Similar to 'Second Nature (2003)'

Actually Second Nature isn't just about what you mentioned.

Similarity: SN is also about a deathrole inmate (killer) given a chance to live if he agree to participate in a research.
Difference: In SN the research is in psychology while Control is a research on drug.

Similarity: Both movies explore the possibility that a cold bloody killer could be rehabilitated, both asked the question throughout the film: Is he really cured? Or will he kill again?
Difference: The nature of the "cure" is different, SN uses "brainwashing" method while Control uses drug.

I think both have the same theme and both plots are very similar if not the same.


Spoiler for the movie Second Nature:
By the way, Alec Baldwin's role wasn't an assassin who lost his memory and family in a plane crash. He was a serial killer who participated in a research that alter his memory (childhood etc) hoping that would change his behaviour from a cold blooded serial killer to another person. The research however was hijacked by a government agency and he was instead programmed to remember himself as an assassin.

Maybe you guys haven't seen La Femme Nikita (1990). It came out before any of the films you've mentioned. Summary: "Convicted felon Nikita, instead of going to jail, is given a new identity and trained, stylishly, as a top secret spy/assassin." This movie was later remade as Point of No Return with Bridget Fonda.