LB0002 SAFETY & EFFICACY OF SEL-212 IN PATIENTS WITH GOUT REFRACTORY TO COVENTIONAL TREATMENT: OUTCOMES FROM TWO RANDOMIZED, DOUBLE BLIND, PLACEBO-CONTROLLED, MULTICENTER PHASE III STUDIES

Background

Despite availability of effective therapies for gout, a small proportion of patients suffer from refractory gout and/or are intolerant to standard therapies [1]. In these patients, the inability to maintain serum uric acid (sUA) levels < 6 mg/dL may lead to severe clinical manifestations for which uricase-based therapies can be highly effective, though also immunogenic. SEL-212 is a once-monthly, novel 2-component, sequential uricase-based infusion therapy being investigated in patients with refractory gout. SEL-212 consists of an infusion of tolerogenic nanoparticles containing rapamycin (SEL-110) followed by pegadricase (SEL-037). The intent of this drug combination is to inhibit the formation of anti-uricase antibodies without the need for separate immunosuppressant therapies [2].

Objectives

DISSOLVE I and II (D1 and D2, respectively) evaluated the safety and efficacy of SEL-212 in adults with refractory gout.

Methods

D1 (US Study, 12 months) and D2 (Global Study, 6 months), were placebo-controlled, double-blind, randomized clinical trials that evaluated two dose levels of SEL-110 (0.15 mg/kg [high-dose] or 0.1 mg/kg [low-dose]) prior to SEL-037 (0.2 mg/kg) infusion in adults (19-80 years). Participants with a history of symptomatic gout were enrolled if they had ≥ 3 gout flares within 18 months prior to screening or ≥ 1 tophus or a current diagnosis of gouty arthritis, failed to normalize sUA and control symptoms with any xanthine oxidase inhibitor, and were not previously exposed to a uricase-based therapy. Participants were randomized 1:1:1 between the two doses of SEL-212 and placebo administered intravenously every 28 days for 6 treatments. D1 participants were continued in a 6-month blinded extension phase under the initial treatment conditions (Fig. 1). The primary endpoint was defined as the percentage of participants who achieved and maintained sUA < 6 mg/dL for ≥ 80% of the sixth 28-day treatment period (TP6) in the active treatment groups versus placebo (response rate). Safety and tolerability were assessed through monitoring of adverse events (AEs) and laboratory testing.

Results

A total of 265 participants (D1, n=112 (96% male, 66% ≥ 50 years); D2, n=153 (97% male, 72% ≥ 50 years) were randomized into the three treatment arms. Response rates in all treatment groups were significantly different from placebo (p ≤ 0.0015), with 56% and 47% of participants responding in the high-dose group and 48% and 41% in the low-dose group for D1 and D2, respectively (Table 1). The response rates in participants aged ≥ 50 years were 65% and 48% in the high-dose groups and 47% and 45% in the low-dose groups for D1 and D2, respectively (p ≤ 0.0044 vs placebo). Across all participants in the treatment groups, median sUA levels were reduced by ~96% and ~75% from baseline at TP6 for D1 and D2, respectively (p<0.001 vs placebo). The safety profile of SEL-212 was favorable, with 3.4% and 4.5% of participants experiencing infusion reactions in the high and low-dose groups, respectively. Reports of gout flares were comparable between treatment groups and placebo. Six participants (3.4%) in the pooled active treatment groups experienced treatment-related serious AEs (n=4 anaphylaxis, n=2 gout flares).

Conclusion

In the DISSOLVE trials, once-monthly treatment with SEL-212 demonstrated statistically significant response rates and reductions in sUA versus placebo. The safety profile of SEL-212 was consistent with that of uricase therapies. Targeted immunomodulation with SEL-212 has the potential to provide a new uricase-based treatment option for patients with gout refractory to conventional therapies without the need for traditional immunosuppressants.

References

[1] Edwards NL. Arthritis Rheum 2008;58(9):2587-90. [2] Sands E, et al. Nat Commun 2022;13:272.

Acknowledgments

We would like to acknowledge all participants, investigators, and study personnel involved in the DISSOLVE phase III clinical studies. Writing support provided by Micheal Wilson, PhD, of Swedish Orphan Biovitrum.

Disclosure of Interests

Herbert S.B. Baraf Consultant of: Horizon Pharmaceuticals, Swedish Orphan Biovitrum, Selecta Biosciences, Speakers bureau: Horizon Pharmaceuticals, Grant/research support from: Horizon Pharmaceuticals, Swedish Orphan Biovitrum, Alan Kivitz Consultant of: AXDEV Group, Amgen, Pfizer, Janssen, Boehringer Ingelheim, AbbVie, Flexion, Gilead, Grünenthal, Orion, Regeneron, Sun Pharma Advance Research, and ECOR1, Speakers bureau: Merck & Co, Eli Lilly, Novartis, Pfizer, Flexion, AbbVie, Amgen, Genentech, Regeneron, UCB, Horizon, and GSK, Shareholder of: Pfizer, GSK, Gilead, Novartis, and Amgen, Sheri Rhodes Consultant of: Selecta Biosciences, Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences, Sheldon Leung Consultant of: Selecta Biosciences, Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences, Olu Folarin Consultant of: Selecta Biosciences, Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences, Tania Gonzalez-Rivera Consultant of: Swedish Orphan Biovitrum, Employee of: Swedish Orphan Biovitrum, Joanna Sobierska Employee of: Swedish Orphan Biovitrum, Jacquie Christie Shareholder of: GSK Pharma, Employee of: Swedish Orphan Biovitrum, Anand Patel Speakers bureau: Lexicon Pharmaceuticals, Wesley DeHaan Consultant of: Selecta Biosciences, Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences, Rehan Azeem Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences, Peter Traber Consultant of: Selecta Biosciences, Shareholder of: Selecta Biosciences, Employee of: Selecta Biosciences.