Pharming Group has recently completed patient enrollment in its Phase III clinical trial (NCT05438407) evaluating the investigational drug leniolisib, an oral, selective phosphoinositide 3-kinase delta (PI3Kδ) inhibitor, in children aged 4 to 11 years with activated phosphoinositide 3-kinase delta syndrome (APDS).

Leniolisib, marketed under the brand name Joenja in the US, received approval from the US Food and Drug Administration (FDA) for the treatment of APDS in adult and pediatric patients 12 years of age and older in March 2023.

Pharming plans to include data from this 4–11-year-old trial in regulatory filings worldwide for the approval of leniolisib for pediatric patients with APDS, beginning in 2025.

Anurag Relan, MD, MPH, Chief Medical Officer of Pharming, commented, “This is the first clinical trial for younger pediatric patients with APDS, who have a significant unmet need for a disease modifying treatment. I am pleased with the progress made in our Phase III pediatric clinical program evaluating leniolisib in children with APDS. By intervening at a younger age, we may help prevent patients from developing immune-related complications that are likely to progress throughout their lives.”

The study enrolled 21 children with APDS ages 4 to 11 years at sites in the United States, Europe, and Japan. The single-arm, open-label clinical trial is evaluating the safety, tolerability, and efficacy of leniolisib. The study’s primary efficacy endpoints are a reduction in index lymph node size and an increased proportion of naïve B cells out of total B cells from baseline at 12 weeks.

Secondary endpoints include an assessment of the ability of leniolisib to modify health-related quality of life based on measures of physical, social, emotional, and school functioning using a validated patient questionnaire. These endpoints mirror those used to evaluate the clinical outcomes in previous leniolisib Phase II/III APDS trials for patients aged 12 and older.

The first patient was dosed in November 2023 in a separate Phase III clinical trial that includes children aged 1 to 6 years with APDS to evaluate a new pediatric formulation of leniolisib. Eligible patients enrolled in either of the pediatric trials will continue to receive leniolisib for a year after the initial 12-week treatment period through an open-label extension trial.