Author(s): Amy Kapczynski
Year: 2012
Abstract:
While
there has been much discussion by policymakers and stakeholders about
the effects of “secondary patents” on the pharmaceutical industry, there
is no empirical evidence on their prevalence or determinants.
Characterizing the landscape of secondary patents is important in light
of recent court decisions in the U.S. that may make them more difficult
to obtain, and for developing countries considering restrictions on
secondary patents.
We read the claims of the 1304 Orange Book
listed patents on all new molecular entities approved in the U.S.
between 1988 and 2005, and coded the patents as including chemical
compound claims (claims covering the active molecule itself) and/or one
of several types of secondary claims. We distinguish between patents
with any secondary claims, and those with only secondary claims and no
chemical compound claims (“independent” secondary patents).
We
find that secondary claims are common in the pharmaceutical industry. We
also show that independent secondary patents tend to be filed and
issued later than chemical compound patents, and are also more likely to
be filed after the drug is approved. When present, independent
formulation patents add an average of 6.5 years of patent life (95%
C.I.: 5.9 to 7.3 years), independent method of use patents add 7.4 years
(95% C.I.: 6.4 to 8.4 years), and independent patents on polymorphs,
isomers, prodrug, ester, and/or salt claims add 6.3 years (95% C.I.: 5.3
to 7.3 years). We also provide evidence that late-filed independent
secondary patents are more common for higher sales drugs.
Policies
and court decisions affecting secondary patenting are likely to have a
significant impact on the pharmaceutical industry. Secondary patents
provide substantial additional patent life in the pharmaceutical
industry, at least nominally. Evidence that they are also more common
for best-selling drugs is consistent with accounts of active “life cycle
management” or “evergreening” of patent portfolios in the industry.
Keywords: patents, pharmaceuticals, innovation, intellectual property, secondary patents, international intellectual property law
Link: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2191728