Author Correction: The cost of drug patent expiration date errors

Subjects

In the version of the article initially published, the dates displayed in the “Corrected patent expiration date” column of Table 1 relied on the original patent expiration date information provided by the US Patent and Trademark Office¹. While conducting subsequent research, we discovered that several of the dates provided by the USPTO were incorrect based on a manual calculation of the patent expiration dates. We have alerted the USPTO to fix its errors and now have updated the third column of our Table 1 accordingly. We have also updated Table 1 to account for regulations in place at the time of the patent expirations and to account for terminal disclaimers that we recently uncovered for two patents (for context, see new Table 1 legend footnote e). Finally, we have added a new Table 1 legend footnote f related to U.S. Patent No. 7,917,224 to clarify why we believe it deserves inclusion in our review.

Apart from the changes to the table, the changes to the text of the paper are: “These errors extended patent protection by a median of 63.5 days (range 32–190) of extra market exclusivity” has been corrected to “These errors extended patent protection by a median of 81.5 days (range 56–190) of extra market exclusivity” and “pro-rated revenue during PTA delay ranged from $37.8 million to $519.6 million” has been corrected to “pro-rated revenue during PTA delay ranged from $32.4 million to $514.8 million.” These corrections have been made to the HTML and PDF versions of the article.

Thus, although accounting for inconsistencies in the USPTO PTA data and for the new terminal disclaimers necessitates updates to the data, the primary results and conclusions remain the same: USPTO PTA errors can be important and expensive for patients and the US health care system.