Activity In Peripheral T-cell Lymphomas Research Articles

Abstract PO-031: Systematic discovery of chemotherapy response biomarkers in Peripheral T Cell Lymphomas

Abstract Background. Identifying which patients will benefit from individual therapies remains a general challenge in oncology. Predictive biomarkers of drug sensitivity, when known, can increase the rate of success of trials, and allow stratification of patients for targeted combination therapies, as recent shown by the GUIDANCE-01 trial in Large B-Cell Lymphoma. Peripheral T-Cell Lymphomas (PTCL) could particularly benefit from this approach, being heterogeneous diseases against which many therapies are active in unpredictable subsets of patients. A central challenge of biomarker discovery is finding true determinants of drug response, which may be multiple genes, among thousands of molecular features that may accidentally correlate. Here, we aim to mitigate this challenge by combining functional genetic screens and gene expression profiling in diverse PTCL cultures, to enable the systematic discovery of drug sensitivity biomarkers. Methods. To discover genes whose expression directly modifies drug sensitivity, we conducted genome-wide CRISPR screens with PTCL cells under treatment with five therapies with clinical activity in PTCL: Romidepsin, Pralatrexate, Gemcitabine, Oxaliplatin, and Bortezomib. To discover genes whose basal expression significantly correlates with specific drug sensitivities, we measured RNAseq and drug response functions for a diverse panel of 27 PTCL cultures. Genes in the intersection of both experiments are causally related to and correlate with drug responses in PTCL, and have the statistical benefit of detection by independent methods. Results. Functional genetic screens on therapy provided mechanistic insights for each drug of interest, and identified genes whose perturbation affects drug sensitivity. Whereas hundreds of genes nominally correlate with drug sensitivity in cell line panels, for each drug a shortlist of only 5 to 20 genes are both CRISPR hits and correlate with response across PTCL cultures. For each drug tested, multi-gene sensitivity scores constructed from hits stratify PTCL cultures into statistically distinct sensitive and non-sensitive subgroups (Mann Whitney P-Values <0.01). These genes’ relationships to drug mechanisms were often supported by prior studies, including functions in DNA repair, cell cycle regulation, and solute carriers required for cellular entry of specific therapies, such as SLC19A1 for Pralatrexate and SLC43A2 for Oxaliplatin. Conclusions. Combining functional genetic screens and correlative drug sensitivity measurements narrowed the search for predictive biomarkers of drug sensitivity, and may be a general means of refining biomarker hypotheses for validation in clinical datasets. Although chemotherapy sensitivity is commonly polygenic, multi-gene scores based on few mechanistically-related genes were able to significantly distinguish drug sensitive from resistant PTCLs. These approaches provide novel hypotheses for drug-gene relationships that may serve as the basis for molecular subtyping of individual lymphomas for precision regimens. Citation Format: Adam C Palmer, Jacob C Pantazis. Systematic discovery of chemotherapy response biomarkers in Peripheral T Cell Lymphomas [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-031.

Abstract A072: Preliminary results of ASTX660, a novel non-peptidomimetic cIAP1/2 and XIAP antagonist, in 107 patients with solid tumors or lymphoma

Abstract Background: ASTX660 is an oral, novel nonpeptidomimetic, small-molecule antagonist of cellular/X-linked inhibitors of apoptosis proteins (cIAP1/2 and XIAP). ASTX660 is currently being evaluated in a first-in-human phase 1–2 study in patients (pts) with advanced solid tumors or lymphoma (ClinicalTrials.gov NCT02503423). In the ongoing phase 2, ASTX660 has demonstrated preliminary evidence of clinical activity in the relapsed/refractory peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL) cohorts (Mehta et al, presented at the EHA Conference 2019, abs PS1073). Here, we report overall efficacy and safety data from the solid tumors (head and neck squamous cell carcinoma [HNSCC]; cervical carcinoma and other solid tumors) and lymphoma (diffuse large B-cell lymphoma [DLBCL], PTCL, CTCL,) phase 2 cohorts. Methods: Pts received treatment with ASTX660 orally at the RP2D 180mg/day on days 1 to 7, and 15 to 22 in a 28-day cycle. In the first stage 14 evaluable pts were enrolled in each of the 6 phase 2 cohorts with the option to expand the cohort if activity was observed. The primary endpoint was response rate as assessed by the investigator according to the Lugano criteria (DLBCL and PTCL), Global Assessment (CTCL), or RECIST 1.1 (solid tumors). Adverse events (AEs) were assessed per CTCAE V4.03. Results: As of June 4, 2019, a total of 107 pts have received ASTX660 in the solid tumors and lymphoma phase 2 cohorts (HNSCC n=14; DLBCL n=16; PTCL n=26; CTCL n=23; cervical carcinoma n=14; other solid tumors n= 14). Median age (range) was 61 (23-84) years and median number (range) of prior anticancer regimens was 3 (0-12). Among all pts, the most common related AEs of any grade (≥ 10%) were rash (35%), lipase elevation (34%), amylase elevation (29%), diarrhea (14%), fatigue (14%), AST elevation (13%), nausea (13%), and anemia (11%). Related AEs ≥ Grade 3 occurring in ≥ 5% of pts were rash (18%), lipase elevation (16%) and amylase elevation (9%). As of 4 June 2019, 86 pts (80%) discontinued study treatment: 64 (60%) due to progressive disease, 13 (12%) due to AE, 4 (4%) due to death, 4 (4%) due to withdrawal by participant and 1 (1%) for investigator’s decision. At the time of analysis, the ORR was 36% in the PTCL cohort and 15% in the CTCL cohort. One PR was reported in a pt with metastatic melanoma after 12 cycles of treatment. No objective responses were reported in the HNSCC, DLBCL or cervical cohorts. Accrual in the PTCL and CTCL continues; updated efficacy and safety data will be presented at the meeting. Conclusion: In the phase 2 part of the study ASTX660 monotherapy has demonstrated a manageable safety profile and encouraging activity in PTCL and CTCL warranting cohort expansion. Future plans include evaluation of ASXT660 both as mono- or combination therapy in selected malignancies. Citation Format: Antoine Hollebecque, Sarit Assouline, Felipe Samaniego, Benoit You, Francine Foss, Anca Prica, Sarah W. Gordon, Marc Webster, Martin JS. Dyer, Dima El-Sharkawi, Geoffrey I. Shapiro, Lisa Nabell, Sarah P. Blagden, John Lister, Susanna V. Ulahannan, Yijun Sun, Danna Chan, Roberta Ferraldeschi, Monica Mita. Preliminary results of ASTX660, a novel non-peptidomimetic cIAP1/2 and XIAP antagonist, in 107 patients with solid tumors or lymphoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A072. doi:10.1158/1535-7163.TARG-19-A072

A Phase 2 Study of the Dual SYK/JAK Inhibitor Cerdulatinib Demonstrates Good Tolerability and Clinical Response in Relapsed/Refractory Peripheral T-Cell Lymphoma and Cutaneous T-Cell Lymphoma

A Phase 2 Study of the Dual SYK/JAK Inhibitor Cerdulatinib Demonstrates Good Tolerability and Clinical Response in Relapsed/Refractory Peripheral T-Cell Lymphoma and Cutaneous T-Cell Lymphoma

PS1311 PI3K‐INHIBITION INCREASES APOPTOTIC PRIMING IN T‐CELL LYMPHOMAS AND SYNERGIZES WITH BH3 MIMETICS.

Background:Peripheral T‐cell lymphomas (PTCL) are a heterogeneous group of lymphoid malignancies that are highly underserved by current therapeutic regimens and still associated with poor outcomes. Recently, inhibition of the phosphatidylinositol‐3 kinase (PI3K) emerged as a promising therapeutic strategy for patients with T‐cell lymphomas. As a single agent, the PI3K inhibitor duvelisib showed a response rate of 50% in patients with PTCL1. However, complete responses were seen in less than 20% of the patients and in vitro‐analyses revealed broad cytostatic but limited cytotoxic activity through induction of apoptosis.Aims:Thus, to maximize the efficacy of PI3K inhibitors, further mechanistic insight in the regulation of apoptosis is needed to develop rational combination strategies.Methods:We utilized a previously characterized set of T‐cell lymphoma cell lines2 and assessed the cytotoxic activity of various isoform‐specific PI3K inhibitors, including the PI3K gamma‐delta inhibitor duvelisib and the pan‐PI3K inhibitor copanlisib. Next, we performed dynamic BH3 profiling to functionally dissect the impact of PI3K inhibitors on the regulation of mitochondrial apoptosis. To further address the underlying mechanism, we performed immunoblotting and Co‐IP experiments. Ultimately, we performed in‐vitro combination testing of PI3K inhibitors and BH3‐mimetics as suggested by dynamic BH3‐profiling.Results:The PI3K inhibitors duvelisib and copanlisib induced apoptosis in only a subset of PTCL cell lines. However, dynamic BH3 profiling revealed a broad and rapid enhancement of apoptotic priming in all tested cell lines (n = 9), as assessed by stimulation with the pro‐apoptotic BIM‐peptide. Furthermore, dynamic BH3‐profiling revealed increased susceptibility to blockade of anti‐apoptotic proteins, predominantly MCL1. Importantly, PI3K inhibitors enhanced the baseline dependence on specific anti‐apoptotic BCL2‐family members as recently identified by BH3 profiling3. Mechanistically, immunoblotting of pro‐ and anti‐apoptotic BCL2‐family members showed an upregulation of various pro‐apoptotic proteins. Protein levels of anti‐apoptotic BCL2 and BCL‐xL were affected heterogeneously with downregulation of either protein in 4 of 6 cell lines. In contrast, protein levels of MCL1 were maintained in all tested cell lines. Co‐IP experiments confirmed enhanced availability of the pro‐apoptotic BIM protein, but also retained binding to the anti‐apoptotic protein MCL1. Based on these data, we performed a combination testing of the PI3K inhibitors duvelisib and copanlisib with the BH3 mimetics ABT‐263 (targeting BCL‐2 and BCL‐xL) and AZD5991 (targeting MCL1). Induction of cell death by single agents and combinations was assess by flow cytometry. As predicted by dynamic BH3 profiling, we saw broad synergistic activity of PI3K inhibitors with BH3 mimetics, particularly the MCL1 inhibitor AZD5991 in 8 of 9 tested cell lines.Summary/Conclusion:Despite their limited single‐agent activity in PTCL, PI3K inhibitors induce a broad increase in apoptotic priming of PTCLs and their dependence on anti‐apoptotic BCL2‐family members. While this increase in apoptotic priming does not suffice to induce apoptosis in most cases, it reasons for a combination strategy with BH3 mimetics. Indeed, we found broad synergistic activity of PI3K‐inhibitors and BH3‐mimetics, particularly the MCL1 inhibitor AZD5991.

Synergistic antitumor effect of histone deacetylase inhibitor and Doxorubicin in peripheral T-cell lymphoma

Chidamide (CS055) is a new and highly selective histone deacetylase inhibitor displaying significant single-agent activity in peripheral T-cell lymphoma (PTCL). But there is little known the synergistic effect between CS055 and chemotherapy. The purpose of this study is to explore the synergistic effect and molecular mechanisms of CS055 combination with Doxorubicin in PTCL cells. We found that CS055 showed dose- and time-dependent inhibition effects on PTCL cell. Meanwhile, the synergistic effect was significantly observed after combination treatment with lower drug-concentration of CS055 and Doxorubicin. Lower drug-concentration of CS055 induced weak apoptosis in PTCL cells, but combination treatment with CS055 and Doxorubicin promoted more significant apoptosis. Combination treatment with CS055 and Doxorubicin significantly changed mitochondrial membrane potential and H3 acetylated level, resulting in up-regulating DNA damage protein p-γH2AX and apoptosis proteins including cleaved-caspase-3, cleaved-caspase-9 and cleaved-PARP, and down-regulating anti-apoptosis protein Bcl-2. In a word, Doxorubicin could increase the CS055-induced inhibition effects on PTCL cells, suggesting that CS055 combination with Doxorubicin or Doxorubicin-based chemotherapy drugs might be a new therapy approach for PTCL patients.

Efficacy of Brentuximab-Vedotin (BV) in Peripheral T-Cell Lymphomas (PTCLs) Other Than Anaplastic Large Cell Lymphoma (ALCL)

Background. BV, an anti-CD30 antibody-drug conjugate, has been approved for the treatment of Hodgkin lymphoma (HL) and ALCL. Of interest, BV has shown activity in PTCLs other than ALCL that express low or even undetectable levels of CD30. In particular BV has been reported effective in angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma not otherwise specified (PTCL-nos). Here, we report 4 cases with relapsed/resistant PTCLs (1 AITL, 1 NK-T nasal type, 1 PTCL with T-helper follicular phenotype-PTCL-TFH and 1 PTCL-nos) who responded to BV therapy.Results. On August 2014, a 53-y-old caucasian male was diagnosed with 5% CD30-positive AITL. The final stage was IIIA, because of a single left axillar node was documented at the PET-TC scan in addition to the excised inguinal lymphadenopathy. A complete metabolic PET remission (PET-CR) was documented after the 3th and confirmed after the 6th cycle of cyclophosphamide, doxorubicin, vincristine, etoposide and prednisone (CHOEP). However, relapsing disease was documented 6 mths later. At that time, diffuse over and under-diaphragm nodal involvement was observed. A PET-CR was achieved after 2 cycles of dexamethasone, cytarabine, and cisplatin (DHAP), but disease progressed shortly after the 4th cycle before the planned autotransplantation (ASCT). A 3th line chemotherapy, consisting of mitoxantrone and high dose ARA-C (modified HAM), was performed and failed to control the disease. Furthermore HAM chemotherapy was associated with severe infectious complications (sepsis from MDR S. Epidermidis and pulmonary aspergillosis). On December 2015, BV was begun. A PET-CR was documented after the 4th and confirmed after the 8th cycle of therapy. The patients is still in CR, in continuous therapy (12th cycle), waiting for HLA matched unrelated donor.On July 2012 a 62-y-old caucasian man was diagnosed with extranodal NK/T-cell nasal type lymphoma. Both Epstein Barr virus (EBV) and CD30 molecule were not expressed by neoplastic cells. Weekly cisplatin and radiotherapy were concomitantly given followed by 3 cycles of etoposide, ifosfamide, cisplatin and dexamethasone. This treatment resulted in PET-CR. At the time of first relapse (Nov 2013), 3 cycles of methotrexate, L-asparaginase and dexamethasone, followed by ASCT (fotemustine, etoposide, cytarabine, melphalan), induced a 2nd PET-CR. However, two subsequent PET evaluations suggested the presence of active disease shortly after (December 2015) a biopsy proven relapse was documented. A PET-CR was observed after 2 and confirmed after 7 cycles of single agent BV. The patient is still undergoing treatment.On September 2015, a 49-y-old african man was diagnosed with PTCL-THF, showing AITL signs, with both EBV and CD30 positive (50-75%) Hodgkin/Reed-Sternberg cells. A progressive disease was documented after the 4th cycle of CHOEP. At that time, patient was not candidate to receive further chemotherapy, because of worsening of perfomance status (PS). BV, given as salvage therapy, resulted in a rapid control of all signs and symptoms after the 6th administration. Because of improved PS and a partial metabolic remission, the DHAP combination was begun on June 2016 and ASCT is now planned as consolidation.On November 2009, a 46-y-old caucasian man was diagnosed with classical HL. The final stage was IEA. The disease was refractory to doxorubicin, bleomycin, vinblastine, dacarbazine and radiotherapy. A PET-CR was achieved in response to ifosfamide, gemcitabine, vinorelbine and prednisone chemotherapy. After 3 yrs, a lymph node biopsy confirmed a relapsed HL. Four cycles of DHAP followed by ASCT resulted in a 2nd PET-CR. After 3 mths, a PTCL-NOS associated with blastic lymphoid B EBV positive cells was diagnosed on an excisional lymph node biopsy. On May 2014 BV as single-agent was started. A PET-CR lasted for 8 mths. Relapsing disease was documented on January 2015. The patient refused further chemotherapy and died because of disease progression on July 2015.Conclusion. In this experience BV, regardless of CD30 expression, has shown significant clinical activity in recurrent or refractory T-cell lymphomas and no significant toxicity, even in heavily pretreated patients. In consideration of the BV activity in PTCLs, combination studies with other molecules, such as romidepsine, are desirable. DisclosuresNo relevant conflicts of interest to declare.

Denileukin Diftitox (Ontak) as Maintenance Therapy for Peripheral T-Cell Lymphomas: Three Cases with Sustained Remission.

Peripheral T-cell lymphomas (PTCL) are rare but markedly aggressive forms of non-Hodgkin's lymphoma (NHL). They carry a poor prognosis, with current therapeutic approach being generally ineffective. The most employed first-line treatment is CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone), which still results in high rates of relapses. Denileukin diftitox is a fusion protein combining the cytotoxic portion of the diphtheria toxin and the receptor-binding domain of the interleukin-2 (IL-2) molecule, thereby targeting cells expressing the IL-2 receptor, including both T-cell and B-cell lymphomas. It has been approved for the treatment of cutaneous T-cell lymphomas, and it has documented activity in PTCL both as a single agent and as part of combination therapy. This report documents three cases of PTCL where denileukin diftitox has been used as long-term maintenance therapy after complete remission was achieved. While the overall survival rate of patients with advanced stage, refractory PTCL is generally poor (with median overall survival of 5.5 months), the three patients described in this report are all experiencing an ongoing complete remission for more than four years.

Novel therapies for T cell lymphoma

Peripheral T-cell lymphomas (PTCL) are a heterogeneous collection of lymphomas that are associated with a very poor prognosis. Conventional therapies, historically based on protocols for aggressive B-cell lymphomas, deliver less than adequate outcomes; the majority of patients experience early relapse after frontline treatment and current 5 year overall survival is only 10–30%. Clearly, new approaches are needed. In recent years there has been a plethora of novel agents showing activity in PTCL, often in patients with advanced relapsed or refractory disease. These agents include antifolate drugs (pralatrexate), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat, belinostat), nucleoside analogues (gemcitabine, forodesine, clofarabine), monoclonal antibodies (anti-CD52, anti-CD4, anti-CD2), immunotoxins (bentuximab vedotin; anti-CD30), fusion toxins (denileukin diftitox; CD25), immunomodulatory agents (IMiDs such as lenalidomide), and proteasome inhibitors (bortezomib). This is an exciting time in the treatment of PTCL, as our ever improving understanding of the distinguishing features, pathogenesis, molecular biology and progression of PTCL and the knowledge of the mechanism and efficacy of novel therapies, may see a real improvement in outcomes for patients. Biomarker co-development will be absolutely critical to advancing the field of PTCL therapy. Already, by dissecting out the biology of the disease, specific targeted approaches are being used (CD30, ALK, CCR4). Understanding the primary mechanism of action and key targets of the less specific agents such as the HDACi, lenalidome or aurora kinase inhibitors, will help us pre-select patients with the highest likelihood of benefit, reducing exposure to potential toxicities while reducing the overall health cost burden.

Therapeutic options in relapsed or refractory peripheral T-cell lymphoma.

Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas with a very poor prognosis. Current therapies, based on historical regimens for aggressive B-cell lymphomas, have resulted in insufficient patient outcomes. The majority of patients relapse rapidly, and current 5-year overall survival rates are only 10-30%. It is evident that new approaches to treat patients with PTCL are required. In recent years, prospective studies in PTCL have been initiated, mainly in patients with relapsed/refractory disease. In some of these, selected histologic subtypes have been evaluated in detail. As a consequence, numerous new therapies have been developed and shown activity in PTCL, including: agents targeting the immune system (e.g. brentuximab vedotin, alemtuzumab, lenalidomide); histone deacetylase inhibitors (romidepsin, belinostat); antifolates (pralatrexate); fusion proteins (denileukin diftitox); nucleoside analogs (pentostatin, gemcitabine); and other agents (e.g. alisertib, plitidepsin, bendamustine, bortezomib). A variety of interesting novel combinations is also emerging. It is hoped that these innovative approaches, coupled with a greater understanding of the clinicopathologic features, pathogenesis, molecular biology, and natural history of PTCL will advance the field and improve outcomes in this challenging group of diseases. This review summarizes the currently available clinical evidence on the various approaches to treating relapsed/refractory PTCL, including the role of stem cell transplantation, with an emphasis on potential new drug therapies.

PTCL Therapies

Peripheral T-cell lymphomas (PTCLs) are relatively uncommon lymphomas, compared with B-cell malignancies, and given short-lived responses to therapies and an aggressive clinical course provide a therapeutic challenge for the clinician. Although anthracycline-based regimens have been a mainstay of therapy, inferior outcomes with these regimens have called attention to the need for the development of novel agents and effective combination therapies. Recently, new agents with activity in PTCL have emerged with evidence of improved efficacy. This review summarizes novel, investigational, and standard treatment options in the management of treatment naive and relapsed refractory PTCL.

Glucuronidation by UGT1A1 Is the Dominant Pathway of the Metabolic Disposition of Belinostat in Liver Cancer Patients

Belinostat is a hydroxamate class HDAC inhibitor that has demonstrated activity in peripheral T-cell lymphoma and is undergoing clinical trials for non-hematologic malignancies. We studied the pharmacokinetics of belinostat in hepatocellular carcinoma patients to determine the main pathway of metabolism of belinostat. The pharmacokinetics of belinostat in liver cancer patients were characterized by rapid plasma clearance of belinostat with extensive metabolism with more than 4-fold greater relative systemic exposure of major metabolite, belinostat glucuronide than that of belinostat. There was significant interindividual variability of belinostat glucuronidation. The major pathway of metabolism involves UGT1A1-mediated glucuronidation and a good correlation has been identified between belinostat glucuronide formation and glucuronidation of known UGT1A1 substrates. In addition, liver microsomes harboring UGT1A1*28 alleles have lower glucuronidation activity for belinostat compared to those with wildtype UGT1A1. The main metabolic pathway of belinostat is through glucuronidation mediated primarily by UGT1A1, a highly polymorphic enzyme. The clinical significance of this finding remains to be determined.Trial RegistrationClinicalTrials.gov NCT00321594

Effect of a combination of epigenetic agents on the malignant phenotype in models of T-cell lymphoma.

e13569 Background: CHOP and CHOP-like chemotherapy are the most used regimens for the treatment of peripheral T-cell lymphomas (PTCLs) despite sub-optimal results. Histone deacetylase inhibitors (HDACIs) have shown class activity in PTCLs. The interaction between the HDACIs (depsipeptide (R), belinostat (B), vorinostat (V) and panobinostat (P)) and a DNMT inhibitor (decitabine (D) was investigated in vitro, in vivo and at the molecular level in T-cell lymphoma and leukemia cell lines (H9, HH, P12, PF-382). Methods: For cytotoxicity assays, luminescence cell viability assay was used (CellTiter-Glo). Drug:drug interactions were analyzed with relative risk ratios (RRR) based on the GraphPad software (RRR<1 defining synergism). Apoptosis was assessed by Yo-Pro-1 and propidium iodine followed by FACSCalibur acquisition. Gene expression profiling was analyzed using Illumina Human HT-12 v4 Expression BeadChip microarrays and Gene Spring Software for the analysis. Results: The IC50s for B, R, V, P, D and 5-Azacytidine alone were assessed at 24, 48 and 72 hours. In cytotoxicity assays the combination of D plus B, R, V or P at 72 hours showed synergism in all the cell lines (RRRs 0.0007-0.9). All the cell lines were treated with D, B or R for 72 hours and all the combinations showed significantly more apoptosis than the single drug exposures and controls (RRR < 1). In vivo, HH SCID beige mice were treated i.p. for 3 cycles with the vehicle solution, D or B or their combination at increasing dose. The combination cohort showed statistically significant tumor growth inhibition compared to all the other cohorts. Gene expression analysis revealed differentially expressed genes and modulated pathways for each of the single agent treatment and the combination. The effects of the two drugs were largely different (only 39 genes modified in common). Most of the effects induced by the single agent were maintained in the combination group. Interestingly, 944 genes were modulated uniquely by the combination treatment. Conclusions: The combination of a DNMTI and HDACIs is strongly synergistic in vitro, in vivo and at the molecular level in model of T-cell lymphoma and these data will constitute the basis for a phase I-II clinical trials.

An open-label phase II study of intravenous bortezomib and oral panobinostat (LBH589) in adult patients with relapsed/refractory peripheral T-cell lymphoma (PTCL) or NK/T-cell lymphoma (NKL) after failure of conventional chemotherapy.

TPS224 Background: Relapsed/refractory PTCL and NKL after conventional chemotherapy carry an extremely poor prognosis and there is currently no proven treatment available. Panobinostat (PAN), a pan-deacetylase inhibitor targets epigenetic and multiple oncogenic pathways, while bortezomib (BTZ) exerts pleotropic antitumor effects, including the inhibition of the NF-KB pathway, leading to cell apoptosis. Separately, both agents have shown activity in PTCL and NKL. In vitro and in vivo studies have demonstrated potent synergistic cytotoxicity of the combination. Additionally, inhibition of HDAC6 by PAN abrogates BTZ-induced protective aggreosome formation and accentuates BTZ induced endoplasmic reticulum stress, leading to further apoptosis. Collectively, these data provide a strong rationale for the first clinical trial of this combination in PTCL and NKL Methods: This is an open label, phase II multicenter, multinational clinical trial(NCT00901147), with a Gehan’s 2- stage design. Aiming for a response rat...

New drug therapies in peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous collection of lymphomas that are associated with very poor prognosis. Conventional therapies, historically based on protocols for aggressive B-cell lymphomas, deliver less than adequate outcomes; the majority of patients experience early relapse after front-line treatment and current 5-year overall survival is only 10–30%. Clearly, new approaches are needed. In recent years there has been a plethora of novel agents showing activity in PTCL, often in patients with advanced relapsed or refractory disease. These agents include antifolate drugs (pralatrexate), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat and belinostat), nucleoside analogues (gemcitabine, forodesine and clofarabine), monoclonal antibodies (anti-CD52, anti-CD4 and anti-CD2), fusion toxins (denileukin diftitox), immunomodulatory agents (lenalidomide) and proteasome inhibitors (bortezomib). This is an exciting time in the treatment of PTCL, as our ever improving understanding of the distinguishing features, pathogenesis, molecular biology and progression of PTCL, and the knowledge of the mechanism and efficacy of novel therapies, may see a real improvement in outcomes for patients. The purpose of this article is to focus on these novel therapies and the results of recent clinical trials in PTCL.

Synergistic Combinations of Histone Deacetylase Inhibitors and Decitabine Induce a Unique Gene Expression and Epigenetic Profile In Models of Diffuse Large B-Cell Lymphoma

AbstractAbstract 435Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoid malignancy, representing approximately 30–40% of all lymphomas. While significant progress has been made in treating this disease over the past decade, it is still regarded as a heterogeneous disease which, after being classified as relapsed or refractory, is fatal in about one-third of patients. Histone deacetylase inhibitors (HDACI) are presently approved for the treatment of relapsed or refractory cutaneous T- cell lymphomas (CTCL), and have marked activity in peripheral T-cell lymphomas (PTCL), though their effectiveness in DLBCL is less established. DNA methyltransferases (DNMTs) are known to recruit and cooperate with histone deacetylases to induce gene silencing. Combinations of drugs affecting these pathways have emerged as active and important, mostly in myeloid leukemias. We hypothesized that the combination of HDACI and DNMT inhibitors (DNMTI) in DLBCL may be active only in combination and not as single agents. We examined the interaction between a broad range of HDACI including vorinostat, depsipeptide, panobinostat and DNMTI using in vivo and in vitro models of DLBCLs, clearly confirming that these agents are in fact synergistic with decitabine. Synergy was measured by relative risk ratio (RRR) and the values obtained were as low as 0.01, representing very strong synergy. This combination of drugs, specifically panobinostat and decitabine, was also shown to be strongly synergistic in a murine xenograft model of DLBCL. In addition, we analyzed the molecular basis for this synergistic effect by evaluating the global gene expression and methylation using microarrays on the cells treated with the single agents and combination in DLBCL. Three DLBCL lines (OCI-Ly1, OCI-Ly10 and Su-DHL6) were treated with decitabine alone (2.5 μ M), panobinostat alone (2.5 nM) or their combination for 48h hours. DNA and RNA from untreated and treated cells were used for genome wide methylation analysis through Illumina Humanmethyation27 platform and gene expression profiling analysis with Illumina HumanHT-12 v3 Expression arrays. 3D principal component analysis clearly clustered the samples treated with panobinostat and combination therapy together and at greater distances from untreated samples and samples treated by decitabine alone. Therefore, the contribution to the gene expression phenotype of the combination was greater from the HDACI than with DNMTI. Consistent with this observation, the top network of genes differentially expressed (p<0.05) by panobinostat involved critical transcription factors like GATA1, GATA4, SMAD and DNMT3A. Additionally, network-functional analysis of genes perturbed by the combination treatments enriched for critical pathways involved in cell death, cell development and cellular proliferation. Surprisingly, differentially expressed genes and networks identified by each of the treatment conditions and by combination therapy were unique with few overlapping genes as shown in Venn diagram in Figure 1a. Genome wide methylation analysis produced similar results with greater contribution to global methylation changes in cells treated by the combination therapy and decitabine as compared to HDACI. Again, methylation status of a distinct set of genes was altered by combination therapy as compared to the individual drugs (Figure 1b). Correlation between genome wide methylation analysis and gene expression profiling identified 16 overlapping genes in the samples treated by the combination of panobinostat and decitabine including known tumor suppressor genes like VHL, DIRAS3 and WT1. Taken together, integrative genomic analysis has provided insights into the relative contribution of independent epigenetic therapies to the combination phenotype. These findings may provide important leads in identifying unique biomarkers of response specific to the combination of panobinostat and decitabine in DLBCL. [Display omitted] Disclosure:O'Connor:Millennium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Epigenetic Modulation and Therapy of Lymphoid Malignancies

AbstractAbstract SCI-30The FDA has approved four epigenetic therapies for oncology: Vidaza™ (azacitidine, 2004), Dacogen® (decitabine, 5-aza-2′-deoxycytidine, 2006), Zolinza™ (vorinostat, 2006), and Istodax® (romidepsin, 2009); and many more are in clinical and preclinical development. While we know the enzymatic targets of these agents, we still do not fully understand the true mechanism of action of these agents. Ostensibly, both classes of agents work to inhibit enzymes that silence genes with tumor suppressor function: DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). Reduction of hypermethylation has been documented following inhibition of DNMT by 5-aza-2-deoxycytidine and 5-azacytidine. Significant clinical activity including durable responses and improvement in survival initially led to approval of these agents in myelodysplastic syndrome (MDS). Although demethylation has been confirmed following treatment with these agents, particularly in the low dose, chronic schedule developed for MDS, the extent of demethylation does not correlate with response, suggesting other factors are important. The genes critical for response are still under study – several known to be hypermethylated in MDS have been intensively studied, including the p15INK4B and the fragile histidine triad (FHIT) genes. There are many parallels for the HDAC inhibitors, which also inhibit enzyme activity and promote gene transcription. FDA approvals for vorinostat and romidepsin are based on clinical activity in cutaneous T-cell lymphoma (CTCL) including durable and complete responses. Activity in peripheral T-cell lymphomas has also been observed in clinical trials with romidepsin and other HDAC inhibitors. Increased global histone acetylation has been noted in clinical samples; however, there is no correlation of this marker with response to vorinostat. Romidepsin, on the other hand, requires activation and our clinical data have suggested a correlation between persistent histone acetylation and clinical response. The gene alterations critical for clinical activity still require definition. Although HDAC inhibitors reliably induce the CDK inhibitor p21, overall about 5% of genes assayed are upregulated by HDAC inhibitors in array studies, and an equal number downregulated. Notably, multiple cellular proteins are also affected by acetylation; some of them potentially responsible for the activity of the HDAC inhibitors. This may depend upon cellular context but in some cell types is likely to be as important if not more important than their effects on gene transcription. T-cell lymphomas in more than one-third of patients show sensitivity to the HDAC inhibitors, and it is not known which of the myriad activities is critical for the activity in the T-cell lymphomas. What we do know is that in a subset of patients, responses can be very good, and of very long duration. Critical needs for epigenetic therapies include a more precise determination of mechanisms of action, so that we may identify the subsets of patients who will have disease response. We need to define mechanisms of resistance that emerge after treatment fails if we hope to prevent that outcome. We need effective combinations with epigenetic therapies to increase their activity in the diseases currently known to be susceptible, but also to extend their range of activity. Epigenetic therapies – originally identified as differentiating agents – are unique among anticancer therapies in having the potential to actually reset the oncogenic phenotype. A significant research effort is needed to harness this potential. Disclosures:Bates:Gloucester Pharmaceuticals: Research Funding. Off Label Use: romidepsin efficacy in peripheral T cell lymphoma is experimental but efficacy data are available.

Aplidin® (Plitidepsin) Activity In Peripheral T-Cell Lymphoma (PTCL): Final Results

AbstractAbstract 1767 Background:Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of NHL, representing 10–15% of all newly diagnosed cases; their prognosis is poor and optimal therapy is yet to be defined. Most patients (pts) relapse after standard first-line chemotherapy and ultimately die from their disease. Though pralatrexate has been recently FDA-approved for this indication, novel active agents are still needed. From December 2004 to June 2008, 46 adult pts with aggressive non-Hodgkin lymphoma (NHL) were treated in a phase II study aimed at evaluating the activity of plitidepsin. An interim analysis showed responses restricted to pts with PTCL (4/17 vs. 0/29 in pts with B-cell NHL; Fisher's test: p=0.01). Thus, PTCL cohort was expanded. Herein, final results are presented. Patients and methods:As of June 2010, 32 pts were treated with plitidepsin 3.2 mg/m2 i.v. infusion over 1-h on days 1, 8 and 15 q4wk. Twenty-nine pts are evaluable for efficacy. Median number of previous regimens was 2 (range, 1–6), including prior stem cell transplantation in 9 pts (28%). Histology: PTCL, NOS 16, anaplastic large-cell 4, angioimmunoblastic 9 and NK/T nasal type 3. Twenty-three pts were male, median age was 57 y (30-80) and ECOG: 0 (14 pts), 1 (12 pts) and 2 (6 pts). Results:Two CR and 4 PR were observed, for a 20% objective response rate (95% CI, 8%-39%). Median duration of response was 2.2 months (range, 1 – 28). Median progression-free survival was 1.6 months (95% CI, 1 – 3) and median overall survival was 10.2 months (95% CI, 4 – 24). Toxicity, particularly haematological, was mild. Two patients developed G3, and 2 G4 neutropenia, and 1 pt G3, and 2 G4 thrombocytopenia. Transient and reversible G3 ALT or AST elevations occurred in 7 and 4 pts, respectively, with no patients experiencing G4 events. Clinical toxicities were mainly G1-2 muscular weakness and myalgia in 14% of pts, and G1-2 fatigue, nausea and vomiting in 21%, 28% and 17% of patients, respectively. Conclusions:Plitidepsin has activity, with an acceptable safety profile in non-cutaneous relapsed/refractory PTCL patients. Remarkably, lack of hematologic toxicity makes plitidepsin an ideal agent either for treating patients with poor bone marrow reserve or combining it with other active agents. A combination of plitidepsin with gemcitabine is currently being explored in this patient population. Disclosures:Szyldergemajn:PharmaMar SAU: Employment. Corrado:PharmaMar SAU: Employment. Extremera:PharmaMar SAU: Employment. Vandermeeren:PharmaMar SAU: Employment.

Denileukin Diftitox (ONTAK) Plus CHOP Chemotherapy in Patients with Peripheral T-Cell Lymphomas (PTCL), the CONCEPT Trial.

PTCL are an aggressive group of lymphomas comprising a number of histopathologic subtypes for which CHOP chemotherapy has been the standard first-line regimen at many centers. Denileukin diftitox (Dd) is a recombinant DNA-derived cytotoxic protein composed of diphtheria toxin fragments A and B and the full length sequence of human interleukin-2 (IL-2). Dd targets T-cells expressing the intermediate and high-affinity IL-2 receptor. Because the mechanism of action of Dd is distinct from traditional cytotoxic chemotherapy and Dd has exhibited minimal myelosuppression, we evaluated the safety, tolerability, and efficacy of combining Dd with CHOP as first-line therapy for patients with PTCL according to the REAL classification. (Pts with mycosis fungoides or Sezary syndrome were not included.) Dd was administered at 18 mcg/kg/day on Days 1 and 2 followed by CHOP on Day 3, and G-CSF support starting Day 4, every 3 weeks for up to 6 cycles. Evaluation of response is performed after every 2 cycles of treatment.Results: Forty-one pts, 18 male/23 female, have been enrolled to date, with a median age of 52. Ten pts are not evaluable for response: 5 discontinued due to an adverse event (AE) prior to assessment of response; 3 due to lack of measurable disease at baseline; and 2 are too early to evaluate. For the 31 response-evaluable patients, the overall response rate is 90%, with 71% (22/31) CR or CRu, 19% (6/31) PR, 6% (2/31) SD, and 3% (1/31) PD. Ten of 28 responders (36%) have progressed, with a median duration of response of 13 months.PTCL subtypeNo. of PatientsNo. evaluableResponsesORRPTCL-nos20153 CR, 5 CRu, 4 PR, 2 SD, 1 PD80%Angioimmunoblastic1093 CR, 5 CRu, 1 PR100%Anaplastic large cell642 CR, 2 CRu100%Enteric T-cell211 CRu100%Hepatosplenic10n/an/aNasal/nasal type T/NK cell111 CRu100%Subcutaneous panniculitic T-cell111 PR100%Toxicities have generally been grade 1–2, were transient, and caused few dose modifications. The most common have been fatigue (62%), nausea (44%), anemia (38%), sensory neuropathy (33%), hypoalbuminemia (33%), elevated ALT (30%), dyspnea (28%), thrombocytopenia (30%), leukopenia (28%), fever (25%), elevated AST (25%), lymphopenia (25%), and hyperglycemia (25%). Forty-three percent (17/40) of patients experienced one or more grade 3–4 hematological toxicities and 40% (16/40) of patients experienced one or more grade 3–4 non-hematological toxicities. Five patients discontinued the study due to AEs, all occurring prior to Cycle 2, for: infusion-related anaphylaxis; elevated LFTs; port-related staph sepsis; pneumonia; and a death possibly resulting from tumor lysis syndrome and rhabdomyolysis.Conclusion: The combination of Dd plus CHOP has a generally manageable safety profile and to date has exhibited promising clinical activity in PTCL.

Management of advanced-stage peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs), several entities with great clinical, histologic, and biologic heterogeneity, represent 8% to 15% of all malignant lymphomas. With current treatment regimens, 5-year survival is only about 30% to 35%. Outcome is poorer with PTCL than with aggressive B-cell lymphoma because of more frequent adverse clinical features at diagnosis, a lower response rate to chemotherapy, and a higher incidence of relapses, but it is also known that the T-cell phenotype itself is associated with a poor prognosis independent of other prognostic factors. Initial treatment of patients with advanced-stage PTCL mostly consists of six to eight courses of anthracycline-based chemotherapy such as CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). In fit elderly patients, standard therapy is still six cycles of CHOP-14, but up-front consolidation with intensive chemotherapy and autologous stem cell transplantation are often used in younger patients. The humanized CD52 monoclonal antibody alemtuzumab has shown activity in some T-cell malignancies; with appropriate antibiotic and virostatic prophylaxis, its use seems feasible for PTCL, both as a single agent and in conjunction with chemotherapy. New drugs such as denileukin diftitox, histone deacetylase inhibitors, and pralatrexate have shown promising activity in PTCL.

A Pilot Study of Alemtuzumab Plus Combination Chemotherapy for Newly Diagnosed Patients with Peripheral T-Cell Lymphomas.

The results of combination chemotherapy for peripheral T cell lymphoma (PTCL) still showed poor, although alemtuzumab monotherapy has therapeutic activity in PTCL. We evaluated the safety and effectiveness of several combination chemotherapies with alemtuzumab for treating newly diagnosed PTCL including advanced stage cutaneous T-cell lymphoma. Nine patients with PTCL were included. The pathologic subtypes were as follows: cutaneous T cell lymphoma (CTCL) in 2 patients, peripheral T cell lymphoma unspecified (PTCLu) in 2 patients, extranodal NK/T cell lymphoma, nasal type in 3 patients, angioimmunoblastic T cell lymphoma (AITL) in 2 patient. Patients received a 30mg of alemtuzumab intravenously over about 8 hours on the first day of combination chemotherapy. The combination chemotherapy regimens included: CHOP (cyclophosphamide, adriamycin, vincristine and prednisolone) in 2 patients; EPOCH (etoposide, prednisolone, vincristine, cyclophosphamide and adriamycin) in 2 patients; IMVP16-PL (ifosfamide plus mesna, methotrexate, etoposide and prednisolone) in 5 patients. Complete remission was achieved in 2 patients, and partial remission was achieved in 5 patients, only one patient encountered treatment related mortality (septic shock). Nine patients received nineteen cycles of alemtuzumab plus combination chemotherapy. Alemtuzumab infusion related adverse events were reported in 10 of 19 cycles and were mainly mild to moderate in severity. The most common events were shivers and chills during the alemtuzumab infusion period, which occurred in 8 of 19 cycles. Six (32%) cycles had one or more episodes of new onset NCI-CTC grade 3 or 4 anemia. In addition, erythropoietin use was reported in 7 patients. All of the cycles had grade 3 or 4 neutropenia and 8 (42%) cycles had grade 3 or 4 thrombocytopenia. Grade 3 hyponatremia and grade 3 or 4 hypokalemia were observed in 1 and 4 cycles, respectively. Ten cycles (53%) with neutropenic fever occurred during the treatments. Six (32%) sepsis, 1 septic shock, 2 pneumonia, 2 fungal infection and 2 herpes zoster were observed. There was no cytomegalovirus reactivation during the treatment. Although alemtuzumab plus combination chemotherapy had significant hematologic and infection complications, we concluded that alemtuzumab plus combination chemotherapy was well tolerated and could be recommended for treating newly diagnosed PTCL. However, evaluation in more patients with long-term follow up is warranted.Patients characteristicsSexAgeStageRegimenCyclesAdditional TxResponseCTCL1Female22IVAAlemtuaumab+EPOCH3RTx4 + 2 IMVP16-PLPartial remissionCTCL2Female48IIIAAlemtuaumab+IMVP16-PL2RTx4Partial remissionPTCLuFemale70IIIAAlemtuaumab+CHOP33 CHOPComplete remissionPTCLuFemale50IVBAlemtuaumab+IMVP16-PL1NoPartial remissionNK/T3Male51IVBAlemtuaumab+IMVP16-PL1NoPartial remissionNK/T3Male46IIEAAlemtuaumab+IMVP16-PL3RTx4 + 1 IMVP16-PLComplete remissionNK/T3Male74IIEAAlemtuaumab+CHOP2NoTRM5(Sepsis)AITLFemale75IIIBAlemtuaumab+EPOCH2NoProgressionAITLMale70IVBAlemtuaumab+IMVP16-PL2NoPartial remission1Subcutaneous panniculitis T cell lymphom2Cutaneous gamma-delta T cell lymphoma3Extranodal T/NK cell lymphoma, nasal type4Radiotherapy5Treatment related mortality