RT Journal Article SR Electronic T1 SB 207499 (Ariflo), a Potent and Selective Second-Generation Phosphodiesterase 4 Inhibitor: In VitroAnti-inflammatory Actions JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 420 OP 426 VO 284 IS 1 A1 Mary S. Barnette A1 Siegfried B. Christensen A1 David M. Essayan A1 Marilyn Grous A1 Uma Prabhakar A1 Julia A. Rush A1 Anne Kagey-Sobotka A1 Theodore J. Torphy YR 1998 UL http://jpet.aspetjournals.org/content/284/1/420.abstract AB First-generation phosphodiesterase 4 (PDE4) inhibitors, such as rolipram, inhibit the activation of immune and inflammatory cells. The clinical use of these compounds is limited by gastrointestinal side effects, such as increased acid secretion and nausea. Consequently, the challenge has been to design novel PDE4 inhibitors that maintain the anti-inflammatory actions of rolipram while achieving an improved side effect profile. Among the first of this new class of PDE4 inhibitors specifically designed to have an improved therapeutic index relative to earlier compounds is SB 207499 (Ariflo) [c-4-cyano-4-(3-cyclopentyloxy-4-methoxy-phenyl)-r-1-cyclohexanecarboxylic acid]. In this study, we compared the anti-inflammatory and gastric secretogogue activities of SB 207499 with those of rolipram. The cellular models used were (1) histamine release from human basophils, (2) tumor necrosis factor-α generation in human monocytes, (3) degranulation of human neutrophils, (4) antigen-driven proliferation and cytokine synthesis from human T cells and (5) acid secretion from isolated rabbit gastric glands. SB 207499 inhibited the activation of a variety of immune and inflammatory cells in a concentration-dependent manner: (1) histamine release in basophils [−log IC25 = 6.6 ± 0.3 vs. 8.0 for (R)-rolipram], (2) lipopolysacchride-induced TNF-α formation in monocytes [−log IC50 = 7.0 ± 0.1vs. 7.2 ± 0.1 for (R)-rolipram], (3) fMLP-induced degranulation in neutrophils [−log IC15= 7.1 ± 0.2 vs. 6.4 ± 0.5 for (R)-rolipram], (4) house dust mite induced-proliferation of peripheral blood mononuclear cells [−log IC40 = 6.5 ± 0.3 vs. 6.4 ± 0.3 for (R)-rolipram] and (5) ragweed-induced production of interferon-γ [−log IC50 = 5.4] and interleukin-5 [−log IC50 = 5.0]. Although SB 207499 inhibits the activation of a variety of immune and inflammatory cells with a potency equal to that of rolipram, it is >100-fold less potent than the latter compound as an acid secretagogue [−log EC50 = 6.1 ± 0.1 vs. 8.3 ± 0.2 for (R)-rolipram]. Collectively, these data indicate that SB 207499 retains the anti-inflammatory activity of the prototypical PDE4 inhibitor rolipram but is substantially less likely to stimulate gastric acid secretion. The American Society for Pharmacology and Experimental Therapeutics