FDA rejects Sobi gout therapy, cites manufacturing concerns

The U.S. Food and Drug Administration declined Friday to approve Swedish Orphan Biovitrum’s NASP therapy for uncontrolled gout, saying it needed more data on chemistry, manufacturing and controls and on contract manufacturing facilities. Sobi said the agency identified no clinical safety or efficacy concerns that would affect approvability, which means the drug’s trial results were not the central problem.

The decision landed at the deadline. FDA accepted the biologics license application on September 10, 2025, and set June 27, 2026, as the Prescription Drug User Fee Act target date. NASP is a once-every-four-weeks infusion of nanoencapsulated sirolimus plus pegadricase, and Sobi has said roughly 200,000 people in the United States live with uncontrolled gout. For patients facing repeated flares and persistent uric acid buildup, the delay pushes back a potential new option in a field with limited choices.

That delay matters because gout remains a major U.S. health burden. The American College of Rheumatology says gout affects about 9.2 million U.S. adults, or 3.9% of the population, and calls it the most common form of inflammatory arthritis. ACR guidance places urate-lowering therapy at the center of care, including for patients with tophi or radiographic damage attributable to gout, underscoring why a stronger option for difficult-to-control disease could have clinical value.

Sobi’s own data had pointed to promise. The company said the pivotal DISSOLVE I and DISSOLVE II studies met the primary endpoint of keeping serum uric acid below 6 mg/dL for at least 80% of month six, with pooled response rates of 51% in the high-dose group and 43% in the low-dose group. The FDA’s action shows how approval can hinge on manufacturing discipline as much as efficacy, and the agency says complete response letters are issued for a range of reasons, most often safety and efficacy concerns, manufacturing deficiencies and bioequivalence issues. Sobi said it will meet with FDA, work with contract manufacturing organizations to address the deficiencies and then pursue resubmission.