The milestones are mostly regulatory, not commercial. IMO Any potential capital gains from the stock ownership is likely not a significant consideration for BMY and its small enough to not impact NKTR control (they had close to 160M shares outstanding before the deal).
People need to keep in mind that Nektar has control of 214 BMY really only got a minority share. If PD-1/PD-L1 companies start competing on price NKTR-214 has a significant lead on any potential IL-2 targetted agents (if they even prove to be competitive) and can set the price accordingly.
To me from NKTR's standpoint its a bad deal for them if you believe 214 is 1 hit wonder for them and competition will come soon.... If you think its a mega-blockbuster with no near-term competition OR think they'll produce other IO assets then it gives them time to add some additional value. How much? enough to justify the wait TBD.
News 
Market Data 
Discover 
