The biological and clinical impact of deletions before and after large chromosomal gains in multiple myeloma.

Acquisition of a hyperdiploid (HY) karyotype or immunoglobulin heavy chain (IGH) translocations are considered key initiating events in multiple myeloma (MM). To explore if other genomic events can precede these events, we analyzed whole-genome sequencing (WGS) data from 1173 MM samples. Integrating molecular time and structural variants (SV) within early chromosomal duplications, we indeed identified pre-gain deletions in 9.4% of HY patients without IGH translocations, challenging HY as the earliest somatic event. Remarkably, these deletions affected tumor suppressor genes (TSG) and/or oncogenes in 2.4% of HY patients without IGH translocations, supporting their role in MM pathogenesis. Furthermore, our study points to post-gain deletions as novel driver mechanisms in MM. Using multi-omics approaches to investigate their biological impact, we found associations with poor clinical outcome in newly diagnosed patients and profound effects on both oncogene and TSG activity, despite the diploid gene status. Overall, this study provides novel insights into the temporal dynamics of genomic alterations in MM.

Genomic Profiling to Contextualize the Results of Intervention for Smoldering Multiple Myeloma.

PURPOSE: Early intervention for High-Risk Smoldering Multiple Myeloma (HR-SMM) achieves deep and prolonged responses. It is unclear if beneficial outcomes are due to treatment of less complex, susceptible disease or inaccuracy in clinical definition of cases entered. EXPERIMENTAL DESIGN: Here, we interrogated whole genome and whole exome sequencing for 54 patients across two HR-SMM interventional studies (NCT01572480, NCT02279394). RESULTS: We reveal that the genomic landscape of treated HR-SMM is generally simple as compared to Newly Diagnosed (ND)MM counterparts with less inactivation of tumor suppressor genes, RAS pathway mutations, MYC disruption, and APOBEC contribution. The absence of these events parallels that of indolent precursor conditions, possibly explaining overall excellent outcomes. However, some patients harboring genomic complexity fail to sustain response and experience resistant, progressive disease. Overall, clinical risk scores do not effectively discriminate between genomically indolent and aggressive disease. CONCLUSIONS: Genomic profiling can contextualize the advantage of early intervention in SMM and guide personalization of therapy.

Impact of prior lenalidomide or proteasome inhibitor exposure on the effectiveness of ixazomib-lenalidomide-dexamethasone for relapsed/refractory multiple myeloma: A pooled analysis from the INSURE study.

OBJECTIVES: To characterize the impact of prior exposure and refractoriness to lenalidomide or proteasome inhibitors (PIs) on the effectiveness and safety of ixazomib-lenalidomide-dexamethasone (IRd) in relapsed/refractory multiple myeloma (RRMM). METHODS: INSURE is a pooled analysis of adult RRMM patients who had received IRd in ≥2 line of therapy from three studies: INSIGHT MM, UVEA-IXA, and REMIX. RESULTS: Overall, 391/100/68 were lenalidomide-naïve/-exposed/-refractory and 37/411/110 were PI-naïve/-exposed/-refractory. Median duration of therapy (DOT) was 15.3/15.6/4.7 months and median progression-free survival (PFS) was 21.6/25.8/5.6 months in lenalidomide-naïve/exposed/refractory patients. Median DOT and PFS in PI-naïve/exposed/refractory patients were 20.4/15.2/6.9 months and not reached/19.8/11.4 months, respectively. The proportion of lenalidomide-naïve/exposed/refractory patients in INSIGHT and UVEA-IXA who discontinued a study drug due to adverse events (AEs) was ixazomib, 31.6/28.2/28.0% and 18.6/6.7/10.5%; lenalidomide, 21.9/28.2/16.0% and 16.1/6.7/10.5%; dexamethasone, 18.4/20.5/16.0% and 10.6/0/10.5%, respectively. The proportion of PI-naïve/exposed/refractory patients in INSIGHT and UVEA-IXA who discontinued a study drug due to AEs was: ixazomib, 44.4/28.8/27.8% and 22.2/16.7/15.7%; lenalidomide, 33.3/22.0/19.4% and 16.7/15.9/11.8%; dexamethasone, 33.3/17.4/16.7% and 16.7/9.5/7.8%, respectively. REMIX AE discontinuation rates were unavailable. CONCLUSION: IRd appeared to be effective in RRMM patients in routine clinical practice regardless of prior lenalidomide or PI exposure, with better outcomes seen in lenalidomide- and/or PI-nonrefractory versus refractory patients.

Round Table Discussion on Optimal Clinical Trial Design in Precursor Multiple Myeloma.

SUMMARY: While the current approach to precursor hematologic conditions is to "watch and wait," this may change with the development of therapies that are safe and extend survival or delay the onset of symptomatic disease. The goal of future therapies in precursor hematologic conditions is to improve survival and prevent or delay the development of symptomatic disease while maximizing safety. Clinical trial considerations in this field include identifying an appropriate at-risk population, safety assessments, dose selection, primary and secondary trial endpoints including surrogate endpoints, control arms, and quality-of-life metrics, all of which may enable more precise benefit-risk assessment.

Genomic Classification and Individualized Prognosis in Multiple Myeloma.

PURPOSE: Outcomes for patients with newly diagnosed multiple myeloma (NDMM) are heterogenous, with overall survival (OS) ranging from months to over 10 years. METHODS: To decipher and predict the molecular and clinical heterogeneity of NDMM, we assembled a series of 1,933 patients with available clinical, genomic, and therapeutic data. RESULTS: Leveraging a comprehensive catalog of genomic drivers, we identified 12 groups, expanding on previous gene expression-based molecular classifications. To build a model predicting individualized risk in NDMM (IRMMa), we integrated clinical, genomic, and treatment variables. To correct for time-dependent variables, including high-dose melphalan followed by autologous stem-cell transplantation (HDM-ASCT), and maintenance therapy, a multi-state model was designed. The IRMMa model accuracy was significantly higher than all comparator prognostic models, with a c-index for OS of 0.726, compared with International Staging System (ISS; 0.61), revised-ISS (0.572), and R2-ISS (0.625). Integral to model accuracy was 20 genomic features, including 1q21 gain/amp, del 1p, TP53 loss, NSD2 translocations, APOBEC mutational signatures, and copy-number signatures (reflecting the complex structural variant chromothripsis). IRMMa accuracy and superiority compared with other prognostic models were validated on 256 patients enrolled in the GMMG-HD6 (ClinicalTrials.gov identifier: NCT02495922) clinical trial. Individualized patient risks were significantly affected across the 12 genomic groups by different treatment strategies (ie, treatment variance), which was used to identify patients for whom HDM-ASCT is particularly effective versus patients for whom the impact is limited. CONCLUSION: Integrating clinical, demographic, genomic, and therapeutic data, to our knowledge, we have developed the first individualized risk-prediction model enabling personally tailored therapeutic decisions for patients with NDMM.

Face-valid phenotypes in a mouse model of the most common mutation in EEF1A2-related neurodevelopmental disorder.

De novo heterozygous missense mutations in EEF1A2, encoding neuromuscular translation-elongation factor eEF1A2, are associated with developmental and epileptic encephalopathies. We used CRISPR/Cas9 to recapitulate the most common mutation, E122K, in mice. Although E122K heterozygotes were not observed to have convulsive seizures, they exhibited frequent electrographic seizures and EEG abnormalities, transient early motor deficits and growth defects. Both E122K homozygotes and Eef1a2-null mice developed progressive motor abnormalities, with E122K homozygotes reaching humane endpoints by P31. The null phenotype is driven by progressive spinal neurodegeneration; however, no signs of neurodegeneration were observed in E122K homozygotes. The E122K protein was relatively stable in neurons yet highly unstable in skeletal myocytes, suggesting that the E122K/E122K phenotype is instead driven by loss of function in muscle. Nevertheless, motor abnormalities emerged far earlier in E122K homozygotes than in nulls, suggesting a toxic gain of function and/or a possible dominant-negative effect. This mouse model represents the first animal model of an EEF1A2 missense mutation with face-valid phenotypes and has provided mechanistic insights needed to inform rational treatment design.

Approach to High-Risk Multiple Myeloma.

Improving the outcome of high-risk myeloma (HRMM) is a key therapeutic aim for the next decade. To achieve this aim, it is necessary to understand in detail the genetic drivers underlying this clinical behavior and to target its biology therapeutically. Advances have already been made, with a focus on consensus guidance and the application of novel immunotherapeutic approaches. Cases of HRMM are likely to have impaired prognosis even with novel strategies. However, if disease eradication and minimal disease states are achieved, then cure may be possible.

Progression-Free Survival of Daratumumab Versus Bortezomib Triplet Combination With Lenalidomide and Dexamethasone in Transplant Ineligible Patients With Newly Diagnosed Multiple Myeloma: TAURUS Chart Review Study.

BACKGROUND: Daratumumab, lenalidomide and dexamethasone (DRd) and bortezomib, lenalidomide and dexamethasone (VRd) are preferred regimens for transplant ineligible (TIE) patients with newly diagnosed multiple myeloma (NDMM). Both DRd and VRd demonstrated superior efficacy versus Rd in the MAIA and SWOG S0777 trials, respectively, but there is no head-to-head (H2H) clinical trial comparing their efficacy. Differing populations in the MAIA and S0777 trials make an unadjusted comparison of outcomes challenging and biased. The current TAURUS study is the first real-world H2H study comparing progression-free survival (PFS) among TIE NDMM patients treated with DRd or VRd as first-line (1L) in similar clinical settings. MATERIALS AND METHODS: A multicenter chart review study was conducted at nine sites across the United States. All TIE patients treated with DRd and a randomly selected population of VRd patients were included. TIE NDMM patients aged ≥65 were included if they initiated 1L DRd/VRd between January 2019 and September 2021. PFS was defined as the time from DRd/VRd initiation until disease progression or death. A doubly-robust multivariable Cox regression model combined with inverse probability of treatment weighting (IPTW) methodology was used to compare PFS between cohorts. RESULTS: Weighted cohorts comprised 91 DRd and 87 VRd patients. Thirteen DRd and 24 VRd patients experienced progression/death. Patients treated with DRd had a lower risk of progression/death versus VRd (adjusted hazard ratio: 0.35, 95% confidence interval: [0.17; 0.73]). CONCLUSION: DRd is associated with a significantly lower risk of disease progression or death compared to VRd as 1L treatment for TIE NDMM patients.

Advanced practice providers in hematology: actionable findings from national paired APP and physician surveys.

ABSTRACT: Advanced practice providers (APPs) are critical to the hematology workforce. However, there is limited knowledge about APPs in hematology regarding specialty-specific training, scope of practice, challenges and opportunities in APP-physician interactions, and involvement with the American Society of Hematology (ASH). We conducted APP and physician focus groups to elucidate major themes in these areas and used results to inform development of 2 national surveys, 1 for APPs and 1 for physicians who work with APPs. The APP survey was distributed to members of the Advanced Practitioner Society of Hematology and Oncology, and the physician survey was distributed to physician members of ASH. A total of 841 APPs and 1334 physicians completed the surveys. APPs reported most hematology-specific knowledge was obtained via on-the-job training and felt additional APP-focused training would be helpful (as did physicians). Nearly all APPs and physicians agreed that APPs were an integral part of their organizations and that physician-APP collaborations were generally positive. A total of 42.1% of APPs and 29.3% of physicians reported burnout, and >50% of physicians felt that working with APPs had reduced their burnout. Both physicians and APPs reported interest in additional resources including "best practice" guidelines for APP-physician collaboration, APP access to hematology educational resources (both existing and newly developed resources for physicians and trainees), and greater APP integration into national specialty-specific professional organizations including APP-focused sessions at conferences. Professional organizations such as ASH are well positioned to address these areas.

Genomic and immune signatures predict clinical outcome in newly diagnosed multiple myeloma treated with immunotherapy regimens.

Despite improving outcomes, 40% of patients with newly diagnosed multiple myeloma treated with regimens containing daratumumab, a CD38-targeted monoclonal antibody, progress prematurely. By integrating tumor whole-genome and microenvironment single-cell RNA sequencing from upfront phase 2 trials using carfilzomib, lenalidomide and dexamethasone with daratumumab ( NCT03290950 ), we show how distinct genomic drivers including high APOBEC mutational activity, IKZF3 and RPL5 deletions and 8q gain affect clinical outcomes. Furthermore, evaluation of paired bone marrow profiles, taken before and after eight cycles of carfilzomib, lenalidomide and dexamethasone with daratumumab, shows that numbers of natural killer cells before treatment, high T cell receptor diversity before treatment, the disappearance of sustained immune activation (that is, B cells and T cells) and monocyte expansion over time are all predictive of sustained minimal residual disease negativity. Overall, this study provides strong evidence of a complex interplay between tumor cells and the immune microenvironment that is predictive of clinical outcome and depth of treatment response in patients with newly diagnosed multiple myeloma treated with highly effective combinations containing anti-CD38 antibodies.

A Meta-Analysis of the Efficacy of Pomalidomide-Based Regimens for the Treatment of Relapsed/Refractory Multiple Myeloma After Lenalidomide Exposure.

INTRODUCTION: The objective was to assess the benefit of pomalidomide-based combination regimens in patients with relapsed/refractory multiple myeloma (RRMM) previously treated with lenalidomide. A pooled estimate was obtained for efficacy outcomes including overall response rate (ORR), complete response (CR) rate, and progression-free survival (PFS) based on multiple trials conducted in this patient population. PATIENTS AND METHODS: A literature search was conducted on March 22, 2022 for relevant trials published between January 1, 2016 and the search date. The search identified 12 eligible trials with publications dated between 2016 and 2021. The meta-analyses were conducted among the intention-to-treat (ITT) population (patients treated in all lines of therapy) and 2 subpopulations: 2L (only patients treated in the second line [2L]) and ≥2L (patients treated in the 2L and beyond). RESULTS: From the meta-analyses, ORR was 69.9% for ITT, 74.4% for ≥2L, and 87.2% for 2L. CR rate was 12.1% for ITT, 17.6% for ≥2L, and 29.7% for 2L. One-year PFS rates were 55.1% for ITT, 59.1% for ≥2L, and 74.0% for 2L. Two-year PFS rates were 29.3% for ITT, 36.0% for ≥2L, and 41.9% for 2L. CONCLUSION: Pomalidomide-based combination regimens were effective in patients with RRMM previously treated with lenalidomide and tended to be associated with better outcomes when used earlier in the treatment pathway. A drug class switch may not always be necessary when making treatment decisions for patients with RRMM for whom the benefits of lenalidomide have been exhausted, although this must be supported by comparative studies.

Maintenance lenalidomide in newly diagnosed transplant eligible and non-eligible myeloma patients; profiling second primary malignancies in 4358 patients treated in the Myeloma XI Trial.

Background: Early trials of long-term lenalidomide use reported an increased incidence of second primary malignancy (SPM), including acute myeloid leukaemia and myelodysplastic syndrome. Later, meta-analysis suggested the link to be secondary to lenalidomide in combination with melphalan. Methods: Myeloma XI is a large, phase III randomised trial in-which lenalidomide was used at induction and maintenance, in transplant eligible (TE) and non-eligible (TNE) newly diagnosed patients (NCT01554852). Here we present an analysis of SPM incidence and profile the SPM type to determine the impact of autologous stem cell transplantation (ASCT) and lenalidomide exposure in 4358 patients treated on study. Data collection took place from the start of the trial in May 2010, to May 2019, as per the protocol timeline. The Median follow-up following maintenance randomisation was 54.5 and 46.1 months for TE and TNE patients, respectively. Findings: In the TE pathway, the overall SPM incidence was 7.7% in lenalidomide maintenance patients compared to 3.2% in those being observed (p = 0.006). Although the TNE lenalidomide maintenance patients had the greatest SPM incidence (15.4%), this was not statistically significant when compared to the observed patients (10%, p = 0.10).The SPM incidence was higher in patients who received lenalidomide at induction and maintenance (double exposure), when compared to those treated with lenalidomide at one time point (single exposure). Again, this was most marked in TNE patients where the overall SPM incidence was 16.9% in double exposed patients, compared to 11.7% in single exposed patients, and 11.2% in patients who did not receive lenalidomide (p = 0.04). This is likely an effect of treatment duration, with the median number of cycles being 27 in the TNE double exposed patients, vs 6 in the single exposure patients.Haematological SPMs were uncommon, diagnosed in 50 patients (incidence 1.1%). The majority of cases were diagnosed in TE patients treated with lenalidomide maintenance (n = 25, incidence 2.8%), suggesting a possible link with melphalan. Non-melanoma skin cancer incidence was highest in patients receiving lenalidomide maintenance, particularly in TNE patients, where squamous cell carcinoma and basal cell carcinoma were diagnosed in 5.5% and 2.6% of patients, respectively. The incidence of most solid tumour types was higher in lenalidomide maintenance patients.Mortality due to progressive myeloma was reduced in patients receiving lenalidomide maintenance, noted to be 16.6% compared 22.6% in those observed in TE patients and 32.7% compared to 41.5% in TNE patients. SPM related mortality was low, 1.8% and 6.1% in TE and TNE lenalidomide maintenance patients, respectively, compared to 0.4% and 2.8% in those being observed. Interpretation: This provides reassurance that long-term lenalidomide treatment is safe and associated with improved outcomes in TE and TNE populations, although monitoring for SPM development should be incorporated into clinic review processes. Funding: Primary financial support was from Cancer Research UK [C1298/A10410].

Endogenous epitope tagging of eEF1A2 in mice reveals early embryonic expression of eEF1A2 and subcellular compartmentalisation of neuronal eEF1A1 and eEF1A2.

All vertebrate species express two independently-encoded forms of translation elongation factor eEF1A. In humans and mice eEF1A1 and eEF1A2 are 92 % identical at the amino acid level, but the well conserved developmental switch between the two variants in specific tissues suggests the existence of important functional differences. Heterozygous mutations in eEF1A2 result in neurodevelopmental disorders in humans; the mechanism of pathogenicity is unclear, but one hypothesis is that there is a dominant negative effect on eEF1A1 during development. The high degree of similarity between the eEF1A proteins has complicated expression analysis in the past; here we describe a gene edited mouse line in which we have introduced a V5 tag in the gene encoding eEF1A2. Expression analysis using anti-V5 and anti-eEF1A1 antibodies demonstrates that, in contrast to the prevailing view that eEF1A2 is only expressed postnatally, it is expressed from as early as E11.5 in the developing neural tube. Two colour immunofluorescence also reveals coordinated switching between eEF1A1 and eEF1A2 in different regions of postnatal brain. Completely reciprocal expression of the two variants is seen in post-weaning mouse brain with eEF1A1 expressed in oligodendrocytes and astrocytes and eEF1A2 in neuronal soma. Although eEF1A1 is absent from neuronal cell bodies after development, it is widely expressed in axons. This expression does not appear to coincide with myelin sheaths originating from oligodendrocytes but rather results from localised translation within the axon, suggesting that both variants are transcribed in neurons but show completely distinct subcellular localisation at the protein level. These findings will form an underlying framework for understanding how missense mutations in eEF1A2 result in neurodevelopmental disorders.

Multiomic Mapping of Acquired Chromosome 1 Copy-Number and Structural Variants to Identify Therapeutic Vulnerabilities in Multiple Myeloma.

PURPOSE: Chromosome 1 (chr1) copy-number abnormalities (CNA) and structural variants (SV) are frequent in newly diagnosed multiple myeloma (NDMM) and are associated with a heterogeneous impact on outcomes, the drivers of which are largely unknown. EXPERIMENTAL DESIGN: A multiomic approach comprising CRISPR, gene mapping of CNAs and SVs, methylation, expression, and mutational analysis was used to document the extent of chr1 molecular variants and their impact on pathway utilization. RESULTS: We identified two distinct groups of gain(1q): focal gains associated with limited gene-expression changes and a neutral prognosis, and whole-arm gains, which are associated with substantial gene-expression changes, complex genetics, and an adverse prognosis. CRISPR identified a number of dependencies on chr1 but only limited variants associated with acquired CNAs. We identified seven regions of deletion, nine of gain, three of chromothripsis (CT), and two of templated insertion (TI), which contain a number of potential drivers. An additional mechanism involving hypomethylation of genes at 1q may contribute to the aberrant gene expression of a number of genes. Expression changes associated with whole-arm gains were substantial and gene set enrichment analysis identified metabolic processes, apoptotic resistance, signaling via the MAPK pathway, and upregulation of transcription factors as being key drivers of the adverse prognosis associated with these variants. CONCLUSIONS: Multiple layers of genetic complexity impact the phenotype associated with CNAs on chr1 to generate its associated clinical phenotype. Whole-arm gains of 1q are the critically important prognostic group that deregulate multiple pathways, which may offer therapeutic vulnerabilities.

Rates of Influenza and Pneumococcal Vaccination and Correlation With Survival in Multiple Myeloma Patients.

BACKGROUND: Infections are a common reason for hospitalization and death in multiple myeloma (MM). Although pneumococcal vaccination (PV) and influenza vaccination (FV) are recommended for MM patients, data on vaccination status and outcomes are limited in MM. MATERIALS AND METHODS: We utilized data from the global, prospective, observational INSIGHT MM study to analyze FV and PV rates and associated outcomes of patients with MM enrolled 2016-2019. RESULTS: Of the 4307 patients enrolled, 2543 and 2500 had study-entry data on FV and PV status. Overall vaccination rates were low (FV 39.6%, PV 30.2%) and varied by region. On separate multivariable analyses of overall survival (OS) by Cox model, FV in the prior 2 years and PV in the prior 5 years impacted OS (vs. no vaccination; FV: HR, 0.73; 95% CI, 0.60-0.90; P = .003; PV: HR, 0.51; 95% CI, 0.42-0.63; P < .0001) when adjusted for age, region, performance status, disease stage, cytogenetics at diagnosis, MM symptoms, disease status, time since diagnosis, and prior transplant. Proportions of deaths due to infections were lower among vaccinated versus non-vaccinated patients (FV: 9.8% vs. 15.3%, P = .142; PV: 9.9% vs. 18.0%, P = .032). Patients with FV had generally lower health resource utilization (HRU) versus patients without FV; patients with PV had higher or similar HRU versus patients without PV. CONCLUSION: Vaccination is important in MM and should be encouraged. Vaccination status should be recorded in prospective clinical trials as it may affect survival. This trial was registered at www. CLINICALTRIALS: gov as #NCT02761187.

A Phase I/II Open-Label Study of Molibresib for the Treatment of Relapsed/Refractory Hematologic Malignancies.

PURPOSE: Molibresib is a selective, small molecule inhibitor of the bromodomain and extra-terminal (BET) protein family. This was an open-label, two-part, Phase I/II study investigating molibresib monotherapy for the treatment of hematological malignancies (NCT01943851). PATIENTS AND METHODS: Part 1 (dose escalation) determined the recommended Phase 2 dose (RP2D) of molibresib in patients with acute myeloid leukemia (AML), Non-Hodgkin lymphoma (NHL), or multiple myeloma. Part 2 (dose expansion) investigated the safety and efficacy of molibresib at the RP2D in patients with relapsed/refractory myelodysplastic syndrome (MDS; as well as AML evolved from antecedent MDS) or cutaneous T-cell lymphoma (CTCL). The primary endpoint in Part 1 was safety and the primary endpoint in Part 2 was objective response rate (ORR). RESULTS: There were 111 patients enrolled (87 in Part 1, 24 in Part 2). Molibresib RP2Ds of 75 mg daily (for MDS) and 60 mg daily (for CTCL) were selected. Most common Grade 3+ adverse events included thrombocytopenia (37%), anemia (15%), and febrile neutropenia (15%). Six patients achieved complete responses [3 in Part 1 (2 AML, 1 NHL), 3 in Part 2 (MDS)], and 7 patients achieved partial responses [6 in Part 1 (4 AML, 2 NHL), 1 in Part 2 (MDS)]. The ORRs for Part 1, Part 2, and the total study population were 10% [95% confidence interval (CI), 4.8-18.7], 25% (95% CI, 7.3-52.4), and 13% (95% CI, 6.9-20.6), respectively. CONCLUSIONS: While antitumor activity was observed with molibresib, use was limited by gastrointestinal and thrombocytopenia toxicities. Investigations of molibresib as part of combination regimens may be warranted.

The addition of vorinostat to lenalidomide maintenance for patients with newly diagnosed multiple myeloma of all ages: results from 'Myeloma XI', a multicentre, open-label, randomised, phase III trial.

Lenalidomide is an effective maintenance agent for patients with myeloma, prolonging first remission and, in transplant eligible patients, improving overall survival (OS) compared to observation. The 'Myeloma XI' trial, for newly diagnosed patients, aimed to evaluate whether the addition of the histone deacetylase inhibitor vorinostat to the lenalidomide maintenance backbone could improve outcomes further. Patients included in this analysis were randomised to maintenance therapy with lenalidomide alone (10 mg/day on days 1-21 of each 28-day cycle), or in combination with vorinostat (300 mg/day on day 1-7 and 15-21 of each 28-day cycle) with treatment continuing until unacceptable toxicity or progressive disease. There was no significant difference in median progression-free survival between those receiving lenalidomide-vorinostat or lenalidomide alone, 34 and 40 months respectively (hazard ratio [HR] 1.18, 95% confidence interval [CI] 0.96-1.44, p = 0.109). There was also no significant difference in median OS, not estimable and 75 months respectively (HR 0.99, 95% CI 0.76-1.29, p = 0.929). Subgroup analysis demonstrated no statistically significant heterogeneity in outcomes. Combination lenalidomide-vorinostat appeared to be poorly tolerated with more dose modifications, fewer cycles of maintenance therapy delivered and higher rates of discontinuation due to toxicity than lenalidomide alone. The trial did not meet its primary end-point, there was no benefit from the addition of vorinostat to lenalidomide maintenance.