About Us

Byondis is an independent, privately held, clinical stage biopharmaceutical company creating innovative precision medicines targeting intractable cancers and autoimmune diseases. Using its proprietary molecular concepts and technologies, Byondis generates next generation antibody-drug conjugates (ADCs). Its broad development portfolio includes the anti-HER2 ADC [vic-]trastuzumab duocarmazine (SYD985), whose pivotal Phase III TULIPĀ® study reported positive topline results. Based in Nijmegen, the Netherlands, Byondis collaborates with leading biotechnology, pharmaceutical and academic research organizations.


Passport Stamp for World ADC San Diego 2022

Passport 2022 SD (5)

Team Members

Patrick Groothius - Byondis NEW

Patrick Groothuis

Principal Scientist

Ruud Coumans - ByondisNEW

Ruud Coumans

Project Leader Antibody-Drug Conjugates


Evelyn Van Den Tweel

Project Leader, Clinical Development