It contains the tension between utilitarianism and the deontological act/omission distinction that the trolley problem is meant to isolate, but clinical trials are philosophically very different in that (1) the risks you cause during a trial are statistical rather than leading reliably to death of any one person, (2) trial participants can and are compensated for this risk, and (above all) (3) the trial participants have consented. In other words, there very little tension/inconsistency in saying that throwing the trolley switch is unethical but running human challenge trials is ethical.
