I remember reading another story on this, and if I remember right he is still under the time needed to compete.
He is not breaking any world records against able bodied athletes, and he is not the fastest person out there because of them either. They talk about requiring less energy to maintain speed, but he competes as a sprinter. You aren't "maintaining" speed like a distance runner would where that would be a clear advantage.
I think that more tests would be necessary to conclude that the prosthetics themselves give him a clear advantage over other runners and that the prosthetics alone were the cause for his winnning/times.
If further testing is done and that is the case then I would support prohibiting him from competing in certain events.