Targeting the T-Cell Lymphoma Epigenome Induces Cell Death, Cancer Testes Antigens, Immune-Modulatory Signaling Pathways.

The peripheral T-cell lymphomas (PTCL) could be considered the prototypical epigenetic disease. As a disease, they are uniquely sensitive to histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors, both alone and in combination, are characterized by a host of mutations in epigenetic genes, and can develop spontaneously in genetically engineered murine models predicated on established recurring mutations in (RHOAG17V) and TET2, an epigenetic gene governing DNA methylation. Given the clinical benefit of HDAC inhibitors (HDACi) and hypomethlyation agents alone and in combination in PTCL, we sought to explore a mechanistic basis for these agents in PTCL. Herein, we reveal profound class synergy between HDAC and DNMT inhibitors in PTCL, and that the combination induces degrees of gene expression that are substantially different and more extensive than that observed for the single agents. A prominent signature of the combination relates to the transcriptional induction of cancer testis antigens and genes involved in the immune response. Interestingly, TBX21 and STAT4, master regulators of TH1 differentiation, were among the genes upregulated by the combination, suggesting the induction of a TH1-like phenotype. Moreover, suppression of genes involved in cholesterol metabolism and the matrisome were also identified. We believe that these data provide a strong rationale for clinical studies, and future combinations leveraging an immunoepigenetic platform.

Belinostat in combination with standard cyclophosphamide, doxorubicin, vincristine and prednisone as first-line treatment for patients with newly diagnosed peripheral T-cell lymphoma.

BACKGROUND: Belinostat is a histone deacetylase inhibitor approved for relapsed refractory peripheral T-cell lymphoma (PTCL). The primary objective of this study was to determine the maximum tolerated dose (MTD) of belinostat combined with CHOP (Bel-CHOP). Secondary objectives included safety/tolerability, overall response rate (ORR), and belinostat pharmacokinetics (PK). METHODS: Patients were ≥ 18 years with histologically confirmed, previously untreated PTCL. Patients received belinostat (1000 mg/m2 once daily) + standard CHOP for 6 cycles with varying schedules using a 3 + 3 design in Part A. Part B enrolled patients at MTD dose. RESULTS: Twenty-three patients were treated. One patient experienced DLT (Grade 3 non-hematologic toxicity) on Day 1-3 schedule, resulting in escalation to Day 1-5 schedule (n = 3). No DLTs were observed and Day 1-5 schedule with 1000 mg/m2 was declared as MTD. Twelve additional patients were enrolled in Part B using MTD. Median relative dose intensity was 98%. All patients experienced adverse events (AEs), including nausea (78%), fatigue (61%), and vomiting (57%). Serious AEs occurred in 43%, with febrile neutropenia (17%) and pyrexia (13%). Overall ORR was 86% with 71% reported CR at MTD. Belinostat PK parameters were similar to single-agent. CONCLUSIONS: Bel-CHOP was well tolerated and MTD in CHOP combination was the same dose and schedule as single agent dosing. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01839097.

Combined oral 5-azacytidine and romidepsin are highly effective in patients with PTCL: a multicenter phase 2 study.

Peripheral T-cell lymphomas (PTCLs) are uniquely vulnerable to epigenetic modifiers. We demonstrated in vitro synergism between histone deacetylase inhibitors and DNA methyltransferase inhibitors in preclinical models of T-cell lymphoma. In a phase 1 trial, we found oral 5-azacytidine and romidepsin to be safe and effective, with lineage-selective activity among patients with relapsed/refractory (R/R) PTCL. Patients who were treatment naïve or who had R/R PTCL received azacytidine 300 mg once per day on days 1 to 14, and romidepsin 14 mg/m2 on days 8, 15, and 22 every 35 days. The primary objective was overall response rate (ORR). Targeted next-generation sequencing was performed on tumor samples to correlate mutational profiles and response. Among 25 enrolled patients, the ORR and complete response rates were 61% and 48%, respectively. However, patients with T-follicular helper cell (tTFH) phenotype exhibited higher ORR (80%) and complete remission rate (67%). The most frequent grade 3 to 4 adverse events were thrombocytopenia (48%), neutropenia (40%), lymphopenia (32%), and anemia (16%). At a median follow-up of 13.5 months, the median progression-free survival, duration of response, and overall survival were 8.0 months, 20.3 months, and not reached, respectively. The median progression-free survival and overall survival were 8.0 months and 20.6 months, respectively, in patients with R/R disease. Patients with tTFH enjoyed a particularly long median survival (median not reached). Responders harbored a higher average number of mutations in genes involved in DNA methylation and histone deacetylation. Combined azacytidine and romidepsin are highly active in PTCL patients and could serve as a platform for novel regimens in this disease. This trial was registered at www.clinicaltrials.gov as #NCT01998035.

Low dose continuous lenalidomide in heavily pretreated patients with relapsed or refractory classical Hodgkin lymphoma: a retrospective case series.

Patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) following autologous stem cell transplant (ASCT) remain a management challenge with few reliably effective treatments. Lenalidomide, an immunomodulatory drug approved for patients with myelodysplastic syndrome with del(5q), multiple myeloma, and mantle cell lymphoma, has demonstrated some activity in patients with R/R cHL, though the toxicity of traditional doses and schedules has been a barrier to consistent use. Low dose continuous (LDC) schedules have emerged as promising, with a more favorable safety profile. We report herein that LDC schedules are associated with a far more tolerable toxicity profile, and exhibit at least equivalent efficacy in this patient population. We report that patients diagnosed with R/R cHL who previously underwent, or were not candidates for, ASCT and/or clinical trials, were administered daily LDC lenalidomide (20 mg orally with dose reduction for toxicity). Among the 19 patients included in this analysis, 11% of patients achieved a partial response (PR), with no documented complete responses (CR). A total of 12 (63%) patients maintained stable disease (SD), with 7 patients (37%) remaining in SD for more than 6 months. The clinical benefit rate (comprised of CR, PR, and SD for greater than 6 months) was 47% (7 out of 19 patients). The median progression-free survival and overall survival of all patients were 9.4 months (range, 4.6-14.4 months) and 90 months (range, 63.6-166.8 months), respectively. In general, the treatment was well tolerated, with grade 3 or 4 adverse events consisting of neutropenia (n = 4), and one case each of thrombocytopenia, fatigue, rash, creatinine elevation, aspartate transaminase/alanine transaminase elevation, and treatment related secondary malignancy. In a heavily treated R/R cHL patient population, daily LDC lenalidomide was associated with a high disease control rate with a favorable toxicity profile.

ATM inhibition overcomes resistance to histone deacetylase inhibitor due to p21 induction and cell cycle arrest.

The antiproliferative effect induced by histone deactylase inhibitors (HDACi) is associated with the up-regulated expression of the cyclin-dependent kinase inhibitor p21. Paradoxically, the increased expression of p21 correlates with a reduced cell killing to the drug. The direct targeting of p21 is not feasible. An alternate approach could selectively target factors upstream or downstream of p21 that affect one or more specific aspects of p21 function. HDAC inhibitors appear to activate p21 expression via ataxia telangiectasia mutated (ATM) activity. KU60019, a specific ATM inhibitor, has shown to decrease the p21 protein levels in a concentration dependent manner. We explored the potential synergistic interaction of the ATM inhibitor with romidepsin, given the potential complementary impact around p21. A synergistic cytotoxic effect was observed in all lymphoma cell lines examined when the HDACi was combined with KU60019. The increase in apoptosis correlates with decreased expression of p21 due to the ATM inhibitor. KU60019 decreased expression of the cyclin-dependent kinase inhibitor at the transcriptional level, compromising the ability of HDACi to induce p21 and cell cycle arrest and ultimately facilitating a shift toward the apoptotic phase. Central to the increased apoptosis observed when romidepsin is combined with KU60019 is the reduced expression of p21 and the absence of a G2/M cell cycle arrest that would be exploited by the tumor cells to evade the cytotoxic effect of the HDAC inhibitor. We believe this strategy may offer a promising way to identify rational combinations for HDACi directed therapy, improving their activity in malignant disease.

Oral 5-azacytidine and romidepsin exhibit marked activity in patients with PTCL: a multicenter phase 1 study.

The peripheral T-cell lymphomas (PTCLs) are uniquely sensitive to epigenetic modifiers. Based on the synergism between histone deacetylase inhibitors and hypomethylating agents that we established in preclinical PTCL models, we conducted a phase 1 study of oral 5-azacytidine (AZA) and romidepsin (ROMI) in patients with advanced lymphoid malignancies, with emphasis on PTCL. According to a 3 + 3 design, patients were assigned to 1 of 7 cohorts with AZA doses ranging from 100 mg daily on days 1 to 14 to 300 mg daily on days 1 to 21, ROMI doses ranging from 10 mg/m2 on days 8 and 15 to 14 mg/m2 on days 8, 15, and 22, with cycles of 21 to 35 days. Coprimary end points included maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). We treated a total of 31 patients. The MTD was AZA 300 mg on days 1 to 14 and ROMI 14 mg/m2 on days 8, 15, and 22 on a 35-day cycle. DLTs included grade 4 thrombocytopenia, prolonged grade 3 thrombocytopenia, grade 4 neutropenia, and pleural effusion. There were no treatment-related deaths. The combination was substantially more active in patients with PTCL than in those with non-T-cell lymphoma. The overall response rate in all, non-T-cell, and T-cell lymphoma patients was 32%, 10%, and 73%, respectively, and the complete response rates were 23%, 5%, and 55%, respectively. We did not find an association between response and level of demethylation or tumor mutational profile. This study establishes that combined epigenetic modifiers are potently active in PTCL patients. This trial was registered at www.clinicaltrials.gov as NCT01998035.

Targeting Translation of mRNA as a Therapeutic Strategy in Cancer.

PURPOSE OF REVIEW: To highlight recent results in targeting mRNA translation and discuss the results and prospects of translation inhibitors in cancer therapy. RECENT FINDINGS: Until recently, inhibitors of mRNA translation have been thought to likely lack a therapeutic window. In 2012, the Food and Drug Administration (FDA) approved omacetaxine mepesuccinate (homoharringtonine) for the treatment of adults with chronic myelogenous leukemia (CML) who are resistant to at least two tyrosine kinase inhibitors. Since then, a few drugs, notably tomivosertib (eFT-508), selinexor (KPT-330), and ribavirin, have entered clinical trials. These drugs are known to inhibit mRNA translation. More recently, a number of interesting studies report that discrete subsets of proteins in cancer cells may be selectively targeted at the translation step, through inhibiting signals such as phospho-4E-BP1, eIF4A, and eIF4E. Promising therapies using these strategies have demonstrated potent anti-tumor activity in preclinical cancer models. The growing number of translation inhibitors with diverse mechanisms, coupled with emerging insights into translational regulation of different cancer-promoting genes, suggests a bright new horizon for the field of therapeutic targeting of mRNA translation in cancer.

Microclimate exerts greater control over litter decomposition and enzyme activity than litter quality in an alpine forest-tundra ecotone.

Plant litter decomposition is an important biogeochemical process in terrestrial ecosystems. Although climate and substrate quality controls over litter decomposition are reasonably well understood, their impacts on lignocellulose degradation and lignocellulolytic enzymes remain elusive. Here, the decomposition of three leaf litters derived from Salix paraplesia (SP), Deyeuxia scabrescens (DS), and Ajuga ovalifolia (AO), was studied across an alpine forest-tundra ecotone during one snow-covered season with the objective of distinguishing between the effects of microclimate and litter quality on litter decomposition rates and lignocellulolytic enzymes. The results showed that both microclimate and litter quality affected lignocellulose degradation rates and lignocellulolytic enzyme activities; however, microclimate factors had the greater effects. Interestingly, freeze-thaw cycles and moisture were the predominant factors explaining the variations in decomposition rate and enzyme activities. Higher cellulose degradation rates were associated with higher cellulose concentrations. Cellulolytic enzymes had a greater effect on litter decomposition than did ligninolytic enzymes at the early decomposition stage. Litter decomposition and enzyme activities should be given more attention under global climate change, as the direction and magnitude of changes in microclimate factors and litter quality could strongly influence the nutrient cycling and energy fluxes of alpine ecosystems.

Umbralisib, a novel PI3Kδ and casein kinase-1ε inhibitor, in relapsed or refractory chronic lymphocytic leukaemia and lymphoma: an open-label, phase 1, dose-escalation, first-in-human study.

BACKGROUND: Umbralisib (TGR-1202) is a novel next-generation inhibitor of phosphatidylinositol 3-kinase (PI3K) isoform p110δ (PI3Kδ), which is structurally distinct from other PI3Kδ inhibitors and shows improved isoform selectivity. Umbralisib also uniquely inhibits casein kinase-1ε, a major regulator of protein translation. The aim of this first-in-human phase 1 study was to establish the safety and preliminary activity profile of umbralisib in patients with haematological malignancies. METHODS: We did an open-label, phase 1, dose-escalation study at seven clinics in the USA. We recruited patients aged at least 18 years with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma, B-cell and T-cell non-Hodgkin lymphoma, or Hodgkin's lymphoma, who had received one or more previous lines of therapy, with measurable and assessable disease, and adequate organ system function. Patients self-administered an umbralisib oral tablet once per day in 28-day cycles, with dose escalation done in a traditional 3 + 3 design to establish safety and determine the maximum tolerated dose. In initial cohorts, patients took umbralisib in a fasting state at a starting dose of 50 mg, increasing to 100, 200, 400, 800, 1200, and 1800 mg until the maximum tolerated dose was reached, or the maximal dose cohort was accrued without a dose-limiting toxicity. Subsequent cohorts self-administered a micronised formulation of umbralisib tablet in a fed state at an initial dose of 200 mg, increased in increments to 400, 800, 1200, and 1800 mg until the maximum tolerated dose or the maximal dose level was accrued. In August, 2014, all patients still on study were transitioned to 800 mg of the micronised formulation and dosing of the initial formulation was discontinued. The primary endpoints of the study were investigator-assessed safety in all treated patients (the safety population), the maximum tolerated dose, and the pharmacokinetics of umbralisib. Secondary endpoints included preliminary assessments of anti-cancer activity (objective responses and duration of response). Follow-up stopped for a patient once they discontinued therapy. This study has been completed and is registered with ClinicalTrials.gov, number NCT01767766. FINDINGS: Between Jan 17, 2013, and Jan 14, 2016, we enrolled and treated 90 patients with umbralisib. The median duration of treatment and follow-up was 4·7 cycles (IQR 2·0-14·0) or 133 days (IQR 55-335). The most common treatment-emergent adverse events irrespective of causality were diarrhoea (in 39 [43%] of 90 patients), nausea (38 [42%]), and fatigue (28 [31%]). The most common grade 3 or 4 adverse events were neutropenia (in 12 [13%] patients), anaemia (eight [9%]) and thrombocytopenia (six [7%]). Serious adverse events considered at least possibly related to umbralisib occurred in seven patients: pneumonia in three (3%) patients, lung infection in one (1%), febrile neutropenia in one (1%), and colitis in two (2%), one of whom also had febrile neutropenia. The maximum tolerated dose was 1200 mg of the micronised formulation, with 800 mg of this formulation selected as the recommended phase 2 dose. Both cases of colitis occurred at above the recommended phase 2 dose. 33 (37%) of the 90 patients enrolled had an objective response to treatment with umbralisib. INTERPRETATION: Umbralisib was well tolerated and showed preliminary signs of activity in patients with relapsed or refractory haematological malignancies. The safety profile of umbralisib in this phase 1 study was distinct from that of other PI3Kδ inhibitors, with fewer occurrences of autoimmune-like toxicities such as colitis. These findings warrant further evaluation of this agent in this setting. FUNDING: TG Therapeutics.

Brentuximab vedotin plus bendamustine in relapsed or refractory Hodgkin's lymphoma: an international, multicentre, single-arm, phase 1-2 trial.

BACKGROUND: Brentuximab vedotin is currently approved for patients with relapsed or refractory Hodgkin's lymphoma who previously received an autologous stem cell transplant or two previous multiagent chemotherapy regimens, and for patients with relapsed or refractory systemic anaplastic large-T-cell lymphoma who previously received at least one chemotherapy regimen. A high proportion of patients with CD30-expressing relapsed or refractory lymphomas have durable responses to single-agent brentuximab vedotin and show longer progression-free survival than do patients treated with chemotherapy. In patients with Hodgkin's lymphoma and peripheral T-cell lymphoma, treatment with bendamustine alone only achieves modest improvements in progression-free survival compared with that for chemotherapy. The objective of this study was to explore the safety and clinical activity of the combination of brentuximab vedotin plus bendamustine in heavily pretreated patients with relapsed or refractory Hodgkin's lymphoma and anaplastic large-T-cell lymphoma. METHODS: In this international, multicentre, single-arm, phase 1-2 trial, eligible patients were aged 18 years or older, had histologically confirmed relapsed or refractory Hodgkin's lymphoma or anaplastic large-T-cell lymphoma, had biopsy-proven CD30-positive tumours, had an Eastern Cooperative Oncology Group performance status of 2 or less, and received at least one previous multiagent chemotherapy regimen. In phase 1, patients were assigned following a 3+3 dose-escalation design to one of four cohorts to receive one dose of either 1·2 mg/kg or 1·8 mg/kg of brentuximab vedotin intravenously on day 1 of a 21 day cycle, plus one dose of bendamustine (70 mg/m2, 80 mg/m2, or 90 mg/m2) on days 1 and 2 of the treatment cycle. In phase 2, all patients were assigned to receive brentuximab vedotin plus bendamustine at the recommended phase 2 dose from phase 1. The primary endpoints were maximum tolerated dose and dose-limiting toxicity for phase 1, and the proportion of patients achieving an overall response in phase 2. For both phases 1 and 2, all patients receiving at least one dose of study drug were evaluable for toxicity and all patients completing at least one cycle of therapy were evaluable for response. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT01657331. FINDINGS: Between July 26, 2012, and May 31, 2017, we enrolled and assigned 65 patients to treatment (64 [98%] with Hodgkin's lymphoma and one [2%] with anaplastic large-T-cell lymphoma; 28 [43%] during phase 1 and 37 [57%] during phase 2). In the phase 1 part, the maximum tolerated dose of the combination was not reached. Dose-limiting toxicities were observed in three (11%) of 28 patients, including grade 4 neutropenia at 1·8 mg/kg brentuximab vedotin plus 80 mg/m2 of bendamustine in two (7%) patients and diffuse rash at 1·2 mg/kg brentuximab vedotin plus 70 mg/m2 of bendamustine in one (4%) patient. The recommended phase 2 dose was deemed to be 1·8 mg/kg of brentuximab vedotin and 90 mg/m2 of bendamustine, which are the standard doses of the drugs when given as single agents. In the phase 2 part, an overall response was achieved in 29 (78% [95% CI 62-91]) of 37 patients. Serious adverse events included grade 3 lung infection in five (14%) of 37 patients in the phase 2, and grade 3-4 neutropenia in 16 (25%) of 65 patients across phases 1 and 2. There were no treatment-related deaths. INTERPRETATION: This study shows that brentuximab vedotin plus bendamustine, with a favourable safety profile, is an active salvage regimen for heavily pretreated patients with relapsed or refractory Hodgkin's lymphoma. This salvage regimen can potentially serve as an efficacious and safe alternative to platinum-based chemotherapy before autologous stem cell transplant. FUNDING: Seattle Genetics, Lymphoma Research Fund of Columbia University and National Center for Advancing Translational Sciences, and National Institutes of Health.

A phase 1 study of romidepsin and pralatrexate reveals marked activity in relapsed and refractory T-cell lymphoma.

Peripheral T-cell lymphomas (PTCL) are a group of rare malignancies characterized by chemotherapy resistance and poor prognosis. Romidepsin and pralatrexate were approved by the US Food and Drug Administration for patients with relapsed/refractory PTCL, exhibiting response rates of 25% and 29% respectively. Based on synergy in preclinical models of PTCL, we initiated a phase 1 study of pralatrexate plus romidepsin in patients with relapsed/refractory lymphoma. This was a single institution dose-escalation study of pralatrexate plus romidepsin designed to determine the dose-limiting toxicities (DLTs), maximum tolerated dose, pharmacokinetic profile, and response rates. Patients were treated with pralatrexate (10 to 25 mg/m2) and romidepsin (12 to 14 mg/m2) on 1 of 3 schedules: every week × 3 every 28 days, every week × 2 every 21 days, and every other week every 28 days. Treatment continued until progression, withdrawal of consent, or medical necessity. Twenty-nine patients were enrolled and evaluable for toxicity. Coadministration of pralatrexate and romidepsin was safe, well tolerated, with 3 DLTs across all schedules (grade 3 oral mucositis × 2; grade 4 sepsis × 1). The recommended phase 2 dose was defined as pralatrexate 25 mg/m2 and romidepsin 12 mg/m2 every other week. Twenty-three patients were evaluable for response. The overall response rate was 57% (13/23) across all patients and 71% (10/14) in PTCL. The phase 1 study of pralatrexate plus romidepsin resulted in a high response rate in patients with previously treated PTCL. A phase 2 study in PTCL will determine the efficacy of the combination. This trial was registered at www.clinicaltrials.gov as #NCT01947140.

Pralatrexate: a comprehensive update on pharmacology, clinical activity and strategies to optimize use.

It has been nearly 8 years since pralatrexate became the first drug approved by the U.S. Food and Drug Administration for the treatment of relapsed or refractory peripheral T-cell lymphoma (PTCL). Like most drugs approved for a particular clinical indication, as much or more is learned once it enters mainstream use as in the years leading up to regulatory approval. Over the past several years, many diverse lines of research have shed new insight into both the agent, and the diseases it treats. In this review, we will bring the reader up to date on the many new aspects related to pralatrexate's pharmacology, activity across the panoply of T-cell lymphoproliferative malignancies, as well as some new and emerging guidelines that are likely to improve its safety profile. Finally, the review will close with the many new lines of evidence building a rationale for the combination of these novels: novel combination, and the vision for new platforms in PTCL care.

A phase 1/2 trial of ublituximab, a novel anti-CD20 monoclonal antibody, in patients with B-cell non-Hodgkin lymphoma or chronic lymphocytic leukaemia previously exposed to rituximab.

This phase 1/2 study evaluated the safety, pharmacokinetic behavior and anti-tumour activity of ublituximab, a unique type I, chimeric, glycoengineered anti-CD20 monoclonal antibody, in rituximab-relapsed or -refractory patients with B-cell non-Hodgkin lymphoma (B-NHL) or chronic lymphocytic leukaemia (CLL). Induction therapy (doses of 450-1200 mg) consisted of 4 weekly infusions in cycle 1 for NHL and 3 weekly infusions in cycles 1 and 2 for CLL. Patients received ublituximab maintenance monthly during cycles 3-5, then once every 3 months for up to 2 years. Enrolled patients with B-NHL (n = 27) and CLL (n = 8) had a median of 3 prior therapies. No dose-limiting toxicities or unexpected adverse events (AEs) occurred. The most common AEs were infusion-related reactions (40%; grade 3/4, 0%); fatigue (37%; grade 3/4, 3%); pyrexia (29%; grade 3/4, 0%); and diarrhoea (26%; grade 3/4, 0%). Common haematological AEs were neutropenia (14%; grade 3/4, 14%) and anaemia (11%; grade 3/4, 6%). The overall response rate for evaluable patients (n = 31) was 45% (13% complete responses, 32% partial responses). Median duration of response and progression-free survival were 9·2 months and 7·7 months, respectively. Ublituximab was well-tolerated and efficacious in a heterogeneous and highly rituximab-pre-treated patient population.

Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies.

Phosphoinositide 3-kinase (PI3K) and the proteasome pathway are both involved in activating the mechanistic target of rapamycin (mTOR). Because mTOR signaling is required for initiation of messenger RNA translation, we hypothesized that cotargeting the PI3K and proteasome pathways might synergistically inhibit translation of c-Myc. We found that a novel PI3K δ isoform inhibitor TGR-1202, but not the approved PI3Kδ inhibitor idelalisib, was highly synergistic with the proteasome inhibitor carfilzomib in lymphoma, leukemia, and myeloma cell lines and primary lymphoma and leukemia cells. TGR-1202 and carfilzomib (TC) synergistically inhibited phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), leading to suppression of c-Myc translation and silencing of c-Myc-dependent transcription. The synergistic cytotoxicity of TC was rescued by overexpression of eIF4E or c-Myc. TGR-1202, but not other PI3Kδ inhibitors, inhibited casein kinase-1 ε (CK1ε). Targeting CK1ε using a selective chemical inhibitor or short hairpin RNA complements the effects of idelalisib, as a single agent or in combination with carfilzomib, in repressing phosphorylation of 4E-BP1 and the protein level of c-Myc. These results suggest that TGR-1202 is a dual PI3Kδ/CK1ε inhibitor, which may in part explain the clinical activity of TGR-1202 in aggressive lymphoma not found with idelalisib. Targeting CK1ε should become an integral part of therapeutic strategies targeting translation of oncogenes such as c-Myc.