I personally know someone who was interviewed two years in a row, and got rejected. After the end of the second year, this student met with the dean to discuss how to improve their application. The student did this, and didn't even get an interview the third year. In March, they called up the med school (after getting rejected), and said that they improved their application for this third year, and didn't get an interview. So they granted the student an interview, and they were accepted a couple of weeks later.
Not the norm, but it has happened.