Publicly traded biopharmaceutical company Arrowhead Pharmaceuticals announced yesterday a $25 million milestone payment triggered by the first subject enrolled in Amgen’s Phase 3 trial of olpasiran, a treatment designed to lower the risk of heart attack and stroke.

Arrowhead, based in Pasadena, is further eligible to receive up to an additional $535 million in aggregate development, regulatory and sales milestone payments from Thousand Oaks-based Amgen and Royalty Pharma, the latter of which is a biopharmaceutical fundraising and royalties company.

“We are pleased with the great progress on the clinical development of olpasiran, which was developed using Arrowhead’s proprietary TRiMTM technology,” Dr. Christopher Anzalone, Arrowhead’s president and chief executive, said in a statement. “This is an important milestone for the program and for Arrowhead, as this is the second TRiMTM-enabled candidate to enter Phase 3 studies. Importantly, as our pipeline continues to advance expeditiously, we anticipate multiple Arrowhead therapies will also reach Phase 3 trials over the coming year.”

Olpasiran was originally developed by Arrowhead using a proprietary targeted molecule platform and licensed to Amgen in 2016.