Genentech‘s Actemra (tocilizumab), a medicine approved for the treatment of certain types of juvenile idiopathic arthritis (JIA), is not linked to a higher risk of infections in children with systemic juvenile idiopathic arthritis (sJIA) or polyarticular-course juvenile idiopathic arthritis (pcJIA), according to results of two Phase 3 trials.
The results, “Neutropenia During Tocilizumab Treatment Is Not Associated With Infection Risk in Systemic or Polyarticular-Course Juvenile Idiopathic Arthritis,” were published in The Journal of Rheumatology.
In previous clinical trials, Actemra — an antibody that prevents interleukin-6 (IL-6) from binding to its receptor, decreasing tissue inflammation — has achieved positive results in the treatment of autoimmune diseases, including rheumatoid arthritis (RA), giant cell arteritis, sJIA and pcJIA.
However, in all trials involving Actemra, some patients developed neutropenia, a condition in which white blood cell counts are abnormally low. This could compromise the body’s ability to fight off pathogens and infections. Although in some cases this effect was only temporary, “the potential relationship between decreased neutrophil [white blood cell] count and increased risk for infection remains a cause of concern, particularly in children treated with [tocilizumab].”
For this reason, researchers now performed a secondary analysis of two Phase 3 clinical trials to assess whether neutropenia associated with Actemra treatment may be linked to a higher risk of infections in children with sJIA or pcJIA.
The analysis was based on data from two randomized, placebo-controlled studies — TENDER (NCT00642460) and CHERISH (NCT00988221) — designed to assess the efficacy and safety of Actemra administered intravenously in children 2-17 years old, with sJIA (112 patients) and pcJIA (188 patients). The study analysis included clinical data up to week 104 in both trials.
Blood cell counts, including absolute neutrophil count (ANC), were monitored for each patient in both studies. Neutropenia severity was classified according to the National Cancer Institute Common Terminology Criteria for Adverse Events, as grade 0 (normal neutrophil levels) up to grade 4 (very low neutrophil levels; severe neutropenia).
Results showed that 25% of sJIA and 5.9% of pcJIA patients experienced a temporary reduction of white blood cells (ANC equal to or greater than grade 3) throughout the trials. In the case of children and adolescents with sJIA, neutropenia seemed to be positively associated with young age and methotrexate use.
During episodes of neutropenia (grade 3 or 4), the most common infections observed in patients with sJIA (292.5 cases per 100 patient-years) and pcJIA (340 cases per 100 patient-years) were upper respiratory infections, influenza (flu), nasopharyngitis (common cold), gastroenteritis (stomach flu) and conjunctivitis (pink eye).
The rate of serious infections was higher in patients with sJIA (10.9 cases per 100 patient-years), than in patients with pcJIA (5.2 cases per 100 patient-years). However, the rates of serious and non-serious infections never increased during periods of neutropenia in either one of the trials.
“In conclusion, our findings indicate that neutropenia in patients with sJIA and patients with pcJIA who were treated with [tocilizumab] was [temporary] and was not associated with the development of infections and serious infections,” researchers said.