When a medical device is clinically tested it is to evaluate the safety of such a device on the human and whether or not the desired result will be obtained from doing the clinical testing of the device.

In the case of medical devices, the results have always been known to improve human wellbeing.

In the case of pharmaceutical drugs, however, I fail to see the purpose of doing clinical testing. No one has ever claimed that their disease was cured by some pharmaceutical drug; in other words, pharmaceutical drugs have never actually improved the direction of human wellbeing.

So what is the clinical testing of pharmaceutical drugs all about? Please help explain this.