Part of what they do is they match patients with clinical trials for whom they would be candidates and then facilitate the process on an on-going basis. Apparently this bypasses a number of bureaucratic hurdles which can be faced by patients; for example a patient receiving care from a particular research institution might not be informed about trials being conducted by other, non-affiliated institutions.
Naturally, there's rather more than this to them, but this part sticks out in my mind.
And finally, take what I'm saying with a bit of a grain of salt because I am remembering from casual dinner-time discussions that I had some time ago with my friend. My memory might be bad, they may have changed what they do since I last talked with my friend about it, etc.