Myelogenous Leukemia in Adults

Patients who develop therapy-related myeloid neoplasm, either myelodysplastic syndrome (t-MDS) or acute myelogenous leukemia (t-AML), have a poor prognosis. An earlier Center for International Blood and Marrow Transplant Research (CIBMTR) analysis of 868 allogeneic hematopoietic cell transplantations (allo-HCTs) performed between 1990 and 2004 showed a 5-year overall survival (OS) and disease-free survival (DFS) of 22% and 21%, respectively. Modern supportive care, graft-versus-host disease prophylaxis, and reduced-intensity conditioning (RIC) regimens have led to improved outcomes. Therefore, the CIBMTR analyzed 1531 allo-HCTs performed in adults with t-MDS (n = 759) or t-AML (n = 772) between and 2000 and 2014. The median age was 59 years (range, 18 to 74 years) for the patients with t-MDS and 52 years (range, 18 to 77 years) for those with t-AML. Twenty-four percent of patients with t-MDS and 11% of those with t-AML had undergone a previous autologous (auto-) HCT. A myeloablative conditioning (MAC) regimen was used in 49% of patients with t-MDS and 61% of patients with t-AML. Nonrelapse mortality at 5 years was 34% (95% confidence interval [CI], 30% to 37%) for patients with t-MDS and 34% (95% CI, 30% to 37%) for those with t-AML. Relapse rates at 5 years in the 2 groups were 46% (95% CI, 43% to 50%) and 43% (95% CI, 40% to 47%). Five-year OS and DFS were 27% (95% CI, 23% to 31%) and 19% (95% CI, 16% to 23%), respectively, for patients with t-MDS and 25% (95% CI, 22% to 28%) and 23% (95% CI, 20% to 26%), respectively, for those with t-AML. In multivariate analysis, OS and DFS were significantly better in young patients with low-risk t-MDS and those with t-AML undergoing HCT with MAC while in first complete remission, but worse for those with previous auto-HCT, higher-risk cytogenetics or Revised International Prognostic Scoring System score, and a partially matched unrelated donor. Relapse remains the major cause of treatment failure, with little improvement seen over the past 2 decades. These data mandate caution when recommending allo-HCT in these conditions and indicate the need for more effective antineoplastic approaches before and after allo-HCT.

Secondary primary malignancies in patients with multiple myeloma: A single institution experience

The purpose of our study is to highlight the demographic characteristics, pathological features, and clinical course of multiple myeloma (MM) patients with secondary primary malignancies (SPM). A retrospective chart review was performed from January 2009 to February 2020. Patients' demographic, pathologic and cytogenetic features, treatment characteristics and clinical outcomes were collected. We identified 871 MM patients including 40 patients who developed SPM. Among the 40 patients with SPM, 17 patients developed hematological SPM and 23 patients developed solid SPM. The median time from diagnosis of MM to the occurrence of hematological SPM was 6.85 versus 3.91 years in solid SPM, with a median overall survival (OS) after diagnosis of SPM of 120 and 880 days, respectively. Interestingly, we observed that there was no significant difference in OS between MM patients with or without SPM. Multivariable analysis showed that age and autologous stem cell transplantation were independent factors associated with patients' clinical outcomes. Our study highlights the importance of understanding the etiology, biology, clinical outcome and management in MM patients with SPM.

Primary mesenchymal stromal cells in co-culture with leukaemic HL-60 cells are sensitised to cytarabine-induced genotoxicity, whilst leukaemic cells are protected

Tumour microenvironments are hallmarked in many cancer types. In haematological malignancies, bone marrow (BM) mesenchymal stromal cells (MSC) protect malignant cells from drug-induced cytotoxicity. However, less is known about malignant impact on supportive stroma. Notably, it is unknown whether these interactions alter long-term genotoxic damage in either direction. The nucleoside analogue cytarabine (ara-C), common in haematological therapies, remains the most effective agent for acute myeloid leukaemia, yet one third of patients develop resistance. This study aimed to evaluate the bidirectional effect of MSC and malignant cell co-culture on ara-C genotoxicity modulation. Primary MSC, isolated from patient BM aspirates for haematological investigations, and malignant haematopoietic cells (leukaemic HL-60) were co-cultured using trans-well inserts, prior to treatment with physiological dose ara-C. Co-culture genotoxic effects were assessed by micronucleus and alkaline comet assays. Patient BM cells from chemotherapy-treated patients had reduced ex vivo survival (P = 0.0049) and increased genotoxicity (P = 0.3172) than untreated patients. It was shown for the first time that HL-60 were protected by MSC from ara-C-induced genotoxicity, with reduced MN incidence in co-culture as compared to mono-culture (P = 0.0068). Comet tail intensity also significantly increased in ara-C-treated MSC with HL-60 influence (P = 0.0308). MSC sensitisation to ara-C genotoxicity was also demonstrated following co-culture with HL60 (P = 0.0116), which showed significantly greater sensitisation when MSC-HL-60 co-cultures were exposed to ara-C (P = 0.0409). This study shows for the first time that malignant HSC and MSC bidirectionally modulate genotoxicity, providing grounding for future research identifying mechanisms of altered genotoxicity in leukaemic microenvironments. MSC retain long-term genotoxic and functional damage following chemotherapy exposure. Understanding the interactions perpetuating such damage may inform modifications to reduce therapy-related complications, such as secondary malignancies and BM failure.

Haematopoietic stem cell transplantation in systemic sclerosis: Challenges and perspectives

Systemic Sclerosis is chronic progressive autoimmune disease, characterised by microangiopathy and fibrosis. Due to disease heterogeneity, in terms of extent, severity, and rate of progression, optimal therapeutic interventions are still lacking. Haematopoietic stem cells may be a new therapeutic option in this disease and, although the results of the first trials are encouraging, several issues remain to be addressed. On these bases, the stem cells transplantation is an area of active investigation, and an overview of the current available literature may help to define the role of this therapeutic strategy. Although the promising results, some unmet needs remain, including the transplantation protocols and their effects on immune system, the selection of the ideal patient and the pre-transplant cardiopulmonary evaluations. An improvement in these fields will allow us to optimize the haematopoietic stem cell therapies in SSc.

[Autologous hematopoietic stem cell transplantation for systemic sclerosis : Position statement of the stem cell therapy working party of the German Society of Rheumatology]

There have been three randomized controlled trials on autologous hematopoietic stem cell transplantation (AHSCT) in systemic sclerosis (SSc) that demonstrated significant superiority with respect to survival, improvement of cutaneous fibrosis, lung function and quality of life compared to standard treatment; however, these advantages must be carefully weighed against the transplantation-related risks. For this reason, an expert group from the stem cell therapy working party of the German Society for Rheumatology (DGRh) has now developed recommendations for the use of AHSCT in SSc. Based on the high-quality evidence, AHSCT is considered as the standard option for the treatment of selected SSc patients. Potential candidates for AHSCT are those with early, rapidly progressive, diffuse cutaneous SSc with visceral manifestations who have not yet developed severe damage to internal organs. A close cooperation between rheumatologists and transplantation centers is crucial for optimizing patient selection and treatment outcomes.

Autologous Hematopoietic Stem Cell Transplantation for Treatment of Systemic Sclerosis

Systemic Sclerosis (SSc) is a complex autoimmune disease, characterized by high mortality and morbidity. The heterogeneity in terms of extent, severity, and rate of progression of skin and internal organ involvement gives rise to many difficulties in finding the optimal therapeutic interventions for SSc and, to date, no disease-modifying agents are available. In this scenario, it is not surprising that SSc was one of the first autoimmune diseases challenged with high-dose immunosuppressive treatment followed by autologous hematopoietic stem cell transplantation (AHSCT). In the last decades, AHSCT has emerged as a treatment option for refractory SSc through a reduction of the aberrant immune cells, followed by re-constitution of a new, self-tolerant immune system. After several case series and pilot studies, more recently three randomized controlled trials have shown a benefit in skin involvement, organ functions and quality of life measures in AHSCT compared to monthly cyclophosphamide. In addition, although AHSCT presents a certain risk of mortality, it has been shown that the overall survival is better, compared to the cyclophosphamide group. Current evidence suggests that SSc patients who are most likely to benefit from AHSCT are early, active, with rapidly progressing diffuse skin disease, and mild involvement of internal organs. As the studies have progressed, it has become evident the need for a more rigorous patient selection, the optimization of transplant and post-transplant procedures, and the intervention of multidisciplinary teams of specialists to increase the safety and efficacy of AHSCT in SSc.

Second neoplasms in adult patients submitted to haematopoietic stem cell transplantation

BACKGROUND AND OBJECTIVE

Patients submitted to haematopoietic stem cell transplantation (HSCT) are at increased risk of late complications, such as second neoplasm (SN). The incidence and risk factors of SN in patients receiving HSCT at a single centre were analysed.

PATIENTS AND METHODS

The follow-up of adult patients who received a first HSCT (autologous [auto-HSCT] or allogeneic [allo-HSCT]) between January 2000 and December 2015 was reviewed. We collected their demographic characteristics, the primary disease and type of HSCT, and analysed the cumulative incidence of SN and their risk factors.

RESULTS

Of 699 transplanted patients (auto-HSCT, n=451; allo-HSCT, n=248), 42 (6%) developed SN (17 haematological and 25 solid), 31 post-auto-HSCT and 11 post-allo-HSCT. Haematologic SN were more frequent after auto-HSCT than after allo-HSCT. The median time between HSCT and SN was 4.09 years [range 0.07-13.15], with no differences between auto-HSCT and allo-HSCT. The cumulative incidence of SN was 5% (95% CI 3-6) at 5 years, 7% (95% CI 5-10) at 10 years and 11% (95% CI 8-15) at 15 years, without differences according to the type of HSCT. Only the age over 40 years correlated with an increased risk of SN.

CONCLUSIONS

In this series, the incidence of post-HSCT SN was similar to that previously described. Patients submitted to an auto-HSCT showed a higher frequency of haematologic SN. A higher incidence of SN was detected in patients older than 40 at the time of HSCT.

Myeloablative Autologous Stem-Cell Transplantation for Severe Scleroderma

BACKGROUND

Despite current therapies, diffuse cutaneous systemic sclerosis (scleroderma) often has a devastating outcome. We compared myeloablative CD34+ selected autologous hematopoietic stem-cell transplantation with immunosuppression by means of 12 monthly infusions of cyclophosphamide in patients with scleroderma.

METHODS

We randomly assigned adults (18 to 69 years of age) with severe scleroderma to undergo myeloablative autologous stem-cell transplantation (36 participants) or to receive cyclophosphamide (39 participants). The primary end point was a global rank composite score comparing participants with each other on the basis of a hierarchy of disease features assessed at 54 months: death, event-free survival (survival without respiratory, renal, or cardiac failure), forced vital capacity, the score on the Disability Index of the Health Assessment Questionnaire, and the modified Rodnan skin score.

RESULTS

In the intention-to-treat population, global rank composite scores at 54 months showed the superiority of transplantation (67% of 1404 pairwise comparisons favored transplantation and 33% favored cyclophosphamide, P=0.01). In the per-protocol population (participants who received a transplant or completed ≥9 doses of cyclophosphamide), the rate of event-free survival at 54 months was 79% in the transplantation group and 50% in the cyclophosphamide group (P=0.02). At 72 months, Kaplan-Meier estimates of event-free survival (74% vs. 47%) and overall survival (86% vs. 51%) also favored transplantation (P=0.03 and 0.02, respectively). A total of 9% of the participants in the transplantation group had initiated disease-modifying antirheumatic drugs (DMARDs) by 54 months, as compared with 44% of those in the cyclophosphamide group (P=0.001). Treatment-related mortality in the transplantation group was 3% at 54 months and 6% at 72 months, as compared with 0% in the cyclophosphamide group.

CONCLUSIONS

Myeloablative autologous hematopoietic stem-cell transplantation achieved long-term benefits in patients with scleroderma, including improved event-free and overall survival, at a cost of increased expected toxicity. Rates of treatment-related death and post-transplantation use of DMARDs were lower than those in previous reports of nonmyeloablative transplantation. (Funded by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health; ClinicalTrials.gov number, NCT00114530 .).

Toxicity and efficacy of autologous hematopoietic cell transplantation in elderly patients with aggressive lymphoma: a historical prospective study

High-dose therapy followed by autologous hematopoietic cell transplantation (HCT) prolongs overall survival in patients under 65 years old with relapsed aggressive lymphoma. We aimed to explore the toxicity and efficacy of HCT in patients over 65 years with aggressive lymphoma compared with younger patients. We compared the transplantation outcomes between patients ≥ 65 years (n = 58) and 55-64 years (n = 44) with chemosensitive aggressive lymphoma (DLBCL, MCL and TCL) that underwent HCT between 1999 and 2016 in the Tel-Aviv Medical Center. The median age was 68 (range, 65-74) and 61 (range, 55-64) years, respectively. There were no differences in the incidences of grade 3-4 mucositis, documented infections and pulmonary complications between the two groups. There was no difference in the incidences of secondary malignancies, relapse (p = .26), non-relapse mortality, (p = .77) and overall survival (p = .53). Multivariate analysis revealed that smoking was a risk factor for non-relapse mortality, while partial remission and > 2 lines of treatment prior HCT were associated with higher risk for relapse. Psycho-socioeconomic score was associated with prolonged hospitalization after HCT and recurrent hospitalizations. We conclude that patients ≥ 65 years old with aggressive lymphoma, compared to younger counterparts, have similar transplantation outcome. Improving habits and psychosocial factors may further improve outcomes in these patients.

Chimeric antigen receptor T-cell therapies for lymphoma

New therapies are needed for patients with Hodgkin or non-Hodgkin lymphomas that are resistant to standard therapies. Indeed, unresponsiveness to standard chemotherapy and relapse after autologous stem-cell transplantation are indicators of an especially poor prognosis. Chimeric antigen receptor (CAR) T cells are emerging as a novel treatment modality for these patients. Clinical trial data have demonstrated the potent activity of anti-CD19 CAR T cells against multiple subtypes of B-cell lymphoma, including diffuse large-B-cell lymphoma (DLBCL), follicular lymphoma, mantle-cell lymphoma, and marginal-zone lymphoma. Importantly, anti-CD19 CAR T cells have impressive activity against chemotherapy-refractory lymphoma, inducing durable complete remissions lasting >2 years in some patients with refractory DLBCL. CAR-T-cell therapies are, however, associated with potentially fatal toxicities, including cytokine-release syndrome and neurological toxicities. CAR T cells with novel target antigens, including CD20, CD22, and κ-light chain for B-cell lymphomas, and CD30 for Hodgkin and T-cell lymphomas, are currently being investigated in clinical trials. Centrally manufactured CAR T cells are also being tested in industry-sponsored multicentre clinical trials, and will probably soon become a standard therapy. Herein, we review the clinical efficacy and toxicity of CAR-T-cell therapies for lymphoma, and discuss their limitations and future directions with regard to toxicity management, CAR designs and CAR-T-cell phenotypes, conditioning regimens, and combination therapies.

Radiation-free, alternative-donor HCT for Fanconi anemia patients: results from a prospective multi-institutional study

Fanconi anemia (FA) is an inherited bone marrow failure syndrome characterized by chromosomal fragility, progressive marrow failure, and cancer predisposition. Hematopoietic cell transplantation (HCT) is curative for FA-related marrow failure or leukemia, but both radiation exposure during transplant and graft-versus-host disease (GVHD) may increase risk of later malignancies of the head and neck and anogenital area. In this study, we tested a radiation-free conditioning regimen with a T-cell-depleted graft to eliminate radiation exposure and minimize early and late toxicities of transplant. Forty-five patients (median age, 8.2 years; range 4.3-44) with FA underwent HCT between June 2009 and May 2014. The preparative regimen included busulfan, cyclophosphamide, fludarabine, and rabbit anti-thymocyte globulin. Busulfan levels were monitored to avoid excess toxicity. All grafts were CD34-selected/T-cell-depleted using the CliniMacs CD34 columns (Miltenyi). Thirty-four patients (75.6%) with marrow failure and 11 (24.4%) with myelodysplastic syndrome underwent HCT using matched unrelated (n = 25, 55.5%), mismatched unrelated (n = 14, 31.1%), or mismatched related donors (n = 6, 13.4%). One year probabilities of overall and disease-free survival for the entire cohort, including patients with myeloid malignancy and those receiving mismatched related/haploidentical grafts, were 80% (±6%) and 77.7% (±6.2%), respectively (median follow-up 41 months). All young children (<10 years of age) undergoing HCT for marrow failure using low-dose busulfan-containing regimen survived. No patients developed acute grade 3-4 GVHD. Sequential reduction of busulfan dose was successfully achieved per study design. Our results show excellent outcomes in patients with FA undergoing alternative donor HCT without radiation exposure. The study is registered to www.clinicaltrials.gov as #NCT01082133.

Secondary primary malignancies during the lenalidomide-dexamethasone regimen in relapsed/refractory multiple myeloma patients

Lenalidomide in combination with dexamethasone (Len‐dex) represents a highly effective treatment in relapsed/refractory multiple myeloma (RRMM) patients. However, an increased risk of secondary primary malignancies (SPMs), including myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML) has been described in patients receiving lenalidomide. In order to assess the incidence and features of this complication, we reviewed 195 patients with RRMM treated with Len‐dex at our institution. The median follow‐up time from diagnosis of MM was 73 months (10–234 months) and from initiation of Len‐dex was 19 months (1–104 months). The median duration of Len‐dex for all patients was 7.8 months (range 1–90 months). The incidence rate (IR) for all SPMs from start of Len‐dex was 2.37 per 100 patient‐years, which reflected an IR of 1.29 for MDS/AML and 1.08 for nonhematologic malignancies (NHM). MDS was the most common SPM noted. The cumulative IR of SPM at 5 years was 1.54% from the time of MM diagnosis and 5.24% from starting Len‐dex. Multivariable cumulative incidence of SPM analysis identified older age (P = 0.005) and prior number of regimens (P = 0.026) as adverse risk factors. We found more concomitant G‐CSF use (P = 0.029) in patients with MDS/AML, however, causal association is not clear. The progression‐free survival after Len‐dex was the longest for patients in MDS/AML group, and the 5‐year overall survival did not differ among groups. Although the rate of SPM was relatively low with Len‐dex, concomitant G‐CSF should be used judiciously and patients receiving this regimen should be observed for the development of this complication.