Background/Purpose:  Tocilizumab is a humanized monoclonal antibody against interleukin-6 receptors and is indicated for the treatment of systemic juvenile idiopathic arthritis (sJIA) in patients 2 years old or older. The purpose of this project is to examine the clinical use of tocilizumab in a single-center sJIA patient population treated at a large academic free-standing children’s hospital. Secondary aims included an evaluation of the safety profile and reasons for discontinuation.

Methods:  This was a retrospective analysis of use of tocilizumab in patients treated at our institution over a 6 year period (October 1, 2010 – September 30, 2016). Patients were included if they were followed by the Texas Children’s Pediatric Rheumatology Service, 18 years of age or younger, and received at least 1 dose of tocilizumab during the course of their treatment for sJIA. General demographic and dosing-related information were collected, as well as infections and infection-related treatment information. All research methods were approved by the institutional review board of Baylor College of Medicine.

Results:  Thirty-five subjects met inclusion criteria. Median age at initiation of treatment was 10.5 years (range: 1.3-18.5) with median weight of 28.8 kg. The mean number of doses per patient was 23 (range: 1-135). One patient received at least 135 doses safely with no reported complications. A confirmed discontinuation was found in 74.3% of patients; 22.9% due to adverse effects, 20% lost to follow up, 17.1% due to lack of response, 8.6% to disease remission, 2.9% were unable to go to the infusion center, and 2.9% discontinued therapy due to the cost of the drug. Adverse effects included – leukopenia (8.6%), fever (5.7%), and rash (5.7%). However, none of our patients experienced any infection or infection-related adverse effects.

For this patient population, 22 patients used steroids as first line therapy. Subsequent therapy included use of anakinra in 11 patients and tocilizumab use in 8 patients. Tocilizumab use was found to be first line treatment in 4 patients. Seven patients also used tocilizumab for symptom management.

Conclusion:  The pattern of usage of tocilizumab in sJIA in a single center was described. Tocilizumab was most commonly used as a second line agent in our center. Observed adverse side effects associated with tocilizumab were minimal.

Table:

Patient Data		n = 35
Median age at initiation, years (1.3-18.5)			10.5
Sex, n	Female	17	48.5%
	Male	18	51.5%
Median weight, kg (10.5-107.4)			28.7
Median Height, cm (38-176.4)			132.7
Race, n	White	24	68.5%
	Black	9	25.7%
	Asian	2	5.7%
Ethnicity, n	Hispanic	11	31.4%
	Non-Hispanic	24	68.5%
Mean number doses (1-135)		23
Reasons for discontinuation	Adverse Effects	8	22.9%
	Lost follow up	7	20%
	Lack of response	6	17.1%
	Active Remission	3	8.6%
	Cost of drug	2	2.9%
	Could not attend infusion	1	2.9%
Adverse Effects	Leukopenia	3	8.6%
	Fever	2	5.7%
	Rash	2	5.7%
	Dyslipidemia	1	2.8%
	Post-infusion reaction	1	2.8%
	Pericardial infusion	1	2.8%
	Worsening Liver function	1	2.8%
Treatment Options	Steroids	22	62.9%
	Anakinra	11	31.4%
	Tocilizumab	8	22.9%
	Symptom Management	7	20%