At this point I certainly regret selling calls so early of course. And a large fear for me would be that the portfolio of Alzheimers drugs in development might tempt some large company to make a bid for PRTA with a large premium. This would presumably be based upon superior knowledge of the science rather than speculation from a run up in PRTA stock price.
Again, I just can't see anything which justifies the huge price increase we've enjoyed and presume more sophisticated drug companies would also expect much lower prices for the stock before making an offer.
Of course, at this time my calls are all under water (a long way) and the only shares I have which are not exposed are in taxable accounts. Beginning to sell calls when the price was $40 sure looks foolish at the moment.