Zainul Hasanali

Cyclophosphamide as a first-line therapy in LGL leukemia.

Letter to the Editor. Large granular lymphocyte (LGL) leukemia is a T or NK clonal disorder characterized by the tissue invasion of marrow, spleen and liver...

Epigenetic therapy overcomes treatment resistance in T cell prolymphocytic leukemia

Epigenetic drugs can overcome resistance to monoclonal antibodies in T-PLL and activate therapeutic targets for antibody-drug conjugates. A second chance for leukemia therapy T cell prolymphocytic leukemia (T-PLL) is a rare and aggressive type of leukemia, which is usually difficult to treat. Alemtuzumab, a monoclonal anti-CD52 antibody, is currently used to treat this disease, but patients quickly develop resistance to alemtuzumab or do not respond to it altogether. Now, Hasanali et al. show that epigenetic therapy can help overcome drug resistance in T-PLL patients. In addition, the epigenetic drugs frequently up-regulated CD30 on the surface of leukemia cells, which allowed subsequent successful treatment with brentuximab vedotin, an antibody-drug conjugate targeting CD30. The findings suggest a new treatment regimen for this challenging disease and demonstrate a potential approach to successfully combining epigenetic and immunotherapy. T cell prolymphocytic leukemia (T-PLL) is a rare, mature T cell neoplasm with distinct features and an aggressive clinical course. Early relapse and short overall survival are commonplace. Use of the monoclonal anti-CD52 antibody alemtuzumab has improved the rate of complete remission and duration of response to more than 50% and between 6 and 12 months, respectively. Despite this advance, without an allogeneic transplant, resistant relapse is inevitable. We report seven complete and one partial remission in eight patients receiving alemtuzumab and cladribine with or without a histone deacetylase inhibitor. These data show that administration of epigenetic agents can overcome alemtuzumab resistance. We also report epigenetically induced expression of the surface receptor protein CD30 in T-PLL. Subsequent treatment with the anti-CD30 antibody–drug conjugate brentuximab vedotin overcame organ-specific (skin) resistance to alemtuzumab. Our findings demonstrate activity of combination epigenetic and immunotherapy in the incurable illness T-PLL, particularly in the setting of previous alemtuzumab therapy.

Suberoylanilide hydroxamic acid (SAHA) and cladribine synergistically induce apoptosis in NK-LGL leukaemia.

Natural killer (NK) large granular lymphocyte (LGL) leukaemia features a clonal proliferation of CD3− NK cells that can be classified into either aggressive or chronic categories. The NKL cell line, derived from an aggressive Asian NK cell leukaemia, and patient samples from chronic NK‐LGL leukaemia were used in our study to probe for synergistic efficacy of the epigenetic drugs vorinostat (SAHA) and cladribine in this disease. We demonstrate that histone deacetylases (HDACs) are over‐expressed in both aggressive and chronic NK leukaemia. Administration of the HDAC inhibitor SAHA reduces class I and II HDAC expression and enhances histone acetylation in leukaemic NK cells. In vitro combination treatment with SAHA and cladribine dose‐dependently exerts synergistic cytotoxic and apoptotic effects on leukaemic NK cells. Expression profiling of apoptotic regulatory genes suggests that both compounds led to caspase‐dependent apoptosis through activation of intrinsic mitochondrial and extrinsic death receptor pathways. Collectively, these data show that combined epigenetic therapy, using HDAC and DNA methyltransferase inhibitors, may be a promising therapeutic approach for NK‐LGL leukaemia.

Vorinostat Downregulates CD30 and Decreases Brentuximab Vedotin Efficacy in Human Lymphocytes

With an increasing number of clinical trials looking at combination therapies in cancer, potential drug–drug interactions require particular attention. One such instance is the treatment of CD30+ tumors after previous vorinostat (SAHA; suberoylanilide hydroxyamic acid) failure with the anti-CD30 antibody–drug conjugate brentuximab vedotin. Using B-, T-, and natural killer (NK)–cell lines in vitro, we demonstrate that SAHA downregulates the expression of CD30 and lowers the efficacy of subsequent brentuximab vedotin treatment if baseline CD30 levels are reduced by 50% or more. Interestingly, low-dose SAHA treatment that maintained 50% or more of basal CD30 expression followed by subsequent treatment with brentuximab vedotin led to enhanced antitumor activity. The downregulation of CD30 was short lived upon SAHA removal, suggesting that allowing SAHA washout may circumvent any interactions with subsequent drug therapies. Our findings confirm the requirement of CD30 for brentuximab vedotin efficacy and suggest that combination treatment with SAHA in CD30dim tumors may decrease efficacy. Combination treatment in highly CD30+ tumors, however, increases efficacy and warrants further consideration as a new treatment paradigm. Mol Cancer Ther; 13(12); 2784–92. ©2014 AACR.

The Epigenetics of Gastrointestinal Malignancies

Gastrointestinal malignancies, including colorectal cancer (CRC), pancreatic cancer, and esophageal cancer, have been classically seen as genetic diseases, involving mutations and/or deletions in oncogenes and tumor suppressor genes. Recent evidence demonstrates that epigenetic changes coexist with these genetic changes and contribute to the malignant phenotype. This review will focus on epigenetic dysregulation in gastrointestinal malignancies involving multiple mechanisms of epigenetic control. Interactions between studied epigenetic alterations and genetic alterations are common.

Combination epigenetic and immunotherapy overcomes resistance to monoclonal antibodies in hematologic malignancies: A new therapeutic approach

We recently reported that addition of epigenetic agents could overcome resistance of leukemic cells to monoclonal antibody-mediated anti-tumor effects in T-cell prolymphocytic leukemia. We also reported that epigenetic agents could induce expression of the CD30 gene, thus providing a therapeutic target for the antibody drug conjugate brentuximab vedotin. Here we discuss these findings and their generality to treatment of other hematologic and solid malignancies.

Does IL-15 have a causative role in large granular lymphocyte leukemia?

Evaluation of: Mishra A, Liu S, Sams GH et al. Aberrant overexpression of IL-15 initiates large granular lymphocyte leukemia through chromosomal instability and DNA hypermethylation. Cancer Cell 22(5), 645-655 (2012). There is increasing evidence identifying a link between inflammation and cancer. A potent proinflammatory cytokine, IL-15, stimulates the proliferation and maintenance of both NK and T cells, and it is therefore likely that it may play a prominent role in certain hematologic malignancies. Previous studies have demonstrated that IL-15 overexpression can initiate leukemic transformation in murine models and that both NK- and T-cell malignancies can develop; the mechanism is explored in this article. The authors illustrate that IL-15 can cause chromosomal instability and DNA hypermethylation in large granular lymphocytes. These aberrations led to an aggressive acute large granular lymphocyte leukemia. Through studying the affected pathways, the authors were able to identify potential therapeutic targets and induce remission in a murine model.

Abstract LB-140: Combined epigenetic and immunotherapy produces dramatic responses in 100% of newly diagnosed mantle cell lymphoma patients.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: Mantle cell lymphoma (MCL) is an incurable disease in which there is no accepted standard of care. While dose intensive approaches are effective, we and others have shown that cladribine and rituximab (RTX) combination therapy is well tolerated and can induce durable remissions. The synergistic effect observed with the combination of cladribine, a purine analogue with known but cryptic epigenetic activity as a hypomethylating agent, and a monoclonal antibody, RTX, prompted us to add a histone deacetylase inhibitor, vorinostat (SAHA), to this combination. We describe a phase II study that uses SAHA and a unique hypomethlating agent, cladribine, that potentially can inhibit both DNA and histone methylation through SAM. In combination with RTX, dramatic durable responses are observed in newly diagnosed MCL (ORR 100%, CR rate 70%) as well as in relapsed MCL and other B cell malignancies. Objectives: The primary objective is overall response rate (ORR). Secondary objectives include progression free survival (PFS) and overall survival (OS) as well as correlative epigenetic, transcriptional and pharmacogenomic studies. Methods: Dosing is as follows: starting dose was vorinostat 400 mg po (days 1-14) combined with cladribine 5mg/m2 IV (days 1-5), and RTX 375 mg/m2 IV (weekly x 4 for cycle 1 and 1x/month) every 28 days for up to 6 cycles. Responses were evaluated after 2 and 6 cycles. The majority of complete responders have received maintenance RTX. Phase II eligibility includes relapsed NHL and previously untreated MCL. Scientific correlatives included epigenetic and gene expression assays. Results: 32 previously untreated MCL patients have been enrolled on the phase II portion of the study. 2 have not yet completed the planned 6 cycles; however, 30 patients have completed ≥ 2 cycles and are evaluable for response. The ORR is 100% (30/30) with 70% (21/30) achieving CR. Of those patients not attaining CR, 3 had blastic MCL and 2 have died, 2 have not yet completed treatment, and 1 withdrew consent after two cycles. At a median follow up of 14.7 months (.07 - 25 months) 4 patients have relapsed and 3 have died. Of the relapsing patients, two had blastic MCL. No patient achieving a CR has relapsed. The estimated PFS curve did not reach the 0.5 level. Toxicities using CTCAE 4 included neutropenia, thrombocytopenia, fatigue, anorexia, and dehydration. We found that cladribine hypomethylates DNA in vivo (6/6 pts) and inhibits histone methylation in MCL cell lines. Upregulated genes after treatment included DUSP2 (3 pts), FOXO3 (2 pts), NOXA1 (2 pts), CEBPβ (2 pts) and p53 (3 pts). Dramatic responses and CRs were also seen in fewer patients with low grade NHLs, but not in DLBCL. Conclusion: Combined epigenetic and immunotherapy (SCR) is nontoxic and effective in the treatment of newly diagnosed mantle cell lymphoma. This therapeutic approach potentially has broader applications in other malignancies. Citation Format: Zainul Hasanali, Kamal Sharma, Stephen Spurgeon, Craig Okada, August Stuart, Sara Shimko, Violetta Leshchenko, Samir Parekh, Yiyi Chen, Mark Kirschbaum, Elliot M. Epner. Combined epigenetic and immunotherapy produces dramatic responses in 100% of newly diagnosed mantle cell lymphoma patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-140. doi:10.1158/1538-7445.AM2013-LB-140