New strategies in peripheral T-cell lymphoma: understanding tumor biology and developing novel therapies

Antagonism of inhibitors of apoptosis proteins reveals a novel, immune response-based therapeutic approach for T-cell lymphoma

Tolinapant (ASTX660) is a potent, nonpeptidomimetic antagonist of cellular inhibitor of apoptosis proteins 1 and 2 (cIAP1/2) and X-linked IAP, which is currently being evaluated in a phase 2 study in T-cell lymphoma (TCL) patients. Tolinapant has demonstrated evidence of single-agent clinical activity in relapsed/refractory peripheral TCL and cutaneous TCL. To investigate the mechanism of action underlying the single-agent activity observed in the clinic, we have used a comprehensive translational approach integrating in vitro and in vivo models of TCL confirmed by data from human tumor biopsies. Here, we show that tolinapant acts as an efficacious immunomodulatory molecule capable of inducing complete tumor regression in a syngeneic model of TCL exclusively in the presence of an intact immune system. These findings were confirmed in samples from our ongoing clinical study showing that tolinapant treatment can induce changes in gene expression and cytokine profile consistent with immune modulation. Mechanistically, we show that tolinapant can activate both the adaptive and the innate arms of the immune system through the induction of immunogenic forms of cell death. In summary, we describe a novel role for IAP antagonists as immunomodulatory molecules capable of promoting a robust antitumor immune response in TCL.

Identification of Hub Genes and Key Pathways Associated with Peripheral T-cell Lymphoma

Peripheral T-cell lymphoma (PTCL) is a very aggressive and heterogeneous hematological malignancy and has no effective targeted therapy. The molecular pathogenesis of PTCL remains unknown. In this study, we chose the gene expression profile of GSE6338 from the Gene Expression Omnibus (GEO) database to identify hub genes and key pathways and explore possible molecular pathogenesis of PTCL by bioinformatic analysis. Differentially expressed genes (DEGs) between PTCL and normal T cells were selected using GEO2R tool. Gene ontology (GO) analysis and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis were performed using Database for Annotation, Visualization and Integrated Discovery (DAVID). Moreover, the Search Tool for the Retrieval of Interacting Genes (STRING) and Molecular Complex Detection (MCODE) were utilized to construct protein-protein interaction (PPI) network and perform module analysis of these DEGs. A total of 518 DEGs were identified, including 413 down-regulated and 105 up-regulated genes. The down-regulated genes were enriched in osteoclast differentiation, Chagas disease and mitogen-activated protein kinase (MAPK) signaling pathway. The up-regulated genes were mainly associated with extracellular matrix (ECM)-receptor interaction, focal adhesion and pertussis. Four important modules were detected from the PPI network by using MCODE software. Fifteen hub genes with a high degree of connectivity were selected. Our study identified DEGs, hub genes and pathways associated with PTCL by bioinformatic analysis. Results provide a basis for further study on the pathogenesis of PTCL.

Outcomes of GDPT (gemcitabine, cisplatin, prednisone, thalidomide) versus CHOP in newly diagnosed peripheral T-cell lymphoma patients

AIM

To compare the outcomes of GDPT [gemcitabine (G), cisplatin (D), prednisone (P), thalidomide (T)] versus CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) in treating newly diagnosed PTCL (peripheral T-cell lymphoma).

METHODS

An open-label prospective clinical trial with 153 newly diagnosed PTCL patients conducted between January 2010 and December 2018 was designed. Patients were randomly assigned to the GDPT (77 cases) and CHOP (76 cases) groups. Patients in each group were further divided into four subgroups: PTCL, not otherwise specified (PTCL-NOS); anaplastic large cell lymphoma (ALCL), angioimmunoblastic T cell lymphoma (AITL), and other types subgroup, in accordance with pathological patterns. Based on expression of RRM1, TOP2A, TUBB3, and ERCC1, patients were divided into groups with high and low gene expression levels. Clinical characteristics, side effects, efficacy, progression-free survival (PFS), and overall survival (OS) were compared.

RESULTS

There were no significant differences in the basic clinical features or side effects between the GDPT and CHOP groups. The overall response rate (ORR) of the GDPT group was better than that of the CHOP group (66.3% versus 50.0%, p = 0.042), as was the complete remission (CR) rate (42.9% versus 27.6%, p = 0.049). Patients in the GDPT group had a longer PFS and OS than the CHOP group. The 4-year PFS and OS rates in the GDPT group were both superior to those in the CHOP group (63.6% versus 53.0% for PFS, p = 0.035; 66.8% versus 53.6% for OS, p = 0.039). In the GDPT group, the difference in CR between the four subgroups was statistically significant (p = 0.046). In the CHOP group, differences in both CR and ORR among the four subgroups were statistically significant (p < 0.001 and p = 0.005, respectively). There were also statistically significant differences in CR between patients treated with CHOP and GDPT in the PTCL-NOS subgroup, AITL subgroup, and the other types subgroup (p = 0.015; p = 0.003; p = 0.005, respectively). The data also showed a significant difference in OS among the four subgroups within the GDPT group (p = 0.001). The OS of AITL was shorter than that of the other three subgroups. Four subgroups of CHOP showed a significant difference in PFS (p = 0.019). There was no statistical association between responses and the gene expression levels of RRM1, ERCC1, TUBB3, and TOP2A.

CONCLUSION

The GDPT group had better response rates and prolonged patient PFS and OS. As a promising new regimen, GDPT is expected to become the first-line therapy for PTCL. New agents should be applied to patients who do not achieve good responses with previous treatment, such as those diagnosed with angioimmunoblastic T cell lymphoma.

TRIAL REGISTRATION

This open randomized prospective clinical trial was registered at ClinicalTrials.gov (NCT01664975).

The efficacy and safety of gemcitabine, cisplatin, prednisone, thalidomide versus CHOP in patients with newly diagnosed peripheral T-cell lymphoma with analysis of biomarkers

We compared the efficacy and safety of gemcitabine, cisplatin, prednisone and thalidomide (GDPT) with standard CHOP regimen (cyclophosphamide, doxorubicin, vincristine, prednisone) for patients with newly diagnosed peripheral T-cell lymphoma (PTCL) in a prospective randomized controlled and open-label clinical trial. Between July 2010 and June 2016, 103 patients were randomly allocated into two groups, of whom 52 were treated with GDPT therapy and 51 with CHOP therapy. The 2-year progression-free survival (PFS) and overall survival (OS) rates were better in the GDPT group than in the CHOP group (57% vs. 35% for 2-year PFS, P = 0·0035; 71% vs 50% for 2-year OS, P = 0·0001). The complete remission rate (CRR) and the overall response rate (ORR) in the GDPT group were higher than in the CHOP group (52% vs. 33%, P = 0·044 for CRR; 67% vs. 49%, P = 0·046 for ORR). Haemocytopenia was the predominant adverse effect, and acute toxicity was moderate, tolerable and well managed in both arms. mRNA expression of ERCC1, RRM1, TUBB3 and TOP2A genes varied among patients but the difference did not reach statistical significance, mainly due to the relatively small sample size. The precise characters of these biomarkers remain to be identified. In conclusion, GDPT is a promising new regimen as potential first-line therapy against PTCL. This study was registered at www.clinicaltrials.gov as #NCT01664975.

Putting the clinical and biological heterogeneity of non-hodgkin lymphoma into context

The lymphomas represent one of the most heterogeneous groups of malignancies in all of cancer medicine. Whether one attempts to understand these diseases in the context of their complicated ontogeny, unique biologic features, or clinical presentation, this heterogeneity has been a mixed blessing. On the one hand, it has created an ever-changing way to classify these diseases, as classification schemes have been compelled to reflect the rapidly emerging information that seems to split the disease into smaller and smaller subtypes. On the other hand, the biologic and clinical dissection of these diseases has allowed for the identification of unique biologic features-features that have led to novel targets and generated a plethora of new drugs. Virtually every subtype of non-Hodgkin lymphoma has benefited from these efforts to understand the biology of the different subtypes. This paradigm has led to new clinical trials that tailor novel drug regimens to specific biologic disease subtypes. As a prelude to this CCR Focus section, we attempt to put this evolving heterogeneity into context, bridging historical and modern-day views of classification of these diseases. Then, some of the world's leading lymphoma researchers share their perspectives on how to formulate new concepts of care in this era of biologic discovery. Over a relatively short time, the advances in lymphoma research have been nothing short of stunning. There now seems to be little doubt that these recent breakthroughs will redound favorably on the majority of patients diagnosed with a lymphoproliferative malignancy. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

PIM kinases as potential therapeutic targets in a subset of peripheral T cell lymphoma cases

Currently, there is no efficient therapy for patients with peripheral T cell lymphoma (PTCL). The Proviral Integration site of Moloney murine leukemia virus (PIM) kinases are important mediators of cell survival. We aimed to determine the therapeutic value of PIM kinases because they are overexpressed in PTCL patients, T cell lines and primary tumoral T cells. PIM kinases were inhibited genetically (using small interfering and short hairpin RNAs) and pharmacologically (mainly with the pan-PIM inhibitor (PIMi) ETP-39010) in a panel of 8 PTCL cell lines. Effects on cell viability, apoptosis, cell cycle, key proteins and gene expression were evaluated. Individual inhibition of each of the PIM genes did not affect PTCL cell survival, partially because of a compensatory mechanism among the three PIM genes. In contrast, pharmacological inhibition of all PIM kinases strongly induced apoptosis in all PTCL cell lines, without cell cycle arrest, in part through the induction of DNA damage. Therefore, pan-PIMi synergized with Cisplatin. Importantly, pharmacological inhibition of PIM reduced primary tumoral T cell viability without affecting normal T cells ex vivo. Since anaplastic large cell lymphoma (ALK+ ALCL) cell lines were the most sensitive to the pan-PIMi, we tested the simultaneous inhibition of ALK and PIM kinases and found a strong synergistic effect in ALK+ ALCL cell lines. Our findings suggest that PIM kinase inhibition could be of therapeutic value in a subset of PTCL, especially when combined with ALK inhibitors, and might be clinically beneficial in ALK+ ALCL.

Mogamulizumab and the treatment of CCR4-positive T-cell lymphomas

Glyco-engineering has been developed to enhance the pharmacological properties of monoclonal antibodies (mAbs) resulting in superior immune effector function. Mogamulizumab is the first approved glyco-engineered therapeutic antibody and first approved mAb to target the CC chemokine receptor 4 (CCR4). CCR4 is principally expressed on Tregs and helper T cells (Th) where it functions to induce homing of these leukocytes to sites of inflammation. Tregs play an essential role in maintaining immune balance; however, in malignancy, Tregs impair host antitumor immunity and provide a favorable environment for tumors to grow. CCR4 is highly expressed by aggressive peripheral T-cell lymphomas (PTCLs), particularly adult T-cell leukemia/lymphoma (ATL) and cutaneous T-cell lymphomas (CTCLs). Mogamulizumab is a humanized anti-CCR4 mAb with a defucosylated Fc region that enhances antibody-dependent cellular cytotoxicity (ADCC). In addition, mogamulizumab depletes CCR4+ Tregs, potentially evoking antitumor immune responses by autologous effector cells. This ability is highly pertinent as subsets of malignant T cells are believed to function as CD4+ Tregs, overexpressing CCR4. Clinical trials with mogamulizumab have demonstrated clinical efficacy and tolerability for the treatment of relapsed/refractory aggressive T-cell lymphomas, previously associated with very poor outcomes.

Myasthenic Crisis Manifesting as Postoperative Respiratory Failure following Resection of Unsuspected Intrathoracic Thymic T-Cell Lymphoma during Thyroidectomy for an Adjacent Large Retrosternal Goiter

A middle-aged female with a goiter of 10 years' duration presented with progressive pressure symptoms, nocturnal choking and dyspnea on exertion for 5 months. Physical examination demonstrated a large simple multinodular goiter. Imaging revealed a deep retrosternal goiter extending below the tracheal bifurcation with marked tracheal deviation. Total thyroidectomy was carried out via a cervical approach and a median sternotomy. Extubation was not possible, and the patient had to be kept intubated. She then went into a myasthenic crisis. Initial ventilatory support was followed by intravenous immunoglobulin, steroids and pyridostigmine. The patient had complete remission and was asymptomatic 18 months later. Histopathology showed a T-cell-rich thymoma in addition to a nodular colloid goiter.

Brentuximab vedotin: a review of its use in patients with hodgkin lymphoma and systemic anaplastic large cell lymphoma following previous treatment failure

Brentuximab vedotin (ADCETRIS(®)) is an antibody-drug conjugate that is specifically targeted against CD30-positive cancer cells such as those in Hodgkin lymphoma or systemic anaplastic large cell lymphoma (ALCL). Intravenous brentuximab vedotin was associated with an overall objective response rate (primary endpoint) of 75 % in 102 patients with Hodgkin lymphoma who had relapsed after high-dose chemotherapy and autologous haematopoietic stem cell transplantation, in a noncomparative, multicentre, phase II trial. In 58 patients with relapsed systemic ALCL after at least one prior treatment, intravenous brentuximab vedotin was associated with an overall objective response rate (primary endpoint) of 86 % in a noncomparative, multicentre, phase II trial. Tumour reductions were observed in 94 % of patients with Hodgkin lymphoma and 97 % of patients with systemic ALCL, and most tumours decreased in size by >65 % and >85 %, respectively. The estimated 12-month survival rates were 89 % and 52 %, respectively. Brentuximab vedotin was generally well tolerated in these trials. The most common adverse event was peripheral neuropathy; approximately one-half of patients with this adverse event experienced complete resolution.

NK/T-cell lymphomas in children

In children, T and NK-cell lymphomas are uncommon in Western Countries. While there has been significant experience treating T-cell lymphoblastic lymphoma (T-LBL) and anaplastic large cell lymphoma (ALCL), other subtypes are very rarely encountered and there are no standard approaches to their management. There are many challenges in defining optimal therapy for many of these diseases but recent progress in elucidating their biology has led to new molecular insights and identified interesting targets for novel drug discovery. In this review, we discuss these disorders in children, how they are approached therapeutically and what lies on the horizon with respect to novel treatment approaches.

Alisertib (MLN8237) an investigational agent suppresses Aurora A and B activity, inhibits proliferation, promotes endo-reduplication and induces apoptosis in T-NHL cell lines supporting its importance in PTCL treatment

Peripheral T-cell lymphomas (PTCL) are a diverse group of rare non-Hodgkin lymphomas (NHL) that carry a poor prognosis and are in need of effective therapies. Alisertib (MLN8237) an investigational agent that inhibits Aurora A Ser/Thr kinase has shown activity in PTCL patients. Here we demonstrate that aurora A and B are highly expressed in T-cell lymphoma cell lines. In PTCL patient samples aurora A was positive in 3 of 24 samples and co-expressed with aurora B. Aurora B was positive in tumor cells in 22 of 32 samples. Of the subtypes of PTCL, aurora B was over-expressed in PTCL (NOS) [73%], T-NHL [100%], ALCL (Alk-Neg) [100%] and AITL [100%]. Treatment with MLN8237 inhibited PTCL cell proliferation in CRL-2396 and TIB-48 cells with an IC50 of 80-100nM. MLN8237 induced endo-reduplication in a dose and time dependent manner in PTCL cell lines leading to apoptosis demonstrated by flow cytometry and PARP-cleavage at concentrations achieved in early phase clinical trials. Moreover, inhibition of HisH3 and aurora A phosphorylation was dose dependent and strongly correlated with endo-reduplication. The data provide a sound rationale for aurora inhibition in PTCL as a therapeutic modality and warrants clinical trial evaluation.

Simultaneous inhibition of pan-phosphatidylinositol-3-kinases and MEK as a potential therapeutic strategy in peripheral T-cell lymphomas

Peripheral T-cell lymphomas are very aggressive hematologic malignancies for which there is no targeted therapy. New, rational approaches are necessary to improve the very poor outcome in these patients. Phosphatidylinositol-3-kinase is one of the most important pathways in cell survival and proliferation. We hypothesized that phosphatidylinositol-3-kinase inhibitors could be rationally selected drugs for treating peripheral T-cell lymphomas. Several phosphatidylinositol-3-kinase isoforms were inhibited genetically (using small interfering RNA) and pharmacologically (with CAL-101 and GDC-0941 compounds) in a panel of six peripheral and cutaneous T-cell lymphoma cell lines. Cell viability was measured by intracellular ATP content; apoptosis and cell cycle changes were checked by flow cytometry. Pharmacodynamic biomarkers were assessed by western blot. The PIK3CD gene, which encodes the δ isoform of phosphatidylinositol-3-kinase, was overexpressed in cell lines and primary samples, and correlated with survival pathways. However, neither genetic nor specific pharmacological inhibition of phosphatidylinositol-3-kinase δ affected cell survival. In contrast, the pan-phosphatidylinositol-3-kinase inhibitor GDC-0941 arrested all T-cell lymphoma cell lines in the G1 phase and induced apoptosis in a subset of them. We identified phospho-GSK3β and phospho-p70S6K as potential biomarkers of phosphatidylinositol-3-kinase inhibitors. Interestingly, an increase in ERK phosphorylation was observed in some GDC -0941-treated T-cell lymphoma cell lines, suggesting the presence of a combination of phosphatidylinositol-3-kinase and MEK inhibitors. A highly synergistic effect was found between the two inhibitors, with the combination enhancing cell cycle arrest at G0/G1 in all T-cell lymphoma cell lines, and reducing cell viability in primary tumor T cells ex vivo. These results suggest that the combined treatment of pan-phosphatidylinositol-3-kinase + MEK inhibitors could be more effective than single phosphatidylinositol-3-kinase inhibitor treatment, and therefore, that this combination could be of therapeutic value for treating peripheral and cutaneous T-cell lymphomas.

T-cell receptor diversity prevents T-cell lymphoma development

Mature T-cell lymphomas (MTCLs) have an extremely poor prognosis and are much less frequent than immature T-cell leukemias. This suggests that malignant outgrowth of mature T lymphocytes is well controlled. Indeed, in a previous study we found that mature T cells are resistant to transformation with known T-cell oncogenes. Here, however, we observed that T-cell receptor (TCR) mono-/oligoclonal mature T cells from TCR transgenic (tg) mice (OT-I, P14) expressing the oncogenes NPM/ALK or ΔTrkA readily developed MTCLs in T-cell-deficient recipients. Analysis of cell surface markers largely ruled out that TCR tg lymphomas were derived from T-cell precursors. Furthermore, cotransplanted non-modified TCR polyclonal T cells suppressed malignant outgrowth of oncogene expressing TCR tg T lymphocytes. A dominant role of an anti-leukemic immune response or Tregs in the control of MTCLs seems unlikely as naïve T cells derived from oncogene expressing stem cells, which should be tolerant to leukemic antigens, as well as purified CD4 and CD8 were resistant to transformation. However, our results are in line with a model in which homeostatic mechanisms that stabilize the diversity of the normal T-cell repertoire, for example, clonal competition, also control the outgrowth of potentially malignant T-cell clones. This study introduces a new innate mechanism of lymphoma control.

Efficacy and safety of the third-generation chloroethylnitrosourea fotemustine for the treatment of chemorefractory T-cell lymphomas

Patients with recurring T-cell non-Hodgkin lymphoma (T-NHL) are incurable and candidate for investigational agents. Here, we report on five patients with T-NHL refractory to multiple chemotherapy lines, including in all cases alkylators and gemcitabine, who received the third-generation chloroethylnitrosourea fotemustine at a dose of 120 mg/m(2) every 21 d, up to eight courses. Median actual dose intensity was 79%; toxicity was manageable and mainly hematological. One complete remission, one partial remission, two protracted disease stabilization, and one transient, minor response were achieved. Time to progression ranged from 48 to 240+ d. This is the first evidence ever reporting the activity of fotemustine in end-stage T-NHL. Formal studies with this agent are warranted in T-cell malignancies.