The available duration of US market exclusivity for originator drugs was modelled by researchers and suggested that a newly approved drug could obtain 14 years of patent protection if it was approved by the FDA within 12 years of filing the patent application [1].

Initiation of clinical trials is a critical step in the development of any new drug. This key milestone can be affected and delayed by many different decisions, including lack of a clear clinical candidate, corporate stop-and-go decisions and delays in research.

The average time taken for clinical development—from first time in humans to regulatory approval—according to the Centre for Medicines Research International is 7.3 years. Since the model predicts a 12 year cut-off for achieving the maximum of 14 years market exclusivity, this suggests that a patent may be filed up to 4.7 years prior to beginning phase I testing without sacrificing market exclusivity.

In order to test the model, data was taken from the US Patent and Trademark Office and the FDA on new chemical entities approved between 2000 and 2010. The data set included 96 patent term extensions, with corresponding patent filing dates, activation dates for investigational new drug (IND) applications and FDA approval dates.

The data showed that the majority of drugs that initiated clinical trials within 4.7 years of their patent filing date (55%) achieved 14 years of exclusivity, whereas only 15% of those with a longer interval achieved the maximum.

The conclusion is therefore that a delayed IND filing is likely to reduce the period of market exclusivity for a newly approved drug.

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Reference

1. Dunn MK. Timing of patent filing and market exclusivity. Nature Reviews. 2011;10:487-8.