It was created at a small pharma company called Pharmasset. The founders also worked on some of the AIDs drugs in the early 90s, and it's based on the same chemistry: nucleic acid analogues. They worked on a variety of drugs, this was their big winner. It was bought by Gilead for $11b at a time when only one phase 2 trial had completed and about 12 patients had been cured for a couple months. It's important to point out that it was by no means a sure thing, and indeed many of these patients relapsed. Only by combining it with an older drug were they able to get these high cure rates.