Isatuximab plus pomalidomide and dexamethasone in patients with relapsed/refractory multiple myeloma in real-world: The retrospective IMAGE study.

BACKGROUND: IMAGE is a retrospective cohort study of patients enrolled in early access programs (EAPs) in France with relapsed/refractory multiple myeloma (RRMM) receiving isatuximab with pomalidomide and dexamethasone (Isa-Pd). METHODS: Patients aged ≥18 years with RRMM who received ≥1 dose of Isa under the EAPs between July 29, 2019 and August 30, 2020 were included. Effectiveness endpoints included progression-free survival (PFS) and response rates. Verbatim terms for adverse events (AEs) were coded using the Medical Dictionary for Regulatory Activities and not graded for severity. RESULTS: A total of 294 and 299 patients were included in the effectiveness and safety populations, respectively. IMAGE included patients who received one prior line of treatment (10.2%) and were daratumumab-refractory (19.1%). At median follow-up of 14.2 months, median PFS in the effectiveness population was 12.4 months (95% CI 9.0-15.0). Overall response and very good partial response rates were 46.3% and 27.9%, respectively. Subgroup analyses reflected similar results. In the safety population, 26.4% of patients reported at least one AE; the most common any-grade AE was neutropenia (9.4%). CONCLUSION: IMAGE demonstrated Isa-Pd had meaningful effectiveness in median PFS and depth of response and no new safety signals in a real-world context, consistent with clinical trial results.

RAS/RAFlandscape in monoclonal plasma cell conditions.

Multiple Myeloma (MM) is characterized by a huge heterogeneity at the molecular level. The RAS/RAF pathway is the most frequently mutated, in about 50% of the patients. However, these mutations are frequently subclonal, suggesting a secondary event. Since these genes are part of our routine next-generation sequencing (NGS) panel, we analyzed >10,000 patients with different plasma cell disorders in order to describe the RAS/RAF landscape. In this large cohort of patients, almost 61% of the patients presented a RAS/RAF mutation at diagnosis or relapse, but much lower frequencies in pre-symptomatic cases. Of note, the mutations were different from that observed in solid tumors (higher proportions of Q61 mutations). In 29 patients with two different mutations, we were able to perform single cell sequencing, showing that in most cases, mutations occurred in different subclones, suggesting an ongoing mutational process. These findings suggest that RAS/RAF pathway is not an attractive target, both on therapeutic and residual disease assessment points of vue.

Prognostic mortality factors in advanced light chain cardiac amyloidosis: A prospective cohort study.

AIMS: Predicting mortality in severe AL cardiac amyloidosis is challenging due to elevated biomarker levels and limited thresholds for stratifying severe cardiac damage. METHODS AND RESULTS: This prospective, observational, cohort study included de novo, confirmed cardiac AL amyloidosis patients at the Henri Mondor National Reference Centre. The goal was to identify predictors of mortality to enhance prognostic stratification and improve informed decision-making regarding therapy. Over the 12-year study period, among the 233 patients included, 133 were NYHA III-IV and 179 Mayo 2004 III. The independent predictors for mortality identified were hsTnT, NT-proBNP, cardiac output, and conjugated bilirubin. A novel prognostic, conditional stratification, Mondor amyloidosis cardiac staging (MACS) was developed with biomarker cut-off values for Stage 1: hsTnT ≤ 107 ng/L and NT-proBNP ≤ 3867 ng/L (n = 77; 33%); for stage 2 NT-proBNP > 3867 ng/L (n = 72; 30%). For stage 3, if troponin >107 ng/L, regardless of NT-proBNP then CB 4 µmol/L, was added (n = 41; 17.5%) and stage 4: CB > 4 µmol/L (n = 43; 18.5%). The median overall survival was 8 months 95% CI [2-24]. At 1 year, 102 (44%) patients died and the Kaplan-Meier median survival with MACS Stage 1 was not reached, while stage 2 was 15.2 months (95% CI [11-18]) and stage 3, 6.6 months (95% CI [1-13]). Notably, among European stage II patients, 17.1%, n = 8 were MACS stage 3 and European stage IIIb 21.4% (n = 23) were MACS stage 4. Importantly, among European stage IIIb patients 42.2% (n = 29) were classified MACS stage 4 and 12.5% n = 9 were only MACS stage 2. CONCLUSIONS: The Mondor prognostic staging system, including conjugate bilirubin may significantly improve prognostic stratification for patients with severe cardiac amyloidosis.

Integrated analysis of randomized controlled trials evaluating bortezomib + lenalidomide + dexamethasone or bortezomib + thalidomide + dexamethasone induction in transplant-eligible newly diagnosed multiple myeloma.

Objective: Providing the most efficacious frontline treatment for newly diagnosed multiple myeloma (NDMM) is critical for patient outcomes. No direct comparisons have been made between bortezomib + lenalidomide + dexamethasone (VRD) and bortezomib + thalidomide + dexamethasone (VTD) induction regimens in transplant-eligible NDMM. Methods: An integrated analysis was performed using patient data from four trials meeting prespecified eligibility criteria: two using VRD (PETHEMA GEM2012 and IFM 2009) and two using VTD (PETHEMA GEM2005 and IFM 2013-04). Results: The primary endpoint was met, with VRD demonstrating a noninferior rate of at least very good partial response (≥ VGPR) after induction vs VTD. GEM comparison demonstrated improvement in the ≥ VGPR rate after induction for VRD vs VTD (66.3% vs 51.2%; P = .00281) that increased after transplant (74.4% vs 53.5%). Undetectable minimal residual disease rates post induction (46.7% vs 34.9%) and post transplant (62.4% vs 47.3%) support the benefit of VRD vs VTD. Treatment-emergent adverse events leading to study and/or treatment discontinuation were less frequent with VRD (3%, GEM2012; 6%, IFM 2009) vs VTD (11%, IFM 2013-04). Conclusion: These results supported the benefit of VRD over VTD for induction in transplant-eligible patients with NDMM. The trials included are registered with ClinicalTrials.gov (NCT01916252, NCT01191060, NCT00461747, and NCT01971658).

Changes in amyloidosis phenotype over 11 years in a cardiac amyloidosis referral centre cohort in France.

BACKGROUND: Early cardiac amyloidosis (CA) diagnosis enables patients to access effective treatments for better long-term outcomes, yet it remains under-recognised, misdiagnosed and inadequately managed. AIM: To reduce diagnostic delays, we aimed to describe the epidemiological and clinical characteristics and changes over an 11-year period. METHODS: This was a retrospective, observational cohort study of all patients referred to the Henri-Mondor Hospital for suspected CA. RESULTS: Overall, 3194 patients were identified and 3022 were included and analysed. Our patients came from varied ethnic backgrounds, and more than half (55.2%) had confirmed CA. Over 11 years, referrals increased 4.4-fold, mostly from cardiologists. Notably, wild-type transthyretin amyloidosis (ATTRwt) became the predominant diagnosis, with referrals increasing 15-fold from 20 in 2010-2012 to 308 in 2019-2020. The number of amyloid light chain (AL) diagnoses increased, whilst variant transthyretin amyloidosis (ATTRv) numbers remained relatively stable. Concerning disease severity, AL patients presented more frequently with severe cardiac involvement whereas an increasing number of ATTRwt patients presented with National Amyloid Centre stage I (22.0% in 2013-2014 to 45.9% in 2019-2020). Lastly, among patients diagnosed with ATTRv in 2019-2020, 83.9% had ATTR Val122Ile cardiac phenotype. CONCLUSIONS: This study shows that increasing cardiologist awareness and referrals have increased CA diagnoses. With improved awareness and non-invasive diagnostic techniques, more patients with ATTRwt with milder disease and more ATTRv Val122Ile mutations are being referred and diagnosed. Although more AL cases are being recognised, patients are diagnosed with severe cardiac involvement.

Precision Medicine Approach Based on Molecular Alterations for Patients with Relapsed or Refractory Multiple Myeloma: Results from the MM-EP1 Study.

BACKGROUND: Despite that cytogenetic and molecular analysis of tumor cells can rapidly identify recurring molecular abnormalities, no personalized therapy is currently available in the setting of relapsed/refractory multiple myeloma (r/r MM). METHODS: MM-EP1 is a retrospective study aimed at comparing a personalized molecular-oriented (MO) versus a non-molecular-oriented (no-MO) approach in r/r MM. Actionable molecular targets and their associated therapies were the BRAF V600E mutation and BRAF inhibitors; t(11;14)(q13;q32) and BCL2 inhibitors; and t(4;14)(p16;q32) with FGFR3 fusion/rearrangements and FGFR3 inhibitors. RESULTS: One hundred three highly pretreated r/r MM patients with a median age of 67 years (range 44-85) were included. Seventeen (17%) patients were treated using an MO approach with BRAF inhibitors (vemurafenib or dabrafenib, n = 6), BCL2 inhibitor (venetoclax, n = 9), or FGFR3 inhibitor (erdafitinib, n = 2). Eighty-six (86%) patients received non-MO therapies. Overall response rate was 65% in MO patients versus 58% in the non-MO group (p = 0.053). Median PFS and OS were 9 and 6 months (HR = 0.96; CI95 = 0.51-1.78; p = 0.88) and 26 and 28 months (HR = 0.98; CI95 = 0.46-2.12; p = 0.98), respectively, in MO and no-MO patients. CONCLUSION: Despite the low number of patients treated with an MO approach, this study highlights the strengths and weakness of a molecular-targeted approach for the treatment of multiple myeloma. Widespread biomolecular techniques and improvement of precision medicine treatment algorithms could improve selection for precision medicine in myeloma.

Pomalidomide and dexamethasone until progression after first salvage therapy in multiple myeloma.

Lenalidomide maintenance in myeloma is well established. Nevertheless, pomalidomide could provide an alternative. Myeloma patients in first relapse, initially treated in the Intergroupe Francophone du Myélome (IFM) 2009 trial, and subsequently in the IFM 2013-01 phase 2 trial, received four cycles of salvage therapy with pomalidomide plus cyclophosphamide plus dexamethasone (PCD) with transplantation plus 2 PCD consolidation or without transplantation but with 5 PCD and for all patients pomalidomide plus dexamethasone maintenance therapy. This consisted of 28-day cycles of pomalidomide 4 mg daily on days 1-21 and dexamethasone 20 mg weekly until progression. The primary endpoint was an improved response to treatment. A total of 75/100 patients reached therapy. The median follow-up time was 73 months. The median duration of treatment was 23.7 months. One third of patients improved their response from the initiation of treatment: 11%, 19% and 4% to a very good partial response, complete response or stringent complete response respectively. The median progression-free survival time was 33.2 months and the median overall survival time was not reached. Among the 75 patients, the reasons for pomalidomide discontinuation were progressive disease (54%), adverse events (AEs) (30%), investigator discretion (11%) and consent withdrawal (5%). Grade (G) 3/4 haematological AEs included neutropenia (51%) and lymphopenia (35%); G3/4 drug-related non-haematological AEs (>5%) comprised 13% infections. Long-term administration of pomalidomide and dexamethasone is feasible and one third of the patients improved their response.

Biallelic deletion of 1p32 defines ultra-high-risk myeloma, but monoallelic del(1p32) remains a strong prognostic factor.

Cytogenetic abnormalities (CAs) are known to be the preponderant prognostic factor in multiple myeloma. Our team has recently developed a prognostic score based on 6 CAs, with which del(1p32) appears to be the second worst abnormality after del(17p). This study aimed to confirm the adverse effect of 1p32 deletion in patients with newly diagnosed multiple myeloma (NDMM). Among 2551 patients with newly diagnosed multiple myeloma, 11% were harboring del(1p32). Their overall survival (OS) was significantly inferior compared with patients without del(1p32) (median OS: 49 months vs 124 months). Likewise, progression-free survival was significantly shorter. More importantly, biallelic del(1p32) conferred a dramatically poorer prognosis than a monoallelic del(1p32) (median OS: 25 months vs 60 months). As expected, the OS of patients with del(1p32) significantly decreased when this abnormality was associated with other high-risk CAs [del(17p), t(4;14), or gain(1q)]. In the multivariate analysis, del(1p32) appeared as a negative prognostic factor; after adjustment for age and treatment, the risk of progression was 1.3 times higher among patients harboring del(1p32), and the risk of death was 1.9 times higher. At the dawn of risk-adapted treatment strategies, we have confirmed the adverse effect of del(1p32) in multiple myeloma and the relevance of its assessment at diagnosis.

Heterogeneity in long-term outcomes for patients with Revised International Staging System stage II, newly diagnosed multiple myeloma.

In the era of personalized treatment in multiple myeloma, high-risk patients must be accurately identified. The International Myeloma Working Group recommends using the Revised International Staging System (R-ISS) to pick out high-risk patients. The main purpose of our work was to explore the heterogeneity of outcome among R-ISS stage II patients assessing the impact of International Staging System (ISS) stage, chromosomal abnormalities and lactate dehydrogenase level in this subgroup. Data were collected from 1,343 patients up to 65 years old with newly diagnosed myeloma, enrolled in three clinical trials implemented by the Intergroupe Francophone du Myélome. All patients were eligible for intensive treatment. Patients in R-ISS stage II but ISS stage I had 1.6 times higher risk of death than patients in R-ISS stage I (adjusted hazard ratio=1.6; 95% confidence interval: 1.1-2.2; P=0.01) and patients in R-ISS stage II but with ISS stage III had a better overall survival than patients in R-ISS stage III (adjusted hazard ratio=0.7; 95% confidence interval: 0.4-0.9, P=0.02). However, among patients classified in R-ISS II, ISS stage and chromosomal abnormalities (del[17p] and t[4;14]) were still relevant prognostic factors for death. Dividing R-ISS stage II into three subgroups: ISS I with standard-risk chromosomal abnormalities, ISS II or III with standard-risk chromosomal abnormalities and patients with high-risk chromosomal abnormalities, median overall survival times were, respectively, not reached, 112 months and 71 months (P<0.001). In conclusion, stratification of patients in the R-ISS stage II group can be improved by taking into account chromosomal abnormalities and ISS. However, this does not improve predictive performance of survival models.

Evaluation of a new ELISA assay for monoclonal free-light chain detection in patients with cardiac amyloidosis.

The causal protein of amyloid light-chain (AL) amyloidosis is a monoclonal immunoglobulin free light chain (mFLC), which must be quantified in the serum for patient diagnosis and monitoring. Several manufacturers commercialize immunoassays that quantify total kappa (κ) and lambda (λ) FLC, but results can differ greatly between these tests. Here, we compared a recently developed enzyme-linked immunosorbent assay (ELISA) (Sebia) with N-Latex immunonephelometry (Siemens) in 96 patients diagnosed with AL amyloidosis (histologically confirmed) and 48 non-AL patients sent to our referral center for suspicion of cardiac amyloidosis. ELISA free-light chain difference (dFLC) were lower than N-Latex values, and agreement between methods was reduced in the case of involved λ FLC. Diagnosis sensitivity and specificity were >85% with both assays. A receiver operating characteristic analysis indicated that ELISA performances could be improved by using a higher value for the lower limit of the κ/λ ratio. We also assessed Freelite (The Binding Site) in a subgroup of these same AL patients, including 18 cases with normal κ/λ ratio by at least one assay. Only two patients had normal κ/λ ratio with all three assays. Overall, ELISA demonstrated slightly lower sensitivity than N-Latex but may be an alternative to nephelometry/turbidimetry in certain difficult cases.

Heart Transplantation, Either Alone or Combined With Liver and Kidney, a Viable Treatment Option for Selected Patients With Severe Cardiac Amyloidosis.

Heart transplantation in cardiac amyloidosis (CA) patients is possible and generally considered for transplantation if other organs are not affected. In this study, we aimed to describe and assess outcome in patients following heart transplantations at our CA referral center. Methods: We assessed all CA patients that had heart transplantations at our center between 2005 and 2018. Patients with New York Heart Association status 3 out of 4, with poor short-term prognosis due to heart failure, despite treatment, and without multiple myeloma, systemic disease, severe neuropathic/digestive comorbidities, cancer, or worsening infections were eligible for transplantation. Hearts were transplanted by bicaval technique. Standard induction and immunosuppressive therapies were used. Survival outcome of CA patients after transplantation was compared with recipients with nonamyloid pathologies in France. Results: Between 2005 and 2018, 23 CA patients had heart transplants: 17 (74%) had light chain (light chain amyloidosis [AL]) and 6 (26%) had hereditary transthyretin (hereditary transthyretin amyloidosis [ATTRv]) CA. Also, 13 (57%) were male, and the mean age at diagnosis was 56.5 y (range, 47.7-62.8). Among AL patients, 13 had heart-only and 5 had heart-kidney transplantations. Among ATTRv patients, 1 had heart-only and 5 had heart-liver transplantations. The 1-y survival rate after transplantation was 78%, 70% with AL, and 100% with ATTRv. At 2 y, 74% were alive: 65% with AL and 100% with ATTRv. Conclusion: After heart transplantation, French CA and nonamyloid patients have similar survival outcomes. Among CA patients, ATTRv patients have better prognosis than those with AL, possibly due to the combined heart-liver transplantation. Selected CA patients should be considered for heart transplantations.

Bortezomib and high-dose melphalan conditioning regimen in frontline multiple myeloma: an IFM randomized phase 3 study.

High-dose melphalan (HDM) and transplantation are recommended for eligible patients with multiple myeloma. No other conditioning regimen has proven to be more effective and/or safer. We previously reported in a phase 2 study that bortezomib can safely and effectively be combined with HDM (Bor-HDM), with a 32% complete response (CR) rate after transplantation. These data supported a randomized phase 3 trial. Randomization was stratified according to risk and response to induction: 300 patients were enrolled, and 154 were allocated to the experimental arm (ie, arm A) with bortezomib (1 mg/m2 intravenously [IV]) on days -6, -3, +1, and +4 and melphalan (200 mg/m2 IV) on day -2. The control arm (ie, arm B) consisted of HDM alone (200 mg/m2 IV). There were no differences in stringent CR + CR rates at day 60 posttransplant (primary end point): 22.1% in arm A vs 20.5% in arm B (P = .844). There were also no differences in undetectable minimum residual disease rates: 41.3% vs 39.4% (P = .864). Median progression-free survival was 34.0 months for arm A vs 29.6 months for arm B (adjusted HR, 0.82; 95% CI, 0.61-1.13; P = .244). The estimated 3-year overall survival was 89.5% in both arms (hazard ratio, 1.28; 95% CI, 0.62-2.64; P = .374). Sixty-nine serious adverse events occurred in 18.7% of Bor-HDM-treated patients (vs 13.1% in HDM-treated patients). The proportion of grade 3/4 AEs was similar within the 2 groups (72.0% vs 73.1%), mainly (as expected) blood and gastrointestinal disorders; 4% of patients reported grade 3/4 or painful peripheral neuropathy in arm A (vs 1.5% in arm B). In this randomized phase 3 study, a conditioning regimen with Bor-HDM did not improve efficacy end points or outcomes compared with HDM alone. The original trial was registered at www.clinicaltrials.gov as #NCT02197221.

Anti-SARS-CoV-2 antibody response after 2 and 3 doses of BNT162b2 mRNA vaccine in patients with lymphoid malignancies.

OBJECTIVES: COVID-19 patients affected by haematological malignancies have a more severe course of the disease and higher mortality, prompting for effective prophylaxis. The present study aims to evaluate the humoral response after mRNA vaccination as well as the impact of a third vaccine dose in patients with lymphoid malignancies. METHODS: We conducted a single-centre study, evaluating the serological responses of mRNA vaccination amongst a cohort of 200 patients affected by lymphoid malignancies after two or three doses using an industrial SARS-CoV-2 serology assay for anti-receptor binding domain (RBD) Spike IgG detection and quantification. RESULTS: Among patients with plasma cell disorders, 59 of 96 (61%) had seroconversion (anti-RBD >50 AU/mL), and recent anti-CD38 therapies were associated with lower serological anti-RBD IgG concentrations (median IgG concentration 137 (IQR 0-512) AU/mL vs. 543 (IQR 35-3496) AU/mL; p < 0.001). Patients with B-cell malignancies had a lower seroconversion rate (20/84, 24%) mainly due to the broad usage of anti-CD20 monoclonal antibodies; only 2 of 53 (4%) patients treated by anti-CD20 antibodies during the last 12 months experienced a seroconversion. A total of 78 patients (44 with plasma cell disorders, 27 with B-cell malignancies, and 7 with other lymphomas) received a third dose of vaccine. The seroconversion rate and antibody concentrations increased significantly, especially in patients with plasma cell disorders, where an increment of anti-RBD IgG concentrations was observed in 31 of 44 (70%) patients, with an anti-RBD concentration median-fold increase of 10.6 (IQR 2.4-25.5). Its benefit in B-cell malignancies is uncertain, with only 2 of 25 (8%) patients having seroconverted after the vaccine booster, without increased median antibody concentration. DISCUSSION: A third mRNA vaccine dose significantly improved humoral responses among patients with plasma cell disorders, whereas the effect was limited among patients with B-cell malignancies.

Primary plasma cell leukemias displaying t(11;14) have specific genomic, transcriptional, and clinical features.

Primary plasma cell leukemia (pPCL) is an aggressive form of multiple myeloma (MM) that has not benefited from recent therapeutic advances in the field. Because it is very rare and heterogeneous, it remains poorly understood at the molecular level. To address this issue, we performed DNA and RNA sequencing of sorted plasma cells from a large cohort of 90 newly diagnosed pPCL and compared with MM. We observed that pPCL presents a specific genomic landscape with a high prevalence of t(11;14) (about half) and high-risk genomic features such as del(17p), gain 1q, and del(1p32). In addition, pPCL displays a specific transcriptome when compared with MM. We then wanted to characterize specifically pPCL with t(11;14). We observed that this subentity displayed significantly fewer adverse cytogenetic abnormalities. This translated into better overall survival when compared with pPCL without t(11;14) (39.2 months vs 17.9 months, P = .002). Finally, pPCL with t(11;14) displayed a specific transcriptome, including differential expression of BCL2 family members. This study is the largest series of patients with pPCL reported so far.

Optimization of whole-body 2-[18F]FDG-PET/MRI imaging protocol for the initial staging of patients with myeloma.

OBJECTIVE: To determine the optimal 2-[18F]FDG-PET/MRI imaging protocol for the initial staging of patients with suspected or confirmed multiple myeloma. METHODS: Radiologists and nuclear medicine specialists reviewed all PET/MRI exams of 104 patients with a monoclonal gammopathy (MG). The presence of focal and diffuse bone marrow involvement (BMI) was assessed using 4 different image datasets: WB-MRI, PET, WB-PET/MRI, and WB-DCE-PET/MRI. A reference standard was established by a panel review of all baseline and follow-up imaging, and biological and pathological information. The diagnostic performance for each image dataset to detect BMI was evaluated and compared (Fisher's exact test). RESULTS: Sensitivity, specificity, and accuracy for focal BMI of WB-MRI was 87%, 97%, and 92%; of PET was 78%, 97%, and 95%; of WB-PET/MRI was 93%, 97%, and 95%; and of WB-DCE-PET/MRI was 93%, 97%, and 95%, respectively. WB-PET/MRI and WB-DCE-PET/MRI were statistically superior to PET (p = 0.036) without decreasing specificity. The sensitivity, specificity, and accuracy of WB-MRI for diffuse BMI detection was 91%, 80%, and 85%; of 3DT1-PET was 53%, 89%, and 74%; of WB-PET/MRI was 98%, 66%, and 79%; and of WB-DCE-PET/MRI was 98%, 59%, and 75%, respectively. PET lacked sensitivity compared to all other dataset studies (p < 0.0001). WB-MRI had the best accuracy without reaching statistical significance when compared to the other datasets. CONCLUSION: The WB-PET/MRI dataset including T1 and T2 Dixon, WB-DWI, and PET images provides optimal diagnostic performance to detect both focal lesions and diffuse BMI, with limited added value of WB-DCE for baseline staging of patients with MG. Key Points • The combination of morphological and functional MRI sequences and metabolic (2-[18F]FDG-PET) images increases the diagnostic performance of PET/MRI to detect focal bone lesions. • The adjunction of dynamic contrast-enhanced sequences did not improve diagnostic performance.

Maintenance with daratumumab or observation following treatment with bortezomib, thalidomide, and dexamethasone with or without daratumumab and autologous stem-cell transplant in patients with newly diagnosed multiple myeloma (CASSIOPEIA): an open-label, randomised, phase 3 trial.

BACKGROUND: CASSIOPEIA part 1 showed superior depth of response and significantly improved progression-free survival with daratumumab, bortezomib, thalidomide, and dexamethasone (D-VTd) versus bortezomib, thalidomide, and dexamethasone (VTd) as induction and consolidation in patients with autologous stem-cell transplant (ASCT)-eligible newly diagnosed multiple myeloma. In part 2, we compared daratumumab maintenance versus observation only. METHODS: CASSIOPEIA is a two-part, open-label, randomised, phase 3 trial of patients aged 18-65 years with newly diagnosed multiple myeloma and Eastern Cooperative Oncology Group performance status 0-2, done in 111 European academic and community practice centres. In part 1, patients were randomly assigned (1:1) to induction and consolidation with D-VTd or VTd. Patients still on study who had a partial response or better were randomly assigned (1:1) by an interactive web-response system to daratumumab 16 mg/kg intravenously every 8 weeks (a reduced frequency compared with standard daratumumab long-term dosing) or observation only for up to 2 years. Stratification factors were induction treatment and depth of response in part 1. The part 2 primary endpoint was progression-free survival from second randomisation. This preplanned interim analysis of progression-free survival was done after 281 events and shall be considered the primary analysis of progression-free survival. Sponsor personnel and designees who were involved in the analysis were masked to treatment group until the independent data monitoring committee recommended that the preplanned interim analysis be considered the main analysis of progression-free survival in part 2. Otherwise, treatment assignments were unmasked. The interaction between induction and consolidation and maintenance was tested at a two-sided significance level of 0·05 by a stratified Cox regression model that included the interaction term between maintenance treatment and induction and consolidation treatment. Efficacy analyses were done in the maintenance-specific intention-to-treat population, which comprised all patients who underwent second randomisation. Safety was analysed in all patients in the daratumumab group who received at least one dose and all patients randomly assigned to observation only. This trial is registered with ClinicalTrials.gov, NCT02541383. Long-term follow-up is ongoing and the trial is closed to new participants. FINDINGS: Between May 30, 2016, and June 18, 2018, 886 patients (458 [84%] of 543 in the D-VTd group and 428 [79%] of 542 in the VTd group) were randomly assigned to daratumumab maintenance (n=442) or observation only (n=444). At a median follow-up of 35·4 months (IQR 30·2-39·9) from second randomisation, median progression-free survival was not reached (95% CI not evaluable [NE]-NE) with daratumumab versus 46·7 months (40·0-NE) with observation only (hazard ratio 0·53, 95% CI 0·42-0·68, p<0·0001). A prespecified analysis of progression-free survival results showed a significant interaction between maintenance and induction and consolidation therapy (p<0·0001). The most common grade 3 or 4 adverse events were lymphopenia (16 [4%] of 440 patients in the daratumumab group vs eight [2%] of 444 patients in the observation-only group), hypertension (13 [3%] vs seven [2%]), and neutropenia (nine [2%] vs ten [2%]). Serious adverse events occurred in 100 (23%) patients in the daratumumab group and 84 (19%) patients in the observation-only group. In the daratumumab group, two adverse events led to death (septic shock and natural killer-cell lymphoblastic lymphoma); both were related to treatment. INTERPRETATION: Daratumumab maintenance every 8 weeks for 2 years significantly reduced the risk of disease progression or death compared with observation only. Longer follow-up and other ongoing studies will shed further light on the optimal daratumumab-containing post-ASCT maintenance treatment strategy. FUNDING: Janssen Research & Development, the Intergroupe Francophone du Myélome, and the Dutch-Belgian Cooperative Trial Group for Hematology Oncology.