Clear Claims for Medical Devices
REFERENCES TO BODY PARTS
In principle, the EPC allows to claim an entity by reference to another unclaimed entity that is related to it through use . For example, when claiming a catheter for treating bifurcations, it is understood that protection is pursued only for the catheter itself, not for the actual treatment of bifurcations.
However, when the reference involves physical characteristics or properties of body parts, such as the tissue elasticity of heart arteries or the gastrointestinal tract, it may give the impression that the invention is defined by the body part itself. This is not allowed since typically, those physical characteristics or properties are not predefined or known.
For example, in T 0641/01, a claim directed to a catheter with a balloon was rejected because the balloon required inflation to a given tissue squeezing pressure. As tissue properties vary significantly among patients, a skilled person like an engineer cannot directly know or isn’t able to determine the necessary pressure to apply in the balloon, so the claim is considered unclear.
When it comes to referencing the dimensions or shape of a body part, similar challenges can arise. The EPC permits references to dimensions or shape based on established standards or knowledge to some extent. However, this is not always possible with the human or animal body. For instance, in T 1912/08, claim 1 concerning a root canal reamer was rejected because its size was determined by the size of the tooth being treated, which is not considered standardised, and variations resulting from chipping or breaking of teeth further complicate the issue of defining dimensions. Looking at the spinal implant from T 0597/96 again, surgeons can determine the intervertebral space based on factors like the patient’s age and the specific vertebra to be fused, so stating that the implant diameter is larger than the disc space between two adjacent vertebrae was allowed.
FUNCTION AND RESULTS TO BE ACHIEVED
It’s quite common to feel tempted to claim medical devices based on the desired outcomes they aim to achieve. This approach is often taken to avoid referencing body parts or providing too many details. For example, imagine a prosthesis designed to improve arm mobility or a pacemaker configured to regulate heart rate. According to the EPC, however, claims that define an invention by results to be achieved are not permitted . Nonetheless, there is a way out – it is possible to carefully draft claims that partially describe the invention in terms of its function.
But, as you might expect, this is easier said than done. For instance, in the case of T 2186/14, a claim directed to a nasal delivery device saying that the nasal device is configured to deposit at least 30% of the dose in a particular region of the nasal airway was rejected, because it did not provide any indication of how the device achieves this result.
An effective approach to tackle this issue is by first describing the key structural characteristics of the device in the claim, and then providing a functional feature as supplementary information to better grasp the invention.
For example, in T 1023/05, a claim stating a distal end of the catheter is closed and extends distally beyond the seal arrangement so as to maintain the patency of the anastomosis and the urethra was allowed. Here, the structure of the distal end of the catheter was described, and the reference to the patency of the anastomosis and the urethra further clarified the relative length of the distal end. This illustrates the importance of recognising whether a combination of structural and functional features can be used to avoid any confusion regarding what is intended to be protected.
THERE’S STILL MORE, TO BE CLEAR!
Bear in mind that there are more aspects to consider than clarity alone. Whether something is allowed or not depends on the unique details of each patent application. Clarity of claims in European patent applications is closely tied to consistency with the description. If the description fails to adequately support and explain the claims, they run the risk of being rejected.
This article is written by trainee patent attorney Karen Rodriguez Hernandez member of NLO’s Health Focus Group.
NB: this article contains royalty-free images which have been added for illustration purposes only (and are not related to the cited case law)