Joenja Approved for APDS in Children Aged 4 to 11

The FDA approved leniolisib (Joenja, Pharming Intellectual Property B.V.) as the first treatment for activated phosphoinositide 3-kinase delta syndrome (APDS) in children aged 4 to 11 years who weigh at least 27 kg. The agency previously approved Joenja in 2023 for patients aged 12 years or older.

Children aged 4 to 11 years receive a weight-based dose of 40mg, 50mg, or 70mg orally twice daily, approximately 12 hours apart. The approved dose for patients aged 12 years or older is 70mg orally twice daily. APDS is caused by mutations in PIK3CD or PIK3R1, which encode phosphoinositide-3 kinase delta, a protein involved in normal white blood cell development and function.

The pediatric expansion was supported by safety and pharmacokinetic data from Study LE 3301. The single-arm, open-label study included 8 children who received the recommended weight-based dosage. FDA reported no clinically significant pharmacokinetic difference between patients younger and older than 12 years.

The efficacy evidence summarized by FDA came from Study 2201, the trial supporting the original approval in patients aged 12 years or older. The 12-week, blinded, randomized, placebo-controlled study included 31 patients with confirmed APDS-associated genetic PI3K delta mutations. Twenty-one patients received leniolisib 70mg twice daily and 10 received placebo. The co-primary endpoints were reduced lymph node size and normalization of immunophenotype, measured by the percentage of naïve B cells among total B cells. By day 85, patients receiving leniolisib had reduced lymph node size and a 37% improvement in naïve B-cell counts compared with placebo.

The most common adverse effects reported in children aged 4 to 11 years were stomach pain, respiratory tract infection, diarrhea, headache, cough, nausea, rhinitis, and alopecia. FDA stated that patients with moderate-to-severe hepatic impairment should not use leniolisib. The therapy received orphan drug designation, rare pediatric disease designation, and Priority Review.

Source: US Food and Drug Administration. FDA approves first treatment for children aged 4-11 years with APDS, a rare genetic disorder of the immune system. US Food and Drug Administration; September 11, 2026. Accessed September 13, 2026.