STOCKHOLM, Sweden, June 26, 2026
Sobi announced that it has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its Biologics License Application (BLA) for NASP (nanoencapsulated sirolimus plus pegadricase), an investigational therapy for adult patients with uncontrolled gout. Importantly, the FDA did not identify any clinical safety or efficacy concerns that would impact the drug’s approvability. Instead, the agency requested additional information related primarily to chemistry, manufacturing and controls (CMC), including the manufacturing control strategy for the biological component of NASP and deficiencies associated with contract manufacturing facilities. The company plans to meet with the FDA to clarify the requirements and prepare for a future resubmission.
FDA Requests Manufacturing Data Rather Than Clinical Evidence
According to the CRL, the FDA’s review focused on manufacturing-related issues rather than the medicine’s clinical performance. The agency requested additional documentation supporting the CMC package, as well as corrective actions addressing observations at third-party manufacturing sites involved in NASP production. Sobi stated that it will work closely with its contract manufacturing organizations while engaging directly with the FDA to establish the most efficient regulatory pathway toward resubmission. The absence of new clinical efficacy or safety concerns indicates that the agency’s current review does not require additional clinical trials before addressing the identified manufacturing deficiencies.
Clinical Data Continue to Support NASP in Uncontrolled Gout
NASP is a novel investigational infusion therapy administered every four weeks that combines nanoencapsulated sirolimus, designed to reduce anti-drug antibody formation, with pegadricase, an enzyme that lowers serum uric acid levels. The therapy is intended for patients with uncontrolled gout, a severe form of the disease affecting approximately 200,000 people in the United States who continue to experience painful flares or tophi despite oral urate-lowering therapies. According to Sobi, clinical studies have demonstrated meaningful reductions in serum uric acid levels, supporting the therapy’s potential to reduce disease burden, prevent irreversible joint damage, and improve long-term patient outcomes by targeting persistent hyperuricemia.
Advertisement
Sobi Remains Committed to Regulatory Resubmission
Despite the regulatory setback, Sobi reaffirmed its confidence in NASP’s therapeutic potential and remains committed to advancing the program toward approval. Company executives emphasized that the FDA’s feedback provides a clear and actionable path forward, allowing the development team to focus on resolving manufacturing requirements while maintaining confidence in the product’s clinical profile. As a global biopharmaceutical company specializing in rare diseases, Sobi continues to invest in innovative therapies addressing significant unmet medical needs. The company expects further discussions with the FDA to determine the timeline for BLA resubmission, bringing NASP one step closer to becoming a potential new treatment option for patients living with uncontrolled gout.
Source: Sobi press release
