Patenting the use of medical devices (T 0941/24)
Rose Hughes
Patenting the use of medical devices (T 0941/24)
Patenting medical devices in Europe is challenging. First, there is the problem that medical use claims are not permitted for medical devices, whilst simultaneously methods of treatment or surgery using a device are excluded from patentability. However, a recent decision from the Board of Appeal in T 0941/24 demonstrates that it is sometimes possible to navigate the fine line of patentability exclusions to claim the use of a surgical device.
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| Medical devices |
Legal background: Exceptions to patentability, clarity, and medical devices
In Europe, methods of treatment by surgery are excluded from patentability (Article 53(c) EPC). Particularly, in G1/07, the EBA found that claims which comprise a step "encompassing" an embodiment which is a method for treatment by surgery are not permittable. However, similarly, second medical use claims are not permitted for medical devices (Article 54(4) EPC). This type of claim is permitted only for "substances or compositions" (IPKat). These prohibitions combined create a problem for MedTech companies. In Europe it is simultaneously not possible to patent the method of surgery using a medical device (i.e. in a method of surgery claim), or a medical device for use in a method of surgery (i.e. EPC 2000 second medical use claim). MedTech innovators are often left with the only option of protecting the device itself, and not its surgical use.
Case background
The case in T 0941/24 concerned European patent application EP 3332729, filed by BrainLab. BrainLab is a Munich-based medical technology company that specialises in image-guided surgery, radiotherapy and digital operating room integration. The patent application related to a medical tracking system involving two sensor devices.
The application described how the invention sought to overcome the limitations of traditional medical tracking systems, which typically rely on bulky and expensive 3D cameras to detect markers attached to tracked objects. In these conventional setups, there is a constant risk that the surgeon or other personnel might obstruct the camera's line of sight. To solve this problem, the patent proposed a system using at least two independently manoeuvrable sensor devices, each equipped with both a marker and a marker detector, such as a camera. Rather than relying on a central camera, the sensors detect each other. A control unit then combines the respective sensor data from both devices. Even if the data from a single sensor is insufficient on its own, combining the data allows the system to accurately determine the relative position of the sensors. This approach, the application explained, reduces the likelihood of obstruction and eliminates the need for an external 3D camera.
During examination, the Examining Division (ED) found that the method claim for the device encompassed an embodiment in which a sensor device was attached to a bone, and that this attachment step was implicit. The claim at issue specified:
"A method of determining a relative position between two sensor devices of a medical tracking system, wherein the sensor devices are independently manoeuvrable and can be positioned in a fixed position relative to targets, comprising the steps of determining, with the two sensor devices, respective sensor data comprising the position of a marker device of another sensor device and transferring the sensor data to a control unit, characterized by determining the relative position between the two sensor devices by the control unit by combining the sensor data."
Citing G1/07, the ED found that the claim, by virtue of being directed to a medical tracking system, encompassed a surgical step and was thus excluded from patentability.
Exceptions to patentability (Article 53(c) EPC)
In its decision, the Board of Appeal took the opportunity to examine the use of the word "encompass" in the G1/07 decision. Interestingly, another recent EBA decision to use the word "encompass" is of course G2/21 (use of post-published evidence to support inventive step). In G2/21, the EBA found that the technical effect relied on for inventive step must be understood by the skilled person to be "encompassed and embodied" by the original disclosure of the application as filed. Following G2/21, there has been much debate as to what is meant by a technical effect to be "encompassed" (IPKat).
The Board of Appeal in the present case noted that if "encompass" meant including any conceivable specific implementation falling under a generic feature, then "virtually all method claims would encompass a surgical step and not be allowable under Article 53(c) EPC" (r. 3.1.4). As such, the Board of Appeal reasoned, additional steps that are, for example, defined only in the dependent claims, are not necessarily encompassed by the independent claim (r. 3.1.7). However, the Board of Appeal noted, the principles of G1/07 could be extended to steps which are claimed implicitly as essential, rather than explicitly (r. 3.1.8).
Applying this to the facts of the case, the Board of Appeal was of the view that the claimed method did not comprise any step of attaching a sensor device to a target, either explicitly or implicitly. The Board of Appeal reasoned that the method could be carried out regardless of whether the sensor was attached to a target, such as a bone, or merely carried by a user. Instead of being attached to a bone, as in the examples, the sensors could instead be attached to imaging devices. Therefore, the Board of Appeal concluded, the step of attaching the sensor device to a bone was not an implicit feature and was thus not encompassed by the claimed method.
The Board of Appeal also considered whether the method comprised moving an exposed bone, another surgical step described in the application's workflows. However, in the Board of Appeal's view, the method concerned "a passive, one-time determination which does not rely on any motion or acceleration by the sensor devices or the targets" (r. 4.3.2). The Board of Appeal thus concluded that the claimed method did not encompass any surgical steps and was not a method of surgery.
The decision under appeal was therefore set aside, and the case remitted to the ED with the order to grant the patent.
Consulting the description to interpret the claims
Notably, to arrive at its conclusions, the Board of Appeal specifically referred to G1/24 (r. 4.1.1). The Board of Appeal particularly noted paragraphs in the description that defined the scope of the invention. Specifically, the last paragraph of the description stated: "It is to be noted that the methods and workflows described herein do not relate to or comprise any surgical step. In particular, attaching a cutting block to a bone and performing a cut are not part of the present invention. This invention solely relates to the step of navigating, tracking and verifying by acquiring and analysing data." This paragraph was in the application as originally filed. This Kat wonders whether it would have been considered similarly influential if it had only been introduced as a description amendment later on. The principles of G1/24 imply that it would have been.
Final thoughts
In this Kat's view, the decision in this case might have been a close one without the language included in the description. Key to the Board of Appeal's decision was the interpretation of the specific terms and steps used in the claims, and whether surgery was necessarily implicated. Crucially, the Board of Appeal also found, contrary to the decision of the ED, that attachment to the bone was not an essential feature of the method. Drafting medical device claims is particularly tricky following G1/24, given that the disclosure in the description may be used to import essential features into the claims. However, as this case shows, the description may also be very helpful for shifting the scope of the claims away from non-patentable subject matter.
Further reading