the immunosuppressive effect of the natural product cyclosporin was discovered in december 1971 in a screening test on immune suppression designed and implemented by hartmann f. stähelin at sandoz. the chemical structure of cyclosporin was determined in 1976, also at sandoz. the success of the drug candidate ciclosporin in preventing organ rejection was shown in kidney transplants by r.y. calne and colleagues at the university of cambridge, and in liver transplants performed by thomas starzl at the university of pittsburgh hospital. the first patient, on 9 march 1980, was a 28-year-old woman. in the united states, the food and drug administration (fda) approved ciclosporin for clinical use in 1983.