A continuation application is often filed while a patent application is pending, allowing inventors to modify or add claims to the pending application without affecting its filing date. Over the past several years, the number of continuation applications filed with the U.S. Patent and Trademark Office has significantly increased – 76,898 applications were filed in fiscal year 2015, compared to 31,271 applications filed in fiscal year 2009. Law360 contacted Finnegan attorney Linda J. Thayer for her insight on filing a continuation application.
Although the number of continuation applications has increased, Thayer noted that one disadvantage of this practice is that examiners may find prior art in a continuation application that was not discovered in the parent application. She said, "If the record reflects that this piece of art is potentially relevant, and the continuation contains claims that are closely related to those of the parent, it may cast a cloud over the parent. [But] it is still preferable to know about the prior art than not knowing and finding out during litigation that the parent patent is invalid. Finding out during prosecution of a continuation means that the claims of the parent could be amended and strengthened in the continuation." To avoid this, she suggested drafting claims that use different language from the parent application so that it’s not as obvious whether art cited in the continuation application brings into question the validity of the parent patent.
Thayer believes that a continuation applications can be helpful in keeping a patent family alive in the midst of changing patent laws. She said, "With the passage of Alice, more patent claims have been found invalid as patent ineligible. If the patent is a member of an open patent family, and there is sufficient supporting material in the specification, the claims—amended to comply with the most recent guidance—may be able to be refiled in a continuation."