Patent applications should include ammunition for future claim amendments; Clot removal system; Reverse Medical Corp.; U.S. Pat. No. 8,343,167
February 19, 2013 Leave a comment
The ’167 patent discloses a catheter-based system for capturing and removing occlusions (e.g., blood clots) from a blood vessel. The claimed system uses a wire made of a shape memory alloy which converts from a straight configuration to a coiled configuration upon applying heat to the wire.
According to its website, Reverse Medical is a privately-held company “focused on expanding the endovascular management of acute stroke and neurovascular disease.” While the company markets its ReCruit™ microcatheter for “retrieval of intravascular foreign objects,” the retrieval element of the marketed product looks quite different from that of the ’167 patent. It may be that the ’167 patent describes a configuration planned for future products, or a configuration that the company sought to patent to keep its competitors from using.
During prosecution of a patent application through the USPTO, it is common for the claims of the application to be modified in response to the arguments raised by the USPTO examiner in rejecting the claims. These modifications are geared towards overcoming these rejections, typically by narrowing the scope of the claims so that they no longer read on the references cited by the examiner. Of course, such narrowing also reduces the scope of protection provided by the resulting patent, so applicants generally seek to make only those amendments that are needed to steer clear of the prior art, and to keep the claims as broad as possible. Any such amendments, however, must be based on descriptions found in the application as originally filed, otherwise they are considered to be adding new matter to the application, which is forbidden.
The ’167 patent provides an example of such an evolution of the claims during prosecution. When the application was originally filed, the retrieval element (called the “obstructive material engaging structure”) of Claim 1 was described broadly as being “transitionable from a collapsed configuration [that is] substantially linear … to an expanded configuration [that] will engage the obstructive material.” However, in view of the arguments that the Examiner made to reject Claim 1, Applicants narrowed the scope of Claim 1 to avoid the prior art references being cited by the Examiner. When it eventually issued, Claim 1 of the ’167 patent was narrowed to recite that the “obstructive material engaging structure” comprises “a shape memory wire comprising a proximal coil segment and a distal coil segment,” that each of these segments is ”transitionable, in response to energy delivered thereto, from a collapsed, straight configuration to an expanded, coiled configuration,” and that the source of energy is operable “to i) selectively cause one of the proximal and distal coil segments to expand while the other does not or ii) cause the proximal and distal coil segments to expand at different expansion rates” (emphasis added). Undoubtedly, Reverse Medical sought to make only those amendments that were perceived as overcoming the rejections being made in the various office actions without unduly narrowing the claims and without adding new matter to the application.
Because claim amendments must be based on the application as originally filed, it is generally good practice to prepare the patent application to include as much description of the various permutations or versions of the invention as can practicably be included within the time and budget constraints. There are other good reasons for such a full “fleshing out” of the invention, but since the basis of rejections by the USPTO cannot be reliably predicted, at least for this reason it’s preferable to have as much “ammunition” in the application as originally filed as possible to be able to strategically select what modifications to make to preserve as much breadth in the claims as possible.