Biopharmaceutical company Pharming Group N.V. (Euronext Amsterdam:PHARM) (NASDAQ:PHAR) announced on Thursday that the US Food and Drug Administration (FDA) has accepted the resubmitted supplemental New Drug Application for Joenja (leniolisib) as a treatment for children aged 4 to 11 years with activated phosphoinositide 3-kinase delta syndrome (APDS), a rare primary immunodeficiency.

The resubmission seeks approval of 40 mg and 50 mg twice-daily dosing for paediatric patients weighing 27 kg or more and includes additional analytical data requested by the FDA following a Complete Response Letter issued in January 2026. The FDA has set a Prescription Drug User Fee Act target action date of 24 October 2026.

If approved, Joenja would become the first approved treatment in the United States for APDS patients aged 4 to 11 years. Pharming also plans to submit a separate supplemental application in the second half of 2026 for lower-dose treatment in patients weighing less than 27 kg.

The filing is supported by Phase III data showing reductions in lymphadenopathy and increases in naive B cells over 12 weeks, indicating correction of the underlying immune defect. Improvements were observed across all dose levels, all treatment-emergent adverse events were mild to moderate, no drug-related serious adverse events were reported, and all patients completed the treatment period.

Joenja was approved by the FDA in March 2023 for APDS patients aged 12 years and older.