What are the Odds that Pfizer Re-formulates it's medication

I have a strong feeling that Pfizer will create a "new" strength or perhaps a new formulation of Viagra such as XR in order to stay relevant for a few more years because any change in strength or release formulation will give Pfizer a few more years of exclusive marketing without worrying about a generic.
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums