VIENNA — Safe and effective options for lowering serum uric acid (sUA) in patients with gout who are refractory to conventional therapies appear to be near, judging from phase 2 and 3 trials that produced positive results at the annual European Congress of Rheumatology.
Reports from the meeting included two phase 2 studies with novel urate anion transporter 1 (URAT1) inhibitors for patients with refractory gout, in addition to extension data from the phase 3 trial program for SEL-212. In all cases, efficacy appeared to be on the same order of currently available drugs with potentially better tolerability, an important unmet need for patients with gout refractory to traditional therapies.
12-Month Outcomes With SEL-212
The extension data with SEL-212 follow the 6-month results presented from the DISSOLVE I and II trials at EULAR 2023. Now at 12 months, the benefits have proven to be generally sustained with no new safety signals, according to Herbert S.B. Baraf, MD, The Center for Rheumatology and Bone Research, Wheaton, Maryland.
Arthritis Foundation
Dr. Herbert S.B. Baraf
SEL-212 is a drug platform involving two components delivered by intravenous infusion once monthly in sequence. The first, SEL-110, consists of tolerogenic nanoparticles containing sirolimus. The second, SEL-037, is the pegylated uricase pegadricase.
On the 1-month dosing schedule, most patients who had responded at 6 months were still responding at 12 months, and both of the two study doses of SEL-212 in the DISSOLVE trials were well tolerated over the extension, Dr. Baraf reported.
On the basis of the data so far, “this will be an effective and well tolerated therapy for refractory gout over a period of at least 12 months,” Dr. Baraf said.
The DISSOLVE I and II trials were identically designed. Patients with refractory gout, defined as failure to normalize sUA or control symptoms with a xanthine oxidase inhibitor, were randomly assigned to receive 0.15 mg SEL-212, 1.0 mg SEL-212, or placebo.
There was a stopping rule for patients who reached a sUA level < 2 mg/dL 1 hour after the infusion.
The primary endpoint was sUA level < 6 mg/dL for at least 80% of the sixth month of the 6-month trial. About 50% of patients on either dose of SEL-212 met this endpoint (vs 4% of those receiving placebo; P < .0001). There was a numerical advantage for the higher dose in both studies.
Patients who completed the 6-month trial were eligible for a 6-month extension, during which they remained on their assigned therapy, including placebo. This phase was also blinded. Patients who met the stopping rule in either the main study or extension did not take the study drug but remained in the study for final analysis.
Of the 265 patients who participated in the main phase of the study, 143 (54%) completed the 6-month extension. Most discontinuations were the result of the stopping rule. Reasons for other patients discontinuing the study included withdrawal of consent in about 10% of each treatment arm and adverse events in 13.8%, 6.8%, and 2.2% of the high-dose, low-dose, and placebo groups, respectively.
At 12 months, when the data from the two trials were pooled, the proportion of patients on therapy and responding remained at about 50% in the high-dose group and 43% in the low-dose group on an intention-to-treat analysis. Relative to the 8% response rate for placebo, the advantage for either dose was highly significant (P < .0001).
In the subgroup of patients with tophi at baseline, representing about half the study group, responses were low at 12 months, whether on high- (41%) or low-dose (43%) SEL-212. The rate of response among placebo patients with baseline tophi was 9%.