Khayat studied medicine at the University of Nice from 1974 to 1980. Over the next five years he undertook internship and residency training at hospitals in Paris, and moved towards the field of oncology.
Later, during his formal studies in oncology, he attained a Master of Science in tumor immunology. Part of these studies were conducted in Israel, at the University of Tel Aviv. Back in France, he became board certified in oncology in 1985.
In 1988, Khayat received a PhD from the University Pierre and Marie Curie, Paris. During his studies there, Khayat worked on the identification and purification of the soluble Fc receptors both in mouse and human sera.
Khayat landed an assistant professorial position at the Department of Medical Oncology at Pitié—Salpetrière, a teaching hospital in the Assistance Publique-Hôpitaux de Paris network, in 1985. He moved onto a full professorship at University Pierre and Marie Curie in 1989 after getting his PhD.
Khayat returned to Pitié—Salpetrière in 1990 as Head of the Department of Medical Oncology. In this role, he developed a research laboratory that worked on tumor immunology and the pharmacokinetics of anti-cancer drugs.
Since April 2004, he has served as the President of the French Cancer National Institute.
Khayat serves as a professor emiritus for a number of educational institutes worldwide, including the Suzhou Institute for oncology, China, and Matsumoto University, Japan. He is also Adjunct Professor of Medicine of the Department of Breast Diseases at the MD Anderson Cancer Center, University of Texas, USA.
National oncology teaching program
Khayat has set up a national oncology teaching program for young French oncologists — the "Master of Excellence in Medicine in Oncology".<Master d'excellence en médecine oncologique> This program is aimed to allow participants to learn the necessary skills to become the future key opinion leaders in oncology and promote French oncology in the international community.
Working to organise French oncologists, he formed the French Federation of Medical Oncologists (FFOM) in 1998. He was elected the Federation's first president and held this position until 2001. Along with Gabriel Hortobagyi, Khayat organised the World Summit Against Cancer in 2000 and 2001, as well as the Charter of Paris Against Cancer in 2000.
He became a member of French President Jacques Chirac's "war on cancer plan"<Plan caner__> in July 2002, and was President of a high-level bilateral committee for Franco-Israeli cooperation.
Khayat sits on several French, European and International Committees. He is steering committee member of the World Alliance of Cancer Research Organizations. He is an advisor to the LEED program at the Organization for Economic and Cooperative Development (OECD). He is the Associate Editor of the Journal of Clinical Oncology and Cancer and is a member of several other editorial boards.
Presently, he is employed at on of the few fully equipped research centers in France that is deeply involved in evaluation of new drugs and new targets for exploitation in treatment and diagnosis of cancer. He works on basic research on factors that can predict response to immunotherapy in melanoma patients, as well as the development of phase I and II studies to test anti-cancer agents that may be used to treat breast cancer, colorectal cancer, lung cancer and melanoma.
The Journal of Clinical Oncology (JCO) has retracted a November 2011 editorial by a group of French cancer researchers, including David Khayat.
Khayat is married and has three daughters, Julie, Barabara and Cécile. Khayat's wife is a former-pharmacist, and presently an art historian at the Louvre School in Paris.