Based on 25 years of research in the field, the doctor had a hunch that the new medicine would be successful.
Depending on 25 years of research in the field, the doctor had a hunch that the new medicine would be successful.
Based on 25 years of research in the field, the doctor had a hunch that the new medicine would be successful.
Depending on 25 years of research in the field, the doctor had a hunch that the new medicine would be successful.
The idiom "based on" is correct for indicating the basis of a decision, perspective, or judgment. The doctor has this experience as his basis. The structure "depending on" sounds awkward here.