Antiarthritic - lumiracoxib
The discovery that cyclooxygenase exists in two forms, COX-1 and COX-2, led to a whole new class of drugs for treating arthritis. Cyclooxygenase is an enzyme involved in generating the prostaglandins responsible for inflammatory effects. However, the COX-1 form was found to have a protective role, and COX-2 caused the gastrotoxic effects. A COX-2 is being investigated by Novartis.
Lumiracoxib is being developed to treat rheumatoid arthritis, osteoarthritis and pain, and several Phase III trials have been completed. In one multicentre double blind parallel group study, more than 1000 patients were given 200 or 400mg lumiracoxib, 800mg ibuprofen or 200mg celecoxib a day for 13 weeks. Significantly lower cumulative gastroduodenal ulcer rates were seen in patients given the COX inhibitors compared with those given ibuprofen. Lumiracoxib's tolerability profile was similar to that of celecoxib.1
Its efficacy and safety were also explored in a comparative trial with diclofenac. Patients with osteoarthritis were given 50, 100, 200mg twice a day or 400mg once a day, or 75mg diclofenac twice a day, or placebo, for four weeks in a multicentre randomised placebo-controlled trial.
The tolerability of lumiracoxib was similar to placebo, and superior to diclofenac. No serious adverse events were seen. Also, the once daily regimen was more effective than the twice daily alternative at reducing pain intensity scores, and similar to those seen with diclofenac.2
Another trial was a randomised double blind parallel study involving 2002 patients with moderate severe pain following the removal of at least two impacted wisdom teeth. It compared single doses of 100 and 400mg lumiracoxib with 400mg ibuprofen. The higher dose gave similar median times to the onset of analgesia to ibuprofen, while being better than ibuprofen in reducing the time to rescue medication use.3
Further Phase III studies are under way, including one involving more than 18,000 patients with osteoarthritis in the US. If successful, it could provide a further alternative treatment for the painful conditions of osteoarthritis and rheumatoid arthritis.