ChEMBL

Here is a plot of the number of WO published patents that contain the words 'kinase' and 'inhibitor' published during a particular year - these were found using the excellent SIMPLE patent system. Of course this is not the same as a hand crafted, expert search of the protein kinase inhibitor patent field, but all I wanted to do here was to see the pattern over time of publication dates.

As can be seen, there is a sharp ramp-up in published patents over the period 1997-2001 - which will correspond to a filing period of 1995-2000 (patents are typically published 18 months after filing). From around 2003 onwards the total number of published patents per year have been relatively constant.