High response rate in the phase I/II study of meloxicam in juvenile rheumatoid arthritis

Use of meloxicam as a selective COX-2 inhibitor for treatment of adult rheumatic diseases decreases the frequency of gastrointestinal (GI) side effects in comparison with nonselective COX inhibitors. Up to 50% of children with juvenile rheumatoid arthritis (JRA) also develop GI side effects through nonselective COX inhibitors. In this 12 week Phase I/II study, with an additional open extension lasting up to 52 weeks, the safety, efficacy, and pharmacokinetics of meloxicam in JRA were investigated.

Meloxicam suspension 0.25 mg/kg once daily was given to 36 patients with JRA who required a nonsteroidal antiinflammatory drug. Safety evaluation and periodic measurement of efficacy were carried out using the Pediatric Rheumatology International Trials Organisation (PRINTO) criteria. Eighteen patients underwent pharmacokinetic (PK) evaluation.

Thirty-one patients completed the study. Four were dropped due to administrative reasons. One patient, who found the drug ineffective, discontinued participation. A response was seen according to PRINTO outcome criteria in 44% of the patients at Week 4, 62% at Week 12, and 74% at Week 52. Drug related adverse events were observed in 5 patients. PK evaluation showed that the maximum plasma concentration Cmax of -34% and AUC(0-infinity) of -28% tended to be lower in younger children (2-6 years) versus older children. Plasma elimination half-life (13 h) was similar in all patients.

Meloxicam suspension 0.25 mg/kg once daily seems to be effective and safe for treating active JRA over a period of 52 weeks.