On December 7, 2016, Selecta Biosciences, Inc. (the “Company”) issued a press release announcing data from the Company’s Phase 1 company-sponsored trial which assessed single ascending dose safety, pharmacokinetic and pharmacodynamics of SEL-212 in patients with elevated uric acid levels.

The Phase 1a trial enrolled 22 U.S. patients with hyperuricemia (uric acid level of >6mg/dL) and evaluated the effect of a single intravenous infusion in a range of 0.1 to 1.2 mg/kg of pegsiticase administered alone. Pegsiticase was generally well tolerated at all tested dose levels. Serum uric acid levels for all patients initially dropped to less than 0.1 mg/dL within approximately 10 hours. However, these levels began rebounding by 14 to 21 days after dosing in a majority of patients. The loss of uric acid level control (defined as uric acid of >6 mg/dL) correlated with the formation of anti-drug antibodies (ADAs). The 0.4 mg/kg dose of pegsiticase was selected as the dose level to carry forward into the Phase 1b trial.

The multicenter Phase 1b trial enrolled 63 U.S. patients. One group received a single intravenous infusion of 0.4 mg/kg of pegsiticase alone. Four groups received either placebo or a single intravenous infusion of SVP-Rapamycin alone in a range of 0.03 to 0.5 mg/kg. As expected, SVP-Rapamycin alone did not significantly affect uric acid levels in these patients. Two serious adverse events (SAEs) of stomatitis were observed at the highest dose level tested (0.5 mg/kg), leading the Company to set 0.3 mg/kg as the maximum tolerated dose of SVP-Rapamycin for the Phase 1b trial. All SAEs resolved completely during the study period.

Four additional groups in the Phase 1b trial received a single fixed dose of 0.4 mg/kg dose of pegsiticase by intravenous infusion in combination with 0.03, 0.1, 0.15 or 0.3 mg/kg of SVP-Rapamycin:

•At the 0.03 mg/kg dose, serum uric acid levels were controlled for at least 21 days in four of the five patients.

•At the 0.1 mg/kg dose, serum uric acid levels were controlled through Day 30 in seven of 10 patients.

•At the 0.15 mg/kg dose, serum uric acid levels were controlled through Day 30 in all five patients.

•At the 0.3 mg/kg dose, serum uric acid levels were controlled through Day 30 in all five patients.

The substantial and sustained reduction in uric acid levels through at least Day 30 was correlated with the prevention of ADAs. These data supported a monthly dosing regimen in the ongoing multi-dose Phase 2 clinical trial.

SEL-212 was generally well tolerated at the clinically active dose levels. One drug-related SAE was reported at the 0.1 mg/kg dose level for a Grade 2 rash which was classified as an SAE due to an emergency room visit. This SAE resolved during the study period without further issues. No SAEs were observed at the 0.03, 0.15 or 0.3 mg/kg dose levels.

About SELECTA BIOSCIENCES, INC. (NASDAQ:SELB)

Selecta Biosciences, Inc. is a clinical-stage biopharmaceutical company. The Company using its synthetic vaccine particle (SVP) technology to discover and develop targeted therapies that are designed to modulate the immune system to treat rare and serious diseases. The Company is engaged in the research and development of nanoparticle immunomodulatory drugs for the treatment and prevention of human diseases. The Company’s product candidates are in development. The Company’s SVP technology encapsulates an immunomodulator in biodegradable nanoparticles to induce antigen-specific immune tolerance to mitigate the formation of anti-drug antibodies (ADAs) in response to life-sustaining biologic drugs. The Company’s technology allows for the design of SVP therapies that can stimulate immune responses against a range of relevant antigens. Its initial immune-stimulating product candidate is a synthetic vaccine against nicotine for the market of smoking cessation and relapse prevention.

SELECTA BIOSCIENCES, INC. (NASDAQ:SELB) Recent Trading Information

SELECTA BIOSCIENCES, INC. (NASDAQ:SELB) closed its last trading session 00.00 at 23.95 with 103,218 shares trading hands.