Thomas joined Novo A/S in 2000. He is a member of the Boards of Directors of Allievex Inc. and Anokion SA.

Thomas held research positions at the Hagedorn Research Institute, Denmark, and at the Scripps Research Institute, La Jolla, USA. In 1990, he joined Novo Nordisk A/S, initially working in Health Care Discovery on various aspects of diabetes immunology and pathogenesis, and from 1996 in Health Care Clinical Drug Development.

Thomas obtained an MD degree from the University of Copenhagen in 1981 and a DMSc degree, also from the University of Copenhagen in 1986.