Désiré José Louis, Baron Collen (Sint-Truiden, 21 June 1943) is a Belgian emeritus professor of KU Leuven Faculty of Medicine, physician, chemist and biotech-entrepreneur.

He gained international prominence in the 1980s and 1990s for the discovery of the potential of t-PA (tissue plasminogen activator) as a life-saving drug for patients with acute myocardial infarction (AMI) or heart attack, and cerebrovascular incidents (CVA) or stroke.

He invested most of the proceeds of his work in scientific research, conferences, chairs, scholarships, university infrastructure, and philanthropy via LSRP, DCS and the “Collen Charitable Trust, CCT “.

In August 1980, Désiré Collen and KU Leuven concluded an agreement with the American company Genentech, which was pioneering in cloned medicines.

Thanks to Genentech collaborator Diane Pennica, the DNA code of t-PA was unraveled, and the enzyme was developed and produced on an industrial scale into a life-saving drug (alteplase) that was approved by the FDA in 1987 under the name Activase®.

With his personal share of the t-PA royalties, Collen founded ThromboGenics NV in 1998, where among other things, ocriplasmin was developed for the treatment of vitreomacular adhesion of the retina in the eye.

The American physician Steve Pakola was charged with the clinical development of ocriplasmin, Chris Buyse became Collen's financial right-hand man.

In 1995, when the VIB (Flemish Institute for Biotechnology) was founded, Désiré Collen became director of the department “Transgene Technology and Gene Therapy”, where with Professor Peter Carmeliet he achieved breakthroughs in the field of vascular biology and neurobiology, such as the role of VEGF (vascular endothelial growth factor) and PIGF (placental growth factor) in angiogenesis, cancer and ALS.