MRD dynamics during maintenance for improved prognostication of 1280 patients with myeloma in the TOURMALINE-MM3 and -MM4 trials.

Measurable residual disease (MRD) evaluation may help to guide treatment duration in multiple myeloma (MM). Paradoxically, limited longitudinal data exist on MRD during maintenance. We investigated the prognostic value of MRD dynamics in 1280 transplant-eligible and -ineligible patients from the TOURMALINE-MM3 and -MM4 randomized placebo-controlled phase 3 studies of 2-year ixazomib maintenance. MRD status at randomization showed independent prognostic value (median progression-free survival [PFS], 38.6 vs 15.6 months in MRD- vs MRD+ patients; HR, 0.47). However, MRD dynamics during maintenance provided more detailed risk stratification. A 14-month landmark analysis showed prolonged PFS in patients converting from MRD+ to MRD- status vs those with persistent MRD+ status (76.8% vs 27.6% 2-year PFS rates). Prolonged PFS was observed in patients with sustained MRD- status vs those converting from MRD- to MRD+ status (75.0% vs 34.2% 2-year PFS rates). Similar results were observed at a 28-month landmark analysis. Ixazomib maintenance vs placebo improved PFS in patients who were MRD+ at randomization (median, 18.8 vs 11.6 months; HR, 0.65) or at the 14-month landmark (median, 16.8 vs 10.6 months; HR, 0.65); no difference was observed in patients who were MRD-. This is the largest MM population undergoing yearly MRD evaluation during maintenance reported to date. We demonstrate the limited prognostic value of a single-time point MRD evaluation, because MRD dynamics over time substantially impact PFS risk. These findings support MRD- status as a relevant end point during maintenance and confirm the increased progression risk in patients converting to MRD+ from MRD- status. These trials were registered at www.clinicaltrials.gov as #NCT02181413 and #NCT02312258.

Carfilzomib induction, consolidation, and maintenance with or without autologous stem-cell transplantation in patients with newly diagnosed multiple myeloma: pre-planned cytogenetic subgroup analysis of the randomised, phase 2 FORTE trial.

BACKGROUND: Patients with newly diagnosed multiple myeloma and high-risk cytogenetic abnormalities (HRCA) represent an unmet medical need. In the FORTE trial, lenalidomide and dexamethasone plus carfilzomib (KRd) induction resulted in a higher proportion of patients with at least a very good partial response as compared with carfilzomib, cyclophosphamide, and dexamethasone (KCd), and carfilzomib plus lenalidomide maintenance prolonged progression-free survival compared with lenalidomide maintenance. In this prespecified analysis of the FORTE trial, we described the outcomes of enrolled patients according to their cytogenetic risk. METHODS: The UNITO-MM-01/FORTE was a randomised, open-label, phase 2 trial done at 42 Italian academic and community practice centres, which enrolled transplant-eligible patients with newly diagnosed multiple myeloma aged 18-65 years. Eligible patients had newly diagnosed multiple myeloma based on standard International Myeloma Working Group criteria, a Karnofsky performance status of at least 60%, and had not received any previous treatment with anti-myeloma therapy. At enrolment, patients were stratified according to International Staging System stage (I vs II/III) and age (<60 years vs 60-65 years) and randomly assigned (1:1:1) to KRd plus autologous stem-cell transplantation (ASCT; four 28-day induction cycles with KRd, melphalan at 200 mg/m2 and ASCT [MEL200-ASCT], followed by four 28-day KRd consolidation cycles), 12 28-day KRd cycles, or KCd plus ASCT (four 28-day induction cycles with KCd, MEL200-ASCT, and four 28-day KCd consolidation cycles), using a web-based system (block randomisation, block size of 12). Carfilzomib was administered at 20 mg/m2 on days 1 and 2 of cycle 1, followed by 36 mg/m2 intravenously administered on days 8, 9, 15, and 16 of cycle 1, and then 36 mg/m2 intravenously administered for all subsequent doses on days 1, 2, 8, 9, 15, 16; lenalidomide 25 mg was administered orally on days 1-21; cyclophosphamide 300 mg/m2 was administered orally on days 1, 8, and 15; and dexamethasone 20 mg was administered orally or intravenously on days 1, 2, 8, 9, 15, 16, 22, and 23. After the consolidation phase, patients were stratified according to induction-consolidation treatment and randomly assigned (1:1; block size of 8) to maintenance treatment with carfilzomib plus lenalidomide or lenalidomide alone. Carfilzomib 36 mg/m2 was administered intravenously on days 1-2 and days 15-16, every 28 days for up to 2 years, and lenalidomide 10 mg was administered orally on days 1-21 every 28 days until progression or intolerance in both groups. The primary endpoints were the proportion of patients with at least a very good partial response after induction with KRd versus KCd and progression-free survival with carfilzomib plus lenalidomide versus lenalidomide alone as maintenance treatment. In this preplanned analysis, we included patients enrolled in the FORTE trial with complete cytogenetic data on del(17p), t(4;14), t(14;16), del(1p), gain(1q) (3 copies), and amp(1q) (≥4 copies) assessed by fluorescence in-situ hybridisation analysis on CD138-positive sorted cells. We assessed progression-free survival, overall survival, minimal residual disease negativity, and 1-year sustained minimal residual disease negativity according to the presence of zero, one, and two or more HRCA across treatment groups. The FORTE trial is ongoing, and registered with ClinicalTrials.gov, NCT02203643. FINDINGS: Between Feb 23, 2015, and April 5, 2017, 477 patients were enrolled, of whom 396 (83%) had complete cytogenetic data and were analysed (176 [44%] of whom were women and 220 [56%] were men). The median follow-up from first randomisation was 51 months (IQR 46-56). 4-year progression-free survival was 71% (95% CI 64-78) in patients with zero HRCA, 60% (95% CI 52-69) in patients with one HRCA, and 39% (95% CI 30-50) in patients with two or more HRCA. Compared with patients with zero HRCA, the risk of progression or death was similar in patients with one HRCA (hazard ratio [HR] 1·33 [95% CI 0·90-1·97]; p=0·15) and higher in patients with two or more HRCA (HR 2·56 [95% CI 1·74-3·75]); p<0·0001) across the induction-intensification-consolidation groups. Moreover, the risk of progression or death was also higher in patients with two or more HRCA versus those with one HRCA (HR 1·92 [95% CI 1·34-2·76]; p=0·0004). 4-year overall survival from the first randomisation was 94% (95% CI 91-98) in patients with zero HRCA, 83% (95% CI 76-90) in patients with one HRCA, and 63% (95% CI 54-74) in patients with two or more HRCA. Compared with patients with zero HRCA, the risk of death was significantly higher in patients with one HRCA (HR 2·55 [95% CI 1·22-5·36]; p=0·013) and two or more HRCA (HR 6·53 [95% CI 3·24-13·18]; p<0·0001). Patients with two or more HRCA also had a significantly higher risk of death than those with one HRCA (HR 2·56 [95% CI 1·53-4·28]; p=0·0004). The rates of 1-year sustained minimal residual disease negativity were similar in patients with zero HRCA (53 [35%] of 153] and with one HRCA (57 [41%] of 138) and were lower in patients with two or more HRCA (25 [24%] of 105). The median duration of follow-up from second randomisation was 37 months (IQR 33-42). 3-year progression-free survival from the second randomisation was 80% (95% CI 74-88) in patients with zero HRCA, 68% (95% CI 59-78) in patients with one HRCA, and 53% (95% CI 42-67) in patients with two or more HRCA. The risk of progression or death was higher in patients with one HRCA (HR 1·68 [95% CI 1·01-2·80]; p=0·048) and two or more HRCA (2·74 [95% CI 1·60-4·69], p=0·0003) than in patients with zero HRCA. INTERPRETATION: This preplanned analysis of the FORTE trial showed that carfilzomib-based induction-intensification-consolidation regimens are effective strategies in patients with standard risk (zero HRCA) and high-risk (one HRCA) myeloma, resulting in similar rates of progression-free survival and 1-year sustained minimal residual disease negativity. Despite promising progression-free survival, patients with ultra-high-risk disease (those with 2 or more HRCA) still have an increased risk of progression and death and therefore represent an unmet medical need. FUNDING: Amgen and Celgene/Bristol Myers Squibb.

Dose/schedule-adjusted Rd-R vs continuous Rd for elderly, intermediate-fit patients with newly diagnosed multiple myeloma.

Lenalidomide-dexamethasone (Rd) is standard treatment for elderly patients with multiple myeloma (MM). In this randomized phase 3 study, we investigated efficacy and feasibility of dose/schedule-adjusted Rd followed by maintenance at 10 mg per day without dexamethasone (Rd-R) vs continuous Rd in elderly, intermediate-fit newly diagnosed patients with MM. Primary end point was event-free survival (EFS), defined as progression/death from any cause, lenalidomide discontinuation, or hematologic grade 4 or nonhematologic grade 3 to 4 adverse event (AE). Of 199 evaluable patients, 101 received Rd-R and 98 continuous Rd. Median follow-up was 37 months. EFS was 10.4 vs 6.9 months (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.51-0.95; P = .02); median progression-free survival, 20.2 vs 18.3 months (HR, 0.78; 95% CI, 0.55-1.10; P = .16); and 3-year overall survival, 74% vs 63% (HR, 0.62; 95% CI, 0.37-1.03; P = .06) with Rd-R vs Rd, respectively. Rate of ≥1 nonhematologic grade ≥3 AE was 33% vs 43% (P = .14) in Rd-R vs Rd groups, with neutropenia (21% vs 18%), infections (10% vs 12%), and skin disorders (7% vs 3%) the most frequent; constitutional and central nervous system AEs mainly related to dexamethasone were more frequent with Rd. Lenalidomide was discontinued for AEs in 24% vs 30% and reduced in 45% vs 62% of patients receiving Rd-R vs Rd, respectively. In intermediate-fit patients, switching to reduced-dose lenalidomide maintenance without dexamethasone after 9 Rd cycles was feasible, with similar outcomes to standard continuous Rd. This trial was registered at www.clinicaltrials.gov as #NCT02215980.

The Metabolic Features of Osteoblasts: Implications for Multiple Myeloma (MM) Bone Disease.

The study of osteoblast (OB) metabolism has recently received increased attention due to the considerable amount of energy used during the bone remodeling process. In addition to glucose, the main nutrient for the osteoblast lineages, recent data highlight the importance of amino acid and fatty acid metabolism in providing the fuel necessary for the proper functioning of OBs. Among the amino acids, it has been reported that OBs are largely dependent on glutamine (Gln) for their differentiation and activity. In this review, we describe the main metabolic pathways governing OBs' fate and functions, both in physiological and pathological malignant conditions. In particular, we focus on multiple myeloma (MM) bone disease, which is characterized by a severe imbalance in OB differentiation due to the presence of malignant plasma cells into the bone microenvironment. Here, we describe the most important metabolic alterations involved in the inhibition of OB formation and activity in MM patients.

Elotuzumab plus lenalidomide and dexamethasone in relapsed/refractory multiple myeloma: Extended 3-year follow-up of a multicenter, retrospective clinical experience with 319 cases outside of controlled clinical trials.

The combination of elotuzumab, lenalidomide, and dexamethasone (EloRd) enhanced the clinical benefit over Rd with a manageable toxicity profile in the ELOQUENT-2 trial, leading to its approval in relapsed/refractory multiple myeloma (RRMM). The present study is a 3-year follow-up update of a previously published Italian real-life RRMM cohort of patients treated with EloRd. This revised analysis entered 319 RRMM patients accrued in 41 Italian centers. After a median follow-up of 36 months (range 6-55), 236 patients experienced disease progression or died. Median progression-free survival (PFS) and overall survival (OS) were 18.4 and 34 months, respectively. The updated multivariate analyses showed a significant reduction of PFS and OS benefit magnitude only in cases with International Staging System stage III. Major adverse events included grade 3/4 neutropenia (18.5%), anemia (15.4%), lymphocytopenia (12.5%), and thrombocytopenia (10.7%), while infection rates and pneumonia were 33.9% and 18.9%, respectively. No new safety signals with longer follow-up have been observed. Of 319 patients, 245 (76.7%) reached at least a partial remission. A significantly lower response rate was found in patients previously exposed to lenalidomide. In conclusion, our study confirms that EloRd is a safe and effective regimen for RRMM patients, maintaining benefits across multiple unfavorable subgroups.

Secondary infections worsen the outcome of COVID-19 in patients with hematological malignancies: A report from the ITA-HEMA-COV.

The impact of secondary infections (SI) on COVID-19 outcome in patients with hematological malignancies (HM) is scarcely documented. To evaluate incidence, clinical characteristics, and outcome of SI, we analyzed the microbiologically documented SI in a large multicenter cohort of adult HM patients with COVID-19. Among 1741 HM patients with COVID-19, 134 (7.7%) had 185 SI, with a 1-month cumulative incidence of 5%. Median time between COVID-19 diagnosis and SI was 16 days (IQR: 5-36). Acute myeloid leukemia (AML) and lymphoma/plasma cell neoplasms (PCN) were more frequent diagnoses in SI patients compared to patients without SI (AML: 14.9% vs. 7.1%; lymphoma/PCN 71.7% vs. 65.3%). Patients with SI were older (median age 70 vs. 66 years, p = 0.002), with more comorbidities (median Charlson Comorbidity Index 5 vs. 4, p < 0.001), higher frequency of critical COVID-19 (19.5% vs. 11.5%, p = 0.046), and more frequently not in complete remission (75% vs. 64.7% p = 0.024). Blood and bronchoalveolar lavage were the main sites of isolation for SI. Etiology of infections was bacterial in 80% (n = 148) of cases, mycotic in 9.7% (n = 18) and viral in 10.3% (n = 19); polymicrobial infections were observed in 24 patients (18%). Escherichia coli represented most of Gram-negative isolates (18.9%), while coagulase-negative Staphylococci were the most frequent among Gram-positive (14.2%). The 30-day mortality of patients with SI was higher when compared to patients without SI (69% vs. 15%, p < 0.001). The occurrence of SI worsened COVID-19 outcome in HM patients. Timely diagnosis and adequate management should be considered to improve their prognosis.

Molecular Features of the Mesenchymal and Osteoblastic Cells in Multiple Myeloma.

Multiple myeloma (MM) is a monoclonal gammopathy characterized by biological heterogeneity and unregulated proliferation of plasma cells (PCs) in bone marrow (BM). MM is a multistep process based on genomic instability, epigenetic dysregulation and a tight cross-talk with the BM microenvironment that plays a pivotal role supporting the proliferation, survival, drug-resistance and homing of PCs. The BM microenvironment consists of a hematopoietic and a non-hematopoietic compartment, which cooperate to create a tumor environment. Among the non-hematopoietic component, mesenchymal stromal cells (MSCs) and osteoblasts (OBs) appear transcriptionally and functionally different in MM patients compared to healthy donors (HDs) and to patients with pre-malignant monoclonal gammopathies. Alterations of both MSCs and OBs underly the osteolytic lesions that characterize myeloma-associated bone disease. In this review, we will discuss the different characteristics of MSCs and OBs in MM patients, analyzing the transcriptome, the deregulated molecular pathways and the role performed by miRNAs and exosome in the pathophysiology of MM.

Carfilzomib with cyclophosphamide and dexamethasone or lenalidomide and dexamethasone plus autologous transplantation or carfilzomib plus lenalidomide and dexamethasone, followed by maintenance with carfilzomib plus lenalidomide or lenalidomide alone for patients with newly diagnosed multiple myeloma (FORTE): a randomised, open-label, phase 2 trial.

BACKGROUND: Bortezomib-based induction followed by high-dose melphalan (200 mg/m2) and autologous stem-cell transplantation (MEL200-ASCT) and maintenance treatment with lenalidomide alone is the current standard of care for young and fit patients with newly diagnosed multiple myeloma. We aimed to evaluate the efficacy and safety of different carfilzomib-based induction and consolidation approaches with or without transplantation and of maintenance treatment with carfilzomib plus lenalidomide versus lenalidomide alone in newly diagnosed multiple myeloma. METHODS: UNITO-MM-01/FORTE was a randomised, open-label, phase 2 trial done in 42 Italian academic and community practice centres. We enrolled transplant-eligible patients with newly diagnosed multiple myeloma aged 65 years or younger with a Karnofsky Performance Status of 60% or higher. Patients were stratified according to International Staging System stage (I vs II/III) and age (<60 years vs 60-65 years) and randomly assigned (1:1:1) to KRd plus ASCT (four 28-day induction cycles with carfilzomib plus lenalidomide plus dexamethasone [KRd], melphalan at 200 mg/m2 and autologous stem-cell transplantation [MEL200-ASCT], followed by four 28-day KRd consolidation cycles), KRd12 (12 28-day KRd cycles), or KCd plus ASCT (four 28-day induction cycles with carfilzomib plus cyclophosphamide plus dexamethasone [KCd], MEL200-ASCT, and four 28-day KCd consolidation cycles). Carfilzomib 36 mg/m2 was administered intravenously on days 1, 2, 8, 9, 15, and 16; lenalidomide 25 mg administered orally on days 1-21; cyclophosphamide 300 mg/m2 administered orally on days 1, 8, and 15; and dexamethasone 20 mg administered orally or intravenously on days 1, 2, 8, 9, 15, 16, 22, and 23. Thereafter, patients were stratified according to induction-consolidation treatment and randomly assigned (1:1) to maintenance treatment with carfilzomib plus lenalidomide or lenalidomide alone. Carfilzomib 36 mg/m2 was administered intravenously on days 1-2 and 15-16 every 28 days for up to 2 years; lenalidomide 10 mg was administered orally on days 1-21 every 28 days until progression or intolerance in both groups. The primary endpoints were the proportion of patients with at least a very good partial response after induction with KRd versus KCd and progression-free survival with carfilzomib plus lenalidomide versus lenalidomide alone as maintenance treatment, both assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02203643. Study recruitment is complete, and all patients are in the follow-up or maintenance phases. FINDINGS: Between Feb 23, 2015, and April 5, 2017, 474 patients were randomly assigned to one of the induction-intensification-consolidation groups (158 to KRd plus ASCT, 157 to KRd12, and 159 to KCd plus ASCT). The median duration of follow-up was 50·9 months (IQR 45·7-55·3) from the first randomisation. 222 (70%) of 315 patients in the KRd group and 84 (53%) of 159 patients in the KCd group had at least a very good partial response after induction (OR 2·14, 95% CI 1·44-3·19, p=0·0002). 356 patients were randomly assigned to maintenance treatment with carfilzomib plus lenalidomide (n=178) or lenalidomide alone (n=178). The median duration of follow-up was 37·3 months (IQR 32·9-41·9) from the second randomisation. 3-year progression-free survival was 75% (95% CI 68-82) with carfilzomib plus lenalidomide versus 65% (58-72) with lenalidomide alone (hazard ratio [HR] 0·64 [95% CI 0·44-0·94], p=0·023). During induction and consolidation, the most common grade 3-4 adverse events were neutropenia (21 [13%] of 158 patients in the KRd plus ASCT group vs 15 [10%] of 156 in the KRd12 group vs 18 [11%] of 159 in the KCd plus ASCT group); dermatological toxicity (nine [6%] vs 12 [8%] vs one [1%]); and hepatic toxicity (13 [8%] vs 12 [8%] vs none). Treatment-related serious adverse events were reported in 18 (11%) of 158 patients in the KRd-ASCT group, 29 (19%) of 156 in the KRd12 group, and 17 (11%) of 159 in the KCd plus ASCT group; the most common serious adverse event was pneumonia, in seven (4%) of 158, four (3%) of 156, and five (3%) of 159 patients. Treatment-emergent deaths were reported in two (1%) of 158 patients in the KRd plus ASCT group, two (1%) of 156 in the KRd12 group, and three (2%) of 159 in the KCd plus ASCT group. During maintenance, the most common grade 3-4 adverse events were neutropenia (35 [20%] of 173 patients on carfilzomib plus lenalidomide vs 41 [23%] of 177 patients on lenalidomide alone); infections (eight [5%] vs 13 [7%]); and vascular events (12 [7%] vs one [1%]). Treatment-related serious adverse events were reported in 24 (14%) of 173 patients on carfilzomib plus lenalidomide versus 15 (8%) of 177 on lenalidomide alone; the most common serious adverse event was pneumonia, in six (3%) of 173 versus five (3%) of 177 patients. One patient died of a treatment-emergent adverse event in the carfilzomib plus lenalidomide group. INTERPRETATION: Our data show that KRd plus ASCT showed superiority in terms of improved responses compared with the other two treatment approaches and support the prospective randomised evaluation of KRd plus ASCT versus standards of care (eg, daratumumab plus bortezomib plus thalidomide plus dexamethasone plus ASCT) in transplant-eligible patients with multiple myeloma. Carfilzomib plus lenalidomide as maintenance therapy also improved progression-free survival compared with the standard-of-care lenalidomide alone. FUNDING: Amgen, Celgene/Bristol Myers Squibb. TRANSLATION: For the Italian translation of the abstract see Supplementary Materials section.

Chemotherapy, targeted therapy and immunotherapy: Which drugs can be safely used in the solid organ transplant recipients?

In solid organ transplant recipients, cancer is associated with worse prognosis than in the general population. Among the causes of increased cancer-associated mortality, are the limitations in selecting the optimal anticancer regimen in solid organ transplant recipients, because of the associated risks of graft toxicity and rejection, drug-to-drug interactions, reduced kidney or liver function, and patient frailty and comorbid conditions. The advent of immunotherapy has generated further challenges, mainly because checkpoint inhibitors increase the risk of rejection, which may have life-threatening consequences in recipients of life-saving organs. In general, there are no safe or unsafe anticancer drugs. Rather, the optimal choice of the anticancer regimen results from a careful risk/benefit assessment, from the awareness of potential pharmacokinetic and pharmacodynamic drug-to-drug interactions, and of the risk of drug overexposure in patients with kidney or liver dysfunction. In this review, we summarize general principles that may help the oncologists and transplant physicians in the multidisciplinary management of recipients of solid organ transplantation with cancer who are candidates for chemotherapy, targeted therapy, or immunotherapy.

Concomitant Primary Hyperparathyroidism in Patients with Multiple Myeloma: A Possible Link?

Hypercalcemia is a significant feature of patients with active multiple myeloma (MM) with extensive bone disease. Among the causes of non-neoplastic hypercalcemia, primary hyperparathyroidism (PHPT) is one of the most common, leading to osteoporosis and bone fractures. Interestingly, some preclinical data indicate that high secretion of parathyroid hormone (PTH) may have a negative impact on bone disease and MM progression. However, concomitant diagnosis of MM and PHPT has rarely been described. Here, we present 4 cases of patients with active MM and hypercalcemia with high or inappropriately normal PTH levels. Interestingly, CD138+ cells from these 4 MM patients lack PTH receptor 1 and PTH-related peptide expressions, indicating that PTH could have a paracrine rather than a direct pro-tumoral effect. Moreover, these cases suggest that the concomitant diagnosis of MM and PHTP may not be so rare and should be considered for the clinical management of MM patients with hypercalcemia.

Oncolytic Virotherapy and Microenvironment in Multiple Myeloma.

Multiple myeloma (MM) is a hematologic malignancy characterized by the accumulation of bone marrow (BM) clonal plasma cells, which are strictly dependent on the microenvironment. Despite the improvement of MM survival with the use of new drugs, MM patients still relapse and become always refractory to the treatment. The development of new therapeutic strategies targeting both tumor and microenvironment cells are necessary. Oncolytic virotherapy represent a promising approach in cancer treatment due to tumor-specific oncolysis and activation of the immune system. Different types of human viruses were checked in preclinical MM models, and the use of several viruses are currently investigated in clinical trials in MM patients. More recently, the use of alternative non-human viruses has been also highlighted in preclinical studies. This strategy could avoid the antiviral immune response of the patients against human viruses due to vaccination or natural infections, which could invalid the efficiency of virotherapy approach. In this review, we explored the effects of the main oncolytic viruses, which act through both direct and indirect mechanisms targeting myeloma and microenvironment cells inducing an anti-MM response. The efficacy of the oncolytic virus-therapy in combination with other anti-MM drugs targeting the microenvironment has been also discussed.

CD14+ CD16+ monocytes are involved in daratumumab-mediated myeloma cells killing and in anti-CD47 therapeutic strategy.

A deep elucidation of the mechanisms of action of anti-CD38 monoclonal antibodies (mAbs), such as daratumumab (DARA), is required to identify patients with multiple myeloma (MM) who are more responsive to this treatment. In the present study, an autologous ex vivo approach was established, focussing on the role of the monocytes in the anti CD38-mediated killing of MM cells. In bone marrow (BM) samples from 29 patients with MM, we found that the ratio between monocytes (CD14+ ) and MM cells (CD138+ ) influences the response to DARA. Further, the exposure of the BM samples to DARA is followed by the formation of a CD138+ CD14+ double-positive (DP) population, that quantitatively correlates with the anti-MM cells killing. These effects were dependent on the presence of a CD14+ CD16+ monocyte subset and on high CD16 expression levels. Lastly, the addition of a mAb neutralising the CD47/signal-regulatory protein α (SIRPα) axis was able to increase the killing mediated by DARA. The effects were observed only in coincidence with high CD14+ :CD138+ ratio, with a significant presence of the DP population and were correlated with CD16 expression. In conclusion, the present study underlines the critical role of the CD16+ monocytes in DARA anti-MM killing effects and gives a rationale to test the combination of an anti-CD47 mAb with anti-CD38 mAbs.

First-line therapy with either bortezomib-melphalan-prednisone or lenalidomide-dexamethasone followed by lenalidomide for transplant-ineligible multiple myeloma patients: a pooled analysis of two randomized trials.

Bortezomib-melphalan-prednisone (VMP) and continuous lenalidomide-dexamethasone (Rd) represent the standard treatment of transplant-ineligible patients with newly diagnosed multiple myeloma (MM). To date, no randomized trial has compared VMP to Rd, and there is no evidence of the optimal treatment for newly diagnosed MM, particularly in patients with high-risk cytogenetics [del(17p), t(4;14) or t(14;16)]. We pooled together data from patients with newly diagnosed MM treated with VMP or Rd induction followed by lenalidomide maintenance 10 mg (Rd-R) enrolled in the GIMEMA-MM-03-05 and EMN01 trials, to evaluate the efficacy of these treatments in different subgroups of patients, focusing on those with standard- and high-risk cytogenetics. Overall, 474 patients were analyzed (VMP: 257 patients; Rd-R: 217 patients). No differences in progression-free survival (hazard ratio=0.96) and overall survival (hazard ratio=1.08) were observed between standard-risk patients treated with VMP or Rd-R, whereas among the high-risk patients, the probabilities of progression (hazard ratio=0.54) and death (hazard ratio=0.73) were lower in the patients treated with VMP than in those treated with Rd-R. In particular, standard-risk patients >75 years benefited less from VMP than from Rd-R (hazard ratio for progression-free survival=0.96; hazard ratio for overall survival=1.81). In this non-randomized analysis, VMP and Rd-R were equally effective in younger (≤75 years), standard-risk patients, while older ones (>75 years) benefited more from Rd-R. In high-risk patients, VMP improved progression-free survival and overall survival irrespective of age. The source trials are registered at ClinicalTrials.gov (NCT01063179 and NCT01093196).

Functional Consequences of Low Activity of Transport System A for Neutral Amino Acids in Human Bone Marrow Mesenchymal Stem Cells.

In cultured human fibroblasts, SNAT transporters (System A) account for the accumulation of non-essential neutral amino acids, are adaptively up-regulated upon amino acid deprivation and play a major role in cell volume recovery upon hypertonic stress. No information is instead available on the expression and activity of SNAT transporters in human bone marrow mesenchymal stromal cells (MSC), although they are increasingly investigated for their staminal and immunomodulatory properties and used for several therapeutic applications. The uptake of glutamine and proline, two substrates of SNAT1 and SNAT2 transporters, was measured in primary human MSC and an MSC line. The amino acid analogue MeAIB, a specific substrate of these carriers, has been used to selectively inhibit SNAT-dependent transport of glutamine and, through its sodium-dependent transport, as an indicator of SNAT1/2 activity. SNAT1/2 expression and localization were assessed with RT-PCR and confocal microscopy, respectively. Cell volume was assessed from urea distribution space. In all these experiments, primary human fibroblasts were used as the positive control for SNAT expression and activity. Compared with fibroblasts, MSC have a lower SNAT1 expression and hardly detectable membrane localization of both SNAT1 and SNAT2. Moreover, they exhibit no sodium-dependent MeAIB uptake or MeAIB-inhibitable glutamine transport, and exhibit a lower ability to accumulate glutamine and proline than fibroblasts. MSC exhibited an only marginal increase in MeAIB transport upon amino acid starvation and did not recover cell volume after hypertonic stress. In conclusion, the activity of SNAT transporters is low in human MSC. MSC adaptation to amino acid shortage is expected to rely on intracellular synthesis, given the absence of an effective up-regulation of the SNAT transporters.

The Circular Life of Human CD38: From Basic Science to Clinics and Back.

Monoclonal antibodies (mAbs) were initially considered as a possible "magic bullet" for in vivo elimination of tumor cells. mAbs represented the first step: however, as they were murine in nature (the earliest experience on the field), they were considered unfit for human applications. This prompted the development of techniques for cloning the variable regions of conventional murine antibodies, genetically mounted on human IgG. The last step in this years-long process was the design for the preparation of fully human reagents. The choice of the target molecule was also problematic, since cancer-specific targets are quite limited in number. To overcome this obstacle in the planning phases of antibody-mediated therapy, attention was focused on a set of normal molecules, whose quantitative distribution may balance a tissue-dependent generalized expression. The results and clinical success obtained with anti-CD20 mAbs revived interest in this type of strategy. Using multiple myeloma (MM) as a tumor model was challenging first of all because the plasma cells and their neoplastic counterpart eluded the efforts of the Workshop on Differentiation Antigens to find a target molecule exclusively expressed by these cells. For this reason, attention was turned to surface molecules which fulfill the requisites of being reasonably good targets, even if not specifically restricted to tumor cells. In 2009, we proposed CD38 as a MM target in virtue of its expression: it is absent on early hematological progenitors, has variable but generalized limited expression by normal cells, but is extremely high in plasma cells and in myeloma. Further, regulation of its expression appeared to be dependent on a variety of factors, including exposure to all-trans retinoic acid (ATRA), a potent and highly specific inducer of CD38 expression in human promyelocytic leukemia cells that are now approved for in vivo use. This review discusses the history of human CD38, from its initial characterization to its targeting in antibody-mediated therapy of human myeloma.

Dependence on glutamine uptake and glutamine addiction characterize myeloma cells: a new attractive target.

The importance of glutamine (Gln) metabolism in multiple myeloma (MM) cells and its potential role as a therapeutic target are still unknown, although it has been reported that human myeloma cell lines (HMCLs) are highly sensitive to Gln depletion. In this study, we found that both HMCLs and primary bone marrow (BM) CD138(+) cells produced large amounts of ammonium in the presence of Gln. MM patients have lower BM plasma Gln with higher ammonium and glutamate than patients with indolent monoclonal gammopathies. Interestingly, HMCLs expressed glutaminase (GLS1) and were sensitive to its inhibition, whereas they exhibited negligible expression of glutamine synthetase (GS). High GLS1 and low GS expression were also observed in primary CD138(+) cells. Gln-free incubation or treatment with the glutaminolytic enzyme l-asparaginase depleted the cell contents of Gln, glutamate, and the anaplerotic substrate 2-oxoglutarate, inhibiting MM cell growth. Consistent with the dependence of MM cells on extracellular Gln, a gene expression profile analysis, on both proprietary and published datasets, showed an increased expression of the Gln transporters SNAT1, ASCT2, and LAT1 by CD138(+) cells across the progression of monoclonal gammopathies. Among these transporters, only ASCT2 inhibition in HMCLs caused a marked decrease in Gln uptake and a significant fall in cell growth. Consistently, stable ASCT2 downregulation by a lentiviral approach inhibited HMCL growth in vitro and in a murine model. In conclusion, MM cells strictly depend on extracellular Gln and show features of Gln addiction. Therefore, the inhibition of Gln uptake is a new attractive therapeutic strategy for MM.

Triplet vs doublet lenalidomide-containing regimens for the treatment of elderly patients with newly diagnosed multiple myeloma.

Lenalidomide-dexamethasone improved outcome in newly diagnosed elderly multiple myeloma patients. We randomly assigned 662 patients who were age ≥65 years or transplantation-ineligible to receive induction with melphalan-prednisone-lenalidomide (MPR) or cyclophosphamide-prednisone-lenalidomide (CPR) or lenalidomide plus low-dose dexamethasone (Rd). The primary end point was progression-free survival (PFS) in triplet (MPR and CPR) vs doublet (Rd) lenalidomide-containing regimens. After a median follow-up of 39 months, the median PFS was 22 months for the triplet combinations and 21 months for the doublet (P = .284). The median overall survival (OS) was not reached in either arms, and the 4-year OS was 67% for the triplet and 58% for the doublet arms (P = .709). By considering the 3 treatment arms separately, no difference in outcome was detected among MPR, CPR, and Rd. The most common grade ≥3 toxicity was neutropenia: 64% in MPR, 29% in CPR, and 25% in Rd patients (P < .0001). Grade ≥3 nonhematologic toxicities were similar among arms and were mainly infections (6.5% to 11%), constitutional (3.5% to 9.5%), and cardiac (4.5% to 6%), with no difference among the arms. In conclusion, in the overall population, the alkylator-containing triplets MPR and CPR were not superior to the alkylator-free doublet Rd, which was associated with lower toxicity. This study was registered at www.clinicaltrials.gov as #NCT01093196.

The Proteasome and Myeloma-Associated Bone Disease.

Bone disease is the hallmark of multiple myeloma (MM), a hematological malignancy characterized by osteolytic lesions due to a severe uncoupled and unbalanced bone remodeling with pronounced osteoblast suppression. Bone metastasis is also a frequent complication of solid tumors including advanced breast or prostate cancer. In the past years, the ubiquitin-proteasome pathway has been proved critical in regulating the balance between bone formation and bone resorption. Proteasome inhibitors (PIs) are a new class of drugs, currently used in the treatment of MM, that affect both tumor cells and bone microenvironment. Particularly, PIs stimulate osteoblast differentiation by human mesenchymal stromal cells and increase bone regeneration in mice. Interestingly, in vitro data indicate that PIs block MM-induced osteoblast and osteocyte cell death by targeting both apoptosis and autophagy. The preclinical data are supported by the following effects observed in MM patients treated with PIs: increase of bone alkaline phosphatase levels, normalization of the markers of bone turnover, and reduction of the skeletal-related events. Moreover, the histomorphometric data indicate that the treatment with bortezomib stimulates osteoblast formation and maintains osteocyte viability in MM patients. This review updates the evidence on the effects of PIs on bone remodeling and on cancer-induced bone disease while focusing on MM bone disease.