 Seagen will supply Pieris with TUKYSA to evaluate the drug in combination with cinrebafusp alfa PRS-343 in gastric cancer Pieris co-development option for one program from existing multi-target collaboration amended to US co-promotion option with increased royalties if exercised Seagen to purchase 13 million equity stake in Pieris common stock BOSTON, MA ACCESSWIRE March 25, 2021 Pieris Pharmaceuticals, Inc. NASDAQ:PIRS, a clinical-stage biotechnology company advancing novel biotherapeutics through its proprietary Anticalin technology platform for respiratory diseases, cancer, and other indications, today announced that Seagen has made a strategic equity investment in Pieris as part of an ongoing collaboration between the companies. In addition, the companies have entered into a clinical trial collaboration agreement to evaluate the safety and efficacy of combining Pieris cinrebafusp alfa PRS-343, a 4-1BBHER2 bispecific, with Seagens TUKYSA tucatinib, a small-molecule tyrosine kinase HER2 inhibitor, for the treatment of gastric cancer patients expressing lower HER2 levels IHC2ISH- IHC1 as part of the upcoming phase 2 study to be conducted by Pieris. 