Michael Hallek

Michael Hallek, MD is Director of the Department of Internal Medicine I (Hematology and Oncology) at the University Hospital of Cologne, Professor of Medicine at the University of Cologne, and founder and longstanding Speaker (Head) of the German CLL Study Group (GCLLSG) — the world's largest and most productive CLL cooperative clinical trial group, having enrolled over 8,000 patients across more than 25 randomized clinical trials. Prof. Hallek is one of the towering figures in CLL worldwide, recognized for establishing the evidence base that has transformed CLL from a disease managed with single-agent chlorambucil to one with curative-intent, MRD-guided fixed-duration regimens and oral targeted therapies. He was the overall Principal Investigator of the landmark CLL11 trial (NEJM 2014), demonstrating obinutuzumab superiority over rituximab combined with chlorambucil in previously untreated unfit CLL — the first study to show a new drug was superior to an existing CLL standard, leading to the first FDA approval of obinutuzumab (GA101). He previously led the CLL8 trial (Lancet 2010), the definitive randomized study establishing FCR (fludarabine, cyclophosphamide, rituximab) as the standard of care for fit CLL patients, demonstrating superior PFS and OS over FC alone (HR 0.68; p<0.001). Prof. Hallek is a lead author of multiple versions of the ESMO CLL guidelines and iwCLL diagnostic and response criteria, which are universally adopted internationally. He has authored over 450 publications, received numerous honorary degrees, and is among the most cited hematologists globally.