However, the upward trend in inter partes filings suggests that any estoppel concern is being outweighed by the perceived benefits of inter partes reexamination, particularly in the current patent litigation landscape. An inter partes reexamination can stay litigation (and its accompanying costs), and can provide a different forum for the litigation. In fact, the statistics suggest that inter partes reexamination is being used more frequently in the context of litigation. Currently 50% of the pending inter partes reexaminations are co-pending with litigation as compared to 26% at the same time last year.

The statistics also confirm that almost all ex parte reexamination requests (92%) are granted by the USPTO. Once granted, the odds are the claims will be amended in some form. The claims are changed in 64% of ex parte reexaminations. Such amendments may give rise to “intervening rights,” which would allow the third party to continue practicing technology implemented before grant of the reexamination, even though such technology may later infringe a claim amended during reexamination. All the claims are confirmed in 26% of ex parte reexaminations, and all claims canceled in only 10% of ex parte reexaminations. In other words, claims are amended or canceled in almost 75% of all ex parte reexaminations.

For inter partes reexaminations, the statistics favor the requester even more (although the statistical sample is much smaller than for ex parte reexaminations). Ninety-six percent of all requests are granted. Only eight inter partes reexaminations have been completed, but all the claims have been canceled in seven of these eight reexaminations.

In sum, the USPTO has seen a marked increase in reexamination filings, apparently due, at least in part, to the increasing confidence of third-party requesters that reexamination will result in a favorable outcome. This is borne out by recent statistics, in which, at least for ex parte filings, claims in almost 75% of those reexaminations were amended or canceled. We suspect the popularity of reexaminations will continue, as clients and litigators come to view the USPTO as a less expensive, more favorable forum than the courtroom in many patent disputes.