T 458/07 – Claimed Effects Can’t Be Missing

Claim 1 of the patent read:

A method for purifying a polypeptide from a composition comprising the polypeptide and a contaminant, which method comprises the following steps performed sequentially:

(a) binding the polypeptide to an ion exchange material using a loading buffer, wherein the loading buffer is at a first conductivity and pH;

(b) washing the ion exchange material with an intermediate buffer at a second conductivity and/or pH so as to elute the contaminant from the ion exchange material;

(c) washing the ion exchange material with a wash buffer which is at a third conductivity and/or pH, wherein the change in conductivity and/or pH from the intermediate buffer to the wash buffer is in an opposite direction to the change in conductivity and/or pH from the loading buffer to the intermediate buffer; and

(d) washing the ion exchange material with an elution buffer at a fourth conductivity and/or pH so as to elute the polypeptide from the ion exchange material.

[…] It has been established by case law such as represented by decision T 939/92 that everything falling within a valid claim has to be inventive, i.e. the technical effect on which acknowledgment of inventive step relies must be produced by essentially all embodiments of the claim.

The [opponent] relies on this decision and argues that this was not so with regard to claim 1 since even the patent teaches […] that only some types of contaminants can be removed by the method, whereas others are unaffected. [95]

The claim at issue in the case underlying decision T 939/92 was directed to a class of compounds. The effect that they are stated to have and on which the inventive contribution relied, i.e. herbicidal activity, was derivable from the description, but not a feature of the claims. Thus, the compounds were not functionally restricted.

In the present case, the claims relate to a method for purification. The board interprets such a claim to mean that any of its embodiments is in fact suited to achieve that stated purpose, i.e. they are suited to achieve purification. Thus, the question of whether certain embodiments of the claim do or do not achieve the expected technical effect does not arise.

The board considers therefore, that the considerations of decision T 939/92 in the assessment of inventive step do not apply here in the context of inventive step. Rather in the present case they arise in the context of the evaluation of A 83 when considering the question of whether or not the claimed subject-matter can be carried out over the whole scope without undue burden, they therefore have been dealt with there […]. [96]

In conclusion the subject-matter of […] claim 1 […] and claims dependent thereon involves an inventive step. The requirements of A 56 are fulfilled. [97]

To read the whole decision, click here.