Learn something new everyday. I had never heard of them before this morning. After quiclky skimming the article I can see why it never had much popularity until now and it's apparently been around sine 07!
The main goal was to raise the ethical bar. To publicly sign up to the UCI’s rules but also to go further. They agreed not to let riders have exemption letters to use cortico-steroids and that in the event a rider needed cortisone for medical reasons they had to observe a 15 day period of rest because you had to be injured to use this.
It's not all golden though.
read more here: http://inrng.com/2013/02/the-mpcc-explained/