Surrozen Inc.’s back-end-loaded deal with Boehringer Ingelheim GmbH for the preclinical frizzled class receptor 4 agonist SZN-413 takes aim at vascular function in retinal diseases. The arrangement brings an up-front payment to South San Francisco-based Surrozen of $12.5 million, plus up to $586.5 million in potential development, regulatory and commercial milestone rewards, along with mid-single-digit to low-double-digit royalties on sales. After an initial period of joint research, Boehringer, of Ingelheim, Germany, will take over development and commercial responsibilities.