A new study has indicated that tailoring dosage of infliximab based on serum levels of tumor necrosis factor–alpha did not increase the sustained remission rate in rheumatoid arthritis patients.
“The results did not support our initial hypothesis that deep remission and subsequent sustained discontinuation of infliximab can be achieved by intensive and finely tuned treatments with appropriate doses of TNF [tumor necrosis factor] inhibitors,” wrote Yoshiya Tanaka, MD, PhD, of the University of Occupational and Environmental Health, Kitakyushu, Japan. The study was published in Annals of the Rheumatic Diseases.
To determine if levels of TNF-alpha should initiate an increase in infliximab dosage, the researchers launched a multicenter, randomized trial of 337 patients with infliximab-naive RA. Patients were assigned to two groups: standard infliximab treatment of 3 mg/kg at weeks 0, 2, 6, and then every 8 weeks (n = 167) or programmed infliximab treatment (n = 170) in which the dose was adjusted at week 14 based on low, intermediate, or high levels of baseline TNF-alpha.
Patients with low levels (below 0.55 pg/mL) continued receiving 3 mg/kg every 8 weeks. Intermediate levels (between 0.55 and 1.65 pg/mL) meant an increase to 6 mg/kg every 8 weeks. High levels (1.65 pg/mL or higher) meant an increase to 6 mg/kg at week 14 and to 10 mg/kg at week 22 and every 8 weeks afterward. The goal was to discontinue infliximab at 54 weeks and reassess 1 year later.
After 54 weeks, 39.4% of patients in the programmed group and 32.3% of patients in the standard group achieved remission, defined as a Simplified Disease Activity Index (SDAI) score of 3.3 or lower. After 106 weeks, 23.5% of the programmed group and 21.6% of the standard group had maintained discontinuation of infliximab (–2.2% difference; 95% confidence interval, –6.6% to 11.0%; P = .631). After analysis, the most significant predictor of sustained discontinuation was a baseline SDAI less than 26.
The authors acknowledged their study’s limitations, including the initial version of the study not being double blinded. In addition, they noted that the short length of treatment and the low dosage overall “might not be intense enough to achieve differences in disease control between the two groups.”
The study was supported by a research grant from the Ministry of Health, Labor and Welfare of Japan. The authors reported numerous potential conflicts of interest, including receiving grants, consulting fees, speaking fees, and/or honoraria from various medical and pharmaceutical companies.
SOURCE: Tanaka Y et al. Ann Rheum Dis. 2019 Oct 19. doi: 10.1136/annrheumdis-2019-216169.