Vildagliptin in drug-naïve patients with type 2 diabetes: a 24-week, double-blind, randomized, placebo-controlled, multiple-dose study.

This 24-week double-blind, randomized, multicenter, placebo-controlled, parallel-group study was performed in 632 drug-naïve patients with type 2 diabetes to assess efficacy and tolerability of vildagliptin (50 mg qd, 50 mg bid, or 100 mg qd). HbA1c decreased modestly in patients receiving placebo (Delta=-0.3+/-0.1%) and to a significantly greater extent in patients receiving vildagliptin 50 mg qd (Delta=-0.8+/-0 .1%), 50 mg bid (Delta=-0.8+/-0.1%), or 100 mg qd (Delta=-0.9+/-0.1%, p<0.01 for all groups VS. placebo) from an average baseline of 8.4%. In patients diagnosed >or=3 months before enrollment, HbA1c increased with placebo (Delta=+0.2+/-0.2%) and between-treatment differences (vildagliptin-placebo) were -0.8+/-0.2% (p<0.001), -0.7+/-0.2% (p=0.003), and -0.9+/-0.2% (p<0.001) with vildagliptin 50 mg qd, 50 mg bid, and 100 mg qd, respectively. There was no apparent dose-response in the overall population; however, in patients with high baseline HbA1c, there were greater reductions with either 100 mg dose regimen (Delta=-1.3+/-0.2% and -1.4+/-0.2%) compared to 50 mg qd (Delta=-0.8+/-0.1%). Body weight decreased modestly in all groups (by 0.3 to 1.8 kg). The incidence of adverse events was similar across all groups and

Effects of cyclosporin A and dinactin on T-cell proliferation, interleukin-5 production, and murine pulmonary inflammation.

We compared the effects of cyclosporin A (CSA) and a macrotetrolide antibiotic, dinactin, on human T-cell proliferation and cytokine production induced by stimulation of the T-cell receptor alone (monoclonal antibody [mAb] directed against CD3) or in combination with costimulatory signals (mAbs directed against CD3 and CD28). These agents were also examined in a murine model of interleukin (IL)-5-mediated pulmonary inflammation. Dinactin inhibited T-cell proliferation induced by IL-2, by mAb to CD3, and by mAbs to CD3 plus alpha-CD28 with identical dose-response curves (IC50 = 10-20 ng/ml). Dinactin inhibited cytokine production with IC50 values of 10 ng/ml for IL-4 and IL-5 and 30 or 60 ng/ml for interferon-gamma or IL-2, respectively. Unlike CSA, exogenous IL-2 did not alter the dinactin-mediated effects on T cells, and nuclear run-on and steady-state messenger RNA (mRNA) analysis showed that dinactin inhibited cytokine production through a post-transcriptional mechanism. CSA selectively blocked T-cell receptor-induced T-cell proliferation and cytokine production (IC50 = 10 ng/ml). Under costimulatory conditions, IL-5 synthesis was only minimally inhibited by high concentrations of CSA, and at CSA concentrations of less than 125 ng/ml, IL-5 was significantly increased above control values. Dinactin and CSA reduced pulmonary eosinophilia when administered within 1 d of airway antigen challenge. Of the cytokine mRNAs examined in the lungs of CSA-pretreated, antigen-challenged mice, IL-5 mRNA levels were the least reduced, paralleling the resistance of IL-5 to CSA observed in vitro and suggesting a role for CD28 in the in vivo induction of IL-5.

Interleukin-5 mRNA stability in human T cells is regulated differently than interleukin-2, interleukin-3, interleukin-4, granulocyte/macrophage colony-stimulating factor, and interferon-gamma.

Interleukin-5 (IL-5) transcriptional activation and mRNA stability were investigated in a human TH0 T-cell clone (SP-B21) and in nonclonal CD4 TH2 cells, differentiated in vitro from peripheral blood T cells. Cells were stimulated with alpha-CD3 monoclonal antibody (mAb) with and without alpha-CD28 mAb. Comparison to other cytokine genes revealed aspects of mRNA regulation unique to IL-5. The half-life (t1/2) of IL-5 mRNA, determined by addition of actinomycin D (ActinoD) or cyclosporin A (CSA) was longer (by >= 2 h) than that of IL-2, IL-3, IL-4, interferon-gamma, or granulocyte/macrophage colony-stimulating factor. With the exception of IL-5, t1/2 values were significantly shorter with CSA as the transcriptional inhibitor than with ActinoD. The t1/2 value of IL-5 mRNA, but not the other cytokine transcripts, determined with either ActinoD or CSA, was longer than predicted from the kinetics of steady-state mRNA decline. Co-stimulation of both cell types with alpha-CD28 mAb increased the stability of cytokine transcripts weakly, and IL-5 remained the most stable transcript. Thus, the degradation pathway that targets IL-5 is distinct from the other cytokine transcripts measured and involves proteins whose transcription is blocked by ActinoD and CSA. From examination of the levels of transcription initiation (nuclear run-on assay) and steady-state mRNA attained in cultures stimulated in the presence of the protein synthesis inhibitor, cycloheximide, only IL-5 transcription initiation had an absolute dependency on new protein synthesis.

The inhibitory effects of topically active glucocorticoids on IL-4, IL-5, and interferon-gamma production by cultured primary CD4+ T cells.

This study was conducted to directly compare the in vitro efficacy and potency of several glucocorticoids in inhibiting T-cell cytokine production. The glucocorticoids tested were fluticasone propionate, budesonide, triamcinolone acetonide, and beclomethasone dipropionate, which are currently inhaled therapies for the treatment of allergic airway disease. Also used were betamethasone phosphate and the newly developed mometasone furorate. With a novel cell culture system, purified peripheral blood CD4+ T cells from normal donors were stimulated with immobilized anti-CD3 and soluble anti-CD28 monoclonal antibodies to induce high levels of IL-4, IL-5, and interferon-gamma. By cell sorting, it was found that the IL-5 produced originated from memory cells, whereas both memory and naive cells produced interferon-gamma. Mometasone and fluticasone inhibited IL-5 and IL-4 similarly (mometasone IL-5 inhibitory concentration of 50% = 0.27 +/- 0.1 nmol/L and IL-4 = 0.19 +/- 0.08 nmol/L). For both cytokines, the results indicate that mometasone and fluticasone were more potent than beclomethasone, triamcinolone, budesonide, and betamethasone. Of clinical importance is the finding that all steroids demonstrated less efficacy versus interferon-gamma than IL-4 and IL-5. Glucocorticoid reduction of Th2 cytokines with lesser effects on interferon-gamma would serve to reverse the exaggerated Th2 response that contributes to pathophysiology observed in allergic disease. Therefore the use of topically active glucocorticoids with low systemic bioactivity for the treatment of allergic inflammation may be particularly effective in modulating the cytokine activity that is an important component of the allergic response.

Effects of in vivo administration of interferon (IFN)-gamma, anti-IFN-gamma, or anti-interleukin-4 monoclonal antibodies in chronic autoimmune graft-versus-host disease.

These studies examined the role of cytokines in chronic autoimmune graft-versus-host disease (GVHD) in B6D2F1 mice injected with lymphoid cells from DBA/2 mice. Anti-interleukin (IL)-4 and anti-interferon (IFN)-gamma mAb, or IFN-gamma, were used in vivo to modulate B cell hyperactivity and disease. Kinetic experiments showed that, 2-3 weeks after induction, GVH mice had 100x elevated serum IgE, while IgG1 and IgG2a were 10x above normal. Early treatment with anti-IL-4 mAb or IFN-gamma decreased serum IgE and IgG1 and had no effect on IgG2a. Anti-IFN-gamma mAb treatment increased serum IgE and IgG1 while reducing IgG2a. This increase in serum immunoglobulins could be correlated with an increased spontaneous secretion of IL-4, IL-5, and IL-6 in spleen cell cultures from anti-IFN-gamma mAb-treated GVH mice. While neither anti-IFN-gamma nor IFN-gamma treatments altered the disease course, anti-IL-4 treatment delayed proteinuria and death in GVH mice. These observations suggest an important role for IL-4 in immune complex-mediated glomerulonephritis in chronic GVHD.