Fair points - but I would address those two issues as such:
The drug has been in use outside the US for a number of years. Since they are not starting from scratch (and in the 10K there is mention of the parent company being part of production) I find it very hard to believe that an inquiring company could not come up with a very accurate estimate of its cost to manufacture. And I would also assume due to the many years it has been in use, production cost have likely been made as efficient as possible, working in Chelsea's favor.
Likewise, the cost to bring this drug to the consumer is greatly dependent on who is responsible for doing so. What I mean here is that Chelsea would be required to start from scratch and pay full expenses for such an endeavor whereas a big pharmaceutical company would incur only marginal expenses to have its drug reps add another product to their portfolio.
In summary, although I agree with the points you made, I do not feel as though they are a large issue when determining value since I see them as "easy" to estimate. From a potential buyer point of view who is privy to more information than me, that is. I can only make an estimate, and a valuation near $1B seems reasonable. Back to the main point I was trying to address, I don't believe the value should be directly tied to the share price at this point in time and a specific % shouldn't be applied when considering the idea of a buyout, IMO.
