Agreed, Pfizer would make a logical buyer, and could likely be more successful with KIT-302 than another buyer, precisely due to the Celebrex brand and sales channels they have. But they'll never see the same peak sales. I would hope for $1.5B from KIT-302 (last year Celebrex sales were ~ $830MM and still dropping). So buying KIT-302 would cannibalize their Celebrex sales, but could double the revenue from it. A net benefit of about $750m annually.
At 4x that benefit, KIT-302 is worth $3B.
All just for fun.. of course I'd be happy with $20/share ;-)