>>So what does Sanofi want to use this for?
Valuing these PPV reminds me of valuing commercial land. One way that is done is to deduct the costs of the development from the expected value and the result is the value of the land.
It is pretty clear, that approach can "justify" big numbers for land or a PPV.
But it is also clear that in the case of PPV's, the buyer is in a better position to determine what it is worth to them.
The inference, as you say, is Sanofi has something big coming.
It is astonishing what foolish things one can temporarily believe if one thinks too long alone ... where it is often impossible to bring one's ideas to a conclusive test either formal or experimental. J.M. Keynes