Two possibilities:
- AMRN gets bought out for stock by the buyer -- then based on the stock for stock deal terms, the AMRN options get converted to (in the money) buyer options, or
- If it's a cash deal, you always have the theoretical right to put up the capital, exercise the options early, and sell the stock. And so the market will buy your options for the spread value minus a capital usage charge (a "rental" charge on the money they have to put up to exercise the options). For instance, if the deal is $50 all cash, and the option strike price is $25, you might be able to sell those options for $24 (the $1 being the capital usage charge)
This capital usage charge concept isn't formal -- it's just a way of explaining why you might not get the full spread value if you try to sell the long-term option after the deal is announced and will clearly close.