Selecta Biosciences presented more new data from an ongoing phase 2 trial of its enzyme treatment for gout, which the company said outperformed standard treatment and has convinced it to soldier on to a phase 3 clinical program before the end of the year.
SEL-212, a monthly regimen combining proprietary formulations of rapamycin and pegylated uricase (pegsiticase), helped more patients gain control of serum uric acid in a retrospective comparison and reduced treatment-related flares over three months, the Watertown, Massachusetts-based company said.
Previous interim data, released in April, were not well-received by Wall Street at first, sending Selecta’s stock down 20% in premarket trading. It slowly recovered later that week, reaching a level not seen since the company’s stock dropped 46% in November 2017, following another release of SEL-212 data that showed treatment effects dropping off at lower doses.
Selecta’s SVP-Rapamycin envelops the immunomodulator with synthetic, biodegradable vaccine particles to mitigate the formation of antidrug antibodies. When co-administered with pegsiticase, it helps induce immune tolerance of the treatment in patients with severe and chronic gout. The uricase enzyme then converts insoluble, gout-causing uric acid in the bloodstream so it can be excreted through the urine.
In its announcement, Selecta compared its results—which showed about 81% of patients achieving serum uric acid control below 6 mg/dl after 12 weeks—with a separate, unrelated study of Horizon Pharma’s uricase therapy Krystexxa (pegloticase), which saw 44% demonstrate similar uric acid control after 16 weeks.
The study saw 17 serious adverse events, with seven infusion reactions previously reported last year, and one infusion reaction in the most recent cohort. Nine were found to be unrelated to the drug. No infusion reactions were reported after the second treatment cycle and SAEs were successfully treated without further issues, Selecta said.
The company’s data were unveiled during a poster presentation at the European League Against Rheumatism Annual European Congress of Rheumatology in Amsterdam. The presentation also noted only about one-third of the patient population experienced gout flares during the first month of treatment, with rates declining thereafter.
“We are very pleased with this continued improvement in clinical activity observed in this expanded patient data set presented today at EULAR, and believe it further demonstrates SEL-212’s potential ability to change the chronic severe gout treatment paradigm by providing better and more sustained serum uric acid control, fewer flares, and less frequent dosing compared retrospectively to Krystexxa,” said Werner Cautreels, president and CEO of Selecta.
“We are now in the fourth treatment cycle of patients receiving five monthly doses of the combination treatment of SEL-212 and plan to report data from those patients at an upcoming medical meeting in the third quarter of this year,” Cautreels added.