Rational Targets of Therapy in Extranodal NK/T-Cell Lymphoma

Extranodal NK/T-cell lymphoma (ENKTL) is an aggressive extranodal non-Hodgkin lymphoma (NHL) with poor outcomes, particularly in advanced-stage and relapsed/refractory disease. Emerging research on molecular drivers of ENKTL lymphomagenesis by next-generation and whole genome sequencing has revealed diverse genomic mutations in multiple signaling pathways, with the identification of multiple putative targets for novel therapeutic agents. In this review, we summarize the biological underpinnings of newly-understood therapeutic targets in ENKTL with a focus on translational implications, including epigenetic and histone regulatory aberrations, activation of cell proliferation signaling pathways, suppression of apoptosis and tumor suppressor genes, changes in the tumor microenvironment, and EBV-mediated oncogenesis. In addition, we highlight prognostic and predictive biomarkers which may enable a personalized medicine approach toward ENKTL therapy

Extreme Peripheral Blood Plasmacytosis Mimicking Plasma Cell Leukemia as a Presenting Feature of Angioimmunoblastic T-Cell Lymphoma (AITL).

Angioimmunoblastic T-cell lymphoma (AITL) is one of four major subtypes of nodal peripheral T cell lymphoma, characterized by its cell of origin, the follicular helper T-cell (TFH). Patients typically present with prominent constitutional (B) symptoms, generalized lymphadenopathy, hepatosplenomegaly, cytopenias, and rash. Here we present a case of a 62-year-old male with progressive cervical adenopathy, fevers and weight loss presenting with extreme polyclonal plasmacytosis and high plasma EBV viral load. While the initial presentation appeared to mimic plasma cell leukemia or severe infection, lymph node biopsy and bone marrow biopsy confirmed a diagnosis of AITL. This case highlights the heterogeneity of the clinical presentation of AITL to enable physicians to more promptly recognize, diagnose and initiate treatment

Outcomes of Medicare-age eligible NHL patients receiving RIC allogeneic transplantation: a CIBMTR analysis

The application of allogeneic hematopoietic cell transplantation (allo-HCT) in non-Hodgkin lymphoma (NHL) patients ≥65 years in the United States is limited by lack of Medicare coverage for this indication. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we report allo-HCT outcomes of NHL patients aged ≥65 years (older cohort; n = 446) compared with a cohort of younger NHL patients aged 55-64 years (n = 1183). We identified 1629 NHL patients undergoing a first reduced-intensity conditioning (RIC) or nonmyeloablative conditioning allo-HCT from 2008 to 2015 in the United States. Cord blood or haploidentical transplants were excluded. The median age was 68 years (range 65-77) for the older cohort vs 60 years (range 55-64) in the younger cohort. The 4-year adjusted probabilities of nonrelapse mortality (NRM), relapse/progression (R/P), progression-free survival (PFS), and overall survival (OS) of the younger and older groups were 24% vs 30% (P = .03), 41% vs 42% (P = .82), 37% vs 31% (P = .03), and 51% vs 46% (P = .07), respectively. Using multivariate analysis, compared with the younger group, the older cohort was associated with increased NRM, but there was no difference between the 2 cohorts in terms of R/P, PFS, or OS. The most common cause of death was disease relapse in both groups. In NHL patients eligible for allo-HCT, there was no difference in OS between the 2 cohorts. Age alone should not determine allo-HCT eligibility in NHL, and Medicare should expand allo-HCT coverage to older adults

Efficacy of checkpoint inhibition after CAR-T failure in aggressive B-cell lymphomas: outcomes from 15 US institutions

Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of patients with relapsed aggressive B-cell lymphomas after CAR-T failure. To define CPI therapy efficacy more definitively in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 US academic centers. Most patients (53%) had diffuse large B-cell lymphoma, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 vs 51 days) and OS (387 vs 131 days) were significantly longer in patients with late (>180 days) vs early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of patients treated with CPI. Most patients (83%) died, commonly because of progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of patients with aggressive B-cell lymphoma treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes

High-Grade B-cell Lymphoma, Not Otherwise Specified: A Multi-Institutional Retrospective Study

In this multi-institutional retrospective study, we examined the characteristics and outcomes of 160 patients with high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS)-a rare category defined by high-grade morphologic features and lack of MYC rearrangements with BCL2 and/or BCL6 rearrangements ( double hit ). Our results show that HGBL-NOS tumors are heterogeneous: 83% of patients had a germinal center B-cell immunophenotype, 37% a dual-expressor immunophenotype (MYC and BCL2 expression), 28% MYC rearrangement, 13% BCL2 rearrangement, and 11% BCL6 rearrangement. Most patients presented with stage IV disease, a high serum lactate dehydrogenase, and other high-risk clinical factors. Most frequent first-line regimens included dose-adjusted cyclophosphamide, doxorubicin, vincristine, and etoposide, with rituximab and prednisone (DA-EPOCH-R; 43%); rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 33%); or other intensive chemotherapy programs. We found no significant differences in the rates of complete response (CR), progression-free survival (PFS), or overall survival (OS) between these chemotherapy regimens. CR was attained by 69% of patients. PFS at 2 years was 55.2% and OS was 68.1%. In a multivariable model, the main prognostic factors for PFS and OS were poor performance status, lactate dehydrogenase \u3e3 × upper limit of normal, and a dual-expressor immunophenotype. Age \u3e60 years or presence of MYC rearrangement were not prognostic, but patients with TP53 alterations had a dismal PFS. Presence of MYC rearrangement was not predictive of better PFS in patients treated with DA-EPOCH-R vs R-CHOP. Improvements in the diagnostic criteria and therapeutic approaches beyond dose-intense chemotherapy are needed to overcome the unfavorable prognosis of patients with HGBL-NOS

Safety and efficacy of tenalisib in combination with romidepsin in patients with relapsed/refractory T-cell lymphoma: results from a phase I/II open-label multicenter study

Tenalisib, a selective phosphoinositide-3-kinase δ/γ, and salt-inducible-kinase-3 inhibitor has shown efficacy and was well-tolerated in patients with T-cell lymphoma (TCL). In vitro studies suggest a synergistic anti-tumor potential for the combination of tenalisib with the histone-deacetylase inhibitor, romidepsin. This multicenter, open-label, phase I/II study was designed to characterize the safety, efficacy and pharmacokinetics of oral tenalisib twice-daily and intravenous romidepsin administered on days 1, 8 and 15 in 28-day cycles in adults with relapsed/refractory TCL. Phase I/dose escalation determined the maximum tolerated dose (MTD)/optimal doses of tenalisib and romidepsin. The phase II/dose expansion assessed the safety and anti-tumor activity of the combination at MTD/optimal dose. Overall, 33 patients were enrolled. In dose escalation, no dose-limiting toxicity was identified. Hence, the recommended doses for dose expansion were tenalisib 800 mg twice daily orally, and romidepsin 14 mg/m2 intravenous. Overall treatment-emergent adverse events of any grade reported in >15% of patients were nausea, thrombocytopenia, increased aspartate aminotransferase, increased alanine aminotransferase, decreased appetite, neutropenia, vomiting, fatigue, anemia, dysgeusia, weight loss, diarrhea, and hypokalemia. Twenty-three patients (69.7%) had related grade ≥3 treatment-emergent adverse events. The overall objective response rate in evaluable patients was 63.0% (peripheral TCL: 75% and cutaneous TCL: 53.3%), with a complete response and partial response of 25.9% and 37.0% respectively. The median duration of response was 5.03 months. Co-administration of tenalisib and romidepsin did not significantly alter the pharmacokinetics of romidepsin. Overall, tenalisib and romidepsin combination demonstrated a favorable safety and efficacy profile supporting its further development for relapsed/refractory TCL (clinicaltrials gov. Identifier: NCT03770000)

Phase I/Ib Study of Tenalisib (RP6530), a Dual PI3K δ/γ Inhibitor in Patients with Relapsed/Refractory T-Cell Lymphoma

Tenalisib (RP6530), a dual phosphoinositide 3-kinase δ/γ inhibitor was evaluated in a phase I/Ib study for maximum tolerated dose (MTD), pharmacokinetics, and efficacy in patients with relapsed/refractory peripheral and cutaneous T-Cell Lymphoma (TCL). Histologically confirmed (TCL) patients, with ≥1 prior therapy received Tenalisib orally in a 28-day cycle in doses of 200 to 800 mg twice daily (800 mg in fasting and fed state) in escalation phase (n = 19) and 800 mg twice daily (fasting) in expansion phase (n = 39). The most frequently reported treatment emergent adverse events (TEAE) and related TEAE were fatigue (45%) and transaminase elevations (33%), respectively. Most frequently reported related Grade ≥3 TEAE was transaminase elevation (21%). Two dose-limiting toxicities occurred in the 800 mg fed cohort; hence, 800 mg fasting dose was deemed MTD. Tenalisib was absorbed rapidly with a median half-life of 2.28 h. Overall response rate in 35 evaluable patients was 45.7% (3 complete response (CR); 13 partial response (PR)) and median duration of response was 4.9 months. Responding tumors showed a marked downregulation of CD30, IL-31 and IL-32α. With an acceptable safety and promising clinical activity, Tenalisib can be a potential therapeutic option for relapsed/refractory TCL. Currently, a phase I/II combination study with romidepsin is ongoing

Epstein-Barr Virus Kinase-Targeted Therapy for Primary Central Nervous System Post-Transplant Lymphoproliferative Disorder

Abstract BACKGROUND: Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is a rare complication of solid organ transplant, with no standard therapy. Epstein-Barr virus (EBV) is ubiquitous making the virus a candidate therapeutic target. For virus targeted therapy to be effective, antiviral agents must be phosphorylated by lytic-phase kinases BXLF1 and BGLF4. We hypothesized that lytic kinases would be constitutively expressed in PCNS-PTLD and that antiviral therapy would prove an attractive therapeutic alternative to high dose methotrexate-based regimens in patients who often have impaired organ function and poor performance status. METHODS: We investigated the safety and efficacy of EBV-kinase targeted therapy with zidovudine (AZT), ganciclovir (GCV), rituximab, and dexamethasone in patients with PCNS-PTLD. Patients with biopsy-proven PCNS-PTLD following solid organ transplantation were eligible for treatment. Immune suppression was reduced in all patients prior to treatment. Induction therapy consisted of 14 days of AZT 1500 mg IV BID, GCV 5 mg/kg IV BID, dexamethasone 10 mg IV BID and rituximab 375 mg/m2 once weekly for four weeks. Maintenance antiviral therapy was initiated on day 15 with valganciclovir 450 mg and AZT 300 mg, both twice daily. Responses were evaluated by serial brain MRIs beginning 4 weeks after initiation of treatment. Brain biopsy specimens were evaluated for expression of BGLF4 and BXLF1 by in situ hybridization or immunohistochemistry. To test the hypothesis that expression of EBV kinases conferred sensitivity to antiviral therapy, 293T cells were transfected with cDNAs (or control vectors) encoding for full length BXLF1 and/or BGLF4. Transiently transfected cells were tested for expression by immunoblot and drug sensitivity to AZT/GCV was performed by MTS and flow cytometry assays. RESULTS: Twelve patients (7 M, 5 F) with a median age of 49 were treated from 1998-2014. Transplant history included kidney (N=11), pancreas (N=2), and liver (N=1). Histology data included diffuse large B-cell lymphoma (N=7) and grade III lymphomatoid granulomatosis (N=5). EBV positivity (EBER-ISH) and CD20 expression were documented in all cases. All patients completed induction therapy. Median follow-up time and median duration of maintenance therapy were 28 months (range 2 - 143). The mean progression free survival (PFS) was 33.8 months. Overall response rate (ORR) was 83.3%. Eight patients achieved a complete response (CR) within a median time of 2 months (range 0.75 – 6 months). Two patients had a partial response (PR) with an average time to response of 1.25 months. Two patients (2/12) had progressive disease (PD). Causes of death included septic shock (n=3), pulmonary embolism (n=1), and poor functional status requiring hospice (n=1). One patient had PD at the time of death. Median overall survival (OS) was 29 months (range 2 – 143 months). Grade 3-4 toxicity was primarily hematologic, including anemia (N=4), thrombocytopenia (N=2), and neutropenia (N=5). Toxicity in the maintenance phase was generally reversible with holding therapy. Three patients required discontinuation of AZT during maintenance treatment for transfusion-dependent anemia persisting after holding AZT for 7 days or neutropenia coinciding with systemic infection. One patient had AZT discontinued due to nausea and vomiting that led to acute kidney injury. Evaluation of BXLF1, BGLF4 and LMP1 was completed in 7 patients and found to be positive in all cases. LMP1 and kinase expression occurred in mutually exclusive regions of the tumor. Expression of BXLF1 and BGLF4 led to enhanced sensitization of 293T cells to antiviral-induced growth inhibition and apoptosis. CONCLUSIONS: EBV-kinase targeted therapy with AZT, GCV, rituximab and dexamethasone appears to be effective treatment for patients with EBV+ PCNS-PTLD. We demonstrated durable responses without disease recurrence and minimal toxicity. Expression of BXLF1 and BGLF4 kinases provides a mechanistic rationale for an antiviral approach to this disease and an attractive option to replace high dose chemotherapeutic regimens with less toxic targeted therapy in patients with compromised transplant organ function. A multi-center phase II trial is in development to further investigate this regimen in patients with immune deficiency-related CNS EBV-LPD. Figure 1 Figure 1. Disclosures Porcu: Infinity: Research Funding; Seattle genetics: Research Funding; Actelion: Honoraria; Celgene: Honoraria; United States Cutaneous Lymphoma Consortium: Membership on an entity's Board of Directors or advisory committees; Cutaneous Lymphoma Foundation: Membership on an entity's Board of Directors or advisory committees