Bexarotene is the first in a novel class of pharmacologic agents, the RXR-selective retinoids, or rexinoids. Bexarotene is orally administered, safe, and generally well tolerated with reversible side effects, and is effective for the treatment of advanced, refractory CTCL.

SummaryBelinostat is a pan-histone deacetylase inhibitor with antitumour and anti-angiogenic properties. An open label, multicentre study was conducted in patients with peripheral T-cell lymphoma (PTCL) or cutaneous T-cell lymphoma (CTCL) who failed ≥1 prior systemic therapy and were treated with belinostat (1000 mg/m 2 intravenously 95 d of a 21-d cycle). The primary endpoint was objective response rate (ORR). Patients with PTCL (n = 24) had received a median of three prior systemic therapies (range 1-9) and 40% had stage IV disease. Patients with CTCL (n = 29) had received a median of one prior skin-directed therapy (range 0-4) and four prior systemic therapies (range 1-9); 55% had stage IV disease. The ORRs were 25% (PTCL) and 14% (CTCL). Treatment-related adverse events occurred in 77% of patients; nausea (43%), vomiting (21%), infusion site pain (13%) and dizziness (11%) had the highest incidence. Treatmentrelated serious adverse events were Grade 5 ventricular fibrillation; Grade 4 thrombocytopenia; Grade 3 peripheral oedema, apraxia, paralytic ileus and pneumonitis; and Grade 2 jugular vein thrombosis. Belinostat monotherapy was well tolerated and efficacious in patients with recurrent/refractory PTCL and CTCL. This trial was registered at www.clinicaltrials.gov as NCT00274651.

Background. The median survival for adults with glioblastoma multiforme (GBM) is 12 months, despite surgery, radiation, and chemotherapy. Regimens using interleukin‐2(IL‐2) plus lymphokine‐activated killer (LAK) cells have been beneficial against systemic cancers, albeit with significant toxicity. Methods. Nineteen adults with recurrent malignant glioma (5 GBMs, and 4 anaplastic astrocytomas (AA)), Karnofsky performance status 60 or greater, were treated with intracavitary autologous LAK cells plus IL‐2 after reoperation. Lymphokine‐activated killer cells and IL‐2 were given on day 1, and IL‐2 alone was given 5 times during a 2‐week cycle. This cycle was repeated at 2 weeks to constitute one 6‐week course of therapy. Each two‐cycle course of treatment was repeated at 3‐month intervals for patients with stable disease or response to therapy. At the conclusion of immunotherapy, all patients were offered chemotherapy, generally carmustine or procarbazine, including responders. Corticosteroids were strictly limited during immunotherapy. Sequential reservoir aspirates were obtained for microbiologic and cytologic analyses. Results. The maximal tolerated dose for a 12‐dose course of therapy was 1.2 million international units (MIU) per dose. Dose‐limiting, cumulative IL‐2‐related central nervous system (CNS) toxicity was observed at 2.4 MIU per dose. Three responses were confirmed by computed tomography scan during therapy: one complete response (CR) (1 AA), and two partial responses (PR) (2 GBM); as well as a significant increase in GBM survival. One additional CR (GBM) was observed at 17 months. The median survival for immunotherapy patients with GBM was 53 weeks after reoperation (N = 15) (mean, 87.9 → 21.4 weeks, standard error for the mean), with 8 of 15 surviving more than 1 year (53%). The median survival for 18 contemporary patients with GBM reoperated and treated with chemotherapy was 25.5 weeks (mean, 27.4 ± 3.7 weeks), with 1/18 alive at 1 year (>6%). Six of the 15 patients with GBM had additional surgery or biopsy, and chemotherapy after immunotherapy. The contribution of subsequent chemotherapy to survival cannot be discounted. Conclusions. Lymphokine‐activated killer cells and IL‐2 can be administered safely within the CNS resulting in improved long term survival in patients with recurrent glioblastoma. Increased survival was associated with significant biologic changes characterized by a regional eosinophilia, and extensive lymphocytic infiltration. A prospective randomized clinical trial is warranted. Cancer 1995; 76:840–52.

Bexarotene (Targretin, Ligand Pharmaceuticals Inc.) is a synthetic retinoid analog with specific affinity for the retinoid X receptor and belongs to a group of compounds called rexinoids. Early clinical trials of this drug demonstrated activity in cutaneous T-cell lymphoma. Subsequent Phase II/III trials have demonstrated a greater than 50% response rate in patients with all stages of cutaneous T-cell lymphoma who were refractory or intolerant to the previous therapy. The principal toxicities of bexarotene include central hypothyroidism, xeroderma and elevation of cholesterol and triglycerides. These toxicities can be managed with dose attenuation or addition of atorvastatin (Lipitor, Pfizer) or fenofibrate (TriCor, Abbott Laboratories). Since bexarotene has little bone marrow toxicity, it is an excellent candidate for combination therapy with other modalities useful in the treatment of cutaneous T-cell lymphoma. These include ultraviolet B irradiation, psoralen and ultraviolet A photochemotherapy, interferons, denileukin diftitox (Ontak, Ligand Pharmaceuticals Inc.) and cytotoxic chemotherapy. Bexarotene has also been investigated in the treatment of breast cancer and non-small cell carcinoma of the lung with promising early results.

Cutaneous T-cell lymphoma is a heterogeneous group of lymphomas characterized by the accumulation of malignant T cells in the skin. The molecular and cellular etiology of this malignancy remains enigmatic, and what role antigenic stimulation plays in the initiation and/or progression of the disease remains to be elucidated. Deep sequencing of the tumor genome showed a highly heterogeneous landscape of genetic perturbations, and transcriptome analysis of transformed T cells further highlighted the heterogeneity of this disease. Nonetheless, using data harvested from high-throughput transcriptional profiling allowed us to develop a reliable signature of this malignancy. Focusing on a key cytokine signaling pathway previously implicated in cutaneous T-cell lymphoma pathogenesis, JAK/STAT signaling, we used conditional gene targeting to develop a fully penetrant small animal model of this disease that recapitulates many key features of mycosis fungoides, a common variant of cutaneous T-cell lymphoma. Using this mouse model, we show that T-cell receptor engagement is critical for malignant transformation of the T lymphocytes and that progression of the disease is dependent on microbiota.

Cutaneous T cell lymphoma (CTCL) is a heterogeneous group of mature T cell neoplasms characterized by the accumulation of clonal malignant CD4+ T cells in the skin. The most common variant of CTCL, Mycosis Fungoides, is confined to the skin in early stages but can be accompanied by extracutaneous dissemination of malignant T cells to the blood and lymph nodes in advanced stages of disease. Sézary Syndrome, a leukemic form of disease is characterized by significant blood involvement. Little is known about the transcriptional and genomic relationship between skin and blood residing malignant T cells in CTCL. To identify and interrogate malignant clones in matched skin and blood from leukemic MF and SS patients, we combine T cell receptor clonotyping, with quantification of gene expression and cell surface markers at the single cell level. Our data reveals clonal evolution at a transcriptional and genetic level within the malignant populations of individual patients. We highlight highly consistent transcriptional signatures delineating skin-derived and blood-derived malignant T cells. Analysis of these two populations suggests that environmental cues, along with genetic aberrations, contribute to transcriptional profiles of malignant T cells. Our findings indicate that the skin microenvironment in CTCL promotes a transcriptional response supporting rapid malignant expansion, as opposed to the quiescent state observed in the blood, potentially influencing efficacy of therapies. These results provide insight into tissue-specific characteristics of cancerous cells and underscore the need to address the patients' individual malignant profiles at the time of therapy to eliminate all sub-clones.

Human immunodeficiency virus 1-related idiopathic thrombocytopenic purpura (HIV-1-ITP) patients have a 4-fold increased percentage of CD5+ B cells and a 4.8-fold increased percentage of serum immune complexes precipitated by polyethylene glycol (PEG-ICs) compared to control subjects, as reported previously. Since CD5+ B cells produce predominantly IgM rheumatoid factor (RF) vs. Fc of IgG and PEG-ICs contain high levels of IgM, we looked for the presence of RF in the immune complexes of HIV-1-ITP patients. PEG-ICs were adsorbed to protein A and dissociated with acid, and IgM and IgG were purified by gel filtration and affinity chromatography. Solid-phase ELISA was used to measure antibody specificity vs. platelets, Fc, and HIV-1 gp120, p24, and CD4. Dissociated IgG antibody reacted with platelets, HIV-1 gp120, p24, and CD4, but not with Fc. Serum IgG did not react with platelets or Fc but did react with HIV-1 gp120, p24, and CD4. Both PEG-IC IgM and serum IgM reacted with Fc as well as the other four antigens. Control IgM and IgG were unreactive. Isolated IgM from PEG-ICs relocated approximately 50% of the IgG preincubated with IgM to the Vo region of a G200 gel-filtration column. Anti-platelet IgG but not IgM could be affinity-purified from fixed platelets. Both F(ab')2 fragments of anti-platelet IgG and the total PEG-IC bound to platelets in a saturation-dependent manner. F(ab')2 of anti-platelet IgG inhibited 50% binding of PEG-IC to platelets at an F(ab')2/complex ratio of 3:1 (wt/wt). Scatchard analysis revealed two classes of binding sites: high-affinity Kd values of 0.8-1.8 nM and lower-affinity Kd values of 6.6-12.3 nM with respective numbers of binding sites of 44,000-57,000 and 122,000-256,000 (n = 4). Anti-platelet IgG of 6/6 patients precipitated GPIIIa from platelet lysates of surface 125I-labeled platelets. Platelet count correlated inversely with anti-platelet IgG (r = -0.73; P < 0.01; n = 27). Thus, PEG-ICs of HIV-1-ITP patients contain IgM RF, which sequesters serum anti-platelet IgG containing anti-GPIIIa. Anti-platelet IgG contributes to binding of immune complexes to platelets and correlates with thrombocytopenia.

Platelet IgG levels, count, and function and easy bruising or bleeding were studied in 25 patients with Graves' disease and 12 with Hashimoto's thyroiditis (normal value for platelet IgG 10.7 +/- 4.5 ng [SD]/10(6) platelets). Eight of 22 patients with Graves' disease and normal platelet counts had elevated platelet IgG averaging 38 +/- 4.0 ng (SEM) (range, 24 to 60). Four of 10 patients with Hashimoto's thyroiditis and normal platelet counts ahd elevated platelet IgG averaging 45 +/- 7.2 ng (range, 27 to 66). Five patients with thrombocytopenia had platelet counts averaging 53000 +/- 12000/microL (SEM) and elevated platelet IgG averaging 154 +/- 40 ng (range, 27 to 300). Twelve of 15 patients with a history of easy bruising or bleeding had elevated platelet IgG compared to five of 22 without easy bruising (p < 0.001). Four of six with elevated platelet IgG had one or more abnormal in-vitro platelet aggregation measurements (particularly with epinephrine) compared to none of six with normal platelet IgG levels (p = 0.03). We conclude that elevated platelet IgG is associated with easy bruising and thrombocytopenia in about half of patients with Graves' disease or Hashimoto's thyroiditis.