FDA rejects Pharming's bid to expand rare disease drug to younger patients

Pharming Group has received a setback from the US Food and Drug Administration (FDA) regarding its drug Joenja®. The agency issued a Complete Response Letter (CRL) for the company's request to expand the use of the medication to children aged 4 to 11 with a rare immune disorder. Despite this, the drug's existing approval for patients aged 12 and older remains unchanged.

The FDA's decision follows Pharming's submission of a supplemental New Drug Application (sNDA) for Joenja® (leniolisib) to treat Activated Phosphoinositide 3-Kinase Delta Syndrome (APDS) in younger patients. APDS is a rare primary immunodeficiency, affecting roughly 1 to 2 people per million globally. Symptoms include severe infections, lymphoproliferation, autoimmunity, and enteropathy.

The application was based on positive results from a Phase III study, which demonstrated improvements in lymphadenopathy and increased naïve B cells in children aged 4 to 11. The FDA had previously granted the submission Priority Review in October 2025, recognising its potential to significantly improve patient outcomes.

However, the CRL highlighted two key concerns. The agency questioned whether younger, lower-weight patients might receive insufficient exposure to the drug and requested further pediatric pharmacokinetic data. It also flagged issues with one of the analytical methods used in production batch testing, asking for additional data and clarification.

Pharming's CEO, Fabrice Chouraqui, stated that the company remains committed to making Joenja available to this younger patient group. The firm plans to work closely with the FDA to address the identified issues and determine the next steps for resubmission.

As of February 2026, Joenja has already gained approval for use in patients under 12 in two regions—the US (since 2023) and the EU (since 2024). Regulatory reviews for this patient group are also underway in the UK, Canada, and Australia.

The FDA's response does not affect Joenja's current approval for patients aged 12 and older. Pharming will now focus on providing the additional data required to support its use in younger patients. The company aims to resolve the outstanding issues and move forward with the regulatory process.