By Stephen Evans
You might think the real battles between drugs companies are fought by scientists in laboratories, competing with each other to get new treatments to people who need them.
Generic drugs sell at a fraction of what the original cost
The truth is that lawyers and the pilots of aircraft have also got big roles to play.
The pilots because when the patent on a drug made by a big pharmaceutical company expires, great cargo planes full of copies are already in the air, ready to land and in markets the following morning.
Take the case of Ramipril, a heart drug made by Actavis as a copy of a drug developed by a big pharmaceutical company.
Literally the moment the patent expired, Actavis flew plane-loads of its copies into big potential markets such as Germany.
"We had seven of the biggest cargo planes, Antonovs, fully loaded and they went into German airspace just after midnight," according to Robert Wessman, chief executive of Actavis.
The lawyers, too, are involved in a continuing battle between the generic drug companies and the originators.
"Sometimes we see that Big Pharma tries to extend their own patent lifetimes with patents that are not novel," Mr Wessman told the BBC.
"We just sue them to get the patents invalidated when the patents are only there to delay us getting to market. And those court cases are running all over the world."
Patents last for 20 years, so typically a completely new drug might take 10 years of development and then 10 years of actually making money through sales.
It might cost $1.5bn to develop each one, compared with $1.5m for the copier to get the regulatory approval once the patent has expired.
GlaxoSmithKline defends its policy on extending patents
Mr Wessman defends his company's copying: "We usually take 90% off the brand price. So it's only fair to the consumer that the brands aren't in there for ever."
The big pharmaceutical companies deny just tweaking drugs to get new patents - and thus, new patent protection.
GlaxoSmithKline told the BBC that "product line extensions" were for the benefit of patients.
The company continually reviewed its products to improve them and the successor took time to be developed.
It has a string of drugs that are successors to products that had just gone out of patent protection:
- Anti-depression drug Paxil CR was launched in the US in 2002 (Paxil went generic in 2003)
- Anti-depression drug Wellbutrin XL was launched in 2003 (Wellbutrin went generic in 2004)
- Heart drug Coreg CR was launched in the US in 2007, the same year that Coreg went generic.
The company said the main factor determining the timing of the launching of successor drugs was the time needed to evaluate how patients reacted to the original drug and what the effects of the changes would be.
With such a high cost of development of drugs from scratch, it is in the interest of pharmaceutical companies to keep products going.
They argue that combining existing products differently is an effective new use. The treatment of HIV, for example, has been improved through modifying existing drugs.
Glaxo says it has 96 completely new "chemical entities" in the pipeline, compared with 37 "product line extensions" so it says it's not true that it relies on variants of existing products rather than completely original research and development.
The pressure on Big Pharma, though, is likely to get much greater. Advances in genetics mean that more and more drugs can be targeted at smaller and smaller groups of people, so spreading the costs over a smaller market.
And whatever they develop, the generic drug manufacturers are watching and copying and stockpiling, ready to sell at a fraction of the cost.
It might seem good for the consumer, but if the current way of making money isn't sustainable for the big companies, what replaces it?
In truth, they don't really know. Neither does anybody else.