Global biopharmaceutical company Sobi has received a Complete Response Letter (CRL) from the US Food and Drug Administration (FDA) regarding its Biologics License Application (BLA) for NASP (Nanoencapsulated Sirolimus Plus Pegadricase), an investigational treatment for adults with uncontrolled gout.

According to the company, the FDA's response primarily requests additional information related to the manufacturing control strategy for the biologic component of NASP and the resolution of deficiencies identified at a contract manufacturing facility. The regulator did not raise any concerns regarding the clinical efficacy or safety of the therapy that would affect its potential approval.

Sobi said it intends to request a meeting with the FDA to better understand the agency's feedback, determine the appropriate path for resubmission and collaborate with its contract manufacturing organisations to address the identified issues.

Lydia Abad-Franch, Chief Medical Officer at Sobi, said the company remains confident in NASP's ability to address a significant unmet medical need among patients with uncontrolled gout. She noted that clinical studies have demonstrated meaningful reductions in serum uric acid levels and added that the FDA's feedback provides a clear and actionable roadmap toward resubmitting the application.

Uncontrolled gout affects an estimated 200,000 people in the United States who continue to experience elevated serum uric acid levels, painful flare-ups and deposits of uric acid crystals despite treatment with conventional oral urate-lowering therapies. Persistent high uric acid levels are also associated with an increased risk of cardiovascular, metabolic, kidney and joint-related complications.

NASP is an investigational therapy designed to lower serum uric acid levels through a sequential infusion of two components administered every four weeks. The treatment combines nanoencapsulated sirolimus, which is intended to reduce the formation of anti-drug antibodies, with pegadricase, a uricase enzyme that helps break down excess uric acid. By lowering uric acid levels, the therapy aims to reduce tissue deposits that can lead to irreversible joint damage and other long-term health complications.

Sobi said it remains committed to advancing the development of NASP and bringing the treatment to patients living with uncontrolled gout once the regulatory requirements have been addressed.