Surrozen, Inc. announced that it voluntarily paused enrollment in the single ascending dose (SAD) portion of the Company's Phase 1 clinical trial evaluating SZN-1326 in healthy volunteers following the observation of treatment-related adverse events. Several subjects experienced asymptomatic liver transaminase elevations, including three subjects with grade 3 ALT and AST elevations. There were no corresponding increases in total bilirubin nor any changes in liver function markers such as coagulation markers or albumin.

No other clinically significant laboratory abnormalities were observed, and the transaminase elevations resolved spontaneously in all subjects. No serious adverse events were observed during the study. SZN-1326 is a Wnt mimetic bi-specific antibody that selectively activates the Wnt pathway and is in development for treatment of patients with ulcerative colitis.

Surrozen intends to further analyze available clinical data with the study investigator and conduct additional pre-clinical experiments to identify the potential mechanism of the transaminase elevations, which had not been observed in the GLP-toxicology studies, and determine next steps in the development program. SZN-043 Update The Phase 1 SAD portion of the SZN-043 trial in healthy volunteers is ongoing. Grade 1 and 2 treatment-related asymptomatic liver transaminase elevations were present in several subjects dosed with SZN-043.

There were no corresponding increases in total bilirubin or GGT nor any changes in liver function markers such as coagulation markers or albumin in these subjects. No other clinically significant laboratory abnormalities were observed, and the transaminase increases for these subjects resolved spontaneously. No serious adverse events were observed during the study.

Surrozen will be re-evaluating the overall clinical development timeline for this program and will provide an update at the appropriate time. SZN-413 for Vascular-associated Retinopathies, including Diabetic Retinopathy and Diabetic Macular Edema, recently partnered to Boehringer Ingelheim SZN-413, a Fzd4-targeted bi-specific antibody, also using Surrozen's SWAP™ technology, has the potential to treat retinal vascular associated diseases including diabetic retinopathy and diabetic macular edema. Surrozen recently entered into a strategic partnership with Boehringer Ingelheim for the research and development of SZN-413 for the treatment of retinal diseases.

Under the terms of the agreement, Boehringer Ingelheim will receive an exclusive, worldwide license to develop SZN-413 and other Fzd4-specific Wnt-modulating molecules for all purposes, including as a treatment for retinal diseases, in exchange for an upfront payment to Surrozen of $12.5 million. Surrozen will also be eligible to receive up to $586.5 million in success-based development, regulatory, and commercial milestone payments, in addition to mid-single digit to low-double digit royalties on sales. After an initial period of joint research, Boehringer Ingelheim will assume all development and commercial responsibilities.