FDA Delays Gout Drug NASP with Complete Response Letter Save

At the end of June, Sobi was awaiting an FDA decision on its Biologics License Application (BLA) for NASP (nanoencapsulated sirolimus plus pegadricase) for the treatment of adult patients with uncontrolled gout. On June 26, 2026, SOBI received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) that will delay a decision on NASP, pending the company's answer to questions regarding the drugs manufacturing at a 3rd party facility in China. 

The FDA has requested information related to manufacturing control strategy and potential contract manufacturing facility deficiencies. 

The FDA identified no concerns regarding the clinical efficacy or safety of NASP that impact approvability. NASP clinical trials data has thus far generated significant efficacy and reductions in serum uric acid levels in uncontrolled gout patients. 

Sobi previously acquired a SEL-212, that also used encapsulated nanoparticles of sirolimus (to inhibit anti-drug antibodies) along with pedricase (pegylated uricase). SEL-212 was also was held up by a CRL for manufacturing and facility issues, but ultimately was redeveloped and renamed NASP, and a new BLA was submitted nearly 2 years ago. NASP has been developed to treat uncontrolled gout patients who have failed traditional oral therapies. 

NASP is administered every 4 weeks as a sequential, two-component, infusion therapy that includes the tolerogenic nanoencapsulated sirolimus (NAS) which mitigates the formation of anti-drug antibodies (ADAs) and a uricase, pegadricase (P), which reduces serum uric acid.