Amarin Corp Plc (AMRN)

[BioInvestor3]

There are plenty, off the top of my head Glucophage XR, Toprol XL, Wellbutrin XL.

These were all BP drugs where they filed 505(b)(2), because of the extension to the name they were not substitutable and no generics can market a copy for 3 years. All were dosed once a day from twice a day. These new formulations became even a bigger seller than the previous versions.

Here is why you go for exclusivity vs a new patent, its not just because of the time and cost, it is that patents can be challenged but exclusivity cannot. Even if Amarin comes out with a new formulation protected by patents generics can make a copy and do "at risk launch", doesn't matter if the patent is still in effect.