Surrozen stops IBD program due to dose concerns and competition

Surrozen’s inflammatory bowel disease treatment is hitting the curb after the biotech had difficulty nailing a safe dose in healthy volunteers.

The company said Thursday that between the dosing challenges and the competitive marketplace, it was discontinuing further development of SZN-1326 for IBD—the only indication the asset was being developed for, according to Surrozen’s pipeline.

“Several” subjects in the 37-person healthy volunteer trial experienced asymptomatic but elevated levels of liver enzymes that can be a sign of liver injury, the biotech said. Four subjects had grade 3 increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST), three of which had previously been reported by the company. Surrozen previously announced it had paused the trial after first identifying the side effects. 

No additional “clinically significant” lab abnormalities have since been identified, the company said, and the elevated liver enzymes resolved on their own.

The doses given in the phase 1 trial ranged from 0.01 mg to 25 mg. Although the lower doses appeared safe, Surrozen said it’s unlikely they would be efficacious.

The company’s near-term focus will be SZN-043, which just completed enrollment in a phase 1a trial consisting of healthy volunteers and patients with chronic liver disease. Safety and pharmacodynamic data is expected later on in the first quarter of this year with enrollment for the phase 1b portion for patients with alcohol-associated hepatitis slated to start “soon.” Surrozen said it could potentially have proof-of-concept data from the phase 1b segment in the second half of 2024. 

“Importantly, SZN-043 represents a different antibody technology and approach to modulating Wnt signaling compared to SZN-1326,” President and CEO Craig Parker said in a release. 

Still to come into the clinic is Surrozen’s Boehringer Ingelheim-partnered med, SZN-413, which is currently aimed at treating retinal damage. Surrozen has not yet specified when it expects to formally ask regulators to enter human trials.