FDA Approves Treatment for Polyarticular Juvenile Idiopathic Arthritis (PJIA)

This afternoon, Genentech announced that the US Food and Drug Administration (FDA) has approved the subcutaneous formulation of tocilizumab (Actemra) as treatment for active polyarticular juvenile idiopathic arthritis (PJIA) in patients 2 years of age and older. While it can be administered alone, it can also be dosed in combination with methotrexate (MTX) PJIA patients.

PJIA is a form of juvenile idiopathic arthritis (JIA), a chronic autoimmune disease. It is often characterized by inflammation in 5 or more joints within the first 6 months of the disease onset with small joints, such as hands and feet, being the most affected.

Sandra Horning, MD, chief medical officer and head of Global Product Development, expressed her excitement over the drug’s approval in a press release. "Polyarticular juvenile idiopathic arthritis is a rare, often painful disease in children. With this approval, we are pleased Actemra offers an alternative delivery option to physicians and parents of children aged two or older to treat this debilitating disease."

The approval comes from positive data found in the JIGSAW-117 study, which was a 52-week, open-label, multicenter, phase 1b pharmacokinetic (PK)/pharmacodynamic (PD) bridging study engineered to find the appropriate dosing regimen of Actemra SC across a range of body weights (BWs) in children with PJIA. Enrollment included 52 PJIA patients aged 1 to 17 years who had previous inadequate response or intolerance to methotrexate who were either tocilizumab naive or were receiving tocilizumab IV with adequate disease control.

Tocilizumab was subcutaneously administered open label in accordance to a body weight (BW)—based dosing regimen. PJIA patients weighing <30 kg received 162 mg of tocilizumab every 3 weeks and PJIA patients weighing ≥30 kg received 162 mg of tocilizumab every 2 weeks for 52 weeks. Model-computed PK and PD parameters along with safety were assessed.

Generally, observed safety for subcutaneous tocilizumab was consistent with the known safety profile of tocilizumab IV except for injection site reactions (ISRs) and neutropenia (low white blood cell count). However, compared to patients treated with tocilizumab SC for other approved indications, a higher frequency of ISRs was observed in tocilizumab SC treated PJIA patients.

Additionally, a frequency of 28.8% (15/52) ISRs was observed in tocilizumab SC treated PJIA patients during the duration of the 1-year study. No ISRs required patient withdrawal from treatment or dose interruption, and all ISRs were mild in severity per report. Also, a decrease in neutrophil counts below 1 × 10⁹ per L occurred in 15.4% of patients and was more frequently observed in the patients less than 30 kg (25.9%) compared to patients at or above 30 kg (4.0%) throughout routine laboratory monitoring in tocilizumab SC treated PJIA patients.

Tocilizumab SC efficacy in children aged 2 to 17 years is based on PK exposure and extrapolation of established efficacy of tocilizumab IV in PJIA patients and tocilizumab SC in patients with RA.

In 2013, the FDA approved the intravenous (IV) formulation of tocilizumab for active PJIA patients 2 years of age and older.

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