VANCOUVER, B.C. – If it’s an option, subcutaneous methotrexate is the way to go for new-onset juvenile idiopathic arthritis, based on a study of 47 patients at Children’s Mercy Hospital in Kansas City, Mo.
In the study, 21 children received subcutaneous methotrexate and 26 received oral methotrexate (MTX). The children, regardless of administration route, were on the same, standard dose of MTX, 15 mg/m2 weekly, plus 1 mg/day of folic acid.
At 3 months, 13 (28%) of the 47 children reached an ACR [American College of Rheumatology] pediatric 70. The measure is defined as a 70% improvement in joint counts, global assessments, and other measures from baseline. Nine (69%) of the 13 had been on subcutaneous methotrexate and 4 (31%) had been on the oral formulation.
Dr. Mara Becker
Additionally, red blood cell concentrations of long-chain MTX polyglutamate, a marker of better response, were higher in the children given subcutaneous methotrexate (82 nmol/L vs. 36 nmol/L) The differences were statistically significant.
"I was a little bit shocked" by the results, said lead investigator Dr. Mara Becker, director of the rheumatology division at Children’s Mercy who is with the department of pediatrics at the University of Missouri–Kansas City. "I’ve been in the camp of saying ‘orally or subcutaneously, however you want to give it.’ This solidified the fact that I’d give SQ first, especially if I want to prevent having to use a biologic."
Although "we are still debating the best way to give methotrexate when it’s started, kids on subcutaneous methotrexate got better faster." That’s likely because of the better bioavailability – and fewer GI side effects – when methotrexate bypasses the gut, she said at the annual meeting of the Pediatric Academic Societies.
Needle phobia, however, is the kicker. "Kids get anxious about having to get a shot each week; that’s why people shy away from it. A lot of times, we start orally and switch to SQ if kids get side effects, but if they have needle phobia, you’re in a difficult place," she said.
The children were, on average, about 10 years old, and the majority of them were girls. There were no significant between-group clinical differences at baseline.
NSAIDS, low-dose prednisone, and steroid joint shots were allowed as needed. At 3 months, NSAID and oral steroid use was statistically the same between the groups, but SQ methotrexate patients were significantly more likely to have gotten joint injections when started on methotrexate. To account for the difference, injected joints were counted as "active joints" in the analysis.
The recent shortage of subcutaneous methotrexate, often the first choice among U.S. physicians, led to the study. About half of the children had to be "on oral because of the shortage, so we said, ‘alright, let’s take a look and see how they do’," Dr. Becker said.
Dr. Becker has no relevant disclosures. The ACR Research Foundation helped fund the work.