@3.29 the potential for 4.50 to 5.00 - if they sell!
Based on the 41 MLN revenue potential for the next 2 years and 44 MLN shares outstanding, the expenses and liabilities accounted for, you have expected income of around 80 cents for the next 2 years which puts it at 1.60 per share along with 1.60 payout now = 3.20
The expiration for royalty revenues extends in some cases to 2016 and 2018 but not in US, which may be the major market.
At 3.30 it is fairly priced, but if you are a holder you can just hang on nothing much to loose. There is tax loss of around 200 MLN for any potential buyer it might worth something.
I suspect some of the licensees might acquire them, just to ensure they hold the rights for a small premium.
Regarding the royalties, you're a little late to the game, on an earlier topic thread "A Conservative NPV for PEGINTRON Royalties" there's a npv calculation for all years all regions for Pegintron Royalties.
BTW the cumulative loss and R&D tax credit valuation is $102m (pg F27 the current 10K). The actual cumulative losses are $150m, but only 35% of that can be written down, and the other components are due to various tax credit advantages that Enzon qualified to recieve. Any purchaser would have to qualify to take advantage of these losses and credits, most US based pharma firms would, but most European and Japanese firms wouldn't.