Generics Web, an Australian company which runs a database of patent information for subscribers, said innovator companies have moved beyond value-added formulations in their attempts to protect patents.
CEO Leighton Howard told in-Pharmatechnologist.com he sees an increase in patents for analytical methods used in bioequivalence or comparator studies. These methods would allow rival companies to prove to regulators their drugs’ identity with small molecule reference products, or similarity to biologics.
“Obviously if you can’t undertake a study to prove bioequivalence of show a product is biosimilar, you can’t get a generic on the market.
“[For example] you patent the method of analysing [what is] in the blood stream – it might be down to the analytical technique.
“You’re not patenting a molecule, you’re patenting a way of showing that a molecule is equivalent.”
Similarly, originator companies are increasingly patenting screening methods which detect the patient populations most likely to respond well to the drug, usually used in oncology.
While these sorts of pre-screening dual diagnostic methods have been around for some time, the idea of patenting them is relatively new.
“It only becomes a blocker [for rival companies] if it gets written into the patient information leaflet, or it becomes an inherent part of using that product that a generic company would also have to do.”
Besides these methods, some drugmakers extend their marketing exclusivity by improving a pharmaceutical formulation so much that the original drug is considered unsafe to market, or is simply far less popular.
“It’s a form of ‘evergreening’ whereby the innovator doesn’t play all of its cards at once,” said Howard. “For example you launch with a product and then you launch with a different strength, that’s not a game-changer, you can do without a different strength.
“But if you launch a product and make it so people can’t abuse it, or it’s much much safer for another reason, then the regulatory authorities won’t let you sell the other product.
“The manner in which those patents are used is a classic tactic of big pharma companies to ‘evergreen’. You can get an extension which gets you extra time – you see that happening all the time.”
Formulation changes can include abuse deterrence technology, once-a-day delivery, or a “safer administrative route.”
In 2008, a UK Court of Appeal upheld pharma company Apotex’s challenge to Servier’s patent on perindopril, which Servier had tried to extend by changing its type of salt. The company claimed ariginine salt had a better safety profile and was more stable.