I don't believe it's possible to estimate earnings potential this early, beyond a ballpark estimate.
AEZS-108 may be successful in numerous cancers, however in each cancer the trial to identify those who it'll work with is being developed. We don't know what percentage of each cancer it works on has the appropriate identifier.
If we look at a similar drug, Herceptin, we know that breast cancer patients are tested for sufficient Her2 identifier. Roughly 30% of them have it in sufficient quantity to successfully treat. Herceptin earns over $5 billion in breast cancer alone, and they're currently looking at some other cancers that have lesser percentages of patients with Her2.
T-DM1 is a conjugate of Herceptin which uses IMGN's technology. Because it can be effective with lower Her2 readings, as an IMGN investors I believe it may have far greater potential than Herceptin. In 5 years or so after approval I believe it could earn $10 billion if it completely replaces Herceptin and expands on it.
That said, depending on trials AEZS-108 might sell $1 billion, or perhaps $25 billion or more, it's a very diverse ballpark estimate, but without data you can only ask, what if it only works in one smaller indication, or if it works in every indication it's tested against.
The term blockbuster applies to any drug selling a billion or more. I believe it will be a blockbuster, probably many times over. For investors that should mean AEZS earns hundreds of millions, to perhaps a billion annually over time on low double digit royalties. With some further dilution anticipated, lets say $125 million in earnings represents $1 a share in earnings. We all have different P/E's we believe companies should be worth. I believe if a company has little or no anticipation of earnings growth, a P/E of 10 is reasonable, but if growth potential is thought to be excellent, 30 or more is easily justified. I believe that by the time AEZS's earnings approach $.5 billion, i.e. $4 a share, the share price ought to be triple digit.
I don't know how long this may take, or if they'll not be bought out before it happens, but I do believe with a pipeline the size of AEZS's it easily has that potential, whether it comes on the strength of AEZS-108 alone, or several approved products I can't say, but ultimately such prices will be based on earnings, and I believe it has the potential to produce that sort of earnings.