Mechanism of action of the new immunomodulator LS2616 on T cell responses

Macrophage immunomodulation in chronic osteolytic diseases-the case of periodontitis

Periodontitis (PD) is a chronic osteolytic disease that shares pathogenic inflammatory features with other conditions associated with nonresolving inflammation. A hallmark of PD is inflammation-mediated alveolar bone loss. Myeloid cells, in particular polymorphonuclear neutrophils (PMN) and macrophages (Mac), are essential players in PD by control of gingival biofilm pathogenicity, activation of adaptive immunity, as well as nonresolving inflammation and collateral tissue damage. Despite mounting evidence of significant innate immune implications to PD progression and healing after therapy, myeloid cell markers and targets for immune modulation have not been validated for clinical use. The remarkable plasticity of monocytes/Mac in response to local activation factors enables these cells to play central roles in inflammation and restoration of tissue homeostasis and provides opportunities for biomarker and therapeutic target discovery for management of chronic inflammatory conditions, including osteolytic diseases such as PD and arthritis. Along a wide spectrum of activation states ranging from proinflammatory to pro-resolving, Macs respond to environmental changes in a site-specific manner in virtually all tissues. This review summarizes the existing evidence on Mac immunomodulation therapies for osteolytic diseases in the broader context of conditions associated with nonresolving inflammation, and discusses osteoimmune implications of Macs in PD.

Effect of Linomide on adhesion molecules, TNF-α, nitrogen oxide, and cell adhesion

Linomide (quinoline-3-carboxamide) is an immunomodulator with anti-inflammatory effects in rodents with autoimmune diseases. Its mode of action still remains to be elucidated. We hypothesized that an investigation of T cell interactions with the extracellular matrix (ECM), composed of glycoproteins such as fibronectin (FN) and laminin (LN), might provide better understanding of their in vivo mode of action in extravascular inflammatory sites. We examined the effect of Linomide on T cell adhesion to intact ECM, and separately to LN, and FN, and on the release and production of tumor necrosis factor (TNFalpha) and nitrogen oxide (NO) in relation to adhesive molecules in non-obese diabetic (NOD) female spleen cells, focusing on intracellular adhesion molecule-1 (ICAM-1) and CD44. NOD female mice that developed spontaneous autoimmune insulitis, which destroys pancreatic islets and subsequently leads to insulin-deficient diabetes mellitus, were studied. Linomide, given in the drinking water or added to tissue cultures in vitro, inhibited the beta1 integrin-mediated adhesion of T cells to ECM, FN and LN, as well as the production and release of TNFalpha and NO, which play a major role in the induction and propagation of T cell-mediated insulitis. In addition, exposure of T cells to Linomide resulted in increased expression of CD44 and ICAM-1 molecules on spleen cells of Linomide-treated mice; such an increase in adhesion molecule expression may lead to more effective arrest of T cell migration in vivo. The regulation of T-cell adhesion, adhesion receptor expression, and inhibition of TNFalpha and NO secretion by Linomide may explain its beneficial role and provide a new tool for suppressing self-reactive T cell-dependent autoimmune diseases.

Linomide inhibits insulitis and modulates cytokine production in pancreatic islets in the nonobese diabetic mouse

Linomide is an immunomodulator which has been shown to potently inhibit autoimmunity in several animal models for human autoimmune diseases, including type I diabetes in the nonobese diabetic (NOD) mouse. In this study, we investigate the basis for Linomide's protective effects in the NOD mouse by immunohistochemical and RT-PCR analysis of the phenotype and cytokine expression by cells infiltrating the islets of Langerhans in the pancreas. Linomide treatment was found to reduce the infiltration of T cells, B cells, dendritic cells (DC) and MHC class II(+) cells into the islets, but did not reduce macrophage (MPhi) infiltration. This was seen following Linomide treatment at 3-5, 4-8 and 14-24 weeks of age and thus appears to be independent of the stage of the autoreactive process and the extent of insulitis. The reduced insulitis may be due to reduced expression of adhesion molecules since decreased numbers of islet-associated blood vessels expressing CD106 and MAdCAM-1 were detected following Linomide treatment. Furthermore, short term Linomide treatment (3 or 7 days), which did not alter the number of infiltrating cells, was found to inhibit the production of TNF-alpha which is known to induce the expression of CD106 and MAdCAM-1. These results suggest that the reduced insulitis observed in Linomide-treated animals is secondary to a functional modulation of infiltrating cells.

Linomide does not prevent spontaneous autoimmune thyroiditis in NOD mice

Linomide is a potent immunomodulator and has been reported to prevent type 1 diabetes mellitus in non-obese diabetic (NOD) mice and to reduce the incidence of other autoimmune diseases in animal models. The mechanisms of action seem to involve antigen expression by down regulation of macrophage activity and to antagonise the activation of Th1 cells during the cellular immune response. With the purpose to investigate the effect of Linomide on the incidence of spontaneous autoimmune thyroiditis (AIT) in female NOD mice we administered Linomide in drinking water (100 mg/kg/day) to NOD mice from 5th to 19th week of age. The mice were sacrificed at the end of week 19. None of the mice developed diabetes during the study period. The incidence of thyroiditis was evaluated on paraffin HE-stained sections and graduated on a scale from 0 to 4. Thirty-two percent of 37 mice treated with Linomide developed thyroiditis compared to 45% of 22 controls (p=0.31, chi2 =1.00). Among the mice who developed thyroiditis no difference in the degree of thyroiditis was found. Therefore no beneficial effect of Linomide on the incidence of spontaneous AIT in NOD mice could be demonstrated.

The immunomodulator Linomide: role in treatment and prevention of autoimmune diabetes mellitus

Insulin-dependent diabetes mellitus (IDDM) is considered to be an autoimmune disorder characterized by destruction of the pancreatic beta-cells by auto-reacting lymphocytes. An attractive therapeutic approach to this disease would be to abrogate the autoimmune process at an early stage, thus preserving a critical mass of pancreatic beta-cells necessary for maintenance of normal glucose tolerance. Linomide (quinoline-3-carboxamide, Roquinimex, LS 2616), is a novel, orally absorbed, immunomodulatory drug that has been shown to be effective in various models of autoimmunity without causing non-specific immunosuppression. In this review, we describe the efficacy of Linomide for ameliorating the autoimmune process and diabetes in the non-obese diabetic (NOD) model of IDDM when administered at early stages of the disease. We also show that advanced disease in the NOD mouse can be treated effectively by combining Linomide with therapeutic modalities designed to increase pancreatic beta-cell mass. Subsequent clinical studies have shown that Linomide preserves beta-cell function in individuals with new-onset IDDM. Based on these data, Linomide or derivatives thereof might be useful for treatment of human IDDM.

Effects of Linomide on immune cells and cytokines inhibit autoimmune pathologies of the central and peripheral nervous system

Linomide (roquinimex, LS 2616) is a quinoline-3-carboxamide with pleiotropic immune modulating capacity and it has therapeutic effects in several experimental animal models of autoimmune diseases. Linomide has been evaluated in clinical trials for multiple sclerosis, and was indeed shown to have disease inhibitory effects. However, due to unexpected side effects recorded in patients treated with Linomide, premature termination of clinical trials was required. The basic mechanism(s) of action of Linomide in inducing beneficial effects in autoimmune diseases is still elusive. Some experimental evidence indicates that Linomide influences the regulation of the cytokine profile, resulting in the inhibition of autoimmune and inflammation pathologies. This review focuses on Linomide applied in models for autoimmune and inflammation pathologies of the central and the peripheral nervous system, and summarises its very encouraging disease inhibitory effects and their potential pharmacological basis. The beneficial effects recorded with Linomide in both experimental and clinical trials emphasise the possible value of substances with Linomide-like activity for clinical use in autoimmune and inflammation pathologies in the near future.

Inhibition of autoimmune disease by the immunomodulator linomide correlates with the ability to activate macrophages

Linomide is a potent immunomodulator that has been shown to inhibit autoimmunity in several animal models of autoimmune disease, including experimental autoimmune encephalomyelitis (EAE). Linomide's mechanism of action is unknown, however, it has been suggested to modulate the function of antigen presenting cells (APC) and that this may account for the inhibition of autoimmune disease. In this study we have been able to show that Linomide treatment of SJL/N mice upregulates the cell surface expression of several activation markers on macrophages and B cells. Thus, we found the following markers, expressed as a % of control, to be significantly upregulated following Linomide treatment; MHC class II (260%), Ly-6A/E (520%), CD11a (280%), CD54 (190%) and CD80 (200%) on macrophages and Ly-6A/E (250%) and CD11a (150%) on B cells. The duration and dosage of Linomide required to obtain these effects is similar to those required for EAE inhibition. Several Linomide analogues were made by the introduction of structural modifications into the Linomide molecule, resulting in a number of compounds with varying effects on EAE. We found a linear relationship between the compound's ability to inhibit EAE and its ability to upregulate MHC class II on macrophages (p<0.001), such that compounds which were able to inhibit EAE also upregulated MHC class II expression, whereas those that did not inhibit EAE were unable to do so. These results suggest that drug-mediated activation of distinct APC functions may be protective in autoimmunity.

Dermatologic changes associated with roquinimex immunotherapy after autologous bone marrow transplant

BACKGROUND

Roquinimex (Linomide) is an immunotherapeutic agent used in conjunction with autologous bone marrow transplantation (ABMT) for treatment of acute and chronic myelogenous leukemia (AML and CML). This agent may induce graft-versus-host reactions (GVHR) as well as graft-versus-leukemia (GVL) effects.

OBJECTIVE

We documented the incidence of acute cutaneous GVHR associated with roquinimex immunotherapy. The presence or absence of autologous GVHR was also correlated with a potential GVL effect in patients with CML treated with ABMT and subsequent roquinimex immunotherapy in the period after the transplant.

METHODS

Fifteen patients undergoing bone marrow transplantation and roquinimex immunotherapy for CML were followed up, and clinicopathologic data were analyzed.

RESULTS

Acute cutaneous GVHRs were observed in 6 of 15 patients (40%) treated with roquinimex. Ten of 11 evaluable patients receiving roquinimex exhibited eccrine sweat gland necrosis (ESGN) (90.9%), which was independent of the acute GVHR. Neither bone marrow engraftment status nor the survival rates of patients with and without GVHR was significantly different.

CONCLUSION

Roquinimex immunotherapy enhances the incidence of GVHR and was associated with a high rate of ESGN in patients with CML who were undergoing ABMT. There was no significant association between ESGN and acute GVHR. Acute autologous GVHR caused by roquinimex did not correlate with a GVL effect in our study of 15 patients with CML.

Roquinimex (Linomide) vs placebo in AML after autologous bone marrow transplantation

Roquinimex, Linomide, a quinoline derivative with pleiotropic immunomodulatory activity, has previously been shown to enhance natural killer (NK) cell number and activity after ABMT in patients with AML. In this study 278 AML patients in remission were randomized to receive Roquinimex 0.2 mg/kg body weight or placebo twice weekly for 2 years following ABMT. Out of 139 patients in each group, 109 Roquinimex patients and 108 placebo patients were in their first CR. Median age at inclusion was 41 years for Roquinimex patients and 39 years for placebo patients. Twelve patients in each group had their marrow purged prior to reinfusion. Relapse and death were study endpoints. Surviving patients were followed for 2.6 to 6. 9 years. The total number of relapses was 60 in the Roquinimex group and 63 in the placebo group (not significant). Leukemia-free and overall survivals were similar in the two groups. Recovery of platelet counts was significantly delayed in the Roquinimex group as compared to placebo. No other significant differences regarding toxicity parameters were recorded. In conclusion, previous findings on NK cells could not be confirmed and the study showed no benefit for Roquinimex over placebo regarding relapse or survival following ABMT for AML in remission.

[Anti-angiogenesis: a new approach to tumor therapy?]

BACKGROUND

The overall mortality due to metastatic cancer has not or only minimally been reduced in spite of intensive research and many innovations in the field of conventional antineoplastic therapy in the past decade. In the last years it has become a fact that tumor growth is angiogenesis-dependent. Therefore, inhibitors of angiogenesis are a new class of antineoplastic substances with a novel mechanism of action that might be a powerful complement to conventional cytostatic therapy. SUBSTANCES AND CLINICAL TRIALS: Inhibitors of tumor-angiogenesis which have entered clinical trials, with their results published until December 1998 are discussed here. Most results originate from phase-I or phase-II clinical trials. They are discussed and compared in respect to toxicity and response. Also some substances with high therapeutic potential which are still in preclinical testing are discussed.

RESULTS

Many of the investigated angiogenesis inhibitors demonstrated anti-tumor effects in phase-I or phase-II clinical trials. The commonest manifestation was stable disease, followed by partial remissions. In a few cases, complete remissions were observed. The toxicities of these substances differ both in type and degree of side effects.

CONCLUSION

Some antiangiogenic drugs appear to be promising candidates for a clinical use in the therapy of solid tumors. Further conclusions can only be drawn after evaluation of the results of ongoing phase-III clinical trials.

Tolerance or rejection: A delicate balance as judged by exposure of heart-transplanted rats to the immunomodulator Linomide

When applied in rodent transplant models most immunosuppressive drugs yield adequate graft protection for as long as the drug is given, and permanent graft survival is often induced. The immunomodulator, Linomide, previously shown to stimulate T cells and prevent apoptosis, usually reduces or abolishes both tolerance induction and the graft-protective effect of the immunosuppressive drug. By chance, we observed that Linomide alone exerted a modest but unequivocal graft-protective effect in the BN to WF strain combination. This finding was analysed by simple genetic mapping of rat strains. Untreated WF recipients kept BN grafts for a median of 8 days, whereas Linomide treatment prolonged graft survival to 12. 5 days (P = 0.0001). In control groups (DA to LEW, BN to LEW, DA to WF and WF to BN), median graft survival was 5.5-7 days irrespective of whether Linomide was given. However, the BN to F1 (LEW x WF) combination also manifested slightly longer graft survival in the presence of Linomide. F1 (BN x WF) to WF grafts survived a median of 15 days without Linomide and 46 days with Linomide treatment. Both in the presence and absence of Linomide, two of the control graft combinations [F1 (BN x DA) to WF and F1 (BN x WF) to BN] manifested 6-7-day graft survival. Taken together, our results suggest a delicate balance between unresponsiveness and rejection, while a single agent (Linomide) may either cause on its own long-term survival of allografts in one setting or rejection despite optimal immunosuppression in another setting.

Linomide downregulates autoimmunity through induction of TH2 cytokine production by lymphocytes

Linomide is a synthetic immunomodulator that has been shown to protect animals against a wide range of spontaneously developing or induced autoimmune diseases. We have previously reported that Linomide blocks both the clinical and the histopathological manifestations of experimental autoimmune encephalomyelitis (EAE) in various animal models. In this study, in an effort to elucidate the mechanisms by which Linomide suppresses EAE, and autoimmunity in general, we investigated the in vivo effects of this drug on the TH1/TH2 lymphocyte balance, which is important for the induction or inhibition of autoireactivity. Naive SJL/J mice were treated orally for 15 days with Linomide (80 mg/kg/day). Spleen cells were obtained at various time points during the treatment period and were stimulated in vitro with concanavalin A. Interleukins IL-4, IL-10 and IL-12, transforming growth factor-beta (TGFbeta) and interferon-gamma (IFNgamma) cytokine production was evaluated both by means of detection of the cytokines in the medium (by ELISA technique) and by detection of the cytokine mRNA production, using a semiquantitative reverse transcriptase polymerase chain reaction method. A significant upregulation of IL-4, IL-10 and TGFbeta was observed following treatment with Linomide, which peaked at day 10 (IL-10) or day 15 (IL-4). On the other hand, IL-12 and IFNgamma production were either unchanged or decreased. It seems therefore that Linomide induces in vivo a shift towards TH2 lymphocytes which may be one of the mechanisms of downregulation of the autoimmune reactivity in EAE. Our observations indicate that downregulation of TH1 cytokines (especially IL-12) and enhancement of TH2 cytokine production may play an important role in the control of T-cell-mediated autoimmunity. These data may contribute to the design of new immunomodulating treatments for a group of autoimmune diseases.

Effect of the synthetic immunomodulator, linomide, on experimental models of thyroiditis

The drug Linomide is an immunomodulator showing marked down-regulation of several experimental autoimmune diseases. In this study, its effect on three different experimental models of thyroid disease and on spontaneous infiltration of salivary glands (sialoadenitis), was investigated. Although very effective at preventing thyroid infiltrates in mice immunized with mouse thyroglobulin and complete Freund's adjuvant and in spontaneous models of thyroiditis and sialoadenitis, it completely failed to modify experimental autoimmune thyroiditis (EAT) induced in mice immunized with mouse thyroglobulin and lipopolysaccharide. There was no significant shift in the observed isotypes of anti-mouse thyroglobulin antibodies and only anti-mouse thyroglobulin antibodies in the spontaneous model were completely down-modulated by the drug. One surprising fact to emerge was that Linomide-treated donor mice, although protected from thyroid lesions themselves, were still able to transfer EAT showing that they must have been effectively primed while being treated with Linomide. It is possible that the drug down modulated EAT by interfering with the trafficking of primed effector cells.

Antithymocyte globulin and cyclosporin A are synergistic in an experimental transplantation tolerance model in the rat

The aim of the present investigation was to study the possible synergistic effect between cyclosporin A (CsA) and antithymocyte globulin (ATG), using the potent immunostimulator, Linomide. DA rats were transplanted with a PVG/c heart to the neck vessels, and the recipients were treated for 10 days with oral CsA (10mg/kg), oral Linomide (160mg/kg) and/or ATG, which was given as a single dose of either 0.02 ml, 0.1 ml or 0.2 ml prior to transplantation. Rats given a combination of ATG and Linomide or CsA and Linomide were used as controls. Synergism between CsA and ATG was tested using the two immunosuppressive drugs given in combination in order to override the challenge of Linomide. CsA or ATG treatment alone resulted in rats with long-term surviving grafts. Addition of Linomide to CsA-treated recipients was followed by early graft rejection. Similarily, Linomide triggered rejection in rats given a low dose of ATG and in recipients given a high dose of ATG if Linomide treatment was prolonged to 21 days. The combination of ATG, CsA and 21 days of Linomide resulted in a significantly prolonged graft survival compared with either ATG + Linomide or CsA + Linomide. These findings demonstrate the synergistic capacity of ATG and CsA in combined immunosuppressive therapy.

Linomide induces apoptotic death of cortical CD4/CD8 double positive thymocytes and thymic atrophy by a corticosteroid-independent pathway

Linomide is a synthetic immunomodulator which was shown to protect animals against a wide range of experimental autoimmune diseases. In this study we have investigated the effects of Linomide on the thymus in an effort to elucidate the mechanisms by which this immunomodulator suppresses autoimmune reactivity. Normal or adrenalectomized SJL/J mice were treated orally for 10 days with linomide (80 mg/kg/day). Thymocytes were tested by FACS for the analysis of the CD4 and CD8 markers and TCR expression on their surface. Thymuses from these animals were examined for size and cellularity and immunohistopathologically for the detection of apoptosis and for the expression of the markers CD4 and CD8. A significant reduction in the thymus size and cellularity was observed in mice treated with Linomide, starting from day 3 after treatment, accompanied by an enhanced apoptotic death of cortical thymocytes, which was first noted on day 1 of treatment and peaked on day 3. FACS analysis and immunohistochemistry revealed a significant depletion of the CD4(+)/CD8(+) (double positive) cells with a parallel relative increase of the more mature, medullar, single positive, lymphocytes. These effects on the thymus were not mediated through a corticosteroid-dependent pathway, and were also observed in adrenalectomized and Linomide-treated animals. These observations may be of importance for the clarification of the role of thymus in autoimmunity and the possible ways for immune intervention with immunomodulators like Linomide at this level.

A feasibility study of roquinimex (Linomide) and alpha interferon in patients with advanced malignant melanoma or renal carcinoma

Thirty-one patients with advanced renal carcinoma or malignant melanoma were treated in the first feasibility study of alpha-interferon (Roferon) and the new oral immunomodulating agent, Linomide. Linomide 5 mg or 10 mg p.o. daily was given for 2 weeks; alpha-interferon was then added at 3 MU s.c. three times weekly, escalating in each patient by 3 MU per week, if tolerable, up to 12 MJ. The combination was poorly tolerated with nausea, vomiting, somnolence and myalgia commonly reported. Adverse events accounted for treatment withdrawal in ten patients and contributed to withdrawal in four other patients. Treatment with Linomide alone in the first 2 weeks led to a significant increase in white blood cells, neutrophils and platelets. When alpha-interferon was added, the platelet count decreased significantly over the following 6 weeks. Nineteen patients had white cell phenotype and function measured. After 2 weeks of 5 mg Linomide, a transient but significant decrease in the absolute number of activated T-helper cells (CD4+DR+) was observed. No changes in natural killer (NK) cell number or activity were observed. Twenty-two patients were evaluable for response. One with metastatic renal cell carcinoma had a complete response and six had stable disease. This study does not support the use of the combination because significant toxicity was seen without the anticipated immunological benefits.

Linomide (roquinimex) affects the balance between pro- and anti-inflammatory cytokines in vitro in multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is characterized by high levels of circulating mononuclear cells (MNC) that respond to myelin proteins like myelin basic protein (MBP) in vitro by expressing mRNA of both pro-inflammatory cytokines, e.g. interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin (LT) that may make MS worse, and anti-inflammatory cytokines like IL-4, IL-10 and transforming growth factor-beta (TGF-beta) that may act beneficially. Substances that down-regulate cytokines such as TNF-alpha or promote IL-10 or TGF-beta can be anticipated to affect MS beneficially.

MATERIAL AND METHODS

In situ hybridization to detect and enumerate IFN-gamma, TNF-alpha, LT, IL-4, IL-10 and TGF-beta mRNA expressing blood MNC after stimulation with myelin basic protein (MBP), control antigens and without antigen in presence and absence of Linomide (roquinimex, LS-2616) was employed. In parallel, ELISPOT assay to detect MBP- and PHA-reactive IFN-gamma secreting blood MNC+/-Linomide was used.

RESULTS

Here we report that Linomide, a synthetic immunomodulator, at concentrations effective in vivo reduces the number of MBP-reactive TNF-alpha and increases MBP-reactive IL-10 and TGF-beta mRNA expressing MNC from MS patients' blood when analysed in vitro. Compared to dexamethasone, Linomide up-regulated levels of blood MNC expressing mRNA of TGF-beta after culture in presence of MBP.

CONCLUSIONS

Changes of cytokine balance towards a production of anti-inflammatory cytokines could be a desirable effect to be evaluated in future drug studies of Linomide-like substances. At present, Linomide is not evaluable in MS clinical trials due to side-effects.

Reduction in basic fibroblast growth factor mediated angiogenesis in vivo by linomide

Linomide (N-phenylmethyl-1,2-dihydro-4-hydroxyl-1-methyl-2-oxoquinoline-3-carboxa mide) is a novel immunomodulator with a potent anti-tumoral activity. This study was undertaken to test the effect of Linomide on basic fibroblast growth factor (bFGF) induced angiogenesis in vivo, which manifests itself in an increased number of blood vessels per unit of cell infiltrated area. Subcutaneously implanted polyvinyl alcohol sponges (PVS) in guinea pigs were used as a model system to quantitate angiogenesis in vivo. Oral treatment with Linomide was able to reduce significantly the bFGF induced blood vessel growth and proliferation within the implanted PVS, relative to untreated controls. In addition, Linomide significantly reduced the bFGF mediated augmentation of protein and collagen content in the implanted PVS, indicating an inhibition in the deposition of extracellular matrix (ECM). We conclude that the potent inhibition of bFGF induced angiogenesis by Linomide in vivo in addition to immunomodulatory effects may have potentially important clinical applications.

Linomide suppresses acute experimental autoimmune encephalomyelitis in Lewis rats by counter-acting the imbalance of pro-inflammatory versus anti-inflammatory cytokines

Linomide (quinoline-3-carboxamide) is a synthetic immunomodulator that suppresses several experimental autoimmune diseases. Here we report the effects of Linomide on experimental autoimmune encephalomyelitis (EAE), a CD4+ T cell-mediated animal model of multiple sclerosis (MS). EAE induced in Lewis rats by inoculation with homogenized guinea pig spinal cord and Freund's complete adjuvant was strongly suppressed by Linomide administered daily subcutaneously from the day of inoculation. Linomide dose-dependently delayed the interval between immunization and onset of clinical EAE, and reduced severity of EAE symptoms. These clinical effects were associated with dose-dependent down-modulation of myelin antigens-induced T cell responses and by suppression of the proinflammatory cytokines IFN-gamma and TNF-alpha, and upregulation IL-4, IL-10 and TGF-beta as evaluated by in situ hybridization for mRNA expression in spleen mononuclear cells and spinal cord sections. These findings suggest that Linomide could be useful in certain T cell dependent autoimmune diseases.

Linomide blocks angiogenesis by breast carcinoma vascular endothelial growth factor transfectants

The blocking of angiogenesis provides a novel therapeutic target to inhibit tumour spreading. In this study, we investigated the effect of linomide on angiogenesis induced in vivo by highly angiogenic breast carcinoma cells. The rabbit cornea was used to assess neovascular growth in the absence of a tumour mass. MCF-7 cells stably transfected with the cDNA encoding for vascular endothelial growth factor 121 (VEGF121) (V12 clone) were used to elicit a potent VEGF-dependent corneal angiogenesis. After tumour cell implant, albino rabbits received 100 mg kg(-1) day(-1) linomide for 5 consecutive days. Daily observation of neovascular progression indicated that linomide blocked angiogenesis. The antiangiogenic effect of linomide was apparent within 48 h from the beginning of the treatment and was both angiosuppressive and angiostatic. The block of neovascular growth lasted over 10 days from treatment suspension, and preformed vessels, which had regressed, remained dormant, suggesting the persistence of unfavourable conditions for capillary progression. Linomide (50-200 microg ml[-1]) was not cytotoxic in vitro on resting capillary endothelial cells but blocked endothelial cell replication induced by VEGF. Our data indicate that linomide can efficiently and persistently block VEGF-dependent angiogenesis in vivo in the absence of a growing tumour mass. These data suggest that linomide could be a chemopreventive drug in breast cancer patients and a valuable tool in clinical settings in which metastatic spreading occurs in the absence of a detectable tumour mass.

Hematopoietic progenitor cell transplantation in breast cancer: current status and future directions

Breast cancer remains the second leading cause of cancer death despite numerous advances in medical science. In vitro, preclinical, and clinical trials have shown that chemotherapy dose intensity is an important component of therapy. Many clinical trials addressing the use of high-dose chemotherapy and hematopoietic cellular rescue have been conducted over the past decade. Early trials undertaken in heavily pretreated patients who had metastatic disease were associated with high treatment-related mortality rates; good response rates were noted but overall survivals were short. Subsequent technological advances, including the use of recombinant hematopoietic growth factors and peripheral blood progenitor cells as the source of cellular rescue, have dramatically lowered the morbidity and mortality of the procedure, as well as shortened hospital stay and markedly reduced cost. As a result, the high-dose chemotherapy approach has been used earlier in the disease course, both in patients with metastatic disease who were responding and in the adjuvant setting in patients at high risk for relapse. Results of many of these phase II trials are extremely encouraging, and phase III prospective, randomized trials comparing autotransplant to conventional approaches are currently under way. This review discusses past, current, and future initiatives of this modality. Included is a discussion of new preparative regimens, the addition of agents such as biochemical modifiers to enhance antitumor activity, and issues regarding timing of autotransplant, stem cell technology, use of allogeneic stem cells, and posttransplantation therapies.

The effects of leflunomide and cyclosporin A on rejection of cardiac allografts in the rat

Leflunomide is a new low molecular weight immunosuppressive drug which inhibits the enzymes dehydroorotate-dehydrogenase and protein tyrosine kinase, both of which are important components in the immune response. As the mechanisms of action of leflunomide and cyclosporin A (CsA) are different, we postulated a synergistic effect of the two drugs and tested graft survival following leflunomide administration alone or in combination with CsA in a rat cardiac transplantation model. Low- and high-responder rat strain combinations were used in parallel and the experiments were performed both with and without challenge with Linomide, an immunomodulator which promotes graft rejection in this model. In the low-responder rat strain combination (Piebald Virol Glaxo graft to Dark Agouti recipient; PVG to DA), graft survival appeared to be a dichotomous variable, being characterized by tolerance or early rejection. Leflunomide (10 or 5 mg/kg) given for 10 days induced tolerance and CsA did likewise; the addition of Linomide abolished the immunosuppressive effect of leflunomide but not that of CsA. In the high-responder combination (DA to PVG), no tolerance was seen and graft survival was moderately prolonged both after leflunomide and after CsA treatment; the addition of Linomide to CsA or to leflunomide (5 mg/kg) abolished the immunosuppressive effect of the drugs. However, when CsA-Linomide or leflunomide-Linomide were supplemented with the second immunosuppressive drug, leflunomide or CsA respectively, graft survival was significantly prolonged (P < 0.001 in both cases). This suggests leflunomide and CsA have additive potential.

The effect of linomide, an immunoregulator in experimental autoimmune diseases, on humoral antibody responses in mice

Linomide (quinoline-3-carboxamide), a well tolerated, orally administered compound was recently shown to be effective in the prevention and treatment of several autoimmune diseases in experimental animal models. We have investigated its effect on specific humoral immune responses directed to T-cell-dependent soluble or particulate antigens and to a T cell-independent antigen in several mouse strains. Linomide administered after antigen priming did not affect primary and secondary antibody responses directed to T-cell particulate antigens (SRBC) or soluble antigens given with or without complete Freund's Adjuvant (CFA). Linomide treatment given prior to antigen priming did not affect the antibody response to a soluble antigen (TNP-KLH) given with an adjuvant. In contrast, dose-dependent down regulation of primary antibody responses was observed when T cell-dependent (BSA-dextran) or T-cell-independent (TNP-Ficoll) antigens were administered in an immunogenic form without adjuvant after starting Linomide treatment. The primary anti-SRBC antibody response was also suppressed by high dose Linomide given prior to immunization although normal secondary responses were retained. It is worth noting that no immunosuppressive effects on antibody responses were found at low dose ranges which effectively reversed T cell dependent autoimmune manifestation.

Single dose anti-CD4 monoclonal antibody for induction of tolerance to cardiac allograft in high- and low-responder rat strain combinations

Repeated administration of monoclonal antibodies (mAb) directed against the CD4 lymphocyte receptor may induce specific, long-lasting unresponsiveness to fully MHC-mismatched cardiac allografts in rats without additional immunosuppression. We assessed the effect of a single dose of murine anti-rat depleting anti-CD4 mAb (OX-38) on allograft survival in high- and low-responder rat strain combinations. Isogenic strains of DA (RT1av1), PVG (RT1c), AUG (RT1c), and WF (RT1u) rats were used. Recipients in antibody treated groups were given one dose of 5 mg/kg OX-38 mAb on the day of transplant, a dose which was shown to effectively deplete (or block) circulating CD4+ T cells. Other groups were treated for 10 days with cyclosporin A (CsA) and/or Linomide, a novel immunomodulator, which is the first compound able to fully eliminate the effect of CsA in the rat cardiac allograft model. The DA strain was identified as a low-responder to the allogeneic haplotype RT1c (PVG or AUG), but not to RT1u (WF), and developed true tolerance following RT1c grafting and OX-38 or low-dose CsA (5 mg/kg) induction, as verified by the response to retransplantation of a graft from the same donor strain or a third-party challenge. PVG recipients of DA grafts were characterized by high response and only modest (OX-38; median 9.5 days) or moderate (CsA; 23.5 days) prolongation of graft survival. Contrasting graft survival results were obtained in the low-responder combination, either very early rejection (at 10 days) or permanent graft survival (> 100 days). Linomide challenge affected CsA treatment in the high-responder combination but not tolerance induction in the low-responder combination, or the effect of OX-38. It was concluded that in rat heart transplantation a single-dose anti-CD4 mAb therapy may induce permanent donor-specific unresponsiveness in a low-responder strain combination, and that anti-CD4 mAb seems to be unique among immunosuppressive agents while being resistent to challenge by Linomide.

Immunomodulation of autoimmunity by linomide: inhibition of antigen presentation through down regulation of macrophage activity in the model of experimental autoimmune encephalomyelitis

Linomide (quinoline-3-carboxamide, LS-2616), a synthetic immunomodulator, protects animals against a variety of experimental autoimmune diseases. In experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), linomide blocks both the clinical and histological signs of the disease, without inducing generalized immunosuppression. In the first clinical trial in patients with MS, linomide was shown to inhibit the progression of the disease. In the present study we investigated several aspects of the mechanisms of action of this immunomodulator. We found that linomide can inhibit acute EAE even when given as pretreatment, prior to induction of disease (days - 10 to 0). This inhibitory effect was reversed by adoptive transfer of naive spleen cells. A short course (7 days) of linomide treatment also inhibited EAE, especially when administered immediately after disease induction. Spleen cells from linomide-treated mice failed to present myelin antigens to T-cell lines in vitro. The defective antigen presentation was normalized by anti-oxidants such as 2-mercaptoethanol. The proportion of Mac1+ cells in the spleens of linomide-treated mice was significantly reduced and macrophage growth was inhibited in long term cultures of spleen cells derived from linomide-treated animals. Our findings suggest that the effect of linomide on EAE may be attributed, at least in part, to inactivation of antigen presenting cells, possibly following a short period of over-stimulation and increased oxidant production. This mechanism may play a universal role in the regulation of autoimmune reactivity and merits further investigation.

EORTC phase II study of daily oral linomide in metastatic renal cell carcinoma patients with good prognostic factors

Following a previous EORTC GU-Group study, in which linomide showed some activity in poor prognosis patients, this study was initiated to determine the effect of linomide in more favourable patients. 35 patients with metastatic renal cell carcinoma with good prognostic factors, i.e. good performance status, prior nephrectomy, no prior systemic therapy, and no liver, bone or brain metastases, were treated with linomide, a quinoline derivative with immunomodulating properties, at a dose of 10 mg daily, after an initial dose escalation during the first 4 weeks of treatment. In 29 evaluable patients, no responses were observed (95% confidence interval 0-10%). Best overall response was no change in 9 patients, for a median duration of 4 months. Linomide in this schedule was poorly tolerated, with 17% (6 patients) of patients being withdrawn and 23% (8 patients) having dose reductions due to adverse events, mostly influenza-like symptoms of myalgia, arthralgia and fatigue. Several cases of pericarditis and neuropathy were observed. In spite of selection of favourable prognosis patients and an optimal daily dosing schedule, linomide was not an effective treatment in renal cell carcinoma. In view of toxicity and lack of efficacy, there is no rationale in further testing the drug in this disease.

An overview of clinical trials involving inhibitors of angiogenesis and their mechanism of action

Angiogenesis is a biologic process whereby endothelial cells divide and migrate to form new blood vessels. This process is required in physiological conditions, but is also a necessary requirement for solid tumors to grow and metastasize. Over the last several years, the growth factors that have both a positive and negative influence on tumor angiogenesis have been delineated. Interfering with tumor angiogenesis was considered a potential therapeutic strategy 25 years ago, but only recently have compounds with an ability to interfere with angiogenesis entered clinical trials. This review will discuss the first generation of angiogenesis inhibitors, their mechanism of action and data from clinical trials.

The first clinical pilot study of roquinimex (Linomide) in cancer patients with special focus on immunological effects

Roquinimex (Linomide) has been demonstrated to suppress tumor growth in animal models. The effect is at least in part related to enhanced numbers and activity of natural killer (NK) cells. In this clinical pilot study, roquinimex was given at increasing doses (0.05 mg/kg to 0.6 mg/kg) to 13 patients (performance status 0-3) with various malignant disorders. Immunology parameters were followed and side effects were observed during the study. The plasma pharmacokinetics of roquinimex was studied at the 0.2 mg/kg dose level. The clinical side effects were dominated by musculoskeletal discomfort, nausea, and pain. No significant hematological or biochemical toxicity was observed. Pharmacokinetic analysis at the 0.2 mg/kg dose level revealed a Cmax of 4.0 mumol/L at tmax of 1.2 hr and an elimination half-life of 42 hr. Increased numbers of phenotypic NK cells, activated T (DR+CD4+) cells, and monocytes were observed after administration of roquinimex compared with pretreatment values. Roquinimex seems to be an active immunomodulator with manageable toxicity. Further exploration of therapeutic efficacy is warranted.

Graft-versus-leukemia effect and its clinical implications

Graft-versus-leukemia (GVL) effect is an immunologically important phenomenon which decreases the relapse rate of leukemia after allogeneic bone marrow transplantation. GVL effect is sometimes associated with the occurrence of graft-versus-host disease (GVHD). Analyses of GVL effect and GVHD showed that these two phenomena were separable in some conditions. Although we cannot yet completely control the development of the GVL effect without inducing GVHD in humans, basic analyses using animal models show potential benefits of the GVL effect for clinical applications. Autologous GVHD is another important phenomenon which can help to eradicate minimal residual disease. Interleukin 2 and/or cyclosporin A are extensively used in animal models and in humans to induce autologous GVHD, showing beneficial effects. In the future, cytokine usage and allogeneic stem cell transplantation or leukocyte infusion appear to be promising in the control of minimal residual disease. Further studies on the mechanisms of GVL effects and GVHD may well open a new era for cell transplantation.

Immunomodulation with linomide: possible novel therapy for multiple sclerosis

Linomide, a synthetic quinoline carboxamide, has the ability to stimulate various lymphocyte subpopulations. We have shown its inhibitory effect on the clinical and histological signs of acute and chronic relapsing EAE. In these models linomide induces suppression of lymphocyte response to antigens, production of autoantibody, antigen presentation to specific T-cell lines and Mac-I expression, and induces activation of NK and suppressor-inducer cells. We have subsequently shown its inhibitory effect on clinical and MRI signs of patients with secondary progressive multiple sclerosis. Results of a double blind, placebo controlled, short term pilot study with p.o. linomide, showed a significant effect on the clinical disability scale (EDSS) (P = 0.045) and on the mean total number of new lesions in serial monthly MRI scans (P = 0.021). The increase of CD45Ra, CD8 and CD16 positive cells in linomide treated patients may indicate the importance of suppressor-inducer, suppressor and NK cells for the inhibition of the autoimmune response in the disease.

Moderate additive immunosuppressive effect of thalidomide combined with cyclosporin A in rat cardiac transplantation

Thalidomide is an immunomodulating agent shown to prolong graft survival in experimental skin, renal, cardiac and bone marrow transplantation. The main purpose of the present study was to investigate the possible additive effect of combining thalidomide with cyclosporin A (CyA). Members of our group have previously created a basis for such studies by demonstrating the ability of Linomide to abolish the effect of CyA. The additional effect of combined treatment with a second drug is thereby more readily evaluated, compared with using subtherapeutic dose levels to induce early rejection. Cardiac grafting was performed in three rat strain combinations (BN to WF, DA to Lew, and BN to Lew). Rats were given no treatment, or thalidomide, CyA and/or Linomide in single, double or triple drug therapy. Except for a consistent beneficial effect of CyA as single drug treatment, graft survival varied depending on the rat strain combination used. In the DA to Lew combination, the expected effects of Linomide were seen, and thalidomide was shown to prolong graft survival significantly (P = 0.004) when added to CyA and Linomide. However, there was no effect of thalidomide when given alone. In WF recipients of BN hearts, thalidomide tended to prolong graft survival (P = 0.07), and surprisingly Linomide manifested a marked immunosuppressive effect (P = 0.0002) and did not counteract the effect of CyA. When transplanting BN grafts to Lew recipients, Linomide reduced significantly but did not abolish completely the effect of CyA. Neither Linomide nor thalidomide had any beneficial impact on graft survival on their own. To sum up, thalidomide was shown to have a minimal or moderate immunosuppressive effect additive to that of CyA. The effects of the two immunomodulating drugs, thalidomide and Linomide, varied depending on the rat strain combination used, and were similar with respect to prolongation of graft survival when used as single drug treatment in BN to WF grafting, a fact which may indicate them to have a similar mechanism of action, both having been shown to exert similar effects on levels of tumour necrosis factor alpha.

Introductory remarks: immunosuppressive and immunomodulating drugs, where and how do they act?

Immunotherapies used in multiple sclerosis are reviewed. The mechanisms of action supporting their clinical application are described according to our current understanding. Immune treatments can be divided into three groups: (1) cytostatic and cytotoxic immunosuppressants which block the cell cycle of immunocompetent cells and/or provoke their deletion; (2) immunomodulators which specifically interfere in cellular or humoral immune mechanisms; (3) immunoregulators which restore immunodeficient states but have also immunosuppressive properties at the same time. Numerous attempts have been made to correct almost all abnormal immune mechanisms underlying disease progression. The results of those clinical trials are reviewed. Recent studies have demonstrated that a severe, unspecific and sustained immunosuppression markedly downregulates the clinical and pathological activity of the disease. Unfortunately, serious delayed adverse effects prevent a long-term administration. Recent specific immunomodulators with an acceptable toxicity have provided modest but unquestionable benefit on the attack rate and MRI lesion burden. No clear effect on progression has been demonstrated to date. There is still much work to be done to improve the efficacy of our current therapies on the attack rate and particularly on the progression. Several promising new compounds are already under evaluation. Another approach is combination therapies which will certainly become critical in MS like in other autoimmune diseases.

The novel immunomodulator, Linomide, stimulates interleukin-2-induced human natural killer (NK) cell and PHA-stimulated T cell proliferation from normal donors

Donor-derived cell-mediated immunotherapy has been shown to be an effective tool for reinduction of remission in chronic myeloid leukaemia (CML) patients who have relapsed post-bone marrow transplantation (BMT). Linomide, quinoline-3-carboxamine (LS 2616), is a new immunomodulator shown to increase the number of NK precursors in mice in addition to upregulating the quantity of CD56(+), CD3(-) and CD16(+) NK cells in the peripheral blood of patients following autologous BMT (ABMT). We investigated the in vitro effects of Linomide on NK activity of normal human donors. Large granular lymphocytes (LGLs) and NK cells were incubated overnight with Linomide (0.02-4.8 mg/ml), recombinant human interleukin-2 (IL-2, 75 IU/ml), or a combination of both. Linomide, at 0.02-0.3 mg/ml, augmented IL-2-induced proliferation of LGLs and NK cells in an inversely proportional manner. In contrast, Linomide at 0.6-4.8 mg/ml inhibited IL-2-induced proliferation of LGLs and NK cells in a dose-dependent manner. Linomide was able to potentiate phytohemaglutinin-induced CD3(+) cell proliferation. In addition, supernatants derived from Linomide treated CD3(+) T cells were able to mimic the direct stimulatory effect of Linomide on activated NK cell proliferation. These supernatants were found to have low levels of tissue necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) and therefore Linomide stimulation of NK and T cell proliferation may be due to its inhibitory effect on the secretion of these cytokines by activated CD3(+) T cells. Linomide had no effect on cytotoxicity nor on the phenotypic expression of resting and IL-2-activated LGLs or NK cells. In view of our results, Linomide could possibly play a potential role in adoptive cell-mediated immunotherapy post-BMT.

Linomide increases plasma corticosterone in normal rats, but does not prevent the inhibitory action of IL-1 on beta-cells in vivo or ex vivo

Recently, the synthetic immunomodulator Linomide (quinoline-3-carboxamide, LS 2616) was reported to prevent IDDM and insulitis in NOD mice. The mechanism for this protective effect is not known. The cytokine interleukin 1 (IL-1) may be a pathogenetic factor in the initial destruction of the beta-cells leading to IDDM. This study was undertaken to investigate the influence of Linomide on IL-1beta induced diabetogenic and hormonal changes in the rat in vivo, and on IL-1beta mediated synthesis of NO and inhibition of insulin secretion in isolated islets of Langerhans ex vivo. Normal male Wistar Kyoto rats received 4.0 microg/kg of recombinant human IL-1beta (rhIL-1beta) i.p. daily for 5 days with or without Linomide (8-9 mg/kg/day) in the drinking water. Litters of neonatal Wistar rats were pretreated for 3 days with injections of 10 mg/kg of Linomide i.p., and pancreatic islets of Langerhans were isolated for ex vivo studies. Linomide alone caused significant hypercorticosteronemia, hypoglucagonemia, lymphopenia and neutrophilia. Linomide had no effect on IL-1beta induced hyperglycemia, hyperglucagonemia, lymphopenia, neutrocytosis, or hypercorticosteronemia on day three and hypocorticosteronemia on day five. Further, Linomide did not prevent rhIL-1beta mediated reduction in insulin secretion or increase in NO synthesis ex vivo. In conclusion, Linomide does not seem to exert its protective effect on IDDM development via inhibition of interleukin 1 action on islet insulin release or NO production, but the increase in plasma corticosterone may contribute to the understanding of the immunomodulatory effects of Linomide.

Enhanced lymphokine-activated killer cell activity by an immunomodulator, Roquinimex

Roquinimex (Roq) is an immunomodulator known to stimulate cellular immune responses. It is currently used for immunotherapy after bone marrow transplantation (BMT). One of the major features of this compound is an enhancement of natural killer (NK) cell activity and numbers. We studied the in vitro effect of Roq on human peripheral blood NK and adherent lymphokine-activated killer cell (ALAK) activities. In cultures supplemented with recombinant interleukin 2 (rIL-2) (1000 U ml-1) and Roq a significant increase in NK and LAK function was observed without a parallel increase in cell numbers. We also examined the generation of NK cells from human bone marrow (BM) immature progenitors, obtained by purging with 4-hydroperoxycyclophosphamide (4HC). NK cell numbers and activity were both increased when cultures with rIL-2 (10 U ml-1) were supplemented with Roq. These results confirm findings obtained in vivo and in vitro in the murine system and suggest that Roq is an active agent on these lymphoid populations. These properties and good tolerability make Roq an attractive tool for immunotherapy.

Roquinimex-induced graft-versus-host reaction after autologous bone marrow transplantation

BACKGROUND

Roquinimex is being used for posttransplantation immunotherapy of autologous bone marrow transplantation for acute and chronic myelogenous leukemia. This immunotherapeutic agent is a cytokine inducer and may induce an autologous graft-versus-host (GVH) and graft-versus-tumor reactions.

OBJECTIVE

Our purpose was to examine patients undergoing this immunotherapy for clinical signs and symptoms of acute GVH reactions and to correlate these symptoms with their clinical outcome.

METHODS

We studied eight patients receiving requinimex therapy.

RESULTS

We found autologous GVH reactions in three of eight patients (38%) treated with this immunotherapy. Their disease was manifested by localized or widespread violaceous papules that on histologic evaluation were compatible with a grade II GVH reaction. The acute cutaneous GVH reaction was associated with eccrine sweat gland necrosis, a dermatologic toxicity usually associated with chemotherapy.

CONCLUSION

Long-term studies of larger numbers of patients treated with this immunotherapy will determine whether these GVH reactions confer significant, sustained, antitumor effects.

Induction of tumor immunity by intact irradiated leukemic B cells (BCL1) bearing a tumor-associated cell-surface idiotype and the costimulatory B7 molecule

The idioptypic (Id) determinant of immunoglobulin expressed on the cell surface of malignant B cells represents a prototypical tumor-associated antigen (TAA), which has been used in a purified soluble form for active immunization in experimental tumor models and human hematological malignancies. Using a spontaneous transplantable murine model of B cell leukemia/lymphoma (BCL1), we have demonstrated the expression of the B7 costimulatory molecules in addition to the previously described Id determinant and class II major histocompatibility antigens. Intact irradiated BCL1 cells bearing these distinct determinants induced long lasting antitumor immunity in naive syngeneic mice. Induction was dose-dependent and most effective when three doses of 30 x 10(6) intact irradiated BCL1 cells were given at intervals of 7-10 days. The induced immunity protected 96% of 28 mice inoculated with a lethal dose of 10(5)-10(6) nonirradiated BCL1 cells and 85% of 27 mice given a second challenge, whereas control mice died on day 20 after inoculation with 10(6) BCL1 cells. Adoptive transfer of splenocytes derived from immune mice did not induce leukemia in syngeneic recipients. Such splenocytes, harvested more than 365 days following immunization and administered together with fresh BCL1 cells to adoptive recipients, were able to confer protection for 90 days, even following a second challenge given 104 days after the first one. BCL1 immune splenocytes transferred into BCL1-bearing mice exerted a therapeutic effect, preventing leukemia onset for at least 180 days. Our results demonstrate the ability of tumor cells to trigger effective anti-tumor immunity. These findings could ultimately be applied to the prevention of tumor relapse in treatment of hematological and other malignancies expressing TAA, class II MHC antigen and costimulatory molecules.

Inhibition of tumor angiogenesis and the therapeutic ability of linomide against rat prostatic cancers

Linomide, a quinoline-3-carboxamide, has growth-inhibitory effects against a series of Dunning R-3327 rat prostatic cancers in vivo [Ichikawa et al.: Cancer Res 52:3022-3028, 1992]. In addition, we have demonstrated that daily linomide treatment can inhibit angiogenic responses in nontumor-bearing rats and reduce tumor blood flow in tumor-bearing rats [Vukanovic et al.: Cancer Res 53:1833, 1993]. In the present study we have demonstrated that the reduced tumor blood flow is due to linomide's ability to inhibit tumor angiogenesis, as documented by decreased number of blood vessels in prostatic carcinomas growing in rats treated daily with linomide. Due to linomide's ability to inhibit tumor angiogenesis, and since tumor angiogenesis is required not only for the growth of the primary cancer but also for its ability to metastasize, the effect of linomide on metastasis was directly tested using a quantitation metastasis assay. These in vivo experiments demonstrated that daily linomide treatment decreased by 3-fold the extent of dissemination of cancer cells to the lungs. To test if this antimetastatic response is due to direct effects of linomide on the metastatic cells themselves as well as an induced effect upon inhibition of tumor angiogenesis, additional studies were performed. These studies demonstrated that linomide is not converted in vivo to metabolite(s) which are directly cytotoxic or cytostatic to the prostatic cancer cells themselves. These studies also demonstrated that linomide does not decrease the attachment, migration, or invasive abilities of metastatic cancer cells. These results suggest that the major mechanism for the antitumor and antimetastatic effects of linomide is via its inhibition of tumor angiogenesis. Additional studies have demonstrated that in vivo linomide treatment results in the apoptotic death of thymocytes. This cytotoxic effect is not required for linomide's antitumor effect, nor is it due to elevated plasma levels of glucocorticoid.

Bone marrow transplantation in low-grade non-Hodgkin's lymphoma

The low-grade histologic types constitute one quarter of all non-Hodgkin's lymphomas (NHL). Conventional chemotherapy and chemo-radiation therapy have failed to significantly alter the course of this disease, and most patients eventually succumb to lymphoma. Despite the fact that NHLs exhibit a steep dose-response relation to cytotoxic therapy, fewer than 30% of eligible patients undergo bone marrow transplantation. Reasons for fewer patients receiving this course of treatment include: elderly patient population, extensive previous chemotherapy and/or radiation therapy, high incidence of bone marrow involvement, and transformation to higher grade NHLs. In recent years, improvements in several areas have enhanced the therapeutic index for bone marrow transplantation. These advances include the use of more effective preparative regimens, recombinant hematopoietic growth factors, extended-spectrum antibiotics, and an increased expertise in blood transfusion techniques and practices. Other, more effective strategies include sophisticated in vitro bone marrow purging approaches and peripheral blood progenitor cell collection. As a result, more patients have been able to receive dose-intensive therapy followed by hematopoietic cellular rescue. Although follow up is short in most series, encouraging results have stimulated some centers to begin transplanting responding patients earlier in their disease course; in more than 200 patients treated in this fashion, long-term disease-free survival has been achieved in nearly 70% of patients, some patients for a period of greater than 6 years. The new purine analogues fludarabine, pentostatin, and 2-chlorodeoxyadenosine also have shown promise in both initial and salvage treatment of low-grade NHLs. It remains to be determined whether this group of drugs will be complimentary to the bone marrow and/or peripheral blood progenitor cell transplant approach.

Prevention of diabetes mellitus in non-obese diabetic mice by Linomide, a novel immunomodulating drug

Oral administration of the synthetic immunomodulating drug quinoline-3-carboxamide (Linomide) in the drinking water to 5-week-old female non-obese diabetic (NOD) mice resulted in complete protection from insulitis and maintenance of normal glucose tolerance for over 40 weeks (impaired glucose tolerance: treated n = 2 of 18; control n = 17 of 18, p < 0.0001). Delayed administration of the drug at 16 weeks resulted in slowing of the progression to diabetes when assessed at 42 weeks (treated with diabetes n = 7 of 25; control with diabetes 25 of 43, p < 0.0234). No gross changes of immune system cell phenotype or function were observed in the Linomide-treated group. Adoptive transfer of spleen and lymph node cells from treated female NOD mice into sub-lethally irradiated male recipients failed to transfer diabetes, whereas a similar transfer of cells obtained from untreated age-matched controls resulted in diabetes in all secondary recipients (diabetes in control group n = 12 of 13; in Linomide group n = 0 of 11, p < 0.0001). Linomide pretreatment of the secondary recipients also inhibited the transfer of diabetes (diabetes in pretreated group n = 2 of 9, control group n = 12 of 13, p < 0.015), as did adoptive co-transfer of cell mixtures obtained from treated female NOD mice, free of diabetes, and from diabetic NOD female mice (diabetes in Linomide group n = 4 of 9; in control group 7 of 7, p < 0.0337).(ABSTRACT TRUNCATED AT 250 WORDS)

MC 1288--a vitamin D analogue with immunosuppressive effects on heart and small bowel grafts

The vitamin D analogue MC 1288 (20-epi-1 alpha,25-dihydroxycholecalciferol) was tested here for its possible immunosuppressive properties in vivo using different rat transplantation models. MC 1288, in a dose of 0.1 microgram/kg daily, administered intraperitoneally for 10 days, was found to be effective in prolonging cardiac allograft survival. Untreated recipients rejected their grafts around day 8 while MC 1288 treatment delayed rejection until day 22 (P < 0.001). Addition of the immunostimulatory drug LS-2616 (Linomide) reduced the immunosuppressive effect of MC 1288 and rejection occurred around day 11. The immunosuppressive effect of MC 1288 on rejection following small bowel transplantation was determined by measuring the amounts of hyaluronan (HA) secreted into the intestinal lumen. On day 6 post-transplantation the amounts of intraluminal HA in untreated animals was 29.2 +/- 5.3 ng/min and cm, while in MC 1288-treated animals it was just 5.0 +/- 1.6 ng/min and cm (P < 0.01). We conclude that MC 1288 has immunosuppressive effects that may make it suitable for the prevention of graft rejection.

Stimulation of wound healing by the immunomodulator LS-2616 (Linomide)

LS-2616 (Linomide), a quinoline-3-carboxamide, is an immunomodulator that has been suggested to act on macrophage-like cells. Based on a hypothesis that LS-2616 would stimulate macrophages in the wound and affect the healing process, the effects of LS-2616 on developing granulation tissue were evaluated using a wound model in rats. Subcutaneously implanted cylindrical cellulose sponges were used as an inductive matrix for the ingrowth of granulation tissue. LS-2616 was continuously present at a concentration of 1.2 mg/ml in the drinking water either for 7 days before implantation or starting at the implantation of sponges. Seven days after implantation LS-2616 treatment increased the mean amounts of nitrogen and collagen hydroxyproline over the control level [+20% (p < 0.05) and +59% (p < 0.05), respectively]. The effect was less pronounced in the rats receiving LS-2616 in advance [+7% (NS) and +38% (p < 0.05), respectively]. The mean amounts of nucleic acids and proteoglycans tended to decrease in the rats receiving LS-2616 in advance compared to the control rats [-12% to 13% (NS) and -25% (p < 0.05), respectively]. It was concluded that continuous oral administration of LS-2616 enhanced wound repair in the rat. This immunoenhancement of wound healing results in increased accumulation of collagen.

The immunomodulator LS-2616 (linomide) more effectively than sensitization of the donor enhances graft-versus-host reaction after small bowel transplantation

The effects of the immunomodulating substance LS-2616 (linomide) on graft-versus-host reaction (GVHR) were investigated in a semi-syngeneic small bowel transplantation model. The entire bowel of Lewis donors were transplanted heterotopically into (Lewis x BN) F1 hybrids. Both untreated animals and animals treated with LS-2616, in a daily dose of 160 mg/kg, developed a lethal GVHR. The median survival time in untreated animals was 14.5 days while in LS-2616 treated animals it was just eight days (p < 0.01). LS-2616 in combination with cyclosporin A (CyA), 15 mg/kg given orally on days 0-20, did not seem to alter the survival times compared with CyA treatment alone; 56% of the animals treated with CyA survived for more than 100 days and after combined treatment with CyA/LS-2616 there were 50% permanent survivors. Also the effect of earlier sensitization of the donor on the course of GVHR was investigated. Hearts from BN rats were transplanted heterotopically to the neck vessels of Lewis rats. The hearts were rejected on about day six; five days later the bowels were harvested and transplanted into (Lewis x BN) F1 hybrids. The median survival time in this group was 12.5 days. Taken together our results, in combination with earlier findings, suggest that, at the level of effector mechanisms, GVHR is not an exact mirror image of rejection. Also, LS-2616 appears to be a useful tool for further studies of the mechanisms of action of GVHR.

Linomide inhibits programmed cell death of peripheral T cells in vivo

Programmed cell death (PCD) is involved in the physiological regulation of lymphocyte turnover, as well in the antigen-driven selection of T and B cells. Here it is shown that the immunomodulator linomide (quinoline-3-carboxamide) inhibits the apoptotic decay of peripheral T lymphocytes in response to three different stimuli. First, linomide reduces the superantigen-mediated apoptosis and deletion of specific T lymphocytes of both the CD4+ and the CD8+ subsets without affecting other superantigen-triggered phenomena such as T cell expansion and anergy. Second, linomide abolishes the T lymphopenia and inhibits PCD of splenic CD4+ and CD8+ T cells induced by exogenous glucocorticoids. This effect is restricted to peripheral T lymphocytes and does not concern thymocytes. Finally, linomide abolishes the development of lymphopenia that follows infection with vaccinia virus, while reducing PCD of CD4+ and CD8+ peripheral T cells. The anti-apoptotic effect of linomide could account for its immunostimulatory properties and might be relevant to the treatment of immunodeficiencies associated with an increased apoptotic decay of T lymphocytes.