On February 2, 2011 the Board of Appeal of the EPO decided in case T1652/07 that a change in claim category from a "method of treatment claim" to a "device for treatment claim" overcame the objection raised under Art.53(c) EPC against European patent application no.00204121.8.

 The claims as filed claimed a method of treatment and were refused by the Examining Division as contravening Art.53(c) EPC.

The Applicant changed the claim category from method to device claim during the appeal procedure and the decision to refuse was rectified and the case remitted to the first instance for further examination. 



The invention of European patent application no.00204121 relates to a method for determining a parameter indicative of the progress of an extracorporeal blood treatment, in particular a purification treatment whose purpose is to alleviate renal insufficiency, such as haemodialysis or haemodiafiltration.

The main claim as filed claims a method for continuously determining a parameter indicative of an extracorporeal blood treatment, consisting in making a patient's blood and a treatment liquid flow, one on either side of the semipermeable membrane of a membrane exchanger.



The Examining Division decided to refuse the application in view of Art.53(c) EPC, as the invention was regarded to be a method of treatment by therapy, since the patient's blood was flowing through the blood exchanger, even though this step was not explicitly stated in the main claim.

However, the Examining Division reasoned that the therapeutic characteristic of this method was made clear by dependent claim 10 as filed, claiming that the method is applied so that a certain parameter of the patient remains within a range of permissible values.

The Examining Division therefore concluded that the method had a therapeutic target and effect.

The Applicant appealed the decision and filed amended claims reformulating the method claims into device claims now relating to a device for determining a parameter indicative of the progress of an extracorporeal blood treatment.

This change of category was admissible in view of Art.123(2) EPC, since the device was sufficiently supported by the description as filed.

The Applicant thus prevented loosing the application by a change of claim category, only possible, because the device was sufficiently disclosed in the application as filed. Extreme care should thus be taken when drafting applications relating to medical treatments/devices to provide for suitable fallback options.