bmrn is effectively paying $52M to fund la jolla to the final look at the data. Unless la jolla had options they were going to run out of money. So considering the high risk of blowing $52M which is a lot of money, i think this was way too much to pay. Not only that, they give la jolla a life preserver and let them keep 50% of the upside.
We can look at any pivotal program in any indication and say if it works the deal is a bargain. What we know is the drug already failed and they're trying again with a much higher dose, we also know every pivotal trial in lupus for the last 30 years has failed including a de facto standard of care. Surprises happen once in a while. Maybe this is it, who knows, but its an expensive lottery ticket for bmrn. bmrn will look like geniuses or morons here.
On what to charge, i'm not sure but if it works it wouldn't come cheap. I'd guess they could charge something similar to MS drugs, $20-30K/year.