The metabolic effects of inhibitors of 5-lipoxygenase and of cyclooxygenase 1 and 2 are an advancement in the efficacy and safety of anti-inflammatory therapy

Chronic treatment of inflammatory diseases with non-steroidal anti-inflammatory drugs is effective but not always devoid of serious side effects. In particular, the use of traditional non-steroidal aspirin-like drugs has been associated with a high incidence of gastrointestinal bleedings. The development of a new class of drugs, the selective cyclooxygenase type 2 (COX-2) inhibitors, has generated much expectation on the possibility to have safer compounds. After the initial enthusiasm of the scientific community, a re-evaluation of some large, randomized double-blind clinical studies performed with two of these compounds, has disclosed that the late serious gastrointestinal complications are not significantly reduced in comparison with non-selective inhibitors and that cardiovascular concerns might arise particularly if theses drugs are utilized in patients with underlying heart diseases. A new promising class of drugs to control inflammatory diseases is in advanced clinical development. The balanced inhibitors of 5-lipoxygenase (5-LOX) and of cyclooxygenase (both types 1 and 2) block the formation of all the enzymatically arachidonic acid-derived metabolites, both prostaglandins (like COX inhibitors) and leukotrienes (LT); these drugs have been shown to possess a very good anti-inflammatory efficacy without serious side effects. Licofelone, previously known as ML3000, is the molecule in the most advanced phase of clinical development (phase III) among this class of compounds; it is a potent, competitive, and well balanced inhibitor of 5-LOX and COX pathways. The drug has been shown to possess analgesic, anti-inflammatory, antipyretic antibronchocostrictory and antiplatelet properties at doses which are safe for the gastrointestinal tract. Moreover, the newly performed preclinical studies, here briefly reviewed, appear to indicate that the compound seems particularly suitable to protect the articular cartilage and the synovial space in degenerative joint disease and to exert a relevant antithrombotic activity. Preliminary results of clinical studies of licofelone in osteoarthritis indicate that the drug has a comparable or slightly better efficacy than that of naproxen but possesses a much better gastrointestinal safety. This latter important aspect has been also evaluated by an endoscopic study in normal volunteers randomly assigned to a 4-week treatment with licofelone, placebo or naproxen. The results indicate that no ulcers occurred in either licofelone group or the placebo group, while ulcers with unequivocal depth were present in 20% of the naproxen-treated subjects.