The U.S. Food and Drug Administration has accepted Sobi's Biologics License Application for NASP (Nanoecapsulated Sirolimus plus Pegadricase), a novel treatment for patients with uncontrolled gout. The Swedish biopharmaceutical company announced that the FDA has set a Prescription Drug User Fee Act target action date of June 27, 2026, for the investigational therapy formerly known as SEL-212.
NASP represents a potential breakthrough for the approximately 200,000 Americans living with uncontrolled gout, a condition characterized by serum uric acid levels above 6 mg/dL despite treatment with oral urate-lowering therapies. The therapy is administered as a sequential, two-component infusion every four weeks, combining tolerogenic nanoencapsulated sirolimus to mitigate anti-drug antibody formation with pegadricase, a pegylated uricase that reduces serum uric acid levels.
Clinical Trial Results Support Regulatory Submission
The BLA submission includes data from the pivotal Phase 3 DISSOLVE I and II placebo-controlled randomized clinical trials, which evaluated the safety and efficacy of two different dose levels of NASP in adult patients with uncontrolled gout. Both studies successfully met their primary endpoint of achieving and maintaining serum uric acid reduction below 6mg/dL for at least 80% of the time during month six.
The pooled response rates demonstrated efficacy across both dosing regimens, with 51% of patients responding to the high dose and 43% responding to the low dose of NASP. Beyond the primary endpoint achievement, the treatment showed rapid and sustained reductions in serum uric acid levels following the first treatment and throughout the study duration.
Clinical benefits extended beyond biochemical markers, with improvements observed in key disease manifestations including tophi resolution, reduced gout flares over time, and enhanced patient-reported quality of life. The therapy was generally well tolerated across both doses in the clinical trials.
Addressing Critical Unmet Medical Need
"There is a significant unmet need for patients living with uncontrolled gout," said Lydia Abad-Franch, MD, MBA, Head of Research, Development, and Medical Affairs, and Chief Medical Officer at Sobi. "People living with uncontrolled gout experience chronic inflammation, often resulting in severe gout flares and a buildup of uric acid, leading to the formation of painful tophi. These clinical manifestations not only affect a patient's physical and mental quality of life but also their comorbid conditions."
Gout affects more than 8.3 million people in the United States, making it the most common form of inflammatory arthritis. The condition results from high uric acid levels that accumulate around joints and tissues, causing intense pain during flares. Elevated serum uric acid levels have been associated with cardiovascular, metabolic, renal, and joint complications.
Innovative Mechanism Targets Immunogenicity Challenge
NASP's unique design addresses a critical challenge in uricase therapy: the development of anti-drug antibodies that reduce treatment efficacy and tolerability. The nanoencapsulated sirolimus component provides targeted immunomodulation to prevent unwanted immune responses against the pegadricase uricase component.
This approach represents a significant advancement in addressing immunogenicity issues that have historically limited the effectiveness of biologic medicines across multiple therapeutic areas, including uncontrolled gout treatment.
The FDA previously granted NASP Fast Track designation in May 2024, recognizing its potential to address a serious condition with high unmet need and limited treatment options. This designation facilitates more frequent FDA communication and potentially expedited review processes for promising therapies addressing unmet medical needs.
