Gilead stock is currently trading at $83.04, down from $123.57 a year ago. A lot of things have happened since last June:
As I mentioned earlier, the people who had the money in the US, bought Harvoni as soon as it became available. That market is pretty much gone.
The insurers covered many of the sickest patients early on. There are a lot of really sick people who don't have insurance or have bad insurance coverage, however. Many are still waiting for access to treatment.
The competition has increased, forcing Gilead to negotiate lower prices for insurance companies as well as entire countries. Australia is a good example.
In addition, generics have come into play. I imagine the health tourism business in India is flourishing.
There are other factors I'm sure, but Gilead's share price seems to have stabilized around $80.00. I imagine it will stay there until someone comes up with a much shorter treatment regimen.