Forget about the 3% royalty. it's only the first 700k. For sure IMGN will get the 5% royalty because TDM1 will be a blockbuster. If you don't believe in that then you should not invest in IMGN. Approval is most certainly.
For years and years the company has been saying "mid single digit royalties". The royalty structure as released today is actually LOW TO MID SINGLE DIGIT ROYALTIES. This will amount to enough to partially offset ongoing costs with other drugs in trials, nothing more. Today's news sucked.