Transplant-eligible Multiple Myeloma Research Articles

Insights from Clinical Trials: Evidence-Based Recommendations for Induction Treatment of Newly Diagnosed Transplant-Eligible Multiple Myeloma

Multiple myeloma (MM) is a hematological malignancy and poses significant therapeutic challenges. This review synthesizes evidence from pivotal clinical trials to guide induction treatment for transplant-eligible (TE), newly diagnosed MM (NDMM) patients. Emphasizing the evolution from three-drug to four-drug induction therapies, we highlight the integration of monoclonal antibodies, particularly CD38 recombinant monoclonal antibody agents, into treatment regimens. This analysis includes a comprehensive literature review of research from major databases and conferences conducted between 2010 and 2023, culminating in the detailed evaluation of 47 studies. The findings underscore the superiority of quadruple regimens in TE NDMM, notably those incorporating daratumumab, in achieving superior responses including progression-free survival (PFS), minimal residual disease (MRD) negativity, objective response rate (ORR), and overall survival (OS) when compared to triple-drug regimens. As treatment regimens evolve with additional agents, the improved outcomes with treatment-related adverse events should be carefully balanced. This review advocates for a paradigm shift towards quadruple induction therapies for TE NDMM, offers a detailed insight into the current landscape of MM treatment, and reinforces a new standard of care.

No Role for Tandem Autologous Stem Cell Transplantation in Modern Treatment Paradigms for Transplant Eligible Multiple Myeloma

No Role for Tandem Autologous Stem Cell Transplantation in Modern Treatment Paradigms for Transplant Eligible Multiple Myeloma

Impact of MRD Status on Survival Rates in Newly Diagnosed Transplant-Eligible Multiple Myeloma Patients: A Systematic Review and Meta-Analysis

Impact of MRD Status on Survival Rates in Newly Diagnosed Transplant-Eligible Multiple Myeloma Patients: A Systematic Review and Meta-Analysis

MM-297 Impact of MRD Status on Survival Rates in Newly Diagnosed Transplant-Eligible Multiple Myeloma Patients: A Systematic Review and Meta-Analysis

MM-297 Impact of MRD Status on Survival Rates in Newly Diagnosed Transplant-Eligible Multiple Myeloma Patients: A Systematic Review and Meta-Analysis

Optimal approach to stem cell mobilization in transplant-eligible multiple myeloma patients

Optimal approach to stem cell mobilization in transplant-eligible multiple myeloma patients

Risk of Secondary Malignancies After Multiple Myeloma: A Nationwide Case-Control Cohort Study

IntroductionIn light of improved survival rates among multiple myeloma (MM) survivors, we sought to assess their risk of secondary malignancies compared to the general population. Materials and MethodsThis nationwide population-based case-control cohort study utilized the Korea National Health Insurance Service (KNHIS) database incorporating data from 2009 to 2020. We analyzed a total of 7348 patients diagnosed with MM in the case cohort. We selected a control group of 29,351 individuals from the general population without MM, employing a 1:4 propensity score matching approach. Matching criteria included age, sex, and comorbidities to ensure a balanced and reliable comparison. ResultsThe cumulative incidence of any secondary malignancy was significantly higher in the case cohort than the control cohort (Hazard ratio [HR] 1.576, 95% confidence interval [CI], [1.381-1.798]). Hematologic malignancy risk was notably higher in the case cohort (HR 8.026, 95% CI, [5.402-11.924]), especially therapy-related myeloid neoplasms (t-MN) (HR 12.063, 95% CI, [6.839-21.278]). No significant difference was shown in nonhematologic malignancy incidence. In subgroup analysis, transplant-eligible MM patients had a significantly higher incidence of any secondary malignancy (HR 1.104, 95% CI, [1.003-1.214]) than transplant-ineligible patients. The incidence of secondary malignancy in MM patients in the lenalidomide-available era was not significantly increased compared to the prelenalidomide era. ConclusionWhile hematologic malignancies, particularly t-MN, are significantly elevated in MM patients compared to general population, nonhematologic malignancies do not appear to be significantly elevated.

Optimizing Autologous Stem Cell Transplantation in Multiple Myeloma: The Impact of Intensive Chemomobilization

Most transplant-eligible multiple myeloma (MM) patients undergo autologous peripheral blood stem cell collection (PBSC) using G-CSF with on-demand plerixafor (G ± P). Chemomobilization (CM) can be used as a salvage regimen after G ± P failure or for debulking residual tumor burden ahead of autologous peripheral blood stem cell transplantation (ASCT). Prior studies utilizing cyclophosphamide-based CM have not shown long-term benefits. At our center, intensive CM (ICM) using a PACE- or HyperCVAD-based regimen has been used to mitigate "excessive" residual disease based on plasma cell (PC) burden or MM-related biomarkers. Given the lack of efficacy of non-ICM, we sought to determine the impact of ICM on event-free survival (EFS), defined as death, progressive disease, or unplanned treatment escalation. We performed a retrospective study of newly diagnosed MM patients who collected autologous PBSCs with the intent to proceed immediately to ASCT at our center between 7/2020 and 2/2023. Patients were excluded if they underwent a tandem autologous or sequential autologous-allogeneic transplant, had primary PC leukemia, received non-ICM treatment (i.e., cyclophosphamide and/or etoposide), or had previously failed G ± P mobilization. To appropriately evaluate the impact of ICM among those who potentially could have received it, we utilized a propensity score matching (PSM) approach whereby ICM patients were compared to a cohort of non-CM patients matched on pre-ASCT factors most strongly associated with the receipt of ICM. Of 451 patients identified, 61 (13.5%) received ICM (PACE-based, n = 45; hyper-CVAD-based, n = 16). Post-ICM/pre-ASCT, 11 patients (18%) required admission for neutropenic fever and/or infection. Among 51 evaluable patients, the overall response rate was 31%; however, 46 of 55 evaluable patients (84%) saw a reduction in M-spike and/or involved free light chains. Among those evaluated with longitudinal peripheral blood flow cytometry (n = 8), 5 patients (63%) cleared circulating blood PCs post-ICM. Compared to patients mobilized with non-CM, ICM patients collected a slightly greater median number of CD34+ cells (10.8 versus 10.2 × 10⁶/kg, P = .018). The median follow-up was 30.6 months post-ASCT. In a PSM multivariable analysis, ICM was associated with significantly improved EFS (hazard ratio [HR] 0.30, 95% CI 0.14 to 0.67, P = .003), but not improved OS (HR 0.38, 95% CI 0.10 to 1.44, P = .2). ICM was associated with longer post-ASCT inpatient duration (+4.1 days, 95% CI, 2.4 to 5.8, P < .001), more febrile days (+0.96 days, 95% CI 0.50 to 1.4, P < .001), impaired platelet engraftment (HR 0.23, 95% CI 0.06 to 0.87, P = .031), more bacteremia (OR 3.41, 95% CI 1.20 to 9.31, P = .018), and increased antibiotic usage (cefepime: +2.3 doses, 95% CI 0.39 to 4.1, P = .018; vancomycin: +1.0 doses, 95% CI 0.23 to 1.8, P = .012). ICM was independently associated with improved EFS in a matched analysis involving MM patients with excessive disease burden at pre-ASCT workup. This benefit came at the cost of longer inpatient duration, more febrile days, greater incidence of bacteremia, and increased antibiotic usage in the immediate post-ASCT setting. Our findings suggest that ICM could be considered for a subset of MM patients, but its use must be weighed carefully against additional toxicity.

Single-Cell DNA Sequencing Reveals an Evolutionary Pattern of CHIP in Transplant Eligible Multiple Myeloma Patients

Clonal hematopoiesis of indeterminate potential (CHIP) refers to the phenomenon where a hematopoietic stem cell acquires fitness-increasing mutation(s), resulting in its clonal expansion. CHIP is frequently observed in multiple myeloma (MM) patients, and it is associated with a worse outcome. High-throughput amplicon-based single-cell DNA sequencing was performed on circulating CD34+ cells collected from twelve MM patients before autologous stem cell transplantation (ASCT). Moreover, in four MM patients, longitudinal samples either before or post-ASCT were collected. Single-cell sequencing and data analysis were assessed using the MissionBio Tapestri® platform, with a targeted panel of 20 leukemia-associated genes. We detected CHIP pathogenic mutations in 6/12 patients (50%) at the time of transplant. The most frequently mutated genes were TET2, EZH2, KIT, DNMT3A, and ASXL1. In two patients, we observed co-occurring mutations involving an epigenetic modifier (i.e., DNMT3A) and/or a gene involved in splicing machinery (i.e., SF3B1) and/or a tyrosine kinase receptor (i.e., KIT) in the same clone. Longitudinal analysis of paired samples revealed a positive selection of mutant high-fitness clones over time, regardless of their affinity with a major or minor sub-clone. Copy number analysis of the panel of all genes did not show any numerical alterations present in stem cell compartment. Moreover, we observed a tendency of CHIP-positive patients to achieve a suboptimal response to therapy compared to those without. A sub-clone dynamic of high-fitness mutations over time was confirmed.

Risk factors of early disease progression and decreased survival for multiple myeloma patients after upfront autologous stem cell transplantation

Multiple myeloma (MM) stands as the second most prevalent hematological malignancy, constituting approximately 10% of all hematological malignancies. Current guidelines recommend upfront autologous stem cell transplantation (ASCT) for transplant-eligible MM patients. This study seeks to delineate factors influencing post–ASCT outcomes in MM patients. Our cohort comprised 150 MM patients from Taipei Veterans General Hospital, with progression-free survival (PFS) as the primary endpoint and overall survival (OS) as the secondary endpoint. A Cox proportional hazards model was employed to discern potential predictive factors for survival. ASCT age ≥ 65 (hazard ratio [HR] 1.94, 95% confidence interval [CI] 1.08–3.47) and the presence of extramedullary disease (HR 2.53, 95% CI 1.53–4.19) negatively impacted PFS. Conversely, treatment response ≥ VGPR before ASCT (HR 0.52, 95% CI 0.31–0.87) and total CD34+ cells collected ≥ 4 × 106 cells/kg on the first stem cell harvesting (HR 0.52, 95% CI 0.32–0.87) were positively associated with PFS. For OS, patients with ISS stage III (HR 2.06, 95% CI 1.05–4.04), the presence of extramedullary disease (HR 3.92, 95% CI 2.03–7.58), light chain ratio ≥ 100 before ASCT (HR 7.08, 95% CI 1.45–34.59), post–ASCT cytomegalovirus infection (HR 9.43, 95% CI 3.09–28.84), and a lower conditioning melphalan dose (< 140 mg/m2; HR 2.75, 95% CI 1.23–6.17) experienced shorter OS. In contrast, post–ASCT day + 15 absolute monocyte counts (D15 AMC) > 500/µl (HR 0.36, 95% CI 0.17–0.79) and post–ASCT day + 15 platelet counts (D15 PLT) > 80,000/µl (HR 0.48, 95% CI 0.24–0.94) were correlated with improved OS. Significantly, early PLT and AMC recovery on day + 15 predicting longer OS represents a novel finding not previously reported. Other factors also align with previous studies. Our study provides real-world insights for post–ASCT outcome prediction beyond clinical trials.

Symptom clusters and their impact on quality of life in multiple myeloma survivors: Secondary analysis of BMT CTN 0702 trial.

Autologous haematopoietic cell transplantation (autoHCT) and continuous post-transplant maintenance therapy are the standard of care in transplant-eligible multiple myeloma (MM) patients. We sought to describe symptom burden and identify symptom clusters occurring in MM patients after autoHCT using data from the BMT CTN 0702 randomized controlled trial comparing the outcomes of three treatment interventions after an autoHCT in 758 MM patients. We analysed individual transplant-related symptoms assessed via the FACT-BMT questionnaire at enrolment and annually for 4-year post-autoHCT. We also described the effect the individual symptoms and symptom clusters have on quality of life (QoL). We identified three stable symptom clusters: malaise symptom cluster (lack of energy, feeling ill, having pain, experiencing nausea, loss of appetite), physical symptom cluster (having skin problems, tremors, worsening eyesight, change in taste, shortness of breath, frequent colds) and emotional symptom cluster (feeling sad, being nervous, experiencing sleep problems). Malaise and emotional symptom clusters have a greater impact on QoL than the physical symptoms cluster. Identifying these symptoms warrant additional support in terms of psychosocial support, in addition to treatment of the physical symptoms themselves.

Serum indicators in functional high-risk multiple myeloma patients undertaking proteasome inhibitors therapy: a retrospective study

ABSTRACT Objectives Multiple myeloma (MM) is a class of malignant plasma cell diseases. An increasing application of autologous stem cell transplantation (ASCT) and anti-myeloma agents represented by proteasome inhibitors (PIs) has improved the response rates and survival of MM patients. Patients progressing within 12 months were recently categorized with functional high-risk (FHR), which could not be clarified by existing genetic risk factors, with poor outcomes. Our study aimed to investigate clinical indices related to FHR and seek prognostic roles in transplant-eligible MM patients. Methods Demographic and individual baseline clinical characteristics were compared by using the Pearson's chi-square and Mann-Whitney U test. Progression-free survival (PFS) and overall survival (OS) were described by Kaplan-Meier estimates and compared using the log-rank test. Logistic regression analysis was used to assess the association of baseline characteristics at MM diagnosis with FHR status. Results From 18th January 2010 to 1st December 2022, 216 patients were included and divided into two groups according to the FHR status. There was no difference in baseline data between the two groups. Renal impairment (RI, Scr > 2 mg/dL) was common in MM patients and made sense in FHR status. AST levels were validated as independent predictors for FHR status (p = 0.019). Discussion Patients with RI or higher AST levels (AST > 40 U/L) tended to have worse outcomes. However, transplants had apparently improved prognoses. Conclusion Therefore, in the PIs era, transplantations are still effective therapies for transplant-eligible MM patients.

EE732 Cost-Effectiveness Analysis of Strategies of Autologous Stem-Cell Transplantation and Maintenance Therapy for Transplant-Eligible Multiple Myeloma in China

EE732 Cost-Effectiveness Analysis of Strategies of Autologous Stem-Cell Transplantation and Maintenance Therapy for Transplant-Eligible Multiple Myeloma in China

Longitudinal Screening of Mutant Hematopoietic Progenitor Cells (HPC) in Multiple Myeloma (MM) and Its Association with Secondary Primary Malignancies (SPM)

Background: The incidence of SPM in transplant eligible MM patients (pts) receiving lenalidomide maintenance is ≥ 12% and is associated with inferior overall survival (OS). Recent evidence suggests that while clonal hematopoiesis does not increase the risk of SPM, specific TP53 mutant HPC may expand under lenalidomide treatment and give rise to therapy related myeloid neoplasms and acute lymphoblastic leukemia. Genetic screening may facilitate personalized treatment to minimize the risk of SPM. However, there are no longitudinal studies in purified HPC to inform on the evolution of specific gene mutations and its association with clinical outcomes. Aim: Analyze the mutational landscape of HPC at diagnosis and throughout lenalidomide based regimens. Methods: This study included 335 pts: 43 with high risk smoldering MM, 223 transplant eligible and 69 ineligible active MM respectively enrolled in the CESAR, GEM2012MENOS/GEM2014MAIN and CLARIDEX clinical trials. Of the 335 pts analyzed at diagnosis, 60 were further investigated after induction, 30 at day 100 after autologous transplant (ASCT) and 47 during maintenance. Two or more studies were available throughout treatment in 36 pts. Fluorescence activated cell sorting of CD34+ HPC was performed in a total of 500 bone marrow aspirates. DNA was analyzed with a panel of 55 genes recurrently mutated in myeloid neoplasms. Sequencing depth was &amp;gt;1000x in 95% of nucleotides. Criteria to filter out included synonymous, intronic, invalid-transcript, 5'UTR, panel error and single nucleotide polymorphisms. The criteria to filter in was a AMP/ACMG classification of uncertain significance, likely pathogenic or pathogenic. Only the latter two were included in downstream analysis. Results: HPC from 184 of the 335 (55%) pts were mutated. The frequency in high-risk smoldering MM, transplant eligible and ineligible active MM was 46%, 26% and 35%, respectively. The genes more frequently mutated were DNMT3A (n=94, 52%), TP53 (n=29, 16%) and TET2 (n=28, 15%). The median variant allele frequency was 4.9, 7.5 and 7.0, respectively. In a pt-paired analysis between diagnosis and induction, 8 mutations were present in both time points, 25 became undetectable and 22 were acquired during treatment. The latter (eg, PPM1D and SF3B1) were observed in 14 of the 60 (23%) pts. In the 30 pts with paired samples at diagnosis and at day 100 after ASCT, 4 mutations were present in both time points, 48 became undetectable and only 3 were acquired during treatment ( ATRX, MPL and SAMDL9). Thus, the frequency of mutant HPC was higher at diagnosis vs ASCT (23% vs 5%, P &amp;lt;.001). In a pt-paired analysis between diagnosis and maintenance, 13 mutations were present in both time points, 12 became undetectable and 30 were acquired during treatment. The latter (eg, PPM1D and SF3B1) were observed in 24 of the 47 (51%) pts screened at both time points, and after a median of 5 years since diagnosis. With a median follow-up of 6 years, 17 of the 335 (5%) pts developed SPM. Mutant HPC were detected in 13 of the 17 pts. Accordingly, presence of mutant HPC was associated with a 2-fold increased risk of SPM (OR: 2.3; P = .03). Of the 13 pts, 3 showed mutations at diagnosis and in 8 these emerged during maintenance. The only case developing a myeloid neoplasm had a TP53 mutation present during maintenance that was undetectable at diagnosis. Pts with mutant vs non-mutated HPC at diagnosis showed similar OS (6y rates of 86% and 81%, respectively; P =.46). Similarly, there were no differences in OS of pts with emerging mutations vs those without mutant HPC after treatment (6y rates of 85% and 83%, respectively; P =.65). Specific mutations in DNMT3A, TP53 and TET2 and were not associated with inferior OS. Conclusions: To our knowledge this is the first study analyzing the mutational landscape of purified HPC throughout lenalidomide based regimens in high risk smoldering MM as well as transplant eligible and ineligible active MM. Deep sequencing of CD34+ HPC uncovered that the frequency of mutations is similar between precursor and malignant disease, and that TP53 is amongst the top mutated genes. There was considerable volatility with presence of both transient and emerging mutations throughout treatment. Importantly, the detection of mutant HPC was associated with increased risk of SPM without differences in survival. Thus, this study supports the longitudinal screening of HPC for the identification of patients at risk of developing SPM.

Lenalidomide Maintenance after VTD Induction and Autologous Stem Cell Transplantation: An Italian Real-Life Study of 558 Patients

According to 2021 ESMO guidelines, treatment of newly diagnosed (ND) transplant eligible (TE) Multiple Myeloma (MM) patients is settled by an induction phase followed by single or tandem autologous stem cell transplantation (ASCT) and Lenalidomide (Len) maintenance. Len maintenance was approved in Italy in May 2018 due to the results of the meta-analysis by McCarthy et al. of three large randomized clinical trials. Before the approval of daratumumab-bortezomib-thalidomide-dexamethasone (D-VTD) regimen, VTD triplet combination was the most used induction regimen across Italian centers. In addition, given the data from the EMN02 trial, in the last years tandem ASCT has been a consolidated practice especially for high-risk cytogenetic patients. However, only a minority of patients enrolled in the meta-analysis of McCarthy received VTD induction and in most of them a single ASCT has been performed. In this context, the aim of this real-life study was to evaluate the efficacy and the safety of Len maintenance after VTD plus single or tandem ASCT in ND TE MM patients. The study cohort included 558 patients with a median age of 59 years (24-74) followed in 21 Italian referral centers. Baseline clinical and biological features are reported in table 1. ISS III and R-ISS III were detected in 111/518 (21.4%) and 44/405 (10.9%) cases, respectively, moreover, 30/327 (9.2%) patients showed R2 ISS stage IV. FISH analysis was available in 408 patients with 70 of them displaying high risk (HR) alterations [including t(4;14), t(14,16) and del17p]. Among the 338 standard risk patients, information about 1q status was available for 320 of them, with 60 patients harboring +1q abnormalities (18.75%). All patients received VTD induction (median number of cycles 4) and single or tandem ASCT was performed in 63.7% and 36.3% of cases, respectively. A median number of 22 cycles of Len maintenance was administered. Complete response (CR) and stringent CR (sCR) rates before starting Len were 31.8% and 14.2%, respectively (overall 46%) and increased with maintenance to 39.6% and 16.6%, respectively (overall 56.2%). Most importantly, 2-year CR and sCR rates in evaluable patients were superimposable (40.6% and 14.9% respectively, 55.5% overall). One hundred ninety-seven patients (35.3%) discontinued treatment, mostly due to progressive disease (134/197, 68.0%). Toxicities were mostly hematological with neutropenia found in 50.4% of cases (grade ≥3 in 17.2%), followed by thrombocytopenia and anemia in 24.4% and 16.1% of cases, respectively (grade ≥3 in 2.1% and 1.8% of cases, respectively). Non-hematological adverse events were primarily gastrointestinal (31.2%, grade ≥3 in 2.3%) and infections (42.3%, grade ≥3 in 3.9%) while skin related disorders affected 7.9% of patients. With a median follow up of 30 months, the 2-year PFS and OS from starting maintenance were 80.6% and 96.7%, respectively. No significant PFS difference was found according to age (&amp;gt;65 years vs ≤65 years, p=0.5924) or ASCT (single vs tandem, p=0.4694). Patients with low-risk disease including ISS I and R-ISS I showed improved PFS as compared to patients with ISS &amp;gt;I and R-ISS &amp;gt;I (2y PFS 84.6% vs 76.6%, p=0.0587 and 87.8% vs 72.7%, p=0.0195, respectively). By R2-ISS, low risk disease (R2-ISS I) confirmed a better outcome as compared to R2-ISS II-III (2y PFS 88.9% vs 72.2%, p=0.0333) and to R2-ISS IV (2y PFS 47.2%, p&amp;lt;0.0001). Finally, considering cytogenetic risk status, standard risk patients displayed a significantly prolonged PFS as compared to high-risk patients (2y PFS 81.6 % vs 56.3%, p&amp;lt;0.0001) and an improved although not significant outcome than patients harboring isolated +1q (2y PFS 77.2%, p=0.09). Moreover, we demonstrated that the accumulation of HR cytogenetic abnormalities reduces patients' outcome, in detail the PFS of patients with at least 2 HR abnormalities was significantly lower than patients with only 1 and without HR aberrations, respectively [2y PFS 44.8% (≥2) vs 73.5% (1), p=0.0301, and 2y PFS 44.8% (≥2) vs 82.8% (0), p&amp;lt;0.0001, figure 1]. To our knowledge, this is the first study evaluating the safety and efficacy of Len maintenance after VTD plus single or tandem ASCT. Our results provide evidence that patients with clinical and biological low risk disease, and more specifically those with R2- ISS I, benefit the most from Len maintenance with a favorable safety profile.

Characterization of Clonal Hematopoietic of Indeterminate Potential (CHIP) Mutations in an Imid-Naïve Multiple Myeloma (MM) Autologous Stem Cell Transplant (ASCT) Population: First Results from a Pre-Transplant Time Point in a Prospective, Longitudinal Study

Background: Clonal Hematopoiesis of Indeterminate Potential (CHIP) is defined by the acquisition of ≥ 1 somatic mutations in the blood of healthy adults, but can also be detected at higher prevalence in patients with malignancies, particularly after DNA damaging therapy. The presence of CHIP mutations in MM confers a reduced overall survival (Mouhieddine, JCO 2020) but high quality, prospective evaluation of CHIP mutation evolution over the transplant sequence, including the impact of high-dose melphalan and immunomodulatory (IMiD)-based therapy, is largely under-studied. Serial assessment of CHIP over the transplant course has been reported from the coMMpass dataset, demonstrating a 4-fold increase in mutation prevalence from 5.8% at diagnosis to 25% after 3.1 years (Mouhieddine, Blood, 2021). In this data set, most patients were exposed to prior IMiD-containing at some point during therapy. Whether the survival benefit reported with IMiD-based maintenance therapy post-transplant is associated with CHIP mutation modulation is unclear. We are therefore investigating the longitudinal evolution of CHIP in a cohort of transplant-eligible, largely IMiD-naïve patients (pts) over the pre- and post-ASCT course in an ongoing study. Here, we present preliminary findings from the pre-transplant time-point after non-IMiD-containing induction but before high-dose melphalan and ASCT. Methods: The ongoing Princess Margaret Cancer Center ARCH 001 trial is a prospective, longitudinal study evaluating evolution of CHIP in a transplant-eligible MM population. Mutation testing is performed using the highly sensitive single-molecule molecular inversion probe (SmMIP) next-generation sequencing (NGS) technique (Abelson, Bioinformatics, 2022). After sequencing with a minimum sequencing depth of 4000x, the list of mutation calls produced by smMIP-tools is subject to various filters to reduce the likelihood of false positives. Synonymous mutations, as well as any variants falling within introns or splice regions are removed. The minor allele frequency of the variant (if available) is required to be above 0.1% so as to exclude mutations that are common SNPs. VAF frequency threshold of 1-30 % is set for calling somatic mutations, with a view to minimize false positives and germ-line mutations. Multiple time points for testing pertinent to therapy include: within 1 month pre-transplant (after induction and stem cell collection), 3 months post-transplant, and two subsequent samples 12 and 24 months post-sample 2. Here we report preliminary results of CHIP mutation testing in the first 66 pts at the pre-transplant time point. Results: Patient, disease and treatment characteristics for all pts and their stratification by the presence of CHIP mutations are outlined in Table 1. The total cohort is typical for a transplant-eligible population with median age 65 years, male predominance (M 59%/F 41%), 60% IgG subtype, 23% high-risk FISH cytogenetics. Most (90%) received a non-IMiD containing induction regimen CyBorD; only 6% received an IMiD pre-ASCT. CHIP mutations were identified in 28/66 pts, for a mutation prevalence rate of 43%; 6 patients (9%) carried ≥ 1 mutation. The median age at transplant as well as other baseline demographics did not differ between those with and without mutations (Table 1). Mutation profiles are shown in Figure 1, and are consistent with those described in the literature with the most commonly mutated genes being DNMT3a, TET2, ASXL1 and PPM1D, and the mutation prevalence rate highest for DNMT3a at 21%. 6 pts (9%) had ≥ 1 mutation (range 2-3) identified, with 3 of 6 involving the DNMT3a gene. Other genes involved in patients with multiple mutations were TET2 (n=3), ASXL1 (n=2), PPM1D (n=2), SRSF2 (n=1), SF3B1 (n=1). Mean allele frequency was 4%, ranging from 1-19. Conclusion: Our results using deep SmMIP sequencing show a mutation prevalence rate of 43% in a cohort of transplant-eligible, largely IMiD-naive MM pts studied after induction. These rates are higher than those generally described in the literature, which may relate to the high sensitivity of the assay used, variation in filtering between institutions, and the deliberate use of a relatively low VAF threshold with the intent to capture clinically significant variants for longitudinal tracking during the course of this ongoing study. Further studies during lenalidomide maintenance will be forthcoming.

Comparison of Response and Survival Outcomes in Standard- and High-Risk Newly Diagnosed Transplant-Eligible Multiple Myeloma (NDMM) Patients Treated with Lenalidomide, Bortezomib and Dexamethasone (RVD) Versus Daratumumab, Lenalidomide, Bortezomib and Dexamethasone (D-RVD)

Introduction: The combination of lenalidomide, bortezomib, and dexamethasone (RVD) is highly effective for newly diagnosed myeloma (NDMM) patients. However, the addition of daratumumab to RVD (D-RVD) has shown improved depth of response and trend towards PFS benefit. Here, we present a real-world comparison of the largest cohort of patients consecutively treated with either D-RVD or RVD induction therapy in terms of response and long-term outcomes for both standard- and high-risk patients. Methods: 1000 consecutive NDMM patients treated with RVD between January 2007- August 2016, and 326 NDMM patients treated with D-RVD induction therapy from April 2018 - August 2022 were included in this analysis. Daratumumab was dosed either IV or subcutaneously weekly throughout induction; lenalidomide was started at 25 mg on days 1-14, bortezomib 1.3 mg/m2 on days 1,4,8,11 and dexamethasone 40 mg on days 1,8,15 all on a 21-day cycle. Of note, in contrast to GRIFFIN, no consolidative cycles were administered in either DRVD or RVD cohorts, and maintenance therapy for standard risk patients with lenalidomide alone while high-risk MM patients were managed with a triplet induction regimen for 3 years (Nooka et al, Leuk 2014). Demographic and clinical characteristics and outcomes data were obtained from our institutional review board-approved myeloma database and with manual abstraction. Responses and progression were evaluated per International Myeloma Working Group Uniform Response Criteria. Results: Patient characteristics for DRVD vs RVD are found in Table 1. Of note, for DRVD vs RVD, 13.8% vs 15.8% had HR disease, and 16% vs 23.3% had ISS 3 and 4.6% vs 11.5% with RISS 3 disease. 98.6% and 99.7% of patients in the RVD vs D-RVD cohorts underwent ASCT. High-risk disease was defined as presence of del(17p), t(4;14), t(4;16), and complex karyotype. Post-induction overall response rate (ORR) was 99.6% in D-RVD versus 97.1% in RVD, with ≥VGPR rates of 86.5% vs 67.6%, respectively. Post-transplant ORR was 99.3% vs 98.5%, with ≥VGPR rates of 95.6% vs 86.8%, respectively. Though the median follow-up for the Dara-RVD cohort is significantly shorter (19.1 months) compared to the RVD cohort (88.4 months), there is already a PFS benefit demonstrated with quadruplet induction for both standard- and high-risk patients. For all patients, the 2-year PFS and OS for D-RVD vs RVD is 93% and 94% compared to 82% and 91%, respectively. For standard risk patients, the 2-year PFS for D-RVD vs RVD is 94% vs 84%, and for high risk patients, 83% vs 69%, respectively. 2-year OS for standard risk patients was 96% in D-RVD vs 93% in RVD, and 94% vs 79% in HR patients, respectively. OS estimates for HR patients also favored D-RVD, though this is more likely than PFS to be impacted by changes in treatment patterns over the past decade. Conclusions: D-RVD is a highly effective induction regimen that can improve upon outcomes in a historical NDMM population treated with RVD in terms of depth of response and PFS benefit. In the absence of phase 3 data supporting D-RVD vs RVD as standard of care induction, this analysis provides evidence of benefit with the addition of daratumumab to RVD in increasing depth of response, and provides an early glimpse of the promising PFS and OS benefit not only in standard risk patients, but also in patients with high-risk cytogenetic and disease features.

CD16, CD57 and DNAM-1 Positive NK Cells Predict MRD Negativity in Newly Diagnosed Multiple Myeloma Patients Treated with Daratumumab, Bortezomib, Thalidomide and Dexamethasone

Introduction: Daratumumab-based quadruplets are the current standard of care for newly diagnosed transplant-eligible multiple myeloma (MM) patients, because of improved depth of response and survival, compared with triplet regimens without daratumumab. Since one of the primary mechanisms of action of daratumumab is the induction of antibody-dependent cellular cytotoxicity (ADCC) via the Fc-gamma receptor CD16 on natural killer (NK) cells, it is crucial to understand the role of NK cells in combination therapy. We therefore set out to comprehensively profile NK cells by flow cytometry in newly diagnosed MM (NDMM) patients treated with either daratumumab, bortezomib, thalidomide, and dexamethasone (D-VTD) or VTD. Methods: A subset of NDMM patients (n = 152) who were treated in the Cassiopeia trial (EudraCT: 2014-004781-15) was included in this immunomonitoring analysis. In this trial, patients were first randomized to receive either four induction cycles and two consolidation cycles of D-VTD or VTD in conjunction with autologous stem cell transplantation (ASCT). In the second part of this trial, patients who achieved partial response or better at day 100 post-ASCT were randomized to either receive daratumumab maintenance or observation for the duration of two years. Bone marrow (BM) and peripheral blood (PB) samples were collected at study entry (baseline), and for PB at additional time points: cycle 1 day 28, cycle 4 day 28, day 100 (post-ASCT) and week 52 (maintenance). All baseline BM and PB samples and a selection of longitudinal PB samples were profiled by flow cytometry, with a focus on NK cell phenotype (CD56, CD16, CD57, DNAM-1, TIGIT, KLRG1, PD1, TIM3, NKG2A, NKG2C, NKG2D). To identify NK cell profiles associated with minimal residual disease (MRD) negativity, baseline PB and BM data were compared between MM patients based on MRD status after consolidation. Additionally, longitudinal data of PB samples collected during treatment were assessed to understand the impact of D-VTD and VTD on NK cell profiles. Results: In this cohort, 49 patients out of 77 (64%) randomized to the D-VTD arm achieved MRD negativity post-consolidation, while this was the case in 28 out of 75 patients (37%) in the VTD arm (fisher exact-test, p = 0.008). Patients with a higher proportion of BM-residing NK cells expressing the ADCC receptor CD16 (median 86 vs 72%, p = 0.007), the activating receptor DNAM-1 (median 94 vs 89%, p = 0.029), or the maturation marker CD57 (median 58 vs 48 %, p = 0.049) at baseline were more likely to achieve MRD-negativity post-consolidation in the D-VTD arm (Figure 1). Notably, this association was not present in the VTD arm. Although not significant, we found a similar trend for CD16 in PB in the D-VTD arm. During D-VTD treatment, we observed an increase in the proportion of CD56 bright and NKG2A + in PB NK-cells, and a corresponding decline in cells expressing CD16, CD57 and DNAM-1 (linear mixed effect model (LME) p &amp;lt;0.001). During VTD treatment we also observed a decrease in CD16 + NK-cells and an increase in CD56 bright and NKG2A + NK-cells (LME p &amp;lt;0.05), although these changes were more pronounced in the D-VTD arm. In patients who were assigned D-VTD at the first randomization and were subsequently randomized to the observation arm, we observed a restoration of the proportion of CD16 +, CD57 +, and CD56 bright NK cells to baseline values at week 52 after ASCT (Figure 2). As expected, the daratumumab associated NK cell changes persisted in the group that was randomized to the daratumumab maintenance arm. Conclusion: This study highlights the importance of NK cell immunophenotypic profiles in bone marrow as predictive markers for MRD negativity in NDMM patients treated with D-VTD in in conjunction with ASCT. Additionally, our findings illustrate that NK cell changes associated with daratumumab return to baseline levels after treatment cessation, indicating the potential for sequential NK cell-based therapies. In conclusion, this study not only provides valuable insights into the role of NK cells in the treatment of NDMM patients with D-VTD and ASCT, but also indicates that further research to optimize NK cell function in the context of combination therapies is warranted.

Efficacy and Tolerance of Isatuximab, Cyclophosphamide, Bortezomib, and Dexamethasone (Isa-CBD) Induction Chemotherapy in Newly Diagnosed, Transplant Eligible Multiple Myeloma: Report of the Phase 2 Multi-Centre, Open Label Canadian Myeloma Research Group (CMRG)-008 Prospective Clinical Trial

Background: The previous standard Canadian approach to autologous stem cell transplantation (ASCT) included CyBorD induction and single-agent lenalidomide maintenance until progression (Cote J, et al. ASH 2022: abstract 117). In an effort to improve outcomes, the current Canadian Myeloma Research Group (CMRG)–008 trial aimed to assess the efficacy and tolerance of a regimen of isatuximab-CyBorD (Isa-CyBorD) induction, stem cell mobilization/collection, high-dose melphalan with ASCT, followed by continuous maintenance with isatuximab and lenalidomide in newly diagnosed multiple myeloma (NDMM) patients eligible for transplant. We now report the first planned analysis of Isa-CyBorD induction and stem cell mobilization and collection. Methods: This is a multi-centre phase 2 prospective study conducted in 8 centres in which transplant-eligible NDMM (TE-NDMM) patients received isatuximab added to four cycles of standard induction CyBorD chemotherapy (cyclophosphamide 300 mg/m 2 PO, bortezomib 1.5 mg/m 2 SC, and dexamethasone 40 mg PO, all given on days 1, 8, 15 and 22 of a 28-day cycle along with isatuximab 10 mg/kg IV days 1, 8, 15 and 22 of cycle 1 and days 1 and 15 of cycles 2-4). Isatuximab premedication also included acetaminophen, H2-antagonist (ranitidine) or proton pump inhibitor and montelukast. No thromboprophylaxis required per protocol. After the completion of induction treatment, subjects achieving ≥ stable disease (SD) proceeded to mobilization and collection of hematopoietic stem cells (SCs) per local institutional standards. Eligible patients with successful SC collection then proceeded to high-dose melphalan 200 mg/m 2 followed by ASCT. Maintenance treatment commenced at 100 days (+/- 7 days) post-ASCT and continued until disease progression. Maintenance treatment consisted of 28-day cycles of isatuximab (10 mg/kg IV on days 1, 8, 15 and 22 of cycle 1; days 1 and 15 of cycles 2-3; then day 1 of each subsequent cycle) administered with lenalidomide (10 mg daily on days 1-21). Results: Between December 2022-January 2023, 71 patients with ECOG ≤ 2 were enrolled: 25 females, 46 males; median age 61 years (range: 31-73); 46.5%, 35.2% and 18.3% were ISS stages I, II and III, respectively. High-risk cytogenetics were documented in 20.6% of evaluable patients (13/63). All completed Isa-CyBorD induction therapy. The treatment was well-tolerated with rare grade 3 - 4 adverse events: neutropenia (8.2%), anemia (8.2%) and febrile neutropenia (4.1%). Common side-effects (All grades combined, ≥20%) included nausea (50%), constipation (28%), fatigue (28%), peripheral neuropathy (27% - all ≤ grade 2 with no dose holds for neuropathy), insomnia (24%), diarrhea (22%), infusion-related reaction (22%). Response assessment at the end of induction was available for 57 pts by the data cut-off date (June 1 st, 2023). All patients had clinical improvement with no primary progressive disease. Complete response (CR), very good partial response (VGPR) and partial response (PR) were documented in 7%, 52.6% and 33.3%, respectively. Four patients (7%) had &amp;lt;50% improvement of M-protein (SD). Three patients did not proceed to stem cell transplantation due to patient / physician choices. SC mobilization utilized cyclophosphamide in 10 (15.4%) and plerixafor in 12 (18.5%) patients; mobilization was successful in all 65 patients mobilized so far with 1-3 apheresis (median 2). The median number of CD34+ cells collected was 5.3 x10^6/kg (range: 2.25-7.28). Conclusion: Isa-CyBorD with weekly bortezomib is an effective induction therapy in patients with NDMM (93% ≥ PR with no progression and no mobilization failures). The treatment was well-tolerated with a side-effect profile comparable to our Canadian prior experience with CyBorD alone. All patients who proceeded to mobilization had successful collection of adequate number of SCs. Further follow-up is ongoing to assess long-term outcomes with this approach.

Impact of the Addition of Daratumumab to the Standard Bortezomib-Thalidomide-Dexamethasone Regimen on Hematopoietic Stem Cell Mobilization and Collection, Post-Transplant Engraftment and Infectious Complications: A Case-Control Multicentre Real-Life Analysis

Background The pivotal clinical trial CASSIOPEIA established the quadruplet Daratumumab-Bortezomib-Thalidomide-Dexamethasone (Dara-VTD) as superior with regards to the standard Bortezomib-Thalidomide-Dexamethasone (VTD) regimen as induction therapy in newly diagnosed transplant-eligible (NDTE) multiple myeloma (MM) patients. As a matter of facts, Dara-VTD is currently the approved induction scheme in NDTE MM patients in Italy. Previous reports showed that adding Daratumumab in induction therapy patients yielded to a higher number of poor mobilizers, with a lower median number of collected hematopoietic stem cells (HSC). However, these reports included different types of induction therapies, merging patients on and off clinical trials, and real-life data focusing exclusively on Dara-VTD is lacking. We report our experience on the impact of Dara-VTD on HSC mobilization and collection, with a retrospective comparison with a cohort of patients treated with VTD and we also provided data concerning post-transplant engraftment and infectious complications. Methods From January 2022 to June 2023, 109 NDTE MM patients from 5 Haematology Institutions received Dara-VTD treatment induction according to the approved doses and schedule. The control group consisted of 116 age-matched patients treated with VTD in the years 2015-2016. Mobilizing therapy consisted of cyclophosphamide 1-3 gr/sqm followed by granulocyte colony-stimulating factor (G-CSF) 10 mcg/kg starting the 5th day thereafter, with HSC harvest planned on the 11th day. Patients received only G-CSF 10 mcg/kg if they were older than 70 years or had renal impairment (i.e., eGFR &amp;lt; 50 ml/min). Poor mobilizer was defined as having less than 20 CD34+/µL in peripheral blood on the 11th day after cyclophosphamide and G-CSF or on the 4th day of G-CSF alone administration. In that case, plerixafor was added at the standard dose of 0.24 mg/kg. Results In the Dara-VTD group, 96/109 patients received cyclophosphamide and G-CSF; among them, 3 patients had failed a previous G-CSF mobilizing therapy, even with the addition of plerixafor. Thirteen patients received G-CSF only. In the VTD group, all patients had received cyclophosphamide and G-CSF. Pre-harvest median number of CD34+/mL in the Dara-VTD group was 26 (range 0.8-279) vs 76 (range 20-294) in the VTD group and the incidence of poor mobilizing patients was 41.7% vs 5.9%, respectively (OR 0.3, 95% CI 0.16-0.54, P &amp;lt; 0.0001). Baseline disease characteristic did not have an impact on poor mobilizing events. On the contrary, patients who developed hematologic toxicity during induction turned out to be poor mobilizers (OR 3.5, 95% IC 1.36-9.59, p= 0.011). Plerixafor was used in 54/109 patients in the Dara-VTD group and in 16/116 patients of the VTD group. Two patients failed HSC mobilization both with G-CSF and cyclophosphamide and G-CSF. All patients that received G-CSF only resulted in poor mobilizers and required plerixafor before HSC harvest; therefore, cyclophosphamide showed to be superior with regards to G-CSF as mobilizing therapy (p= 0.011). The median number of collected HSC was significantly lower in the Dara-VTD group vs VTD group: 5.17 x 10^6/Kg (IQR 3.9-5.47) vs 8.7 x 10^6/kg (IQR 6.35-11.15), respectively (p &amp;lt; 0.0001). 33% of patients in Dara-VTD group collected at least 6 x 10^6 CD34+/Kg). Median time to neutrophils and platelets engraftment were different between the two groups (13 and 11 days, respectively, P &amp;lt; 0.0001), but we did not observe any difference in terms of infection incidence. Notably, post-transplant infections incidence in Dara-VTD group was 43%. Although the second transplant was planned for 36 patients treated with Dara-VTD, it was performed in 10 patients only, mainly because of insufficient HSC harvest. Conclusions Our experience with Dara-VTD confirms an increased number of poor mobilizers, a higher need for the use of plerixafor and a lower number of collected HSC. We observed a slightly lower engraftment in Dara-VTD group, probably because of a lower number of infused HSC. The lower number of collected HSC hampers the possibility of a double transplant.

A Phase 1/2 Study of Carfilzomib, Iberdomide and Dexamethasone (KID) in Patients with Newly Diagnosed Transplant-Eligible Multiple Myeloma

Background: Iberdomide is a next generation cereblon-E3 ligase modulating agent (CELMoD) that has increased antitumor activity relative to earlier thalidomide analogs (IMiDs). This is due to direct effects on tumor cells and increased immune surveillance. Herein, we report preliminary dose escalation, safety and efficacy data from this ongoing investigator-initiated study of carfilzomib (CFZ), iberdomide, and dexamethasone (DEX) (KID) as induction therapy in patients with transplant-eligible, newly diagnosed multiple myeloma (NDMM). Methods: This multicenter trial included a phase 1 dose escalation study to determine the maximum tolerated dose (MTD) of iberdomide in combination with CFZ and DEX, followed by a phase 2 dose expansion study. Key inclusion criteria included NDMM, eligible for autologous stem cell transplantation (ASCT), ECOG performance status 0-2, and ≤1 cycle of prior induction therapy. In phase 1, patients were enrolled in a standard 3+3 design starting with iberdomide 1 mg on D1-21 of C1-4 in combination with CFZ (IV; 20 mg/m 2 on C1D1; 56 mg/m 2 C1D8, D15; 56 mg/m 2 C2-4, D1, 8, 15) and DEX (40 mg or 20 mg if &amp;gt;75 years on C1-4, D1, 8, 15) in 28-day cycles (Figure 1). Iberdomide dose escalation to 1.3 mg and 1.6 mg (maximum dose) occurred in subsequent cohorts based on the absence of dose-limiting toxicities (DLTs). Phase 1 is complete and there is ongoing enrollment in the phase 2 study. The phase 1 primary objective was to determine the safety and tolerability of KID. The phase 2 primary objective is to evaluate the rate of complete remission (CR) + stringent CR (sCR) after 2-4 cycles of KID. Patients could collect stem cells and undergo ASCT after 2-4 cycles of KID at physician's discretion. Secondary objectives include the overall response rate (ORR) and progression-free survival (PFS). Results: At data cutoff (July 14, 2023), there were 13 patients enrolled, which included 11 and 2 patients enrolled in the phase 1 and 2 studies, respectively. Ten patients are on trial, 2 were screen failures, and 1 is in screening. Of the 10 patients on trial, the median age was 66 years (range 46-78), 40% male, 70% white, and 30% had ISS stage II MM. Four unique patients had high-risk cytogenetics, which included 2 patients with t(4;14), 2 with 1q21 duplication, 1 with t(14;16), 1 with del(17p)/monosomy 17, and 1 with TP53 mutation. In the phase 1 study, 3 patients enrolled at the starting dose level of iberdomide 1 mg. Grade 1-2 TEAEs occurred in all 3 patients, but no DLTs occurred. The next 3 patients were enrolled at the iberdomide dose of 1.3 mg. Grade 1-2 TEAEs occurred in 2 patients (rash and pruritus), but no grade ≥3 TEAEs were observed. Three patients were enrolled into the final dose level of iberdomide 1.6 mg. Grade 1-2 TEAEs occurred in 2 patients, and 2 patients experienced grade 3 TEAEs (rash and neutropenia). As no DLTs occurred, the MTD of iberdomide was determined to be 1.6 mg given in combination with CFZ and DEX. Patients on trial (n=10; 6 in follow-up and 4 actively receiving treatment) have completed a median of 3 (range 2-4) cycles of KID. Of these patients, 7/10 experienced TEAEs (Table 1). No treatment-related deaths occurred. The most common TEAEs were maculopapular rash (46%), elevated liver function tests (38%), gastrointestinal symptoms (31%), and neutropenia (23%). Grade 3 TEAEs occurred in 2 patients (rash and neutropenia). One patient experienced a SAE of erythema multiforme on two separate occurrences (grade 1 and grade 2), which resolved with drug interruption. In 9 patients with response data available, the best ORR was 100% (CR, 1 [12%]; very good partial response [VGPR], 4 [44%]; partial response [PR], 4 [44%]). Six patients proceeded to ASCT with a median amount of stem cells mobilized of 9.42 x 10 6 cells/kg (range 4.84-13.53). At 3-months post-ASCT, the ORR was 100% (CR, 3 [50%]; VGPR, 2 [33%]; PR, 1 [17%]). One patient had documented sCR and MRD-negativity at data cutoff. Median PFS was not reached (NR) (95% CI, NR-NR). Conclusions: Induction therapy with KID appears safe with the only grade 3 TEAEs reported being rash and neutropenia. In patients who completed treatment, induction cycles with KID did not interfere with stem cell mobilization. Correlative and additional clinical data are being collected and will be presented. Clinical trial information: NCT05199311.