I am switching from 4y top biopharma R&D (only bachelor's degree though) to MBA. Going to Kellogg this fall. It's definitely possible. But you might want to come up with a goal that link your past with your future. Say you want to switch to IB is not the best idea. Something online with VC/tech might be better. It's all about the story. Also, depending on your age, you might want to focus on M7s or top 15 that take a liking to older applicants (i.e, possibly forgo HBS/Stanford....)