"Go upstream, young man": lessons learned from the p38 saga.
Despite the success of biological therapies in rheumatoid arthritis (RA), orally active small-molecule drugs are desirable. Signal transduction inhibitors have been the focus of intense efforts, with some recent notable successes and failures. p38alpha is a signalling molecule that regulates proinflammatory cytokines, which makes it a logical target for RA. Unfortunately, selective p38alpha inhibitors have limited efficacy. An attempt is made here to put these studies into perspective and offer possible explanations for the failure of p38alpha blockers. Alternative strategies, such as targeting kinases higher in the signalling cascade or using less selective compounds, might be more successful as suggested by the efficacy seen with Syk and JAK inhibitors.
Hammaker
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Division of Rheumatology, Allergy and Immunology, UC San Diego School of Medicine, La Jolla, CA 92093-0656, USA. dhammaker@ucsd.edu
Firestein
G S
GS
D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001169:Arthritis, Experimental / Q000188:drug therapy / Q000201:enzymology; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000201:enzymology; D006801:Humans; D051379:Mice; D047428:Protein Kinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*
D018501:Antirheumatic Agents; D047428:Protein Kinase Inhibitors; D048051:p38 Mitogen-Activated Protein Kinases