Pharming Faces FDA Setback for Joenja Pediatric SNDA Over Dosing Concerns

Pharming Group disclosed that the U.S. Food and Drug Administration has issued a Complete Response Letter regarding its supplemental New Drug Application for Joenja (leniolisib), signaling regulatory headwinds for the company’s pediatric expansion strategy. The oral medication is an investigational selective phosphoinositide 3-kinase delta (PI3Kd) inhibitor designed to treat children ages 4 to 11 with activated phosphoinositide 3-kinase delta syndrome (APDS), a rare primary immunodeficiency disorder affecting the immune system’s ability to function properly.

The Core Regulatory Challenge: Dosing and Pharmacokinetic Data

The FDA flagged specific technical concerns with Pharming’s proposed pediatric dosing regimen. The Agency’s primary worry centers on potential underexposure in younger patients with lower body weight, meaning the current dose may not deliver sufficient drug levels to be therapeutically effective in these children. To move forward, regulators have requested additional pediatric pharmacokinetic data—essentially requiring the company to generate more evidence showing how the drug is absorbed, distributed, and eliminated in children across different weight ranges. This data must demonstrate that lower-weight pediatric patients can achieve comparable drug exposure levels to those seen in the already-approved adult and adolescent treatment protocols.

Manufacturing and Testing Obstacles

Beyond dosing concerns, the CRL also highlighted deficiencies in one of the analytical methods employed for production batch testing. The FDA is seeking further technical data and clarification on the company’s manufacturing and quality control procedures. These issues are separate from the clinical pharmacokinetic question but equally important for final approval.

Pharming’s Strategic Response and Next Steps

The company remains optimistic, stating that the regulatory concerns can be addressed through targeted additional studies and data submissions. Pharming plans to engage directly with the FDA through a Type A meeting—a formal, pre-submission consultation designed to clarify expectations and chart a path toward resubmission. This engagement will be critical for Pharming to understand precisely what evidence the Agency needs before reconsidering the application.

Notably, Joenja’s existing FDA approval for treating APDS in patients aged 12 years and older remains unaffected by this regulatory decision, preserving Pharming’s commercial foothold in the APDS market segment.

Market Reaction

Following the announcement, Pharming’s stock initially declined, closing on January 30 at $20.47, representing a $0.40 drop or 1.92% decrease. However, investor sentiment shifted in after-hours trading, with the stock rebounding to $20.87, gaining $0.40 or 1.95%, signaling cautious optimism about the company’s ability to resolve the FDA’s concerns.