SEL-212 for Uncontrolled Gout

How does SEL-212 work against uncontrolled gout?

Urate-lowering biologic treatment faces a practical obstacle: the immune system can recognize an administered enzyme as foreign and produce antibodies that undermine its activity. Nanoencapsulated sirolimus plus pegadricase, also called NASP and previously SEL-212, was developed to address that problem. Pegadricase is a modified uricase enzyme, while the accompanying nanoparticles contain sirolimus, an immune-modulating medicine.

The strategy aims to preserve the enzyme's uric acid-lowering effect by limiting anti-drug antibody formation. In the development program, the components were administered sequentially by intravenous infusion. Earlier dose-finding research examined whether this combination could sustain urate control and help identify doses for subsequent phase 3 testing. The approach concerns ongoing disease control rather than immediate relief of an isolated painful flare. [Phase 2 dose-finding study](https://pubmed.ncbi.nlm.nih.gov/37069364/).

What did the phase 3 gout trials find?

The DISSOLVE I and DISSOLVE II results, published in Arthritis & Rheumatology in June 2026, evaluated treatment given every four weeks. The primary endpoint required serum urate below 6 mg/dL for at least 80% of the assessment period during weeks 21–24. In the pooled analysis, 51% of participants receiving the higher sirolimus dose and 43% receiving the lower dose met that endpoint, compared with 8% receiving placebo. These percentages describe a defined laboratory response, not the proportion cured of gout. [Published phase 3 results](https://acrjournals.onlinelibrary.wiley.com/doi/abs/10.1002/art.70266).

The placebo-controlled findings establish an effect on urate levels but do not establish superiority over another active treatment. Safety also matters: reported adverse events included gout flares, infections and mouth inflammation, and infusion reactions occurred. Sobi supported the trials. Their publication provides evidence for evaluating the treatment; it should not itself be interpreted as an announcement of regulatory approval. [DISSOLVE efficacy and safety report](https://acrjournals.onlinelibrary.wiley.com/doi/abs/10.1002/art.70266).

Who might need treatment beyond standard gout tablets?

The American College of Rheumatology's 2020 guideline recommends allopurinol as the preferred initial urate-lowering medicine, including for many patients with chronic kidney disease. It favors adjusting treatment according to repeated blood measurements toward a serum urate target below 6 mg/dL. Persistent symptoms therefore warrant reviewing medication use, tolerability and dose optimization before assuming that oral treatment has failed. [ACR gout management guideline](https://pmc.ncbi.nlm.nih.gov/articles/PMC10563586/).

The guideline supports escalation to the established uricase medicine pegloticase when other approaches fail and patients continue to have frequent flares or unresolved tophi, the deposits of urate crystals that can form beneath the skin. That recommendation provides context for the population targeted by newer enzyme-based therapies; it is not a recommendation for NASP. For emerging treatments, clinicians must weigh sustained control, adverse effects and the burden of repeated infusions against available alternatives. [ACR recommendations on treatment escalation](https://pmc.ncbi.nlm.nih.gov/articles/PMC10563586/).