Chalid Assaf

Synergistic interaction of the histone deacetylase inhibitor SAHA with the proteasome inhibitor bortezomib in cutaneous T cell lymphoma

Proteasome inhibitors and histone deacetylase (HDAC) inhibitors are novel targeted therapies being evaluated in clinical trials for cutaneous T‐cell lymphoma (CTCL). However, data in regard to tumor biology are limited with these agents. In the present study we analyzed the effects of the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) and the proteasome inhibitor bortezomib on human CTCL cells. Four CTCL cell lines (SeAx, Hut‐78, MyLa, and HH) were exposed to bortezomib and/ or SAHA at different concentrations. Cell viability was quantified using the MTT assay. In addition, apoptosis and generation of reactive oxygen species were analyzed. Both agents potently inhibited cell viability and induced apoptosis. After 48 h of incubation, IC50 of bortezomib was noted at 8.3 nm, 7.9 nm, 6.3 nm, and 22.5 nm in SeAx, Hut‐78, HH, and MyLa cells, respectively. For SAHA, the IC50 values were at 0.6 μm in SeAx cells, 0.75 μm in Hut‐78 cells, 0.9 μm in HH cells, and 4.4 μm in MyLa cells. Importantly, combined treatment resulted in synergistic cytotoxic effects, as indicated by Combination indices values <1 using the median effect method of Chou and Talalay. We furthermore found that combined treatment with both agents lead to a decreased proteasome activity, an upregulation of the cell regulators p21 and p27 and increased expression of phosphorylated p38. In addition, we showed that SAHA reduced the vascular endothelial growth factor production of CTCL cells. Our results demonstrate that bortezomib and SAHA synergistically induce apoptosis in CTCL cells and thus provide a rationale for clinical trials of combined proteasome and histone deacetylase inhibition in the treatment of CTCL.

Phase III Placebo-Controlled Trial of Denileukin Diftitox for Patients With Cutaneous T-Cell Lymphoma

PURPOSE This phase III, placebo-controlled, randomized trial was designed to investigate efficacy and safety of two doses of denileukin diftitox (DD; DAB(389)-interleukin-2 [IL-2]), a recombinant fusion protein targeting IL-2 receptor-expressing malignant T lymphocytes, in patients with stage IA to III, CD25 assay-positive cutaneous T-cell lymphoma (CTCL), including the mycosis fungoides and Sézary syndrome forms of the disease, who had received up to three prior therapies. The primary end point was overall response rate (ORR). PATIENTS AND METHODS Patients (N = 144) with biopsy-confirmed, CD25 assay-positive CTCL were randomly assigned to DD 9 microg/kg/d (n = 45), DD 18 microg/kg/d (n = 55), or placebo infusions (n = 44), administered for 5 consecutive days every 3 weeks for up to eight cycles. Patients were monitored for drug efficacy, clinical benefit, and safety of DD. RESULTS ORR was 44% for all participants treated with DD (n = 100; 10% complete response [CR] and 34% partial response [PR]) compared with 15.9% for placebo-treated patients (2% CR and 13.6% PR). ORR was higher in the 18 microg/kg/d group versus the 9 microg/kg/d group (49.1% v 37.8%, respectively), and both doses were significantly superior to placebo. Progression-free survival (PFS) was significantly longer (median, > 2 years) for both DD doses compared with placebo (median, 124 days; P < .001). Rates of moderately severe and severe adverse events (AEs) were slightly higher in the DD groups, whereas moderate and mild AEs were similar to placebo. No statistical differences were observed for drug-related serious AEs. CONCLUSION DD had a significant and durable effect on ORR and PFS with an acceptable safety profile in patients with early- and late-stage CTCL.

Granulomatous mycosis fungoides and granulomatous slack skin: a multicenter study of the Cutaneous Lymphoma Histopathology Task Force Group of the European Organization For Research and Treatment of Cancer (EORTC)

BACKGROUND Granulomatous cutaneous T-cell lymphomas (CTCLs) are rare and represent a diagnostic challenge. Only limited data on the clinicopathological and prognostic features of granulomatous CTCLs are available. We studied 19 patients with granulomatous CTCLs to further characterize the clinicopathological, therapeutic, and prognostic features. OBSERVATIONS The group included 15 patients with granulomatous mycosis fungoides (GMF) and 4 with granulomatous slack skin (GSS) defined according to the World Health Organization-European Organization for Research and Treatment of Cancer classification for cutaneous lymphomas. Patients with GMF and GSS displayed overlapping histologic features and differed only clinically by the development of bulky skin folds in GSS. Histologically, epidermotropism of lymphocytes was not a prominent feature and was absent in 9 of 19 cases (47%). Stable or progressive disease was observed in most patients despite various treatment modalities. Extracutaneous spread occurred in 5 of 19 patients (26%), second lymphoid neoplasms developed in 4 of 19 patients (21%), and 6 of 19 patients (32%) died of their disease. Disease-specific 5-year survival rate in GMF was 66%. CONCLUSIONS There are clinical differences between GMF and GSS, but they show overlapping histologic findings and therefore cannot be discriminated by histologic examination alone. Development of hanging skin folds is restricted to the intertriginous body regions. Granulomatous CTCLs show a therapy-resistant, slowly progressive course. The prognosis of GMF appears worse than that of classic nongranulomatous mycosis fungoides.

The optimal use of bexarotene in cutaneous T‐cell lymphoma

The management goal in cutaneous T‐cell lymphomas (CTCLs) is to improve symptoms and induce remission. Early‐stage disease is generally treated with skin‐directed therapies. However, if these do not control the disease, systemic therapy becomes necessary. Bexarotene, a novel rexinoid, is an oral, noncytotoxic drug that has been approved in Europe for the treatment of refractory advanced‐stage CTCL and in the U.S.A. for refractory CTCL. We provide guidance on the use of bexarotene in the management of CTCL, based on data from phase II/III clinical trials and the authors’ clinical experience, and suggest how the potential of the drug can be maximized. The clinical trial results with bexarotene are reviewed, especially in comparison with interferon‐α, which is the other commonly used noncytotoxic systemic therapy for CTCL. A treatment algorithm for bexarotene in refractory CTCL is suggested. As bexarotene may take time to achieve a maximum response, this algorithm recommends that therapy should be continued for a sufficient period to allow for a delayed onset of action. In addition, possible combination therapies with bexarotene are discussed. We conclude that bexarotene is effective in the management of CTCL, and has the advantage of oral administration. An on‐going randomized clinical trial comparing psoralen plus ultraviolet A (PUVA) with PUVA plus bexarotene will provide valuable information about this combination regimen in early‐stage disease, but further data are needed on the relative efficacies of other combination therapies with bexarotene in CTCL.

Minimizing adverse side-effects of oral bexarotene in cutaneous T-cell lymphoma: an expert opinion

Bexarotene is an oral retinoid therapy that is effective for the treatment of early and advanced‐stage cutaneous T‐cell lymphoma (CTCL) in patients who have failed on other therapies. However, bexarotene treatment is associated with unavoidable side‐effects, in particular hypertriglyceridaemia and hypothyroidism, which are manageable with adequate concomitant medications and are reversible on cessation of treatment. A pragmatic strategy for minimizing bexarotene‐associated hypertriglyceridaemia and hypothyroidism is suggested, based on data from the studies with bexarotene in CTCL and on day‐to‐day experience with this agent in the clinical setting. The strategy anticipates that these common adverse events are likely to occur and recommends the early use of preventive therapy to lower triglycerides and elevate thyroid hormone levels in the blood, followed by subsequent monitoring, dose adjustment during bexarotene treatment, and titration of the daily bexarotene dose from 150 to 300 mg m−2, which is optimal for most patients. When further information becomes available on how bexarotene interacts with lipid metabolism and thyroid function, the management approach suggested here may need to be changed.

Guidelines on the use of extracorporeal photopheresis

After the first investigational study on the use of extracorporeal photopheresis for the treatment of cutaneous T‐cell lymphoma was published in 1983 with its subsequent recognition by the FDA for its refractory forms, the technology has shown significant promise in the treatment of other severe and refractory conditions in a multi‐disciplinary setting. Among the major studied conditions are graft versus host disease after allogeneic bone marrow transplantation, systemic sclerosis, solid organ transplant rejection and inflammatory bowel disease.

Panobinostat activity in both bexarotene-exposed and -naïve patients with refractory cutaneous T-cell lymphoma: results of a phase II trial.

BACKGROUND Panobinostat is a potent, oral pan-deacetylase inhibitor (pan-DACi) that increases the acetylation of proteins involved in multiple oncogenic pathways. Here, panobinostat is studied in bexarotene-exposed and -naïve patients with refractory cutaneous T-cell lymphoma (CTCL). PATIENTS AND METHODS Patients with CTCL subtypes mycosis fungoides and Sézary syndrome who received ⩾2 prior systemic therapy regimens received panobinostat (20mg) three times every week. The primary objective was overall response rate (ORR) as determined by a combined evaluation of skin disease and involvement of lymph node and viscera. Disease progression was defined as an unconfirmed, ⩾25% increase in modified Severity Weighted Assessment Tool (mSWAT) compared with nadir. RESULTS Seventy-nine bexarotene-exposed and 60 bexarotene-naïve patients were enrolled. Reductions in baseline mSWAT scores were observed in 103 patients (74.1%). The ORR was 17.3% in all patients in the primary analysis (15.2% and 20.0% in the bexarotene-exposed and -naïve groups, respectively). The median progression-free survival was 4.2 and 3.7 months in the bexarotene-exposed and -naïve groups, respectively. The median duration of response was 5.6 months in the bexarotene-exposed patients and was not reached at data cutoff in the bexarotene-naïve patients. Additional responses were observed when less-stringent progression criteria were used. The most common adverse events were thrombocytopenia, diarrhoea, fatigue and nausea. Thrombocytopenia and neutropenia were the only grade 3/4 adverse events in >5% of patients and were manageable. CONCLUSION Despite a very conservative definition of disease progression, panobinostat demonstrated activity with a manageable safety profile in bexarotene-exposed and -naïve CTCL patients. ClinicalTrials.gov Identifier: NCT00425555.

Gene deregulation and spatial genome reorganization near breakpoints prior to formation of translocations in anaplastic large cell lymphoma

Although the identification and characterization of translocations have rapidly increased, little is known about the mechanisms of how translocations occur in vivo. We used anaplastic large cell lymphoma (ALCL) with and without the characteristic t(2;5)(p23;q35) translocation to study the mechanisms of formation of translocations and of ALCL transformation. We report deregulation of several genes located near the ALCL translocation breakpoint, regardless of whether the tumor contains the t(2;5). The affected genes include the oncogenic transcription factor Fra2 (located on 2p23), the HLH protein Id2 (2p25), and the oncogenic tyrosine kinase CSF1-receptor (5q33.1). Their up-regulation promotes cell survival and repression of T cell-specific gene expression programs that are characteristic for ALCL. The deregulated genes are in spatial proximity within the nuclear space of t(2;5)-negative ALCL cells, facilitating their translocation on induction of double-strand breaks. These data suggest that deregulation of breakpoint-proximal genes occurs before the formation of translocations, and that aberrant transcriptional activity of genomic regions is linked to their propensity to undergo chromosomal translocations. Also, our data demonstrate that deregulation of breakpoint-proximal genes has a key role in ALCL.

CD56-positive haematological neoplasms of the skin: a multicentre study of the Cutaneous Lymphoma Project Group of the European Organisation for Research and Treatment of Cancer

Background: Cutaneous lymphomas expressing CD56, a neural cell adhesion molecule, are characterised in most cases by a highly aggressive clinical course and a poor prognosis. However, prognostic subsets within the CD56+ group have been difficult to identify due to the lack of uniform clinicopathological and immunophenotypical criteria. Methods: A multicentre study was conducted by the Cutaneous Lymphoma Task Force of the European Organisation for Research and Treatment of Cancer to define prognostic parameters and establish diagnostic and therapeutic guidelines for CD56+ haematological neoplasms presenting primarily in the skin. Results: Four different subtypes of lymphoproliferations with CD56 expression were identified: (1) haematodermic neoplasm; (2) skin infiltration as the first manifestation of CD56+ acute myeloid leukaemia; (3) nasal-type extranodal natural killer/T-cell lymphoma; and (4) “classical” cases of cutaneous T-cell lymphoma (CTCL) with co-expression of the CD56 molecule. Patients in the first three groups had a poor outcome (93% died) with a median survival rate of 11 months (95% CI 2–72 months), whereas all patients with CD56+ CTCL were alive at the last follow-up. Conclusion: Results show that CD56+ cutaneous lymphoproliferative disorders, with the exception of CD56+ CTCL have a very poor prognosis. It is therefore clinically important to separate CD56+ CTCL from the remaining CD56+ haematological disorders.

Cutaneous lymphomas in Germany: an analysis of the Central Cutaneous Lymphoma Registry of the German Society of Dermatology (DDG).

Background: Primary cutaneous lymphomas form a heterogenous group of lymphatic neoplasias.They manifest themselves on the skin and are the second most frequent group of non‐Hodgkin lymphoma (NHL) following gastrointestinal lymphomas.The number of epidemiologic studies is small due to limited availability and limited comparability on population‐based data.