His research interest lies in the characterization of the molecular mechanism of action IBD therapies and the identification of individual response predictors (e.g. molecular endoscopy), as well as resistance mechanisms to biological therapies. He has been involved as Coordinating Investigator in multicenter clinical IBD trials. Raja has been a recipient of the Paul Ehrlich and Ludwig Darmstaedter Prize for Young Researchers from the Paul Ehrlich Foundation, the Theodor Frerichs Award from the German Society for Internal Medicine; the Rising Star Award from the United European Gastroenterology Federation, and the International Award of the American College of Gastroenterology.