Nope.
Not even sure where to start tbh.
Patents are based on active ingredient and formulation, plus usage. That may or may not be molecular. Cf Norovir which has three formulations patented and usages that come off patent at different times.
Generic manufacturers don't just leap in and make drugs on a whim- they still have to complete the abbreviated new drug application process (anda) that takes up to 2 years. It tests bio equivalence, efficacy, manufacturing conditions, strength, dosage, method of administration etc. generics are usually tee-ed up long in advance- see the fda website for a list of what generics are approved but not yet available- they are basically waiting for patents to expire.
This drug is used on less than 200,000 people a year. It isn't a prime target.
There is no agreed cost for r&d for a new drug. The Tufts estimate- $2.6bn is hotly debated, with numbers between $1.15 and $5bn tossed around depending on who you talk to. There are so many variables- large or small molecule, innovator compound or patent extension, codification of off label use. Do you include regulatory costs, failure costs? And these days when so many discoveries are initiated outside the big pharma firms and then bought as incubators, how much of that cost do you include?
Pfizer and GSK are not brilliant at R&D at the moment. They are outstanding at refining and then nursing drugs through the regulatory process- so much so that they are slashing r&d spending and instead setting up their own hedge funds that basically buy ideas from universities, biotech, start up etc
The pharma industry doesn't work on the normal rules of competition bringing down price- it's one of the conundrums and issues with it.