Polymorphs and Prodrugs and Salts (Oh My!): An Empirical Analysis of “Secondary” Pharmaceutical Patents

-Secondary patent claims are extremely common (more common than chemical compound patent claims), and have a significant effect on the patent-life of drugs

-TRIPS does require member countries to adopt patent protection, but these requirements are general and do not mention secondary patents (reference number 21: Harmonization and Its Discontents: A Case Study of TRIPS Implementation in India’s Pharmaceutical Sector. )

-only 64% of the investigated drugs had patents with chemical compound claims, meaning 36% were protected mostly through secondary patents (data based on the 528 new molecular entities (NMEs) approved by the FDA 1988-2005).

-“Drugs that do not have chemical compound patents rely much more substantially on secondary patents for exclusivity: here, when there are secondary patents, they generate an average of 9 and 11 years of patent term beyond the standard data exclusivity period.”

-“Firms’ propensity to obtain independent secondary patents after drug approval increases over the sales distribution, suggesting they reflect deliberate attempts by branded firms to
lengthen their monopoly for more lucrative drugs.”


“Our data also reveal the stakes of the decision that developing countries must make about the permissible scope of patents. Although the World Trade Organization’s Trade-Related Aspects of Intellectual Property Agreement does require member countries to adopt patent protection for medicines, its requirements are general, and do not clearly require countries to permit secondary patents [21]. We can quantify the stakes of such decisions: If the future looks like the past (and the patent landscape in other countries like that in the U.S.) a conservative estimate is that eliminating secondary patents could free up 36% of new medicines for generic production, since only 64% of drugs in our sample had patents with chemical compound claims.

Additionally, for those drugs that still come under patent because a chemical compound claim exists, exclusions on secondary patents could limit the duration of patent protection by 4–5 years. The converse is that this study reveals the very substantial implications of new trade agreements. Negotiations are now underway for a new “Trans-Pacific Partnership” treaty, and the U.S. has apparently proposed barring exactly the kind of limits on secondary patents adopted by India, and under consideration by other countries.”

“We show, first, that patents with secondary claims are extremely
common – indeed, more common than chemical compound
patents, for the new molecular entities in our sample. While it is
sometimes assumed that a new active ingredient is associated with
a chemical compound patent, for example, we show that if an
NME is associated with a patent (which the vast majority are), it is
more frequently associated with a formulation patent (81% of
drugs) or a method of treatment/use patent (83%) than with a
chemical compound patent (64%). Patent claims covering new
forms of known substances (PIPES) are also very common, present
in half of all drugs (51%).
(‘‘PIPES’’ refers to Polymorph, Isomer, Prodrug, Ester, and Salt claims.)”


One comment

  1. richardbenson2110 · · Reply

    Amazing story ..i appreciate your effort

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