Need to make a drug out of the small molecule inhibitor. There is a medicinal chemistry process that takes quite a while (several years at times) to get to something you can actually give to people.

Then there is safety testing in animals. Then regulatory approval. Then starting the phase I trial. The trial might take a year or more. Then you need to show the drug works compared to some standard treatment, which in a phase 3 trial in breast cancer takes 3 years and many hundreds of patients at least. Longer if you want to show it prolongs overall survival. Then the drug needs to be approved.

There is also the matter of funding but there is a lot of money for early stage biotechs at the moment.