Abstract 4437: Down-modulation of ADAR1-mediated GLI1 editing alters extracellular and immune response genes in multiple myeloma

Introduction: Representing 10% of hematologic malignancies, multiple myeloma (MM) is typified by clonal plasma cell proliferation in the bone marrow (BM) and may progress to therapy-resistant plasma cell leukemia (PCL). Despite many novel therapies, relapse rates remain high as a result of malignant regeneration (self-renewal) of MM cells in inflammatory microenvironments. In addition to recurrent DNA mutations and epigenetic deregulation, inflammatory cytokine-responsive adenosine deaminase associated with RNA (ADAR1)-mediated adenosine to inosine (A-to-I) RNA editing has emerged as a key driver of cancer relapse and progression. In MM, copy number amplification of chromosome 1q21, which contains both ADAR1 and interleukin-6 receptor (IL-6R) gene loci, portends a poor prognosis. Thus, we hypothesized that ADAR1 copy number amplification combined with inflammatory cytokine activation of ADAR1 stimulates malignant regeneration of MM and therapeutic resistance.

Methods and Results: Analysis of MMRF CoMMpass RNA sequencing (RNA-seq) data revealed that high ADAR1 expression (n=162 patients) correlated with significantly reduced progression-free and overall survival compared with a low ADAR1 subset (n=159 patients). In contrast to lentiviral ADAR1 shRNA knockdown and overexpression of an editase defective ADAR1 mutant (ADAR1E912A), lentiviral wild-type ADAR1 overexpression enhanced editing of GLI1, a Hedgehog (Hh) pathway transcriptional activator and self-renewal agonist. Editing of GLI1 transcripts enhanced GLI transcriptional activity in luciferase reporter assays, and promoted lenalidomide resistance in vitro. Finally, lentiviral shRNA ADAR1 knockdown reduced regeneration of high-risk MM in humanized serial transplantation mouse models, indicative of reduced malignant self-renewal capacity. Whole-transcriptome RNA-sequencing of primary samples after lentiviral shRNA knockdown of ADAR1 revealed specific modulation of extracellular and immune response genes, while overexpression of wild-type versus edited GLI1 elicited distinct gene expression changes in human myeloma cells analyzed using NanoString nCounter assays. These data demonstrate that ADAR1 promotes malignant self-renewal of MM and, if selectively inhibited, may prevent progression and relapse through modulation of extracellular and immune response genes.

Conclusions: Deregulated RNA editing, driven by aberrant ADAR1 activation, represents a unique source of transcriptomic and proteomic diversity, resulting in self-renewal of MM cells in inflammatory microenvironments. In summary, both genetic (1q21 amplification) and microenvironmental factors (inflammatory cytokines, IMiDs) combine to drive GLI1-dependent malignant regeneration in MM. Thus, ADAR1 represents both a vital prognostic biomarker and therapeutic target in MM.

Citation Format: Leslie A. Crews, Elisa Lazzari, Phoebe K. Mondala, Nathaniel Delos Santos, Amber Miller, Gabriel Pineda, Qingfei Jiang, Anusha-Preethi Ganesan, Christina Wu, Caitlin Costello, Mark Minden, Raffaella Chiaramonte, A. Keith Stewart, Catriona H. M. Jamieson. Down-modulation of ADAR1-mediated GLI1 editing alters extracellular and immune response genes in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4437.

Selective Inhibition of Nuclear Export With Oral Selinexor for Treatment of Relapsed or Refractory Multiple Myeloma

Purpose Selinexor, a first-in-class, oral, selective exportin 1 (XPO1) inhibitor, induces apoptosis in cancer cells through nuclear retention of tumor suppressor proteins and the glucocorticoid receptor, along with inhibition of translation of oncoprotein mRNAs. We studied selinexor in combination with low-dose dexamethasone in patients with multiple myeloma refractory to the most active available agents. Patients and Methods This phase II trial evaluated selinexor 80 mg and dexamethasone 20 mg, both orally and twice weekly, in patients with myeloma refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide (quad-refractory disease), with a subset also refractory to an anti-CD38 antibody (penta-refractory disease). The primary end point was overall response rate (ORR). Results Of 79 patients, 48 had quad-refractory and 31 had penta-refractory myeloma. Patients had received a median of seven prior regimens. The ORR was 21% and was similar for patients with quad-refractory (21%) and penta-refractory (20%) disease. Among patients with high-risk cytogenetics, including t(4;14), t(14;16), and del(17p), the ORR was 35% (six of 17 patients). The median duration of response was 5 months, and 65% of responding patients were alive at 12 months. The most common grade ≥ 3 adverse events were thrombocytopenia (59%), anemia (28%), neutropenia (23%), hyponatremia (22%), leukopenia (15%), and fatigue (15%). Dose interruptions for adverse events occurred in 41 patients (52%), dose reductions occurred in 29 patients (37%), and treatment discontinuation occurred in 14 patients (18%). Conclusion The combination of selinexor and dexamethasone has an ORR of 21% in patients with heavily pretreated, refractory myeloma with limited therapeutic options.

Improvement in Overall Survival With Carfilzomib, Lenalidomide, and Dexamethasone in Patients With Relapsed or Refractory Multiple Myeloma

Purpose

In the ASPIRE study of carfilzomib, lenalidomide, and dexamethasone (KRd) versus lenalidomide plus dexamethasone (Rd) in patients with relapsed or refractory multiple myeloma, progression-free survival was significantly improved in the carfilzomib group (hazard ratio, 0.69; two-sided P < .001). This prespecified analysis reports final overall survival (OS) data and updated safety results.

Patients and Methods

Adults with relapsed multiple myeloma (one to three prior lines of therapy) were eligible and randomly assigned at a one-to-one ratio to receive KRd or Rd in 28-day cycles until withdrawal of consent, disease progression, or occurrence of unacceptable toxicity. After 18 cycles, all patients received Rd only. Progression-free survival was the primary end point; OS was a key secondary end point. OS was compared between treatment arms using a stratified log-rank test.

Results

Median OS was 48.3 months (95% CI, 42.4 to 52.8 months) for KRd versus 40.4 months (95% CI, 33.6 to 44.4 months) for Rd (hazard ratio, 0.79; 95% CI, 0.67 to 0.95; one-sided P = .0045). In patients receiving one prior line of therapy, median OS was 11.4 months longer for KRd versus Rd; it was 6.5 months longer for KRd versus Rd among patients receiving ≥ two prior lines of therapy. Rates of treatment discontinuation because of adverse events (AEs) were 19.9% (KRd) and 21.5% (Rd). Grade ≥ 3 AE rates were 87.0% (KRd) and 83.3% (Rd). Selected grade ≥ 3 AEs of interest (grouped terms; KRd v Rd) included acute renal failure (3.8% v 3.3%), cardiac failure (4.3% v 2.1%), ischemic heart disease (3.8% v 2.3%), hypertension (6.4% v 2.3%), hematopoietic thrombocytopenia (20.2% v 14.9%), and peripheral neuropathy (2.8% v 3.1%).

Conclusion

KRd demonstrated a statistically significant and clinically meaningful reduction in the risk of death versus Rd, improving survival by 7.9 months. The KRd efficacy advantage is most pronounced at first relapse.

Experience with precision genomics and tumor board, indicates frequent target identification, but barriers to delivery

Background

The ability to analyze the genomics of malignancies has opened up new possibilities for off-label targeted therapy in cancers that are refractory to standard therapy. At Mayo Clinic these efforts are organized through the Center for Individualized Medicine (CIM).

Results

Prior to GTB, datasets were analyzed and integrated by a team of bioinformaticians and cancer biologists. Therapeutically actionable mutations were identified in 65% (92/141) of the patients tested with 32% (29/92) receiving genomically targeted therapy with FDA approved drugs or in an independent clinical trial with 45% (13/29) responding. Standard of care (SOC) options were continued by 15% (14/92) of patients tested before exhausting SOC options, with 71% (10/14) responding to treatment. Over 35% (34/92) of patients with actionable targets were not treated with 65% (22/34) choosing comfort measures or passing away.

Materials and Methods

Patients (N = 165) were referred to the CIM Clinic between October 2012 and December 2015. All patients received clinical genomic panel testing with selected subsets receiving array comparative genomic hybridization and clinical whole exome sequencing to complement and validate panel findings. A genomic tumor board (GTB) reviewed results and, when possible, developed treatment recommendations.

Conclusions

Treatment decisions driven by tumor genomic analysis can lead to significant clinical benefit in a minority of patients. The success of genomically driven therapy depends both on access to drugs and robustness of bioinformatics analysis. While novel clinical trial designs are increasing the utility of genomic testing, robust data sharing of outcomes is needed to optimize clinical benefit for all patients.

Health-Related Quality-of-Life Results From the Open-Label, Randomized, Phase III ASPIRE Trial Evaluating Carfilzomib, Lenalidomide, and Dexamethasone Versus Lenalidomide and Dexamethasone in Patients With Relapsed Multiple Myeloma

Purpose To determine the effects of carfilzomib, lenalidomide, and dexamethasone (KRd) versus lenalidomide and dexamethasone (Rd) on health-related quality of life (HR-QoL) in the Carfilzomib, Lenalidomide, and Dexamethasone Versus Lenalidomide and Dexamethasone for the Treatment of Patients With Relapsed Multiple Myeloma (ASPIRE) trial. Methods Patients with relapsed multiple myeloma were randomly assigned to receive KRd or Rd. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 and myeloma-specific module were administered at baseline; day 1 of cycles 3, 6, 12, and 18; and after treatment. The Global Health Status/Quality of Life (GHS/QoL) scale and seven subscales (fatigue, nausea and vomiting, pain, physical functioning, role functioning, disease symptoms, and adverse effects of treatment) were compared between groups using a mixed model for repeated measures. The percentages of responders with ≥ 5- or 15-point GHS/QoL improvement at each cycle were compared between groups. Results Baseline questionnaire compliance was excellent (94.1% of randomly assigned patients). KRd patients had higher GHS/QoL scores versus Rd patients over 18 treatment cycles (two-sided P < .001). The minimal important difference was met at cycle 12 (5.6 points) and approached at cycle 18 (4.8 points). There was no difference between groups for the other prespecified subscales from ASPIRE. A higher proportion of KRd patients met the GHS/QoL responder definition (≥ 5-point improvement) with statistical differences at cycle 12 (KRd v Rd patients, 25.5% v 17.4%, respectively) and 18 (KRd v Rd patients, 24.2% v 12.9%, respectively). Conclusion KRd improves GHS/QoL without negatively affecting patient-reported symptoms when compared with Rd. These data further support the benefit of KRd in patients with relapsed multiple myeloma.

Alu-dependent RNA editing of GLI1 promotes malignant regeneration in multiple myeloma

Despite novel therapies, relapse of multiple myeloma (MM) is virtually inevitable. Amplification of chromosome 1q, which harbors the inflammation-responsive RNA editase adenosine deaminase acting on RNA (ADAR)1 gene, occurs in 30–50% of MM patients and portends a poor prognosis. Since adenosine-to-inosine RNA editing has recently emerged as a driver of cancer progression, genomic amplification combined with inflammatory cytokine activation of ADAR1 could stimulate MM progression and therapeutic resistance. Here, we report that high ADAR1 RNA expression correlates with reduced patient survival rates in the MMRF CoMMpass data set. Expression of wild-type, but not mutant, ADAR1 enhances Alu-dependent editing and transcriptional activity of GLI1, a Hedgehog (Hh) pathway transcriptional activator and self-renewal agonist, and promotes immunomodulatory drug resistance in vitro. Finally, ADAR1 knockdown reduces regeneration of high-risk MM in serially transplantable patient-derived xenografts. These data demonstrate that ADAR1 promotes malignant regeneration of MM and if selectively inhibited may obviate progression and relapse.

The treatment of multiple myeloma is challenging due to high relapse rates. Here the authors show that expression of ADAR1 correlates with poor patient outcomes, and that ADAR1-mediated editing of GLI1 is a mechanism relevant in the context of multiple myeloma progression and drug resistance.

Molecular Modeling and Functional Analysis of Exome Sequencing–Derived Variants of Unknown Significance Identify a Novel, Constitutively Active FGFR2 Mutant in Cholangiocarcinoma

Purpose

Genomic testing has increased the quantity of information available to oncologists. Unfortunately, many identified sequence alterations are variants of unknown significance (VUSs), which thus limit the clinician’s ability to use these findings to inform treatment. We applied a combination of in silico prediction and molecular modeling tools and laboratory techniques to rapidly define actionable VUSs.

Materials and Methods

Exome sequencing was conducted on 308 tumors from various origins. Most single nucleotide alterations within gene coding regions were VUSs. These VUSs were filtered to identify a subset of therapeutically targetable genes that were predicted with in silico tools to be altered in function by their variant sequence. A subset of receptor tyrosine kinase VUSs was characterized by laboratory comparison of each VUS versus its wild-type counterpart in terms of expression and signaling activity.

Results

The study identified 4,327 point mutations of which 3,833 were VUSs. Filtering for mutations in genes that were therapeutically targetable and predicted to affect protein function reduced these to 522 VUSs of interest, including a large number of kinases. Ten receptor tyrosine kinase VUSs were selected to explore in the laboratory. Of these, seven were found to be functionally altered. Three VUSs (FGFR2 F276C, FGFR4 R78H, and KDR G539R) showed increased basal or ligand-stimulated ERK phosphorylation compared with their wild-type counterparts, which suggests that they support transformation. Treatment of a patient who carried FGFR2 F276C with an FGFR inhibitor resulted in significant and sustained tumor response with clinical benefit.

Conclusion

The findings demonstrate the feasibility of rapid identification of the biologic relevance of somatic mutations, which thus advances clinicians’ ability to make informed treatment decisions.

Diagnosis and Management of Waldenström Macroglobulinemia: Mayo Stratification of Macroglobulinemia and Risk-Adapted Therapy (mSMART) Guidelines 2016

Importance

Waldenström macroglobulinemia (WM), an IgM-associated lymphoplasmacytic lymphoma, has witnessed several practice-altering advances in recent years. With availability of a wider array of therapies, the management strategies have become increasingly complex. Our multidisciplinary team appraised studies published or presented up to December 2015 to provide consensus recommendations for a risk-adapted approach to WM, using a grading system.

Observations

Waldenström macroglobulinemia remains a rare, incurable cancer, with a heterogeneous disease course. The major classes of effective agents in WM include monoclonal antibodies, alkylating agents, purine analogs, proteasome inhibitors, immunomodulatory drugs, and mammalian target of rapamycin inhibitors. However, the highest-quality evidence from rigorously conducted randomized clinical trials remains scant.

Conclusions and Relevance

Recognizing the paucity of data, we advocate participation in clinical trials, if available, at every stage of WM. Specific indications exist for initiation of therapy. Outside clinical trials, based on the synthesis of available evidence, we recommend bendamustine-rituximab as primary therapy for bulky disease, profound hematologic compromise, or constitutional symptoms attributable to WM. Dexamethasone-rituximab-cyclophosphamide is an alternative, particularly for nonbulky WM. Routine rituximab maintenance should be avoided. Plasma exchange should be promptly initiated before cytoreduction for hyperviscosity-related symptoms. Stem cell harvest for future use may be considered in first remission for patients 70 years or younger who are potential candidates for autologous stem cell transplantation. At relapse, retreatment with the original therapy is reasonable in patients with prior durable responses (time to next therapy ≥3 years) and good tolerability to previous regimen. Ibrutinib is efficacious in patients with relapsed or refractory disease harboring MYD88 L265P mutation. In the absence of neuropathy, a bortezomib-rituximab-based option is reasonable for relapsed or refractory disease. In select patients with chemosensitive disease, autologous stem cell transplantation should be considered at first or second relapse. Everolimus and purine analogs are suitable options for refractory or multiply relapsed WM. Our recommendations are periodically updated as new, clinically relevant information emerges.

CRISPR Genome-Wide Screening Identifies Dependence on the Proteasome Subunit PSMC6 for Bortezomib Sensitivity in Multiple Myeloma

Bortezomib is highly effective in the treatment of multiple myeloma; however, emergent drug resistance is common. Consequently, we employed CRISPR targeting 19,052 human genes to identify unbiased targets that contribute to bortezomib resistance. Specifically, we engineered an RPMI8226 multiple myeloma cell line to express Cas9 infected by lentiviral vector CRISPR library and cultured derived cells in doses of bortezomib lethal to parental cells. Sequencing was performed on surviving cells to identify inactivated genes responsible for drug resistance. From two independent whole-genome screens, we selected 31 candidate genes and constructed a second CRISPR sgRNA library, specifically targeting each of these 31 genes with four sgRNAs. After secondary screening for bortezomib resistance, the top 20 "resistance" genes were selected for individual validation. Of these 20 targets, the proteasome regulatory subunit PSMC6 was the only gene validated to reproducibly confer bortezomib resistance. We confirmed that inhibition of chymotrypsin-like proteasome activity by bortezomib was significantly reduced in cells lacking PSMC6. We individually investigated other members of the PSMC group (PSMC1 to 5) and found that deficiency in each of those subunits also imparts bortezomib resistance. We found 36 mutations in 19S proteasome subunits out of 895 patients in the IA10 release of the CoMMpass study (https://themmrf.org). Our findings demonstrate that the PSMC6 subunit is the most prominent target required for bortezomib sensitivity in multiple myeloma cells and should be examined in drug-refractory populations. Mol Cancer Ther; 16(12); 2862-70. ©2017 AACR.

High somatic mutation and neoantigen burden are correlated with decreased progression-free survival in multiple myeloma

Tumor-specific mutations can result in immunogenic neoantigens, both of which have been correlated with responsiveness to immune checkpoint inhibitors in highly mutagenic cancers. However, early results of single-agent checkpoint inhibitors in multiple myeloma (MM) have been underwhelming. Therefore, we sought to understand the relationship between mutation and neoantigen landscape of MM patients and responsiveness to therapies. Somatic mutation burden, neoantigen load, and response to therapy were determined using interim data from the MMRF CoMMpass study (NCT01454297) on 664 MM patients. In this population, the mean somatic and missense mutation loads were 405.84(s=608.55) and 63.90(s=95.88) mutations per patient, respectively. There was a positive linear relationship between mutation and neoantigen burdens (R²=0.862). The average predicted neoantigen load was 23.52(s=52.14) neoantigens with an average of 9.40(s=26.97) expressed neoantigens. Survival analysis revealed significantly shorter progression-free survival (PFS) in patients with greater than average somatic missense mutation load (N=163, 0.493 vs 0.726 2-year PFS, P=0.0023) and predicted expressed neoantigen load (N=214, 0.555 vs 0.729 2-year PFS, P=0.0028). This pattern is maintained when stratified by disease stage and cytogenetic abnormalities. Therefore, high mutation and neoantigen load are clinically relevant risk factors that negatively impact survival of MM patients under current standards of care.

Pomalidomide, bortezomib, and dexamethasone for patients with relapsed lenalidomide-refractory multiple myeloma

This phase 1/2 trial evaluated the maximum tolerated doses, safety, and efficacy of pomalidomide, bortezomib, and dexamethasone (PVD) combination in patients with relapsed lenalidomide-refractory multiple myeloma (MM). In phase 1, dose level 1 consisted of pomalidomide (4 mg by mouth on days 1 to 21), IV or subcutaneous bortezomib (1.0 mg/m2 on days 1, 8, 15, and 22), and dexamethasone (40 mg by mouth on days 1, 8, 15, and 22) given every 28 days. Bortezomib was increased to 1.3 mg/m2 for dose level 2 and adopted in the phase 2 expansion cohort. We describe the results of 50 patients. Objective response rate was 86% (95% confidence interval [CI], 73-94) among all evaluable patients (stringent complete response, 12%; complete response, 10%; very good partial response, 28%; and partial response, 36%) and 100% among high-risk patients. Within a median follow-up of 42 months, 20% remain progression free, 66% are alive, and 4% remain on treatment. Median progression-free survival was 13.7 months (95% CI, 9.6-17.7). The most common toxicities were neutropenia (96%), leukopenia (84%), thrombocytopenia (82%), anemia (74%), and fatigue (72%); however, the majority of these were grade 1 or 2. The most common grade ≥3 toxicities included neutropenia (70%), leukopenia (36%), and lymphopenia (20%). Deep vein thrombosis occurred in 5 patients. In conclusion, PVD is a highly effective combination in lenalidomide-refractory MM patients. Weekly administration of bortezomib enhanced tolerability and convenience. Toxicities are manageable, mostly consisting of mild cytopenias with no significant neuropathy. This trial was registered at www.clinicaltrials.gov as #NCT01212952.

Pomalidomide-dexamethasone in refractory multiple myeloma: long-term follow-up of a multi-cohort phase II clinical trial

Despite therapeutic advances, multiple myeloma remains incurable, with limited options for patients with refractory disease. We conducted a large, multi-cohort clinical trial testing various doses and treatment schedules of pomalidomide and dexamethasone (Pom/dex) in patients with refractory multiple myeloma. Overall, 345 patients were enrolled to six cohorts based on number and type of prior lines of therapy, pomalidomide dose and schedule. Median prior lines of therapy were three with near universal prior exposure to proteasome inhibitors and/or immunomodulatory drugs. A confirmed response rate of 35% was noted for all cohorts (range 23-65%) with higher responses in cohorts with fewer prior lines of therapy. Median time to confirmed response was ⩽2 months and the longest progression-free survival and overall survival seen in any cohort were 13.1 and 47.9 months, respectively. Observed adverse reactions were as expected, with myelosuppression and fatigue being the most common hematologic and non-hematologic adverse events (AEs), respectively. Longer durations of treatment and response, higher response rates and fewer AEs were noted with the 2 mg pomalidomide dose. This is the longest follow-up data for Pom/dex in refractory multiple myeloma and will help shape the real-world utilization of this regimen.

Blood Stem Cell Collection: Factors Influencing the Recovery of Granulocyte-Macrophage Colony Forming Cells

We evaluated data from all blood cell (BC) collections performed in our institution between 1989 and 1995 to determine factors influencing the outcome of collection. One hundred and thirty-three collections were performed on 106 patients. Malignant diagnoses were: non-Hodgkins lymphoma (NHL) in 35%, multiple myeloma in 31%, breast cancer in 26%, and Hodgkin's disease in 8%. Collections were obtained routinely in myeloma and breast cancer and due to bone marrow involvement with malignancy or inaspirable bone marrow in lymphoma patients. Collections were obtained on a Cobe Spectra or Baxter-Fenwall CS3000+. Engraftment potential was determined by methylcellulose colony assay (CFU-GM), with a target of >10 × 104 CFU-GM/kg. Apheresis nucleated cell count correlated significantly, albeit weakly (r = 0.26), with CFU-GM with a cell count of >5 × 10s/kg resulting in an adequate number of CFU-GM in 78% of patients. In univariant analysis outcome of collection was significantly influenced by the patients age (p = 0.01), malignant diagnosis (p < 0.001), reason for collection (p = 0.002), and the mobilization regimen (p = 0.01). The nature of the apheresis device used did not influence outcome. Only malignant diagnosis was significant (p < 0.001) in multivariate analysis. We conclude that the outcome of BC is most strongly influenced by patient factors such as malignant diagnosis. These factors must be considered when comparing the outcome of different mobilization regimens and when planning collection strategies.

Bone Marrow Mononuclear Cell Count does not Predict Neutrophil and Platelet Recovery following Autologous Bone Marrow Transplant: Value of the Colony-Forming Unit Granulocyte-Macrophage (CFU-GM) Assay

The common use of the marrow autograft mononuclear cell (MNC) count derives from positive correlative studies following allogeneic transplantation and from earlier conflicting data regarding the value of the bone marrow autograft colony-forming unit granulocyte-macrophage (CFU-GM) assay for predicting hematologic recovery after ABMT. We conducted a retrospective analysis at our institution to determine whether autograft CFU-GM levels predict engraftment of neutrophils and platelets after ABMT in heavily pretreated patients with hematologic malignancies. Between 1 January 1993 and 1 March 1995, 58 heavily pretreated patients received only marrow cells as the autograft product. Patients with Hodgkin's disease (n = 25), acute myeloid leukemia (n = 19), and non-Hodgkin's lymphoma (n = 14) underwent intensive therapy with etoposide and melphalan. Unpurged marrow containing a minimum of 1.5 × 108/kg (range: 1.5-4.8) was infused. Median time to an absolute neutrophil count ≥0.5 × 109/L was 21 days (range 10-270) and median time to a platelet count ≥20 × 109/L independent of transfusions was 44 days (range 13-317). There was no correlation between autograft MNC count and neutrophil or platelet engraftment. However, a correlation between autograft CFU-GM and both platelet and neutrophil recovery was demonstrated with a threshold CFU-GM of 3 × 104/kg; delayed neutrophil recovery was observed in 79% of patients below this threshold compared to only 9% in those with an autograft CFU-GM level of more than 3 × 104/kg (p = 0.0001). Similarly, platelet recovery was delayed in 76% of patients below, and 20% of those above this threshold (p = 0.003). We conclude that marrow autograft CFU-GM is predictive of engraftment of both platelets and neutrophils in heavily pretreated patients after ABMT for hematological malignancies.

Loss of FAM46C Promotes Cell Survival in Myeloma

FAM46C is one of the most recurrently mutated genes in multiple myeloma; however its role in disease pathogenesis has not been determined. Here we demonstrate that wild-type (WT) FAM46C overexpression induces substantial cytotoxicity in multiple myeloma cells. In contrast, FAM46C mutations found in multiple myeloma patients abrogate this cytotoxicity, indicating a survival advantage conferred by the FAM46C mutant phenotype. WT FAM46C overexpression downregulated IRF4, CEBPB, and MYC and upregulated immunoglobulin (Ig) light chain and HSPA5/BIP Furthermore, pathway analysis suggests that enforced FAM46C expression activated the unfolded protein response pathway and induced mitochondrial dysfunction. CRISPR-mediated depletion of endogenous FAM46C enhanced multiple myeloma cell growth, decreased Ig light chain and HSPA5/BIP expression, activated ERK and antiapoptotic signaling, and conferred relative resistance to dexamethasone and lenalidomide treatments. Genes altered in FAM46C-depleted cells were enriched for signaling pathways regulating estrogen, glucocorticoid, B-cell receptor signaling, and ATM signaling. Together these results implicate FAM46C in myeloma cell growth and survival and identify FAM46C mutation as a contributor to myeloma pathogenesis and disease progression via perturbation in plasma cell differentiation and endoplasmic reticulum homeostasis. Cancer Res; 77(16); 4317-27. ©2017 AACR.

Clinical utility of molecular testing to select therapy in relapsed/refractory non-Hodgkin lymphoma: Mayo Clinic Center for Individualized Medicine experience

11571

Background: Relapsed/refractory (R/R) non-Hodgkin lymphomas (NHL) have a poor prognosis with limited treatment options. Our expanding knowledge of molecular alterations seen in R/R NHL allows identification of patients that potentially may benefit from a precision medicine approach. However, experience in routine clinical implementation of precision medicine has been limited. Here, we summarize our clinical experience in molecular characterization of RR NHL targeted therapy (TT) using next-generation sequencing (NGS), and selection of targeted therapy (TT) based on molecular profile. Methods: We conducted a prospective study in RR NHL through the Center for Individualized Medicine at Mayo Clinic. Consenting patients underwent NGS using FoundationOne Heme panel from biopsies done at time of relapse. Results of NGS were discussed at the Genomic Tumor Board and recommendations for TT were given based on matching specific molecular alteration(s) with potential agent(s) predicted to be active based on NGS. The agents could include FDA-approved, off-label use and clinical trial therapies. Results: 28 cases were enrolled: 18 aggressive NHL, 10 follicular lymphoma (FL). Molecular alterations were present in all cases. In aggressive B-cell NHL, CDKN2A/B gene cluster alterations were seen in 73% (8/11), while seen in only 1/7 T-cell lymphomas (TCL), and 1/10 FL. TP53 deletions were second most common genomic alterations in DLBCL (57%) and seen in 40% FL. JAK-STAT and ERBB pathways were altered in TCL (2/7 each). IGH-BCl-2 gene rearrangement were common in FL (70%), followed by MLL gene alterations (50%). Targetable mutations were present in 86% (24/28) of cases. A TT was recommended in all 24 cases, but received by 2 patients only. Remaining patients did not due to benefit from current therapy (10/24), ineligibility or lack of clinical trial (7/24) or interim clinical deterioration (5/24). Conclusions: Targetable mutations were identified in most cases of RR NHL with TT recommended for all cases. However, access to TT limits potential clinical benefit of molecular-based matching strategy. More studies are needed to assess impact on clinical outcomes.

A phase Ib study of atezolizumab (atezo) alone or in combination with lenalidomide or pomalidomide and/or daratumumab in patients (pts) with multiple myeloma (MM)

TPS8053

Background: The advent of proteasome inhibitors and immunomodulatory drugs (IMiDs) have significantly improved outcomes in MM, and the first monoclonal antibodies for MM have been recently approved (daratumumab, elotuzumab). Despite novel therapies and improved disease management, MM is still considered incurable and most pts relapse, confirming the need for additional treatment options. MM cells express PD-L1, with higher levels observed after relapse and with advanced disease. Additionally, PD-L1–expressing immune cells in the microenvironment promote MM cell survival and potential immune escape. However, anti–PD-1 monotherapy did not result in objective responses in the MM cohort of a Ph I study, suggesting that MM pts need combination therapy. Daratumumab has activity as a single agent, as well as in combination with IMiDs plus dexamethasone and bortezomib plus dexamethasone in R/R MM. Immunomodulatory activity for daratumumab has also been reported. Thus, disruption of the PD-L1/PD-1 pathway may be additive or synergistic. The safety and efficacy of atezo (anti–PD-L1) alone or with lenalidomide or pomalidomide and/or daratumumab will be evaluated in a Ph Ib study of MM pts. NCT02431208. Methods: R/R MM pts with ≤ 3 prior therapies will be enrolled in Cohorts A (atezo), B (atezo + lenalidomide), D (atezo + daratumumab) and E (atezo + daratumumab + lenalidomide); MM pts with measurable disease after ASCT (Cohort C: atezo) or ≥ 3 prior therapies (Cohort F: atezo + daratumumab + pomalidomide) will also be enrolled. Cohorts B, D, E and F include a safety run-in (D) or dose escalation phase (B, E, F) and an expansion. Lenalidomide and pomalidomide will be dose escalated and the MTD evaluated in expansion phases. Atezo will be given at 1200 mg IV (A, B, C) or 840 mg IV (D, E, F); pts will get daratumumab at 16 mg/kg IV (D, E, F). All pts will be ECOG PS ≤ 2. Primary endpoints are ORR and the RP2D of lenalidomide and pomalidomide with atezo and daratumumab and the RP2D of lenalidomide with atezo. DOR and PFS are secondary endpoints; safety, PK and the relationship between biomarkers and other endpoints, including efficacy, will be assessed. Pts will be enrolled at 19 US sites. Clinical trial information: NCT02431208.

The use of proteasome inhibitors among patients with POEMS syndrome

e19530

Background: Neuropathy is a universal symptom of patients with POEMS syndrome, which makes the use of bortezomib less appealing. However, proteasome inhibitors (PIs) can provide rapid and deep hematologic responses in plasma cell disorders. Because there is very little data regarding the use PIs in POEMS syndrome, we performed a study of patients with POEMS syndrome treated with PIs. Methods: Among the 167 patients with POEMS syndrome seen at our institution between 2001-2016, we identified 12 patients who received a PI. One patient receiving < 1 cycle of bortezomib because of worsening neuropathy was included but was excluded from response analyses. One patient received 2 different PIs at separate points during the disease course and each course was considered separately. Four response categories were considered: hematologic, PET, VEGF and clinical as previously described (Dispenzieri et. al AJH 2015). Results: Among the 12 patients who received 13 courses of therapy, the median age at PI initiation was 59; 8 patients were male. Median number of prior therapies was 1 (0-4) and median time from diagnosis to initiation of PI was 75 months. Excluding steroids, regimens were as follows: bortezomib, n=3; bortezomib and cyclophosphamide, n=4; carfilzomib, n=1; and ixazomib, n=1. With a median follow-up from PI initiation of 18 months, the median duration of treatment was 7 months (1-18). Three patients achieved a hematologic CR. Of 6 patients with an abnormal baseline VEGF, 3 achieved normalization VEGF levels. Of 5 patients with an abnormal baseline PET, 2 achieved normalization of their PET. Two patients had improvement of their neuropathy, with the rest having stable symptoms. Of 9 patients with fluid overload, 8 improved. Only 2 patients stopped therapy due to worsening neuropathy related to PIs. Median PFS and OS from initiation of PI were 50 months and 53 months, respectively. Conclusions: We show that PI use in patients with POEMS syndrome can be safe and effective. Nearly 75% of patients treated with bortezomib had no exacerbation of their neuropathy. Clinical improvement in severe fluid overload symptoms (edema, ascites, pleural effusions) is almost universal, making PI-based therapy an attractive potential option in these patients.

Carfilzomib, lenalidomide, and dexamethasone in patients with relapsed multiple myeloma categorised by age: secondary analysis from the phase 3 ASPIRE study

A primary analysis of the ASPIRE study found that the addition of carfilzomib to lenalidomide and dexamethasone (carfilzomib group) significantly improved progression-free survival (PFS) compared with lenalidomide and dexamethasone alone (control group) in patients with relapsed multiple myeloma (RMM). This post hoc analysis examined outcomes from ASPIRE in patients categorised by age. In the carfilzomib group, 103/396 patients were ≥70 years old, and in the control group, 115/396 patients were ≥70 years old. Median PFS for patients <70 years old was 28·6 months for the carfilzomib group versus 17·6 months for the control group [hazard ratio (HR), 0·701]. Median PFS for patients ≥70 years old was 23·8 months for the carfilzomib group versus 16·0 months for the control group (HR, 0·753). For patients <70 years the overall response rate (ORR) was 86·0% (carfilzomib group) and 66·9% (control group); for patients ≥70 years old the ORR was 90·3% (carfilzomib group) and 66·1% (control group). Within the carfilzomib group, grade ≥3 cardiovascular adverse events occurred more frequently among patients ≥70 years old compared with patients <70 years old. Carfilzomib-lenalidomide-dexamethasone has a favourable benefit-risk profile for patients with RMM, including elderly patients ≥70 years old.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01080391.

A phase 2 study of lenalidomide, rituximab, cyclophosphamide, and dexamethasone (LR-CD) for untreated low-grade non-Hodgkin lymphoma requiring therapy

Patients with indolent non-Hodgkin lymphoma (NHL) have multiple treatment options yet there is no consensus as to the best initial therapy. Lenalidomide, an immunomodulatory agent, has single agent activity in relapsed lymphoma. This trial was conducted to assess feasibility, efficacy, and safety of adding lenalidomide to rituximab, cyclophosphamide, and dexamethasone (LR-CD) in untreated indolent NHL patients requiring therapy. This was a single institution phase II trial. Treatment consisted of IV rituximab 375 mg/m² day 1; oral lenalidomide 20 mg days 1-21; cyclophosphamide 250 mg/m² days 1, 8, and 15; and dexamethasone 40 mg days 1, 8, 15, and 22 of a 28-day cycle. Treatment continued 2 cycles beyond best response for a maximum of 12 cycles without rituximab maintenance. Thirty-three patients were treated. Median age was 68 (43-83 years). 39% had stage IV disease. Histologic subtypes included 8 follicular lymphoma (FL), 7 marginal zone lymphoma (MZL) (1 splenic, 2 extranodal, and 4 nodal), 15 Waldenström's macroglobulinemia (WM), 1 lymphoplasmacytic lymphoma, 1 small lymphocytic lymphoma, and 1 low-grade B-cell lymphoma with plasmacytic differentiation (unable to be classified better as MZL or LPL). Hematologic toxicity was the most common adverse event. Median time of follow-up was 23.4 months (range 1.8-50.9). The overall response rate was 87.9%, with 30.3% complete response. The median duration of response was 38.7 months. The median progression free survival was 39.7 months, while median overall survival (OS) has not yet been reached. Lenalidomide can be safely added to a simple regimen of rituximab, oral cyclophosphamide, and dexamethasone and is an effective combination as initial therapy for low-grade B-cell NHL.

Therapy for Relapsed Multiple Myeloma: Guidelines From the Mayo Stratification for Myeloma and Risk-Adapted Therapy

Life expectancy in patients with multiple myeloma is increasing because of the availability of an increasing number of novel agents with various mechanisms of action against the disease. However, the disease remains incurable in most patients because of the emergence of resistant clones, leading to repeated relapses of the disease. In 2015, 5 novel agents were approved for therapy for relapsed multiple myeloma. This surfeit of novel agents renders management of relapsed multiple myeloma more complex because of the occurrence of multiple relapses, the risk of cumulative and emergent toxicity from previous therapies, as well as evolution of the disease during therapy. A group of physicians at Mayo Clinic with expertise in the care of patients with multiple myeloma regularly evaluates the evolving literature on the biology and therapy for multiple myeloma and issues guidelines on the optimal care of patients with this disease. In this article, the latest recommendations on the diagnostic evaluation of relapsed multiple myeloma and decision trees on how to treat patients at various stages of their relapse (off study) are provided together with the evidence to support them.

Clinical Implementation of Integrated Genomic Profiling in Patients with Advanced Cancers

DNA focused panel sequencing has been rapidly adopted to assess therapeutic targets in advanced/refractory cancer. Integrated Genomic Profiling (IGP) utilising DNA/RNA with tumour/normal comparisons in a Clinical Laboratory Improvement Amendments (CLIA) compliant setting enables a single assay to provide: therapeutic target prioritisation, novel target discovery/application and comprehensive germline assessment. A prospective study in 35 advanced/refractory cancer patients was conducted using CLIA-compliant IGP. Feasibility was assessed by estimating time to results (TTR), prioritising/assigning putative therapeutic targets, assessing drug access, ascertaining germline alterations, and assessing patient preferences/perspectives on data use/reporting. Therapeutic targets were identified using biointelligence/pathway analyses and interpreted by a Genomic Tumour Board. Seventy-five percent of cases harboured 1–3 therapeutically targetable mutations/case (median 79 mutations of potential functional significance/case). Median time to CLIA-validated results was 116 days with CLIA-validation of targets achieved in 21/22 patients. IGP directed treatment was instituted in 13 patients utilising on/off label FDA approved drugs (n = 9), clinical trials (n = 3) and single patient IND (n = 1). Preliminary clinical efficacy was noted in five patients (two partial response, three stable disease). Although barriers to broader application exist, including the need for wider availability of therapies, IGP in a CLIA-framework is feasible and valuable in selection/prioritisation of anti-cancer therapeutic targets.

Population Pharmacokinetics and Exposure-Response Relationship of Carfilzomib in Patients With Multiple Myeloma

A population pharmacokinetic (PK) model and exposure-response (E-R) analysis was developed using data collected from 5 phase 1b/2 and 2 phase 3 studies in subjects with multiple myeloma. Subjects receiving intravenous infusion on 2 consecutive days each week for 3 weeks (days 1, 2, 8, 9, 15, and 16) in each cycle at doses ranging from 15 to 20/56 mg/m² (20 mg/m² in cycle 1 and, if tolerated, escalated to 56 mg/m² on day 8 of cycle 1). The population PK analysis indicated that among all the covariates tested, the only statistically significant covariate was body surface area on carfilzomib clearance; however, this covariate was unlikely to be clinically significant. Despite inclusion of different populations (relapsed or relapsed/refractory), treatments (carfilzomib monotherapy or combination therapy), infusion lengths (2 to 10 minutes or 30 minutes), and different doses, the E-R analysis of efficacy showed that after adjusting for baseline characteristics, higher area under the concentration-time curve was associated with improved overall response rate (ORR), from 15 to 20/56 mg/m² . No positive relationships between maximum concentration and ORR were identified, indicating that ORR would not be expected to be impacted by infusion length. For safety end points, no statistically significant relationship between exposure and increasing risk of adverse events was identified. The results of an E-R analysis provided strong support for a carfilzomib dose at 20/56 mg/m² as a 30-minute infusion for monotherapy and combination therapy. This article illustrates an example of application of E-R analysis to support labeling dose recommendation in the absence of extensive clinical data.

Multidisciplinary model to implement pharmacogenomics at the point of care

Purpose

Despite potential clinical benefits, implementation of pharmacogenomics (PGx) faces many technical and clinical challenges. These challenges can be overcome by a comprehensive and systematic implementation model.

Methods

The development and implementation of PGx was organized into eight interdependent components addressing resources, governance, clinical practice, education, testing, knowledge translation, clinical decision support (CDS) and maintenance. Several aspects of the implementation were assessed including adherence to the model, production of PGx-CDS interventions and access to educational resources.

Results

Between 8/2012 and 6/2015, 21 specific drug-gene interactions were reviewed and 18 of them were implemented in the electronic medical record as PGx-CDS interventions. There was complete adherence to the model with variable production time (98 to 392 days) and delay time (0 to 148 days). The implementation impacted approximately 1247 unique providers and 3788 unique patients. A total of 11 educational resources complementary to the drug-gene interactions and 5 modules specific for pharmacists were developed and implemented.

Conclusion

A comprehensive operational model can support PGx implementation into routine prescribing. Institutions can use this model as a roadmap to support similar efforts. However, we also identified challenges that will require major multidisciplinary and multi-institutional efforts to make PGx a universal reality.

Panel sequencing for clinically oriented variant screening and copy number detection in 142 untreated multiple myeloma patients

We employed a customized Multiple Myeloma (MM)-specific Mutation Panel (M³P) to screen a homogenous cohort of 142 untreated MM patients for relevant mutations in a selection of disease-specific genes. M³Pv2.0 includes 77 genes selected for being either actionable targets, potentially related to drug–response or part of known key pathways in MM biology. We identified mutations in potentially actionable genes in 49% of patients and provided prognostic evidence of STAT3 mutations. This panel may serve as a practical alternative to more comprehensive sequencing approaches, providing genomic information in a timely and cost-effective manner, thus allowing clinically oriented variant screening in MM.

Carfilzomib and the cardiorenal system in myeloma: an endothelial effect?

Carfilzomib (Cfz) has been associated with an ~5% incidence of unexplained and unpredictable cardiovascular toxicity in clinical trials. We therefore implemented a detailed, prospective, clinical cardiac and renal evaluation of 62 Cfz-treated myeloma patients, including serial blood pressure (BP), creatinine, troponin, NT-proBNP and pre- and post-treatment echocardiograms, including ejection fraction (EF), average global longitudinal strain and compliance. Pre-treatment elevations in NT-proBNP and BP, as well as abnormal cardiac strain were common. A rise in NT-proBNP occurred frequently post-treatment often without corresponding cardiopulmonary symptoms. A rise in creatinine was common, lessened with hydration and often reversible. All patients had a normal EF pre-treatment. Five patients experienced a significant cardiac event (four decline in EF and one myocardial infarction), of which 2 (3.2%) were considered probably attributable to Cfz. None were rechallenged with Cfz. The ideal strategy for identifying patients at risk for cardiac events, and parameters by which to monitor for early toxicity have not been established; however, it appears baseline echocardiographic testing is not consistently predictive of toxicity. The toxicities observed suggest an endothelial mechanism and further clinical trials are needed to determine whether or not this represents a class effect or is Cfz specific.

A Primitive Growth Factor, NME7AB , Is Sufficient to Induce Stable Naïve State Human Pluripotency; Reprogramming in This Novel Growth Factor Confers Superior Differentiation

Scientists have generated human stem cells that in some respects mimic mouse naïve cells, but their dependence on the addition of several extrinsic agents, and their propensity to develop abnormal karyotype calls into question their resemblance to a naturally occurring "naïve" state in humans. Here, we report that a recombinant, truncated human NME7, referred to as NME7AB here, induces a stable naïve-like state in human embryonic stem cells and induced pluripotent stem cells without the use of inhibitors, transgenes, leukemia inhibitory factor (LIF), fibroblast growth factor 2 (FGF2), feeder cells, or their conditioned media. Evidence of a naïve state includes reactivation of the second X chromosome in female source cells, increased expression of naïve markers and decreased expression of primed state markers, ability to be clonally expanded and increased differentiation potential. RNA-seq analysis shows vast differences between the parent FGF2 grown, primed state cells, and NME7AB converted cells, but similarities to altered gene expression patterns reported by others generating naïve-like stem cells via the use of biochemical inhibitors. Experiments presented here, in combination with our previous work, suggest a mechanistic model of how human stem cells regulate self-replication: an early naïve state driven by NME7, which cannot itself limit self-replication and a later naïve state regulated by NME1, which limits self-replication when its multimerization state shifts from the active dimer to the inactive hexamer.

SnapShot: Multiple Myeloma

Multiple myeloma (MM) is a plasma cell malignancy characterized by a heterogeneous clinical presentation. Genetic abnormalities are not only key events in the origin and progression of the disease but are also useful tools for prognosis, risk stratification, and therapeutic decision making. Although still incurable, a revolution in the treatment of MM is currently ongoing, leading to a significant improvement of clinical outcome and survival. To view this SnapShot, open or download the PDF.

Abstract CT112: Implementation of CLIA enabled integrated whole genome (WGS)/exome (WES)/transcriptome (RNAseq) next-gen sequencing to identify therapeutically relevant targets in advanced cancer patients

Background: Genomic assessment of cancer has been revolutionized by Next-Generation sequencing and is increasingly being applied to guide clinical prognostic and therapeutic decision-making. Initial clinical applications have been limited to gene panels and whole exome based strategies due to challenges with time to reporting of results, specimen quantity, analyte quality, and ethical-legal-social issues (ELSI).

Methods: Excisional or core tumor biopsies or bone marrow biopsies were obtained from consenting participants. Nucleic acid was extracted from fresh or frozen samples followed by WGS/WES/RNASeq on the Illumina HiSeq2000 or HiSeq2500 and bioinformatics analysis. Therapeutic targets were then prioritized by a multi-disciplinary Genomic Tumor Board (GTB) and CLIA validated using Sanger sequencing, RT-qPCR, FISH and/or IHC. Treatment was delivered using on/off-label FDA approved drugs, available clinical trials and single patient INDs.

Results: We consented 64 and enrolled 35 patients with advanced, treatment-refractory cancers. Median age was 59 (range 27-91) with 62% male. The majority had ECOG scores of 1 (94%). A median of 79 (range 28-8891) potentially functional somatic point mutations were identified in each case. One to two mutations/case were further identified as therapeutically targetable in 60% of the cases. The median time from tissue acquisition to CLIA validated results was 116 days (range 42-282) with CLIA validation of targets achieved in 21 of 22 patients. Genomic, target directed treatment was ultimately instituted in 13 patients utilizing: on/off label FDA approved drugs (n = 9), clinical trial (n = 3) and single patient IND (n = 1). Preliminary clinical efficacy was noted in 5 patients (2 PR, 3 SD). Integration of WES, long-insert WGS and RNA-Seq identified a case with an ERRFI1 mutant allele present in only 11% of the DNA reads while 82% of the RNA-Seq reads had the mutant transcript. The patient was treated with erlotinib and achieved a partial response by RECIST criteria. In another case, a fusion between FGFR2-MGEA5 was observed in WES and RNA-Seq data leading to prioritization as a drug target. Reasons for patients not receiving targeted therapy included: inability to access treatment (n = 1), death prior to intended treatment (n = 3), results returned after death (n = 3), no targets identified (n = 2) and decision to pursue alternate therapy (n = 5).

Conclusions: Integrating whole genome analysis in a CLIA setting is not only feasible, but also valuable, in the prioritization and selection of potential targeted therapies for patients with advanced tumors. Continued barriers to broad application include the need for shorter time to reporting as well as broad availability of therapies through basket studies.

Citation Format: Mitesh J. Borad, Jan Egan, Mia Champion, Katherine Hunt, Robert McWilliams, Ann McCullough, Jessica Aldrich, Sara Nasser, Winnie Liang, Michael Barrett, David Craig, Ramesh Ramanathan, John Carpten, A. Keith Stewart, Alan Bryce. Implementation of CLIA enabled integrated whole genome (WGS)/exome (WES)/transcriptome (RNAseq) next-gen sequencing to identify therapeutically relevant targets in advanced cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT112. doi:10.1158/1538-7445.AM2015-CT112

Carfilzomib for the treatment of patients with relapsed and/or refractory multiple myeloma

Carfilzomib is a proteasome inhibitor that irreversibly binds to its target, resulting in sustained proteasomal inhibition with minimal off-target effects. As a single agent, carfilzomib has demonstrated durable antimyeloma activity with manageable toxicities, which has resulted in its approval in Argentina, Israel, Mexico and the USA for the treatment of patients with relapsed and refractory multiple myeloma. Data from ongoing Phase III studies that are evaluating carfilzomib in earlier lines of therapy may facilitate an expanded indication for this agent, as well as for regulatory approval in the EU. This article summarizes the chemistry, pharmacokinetics, pharmacodynamics and available clinical data for carfilzomib in the treatment of patients with multiple myeloma.

Genome-Wide Analysis Uncovers Novel Recurrent Alterations in Primary Central Nervous System Lymphomas

PURPOSE

Primary central nervous system lymphoma (PCNSL) is an aggressive non-Hodgkin lymphoma confined to the central nervous system. Whether there is a PCNSL-specific genomic signature and, if so, how it differs from systemic diffuse large B-cell lymphoma (DLBCL) is uncertain.

EXPERIMENTAL DESIGN

We performed a comprehensive genomic study of tumor samples from 19 immunocompetent PCNSL patients. Testing comprised array-comparative genomic hybridization and whole exome sequencing.

RESULTS

Biallelic inactivation of TOX and PRKCD was recurrently found in PCNSL but not in systemic DLBCL, suggesting a specific role in PCNSL pathogenesis. In addition, we found a high prevalence of MYD88 mutations (79%) and CDKN2A biallelic loss (60%). Several genes recurrently affected in PCNSL were common with systemic DLBCL, including loss of TNFAIP3, PRDM1, GNA13, TMEM30A, TBL1XR1, B2M, CD58, activating mutations of CD79B, CARD11, and translocations IgH-BCL6. Overall, B-cell receptor/Toll-like receptor/NF-κB pathways were altered in >90% of PNCSL, highlighting its value for targeted therapeutic approaches. Furthermore, integrated analysis showed enrichment of pathways associated with immune response, proliferation, apoptosis, and lymphocyte differentiation.

CONCLUSIONS

In summary, genome-wide analysis uncovered novel recurrent alterations, including TOX and PRKCD, helping to differentiate PCNSL from systemic DLBCL and related lymphomas.

Cereblon binding molecules in multiple myeloma

Immunomodulation is an established treatment strategy in multiple myeloma with thalidomide and its derivatives lenalidomide and pomalidomide as its FDA approved representatives. Just recently the method of action of these cereblon binding molecules was deciphered and results from large phase 3 trials confirmed the backbone function of this drug family in various combination therapies. This review details the to-date knowledge concerning mechanism of IMiD action, clinical applications and plausible escape mechanisms in which cells may become resistant/refractory to cereblon binding molecule based treatment.