EOS Neuroscience: method of treatment excluded subject matter

The patent application at issue related to compositions and methods for the selective silencing of neurons in pain pathways using a combination of inhibitory light-sensitive protein gene transfer and wavelength specific illumination. It disclosed a recombinant nucleic acid comprising a nucleic acid fragment encoding a light-sensitive protein and a regulatory nucleic acid fragment that was capable of directing selective expression of the light sensitive protein in cells of the dorsal root ganglion (DRG). The application explained that neuropathic pain in a subject could be treated by controlling the neural activity in a DRG cell expressing the claimed recombinant nucleic acid using an optical source to modulate the expression of the light-sensitive protein.

In particular, claim 1 of the main request claimed:

“A recombinant nucleic acid for use in a method of relieving neuropathic pain, wherein the recombinant nucleic acid comprises: a nucleic acid fragment encoding a light-sensitive protein; and

a regulatory nucleic acid fragment that is capable of directing selective expression of said light-sensitive protein in a cell of the central nervous system (CNS); and wherein the method comprises: expressing in a cell of the dorsal root ganglia in a subject the recombinant nucleic acid; and

controlling the neural activity of said cell with a light beam to modulate the activity of said light-sensitive protein, thereby relieve the neuropathic pain in said subject.”

The examiner held that the claim was unpatentable for excluded subject matter, reasoning:

“It is my opinion that the step ‘controlling the neural activity of said cell with a light beam to modulate the activity of said light-sensitive’ is not related to the administration of the recombinant nucleic acid but is considered to be an entirely separate method step which would require surgery to implement.”

On appeal, the Hearing Officer first considered whether the invention related to a non-patentable method of treatment by surgery.

Section 4A of the UK Patents Act 1977 explains that:

“(1) A patent shall not be granted for the invention of- (a) a method of treatment of the human or animal body by surgery or therapy ...

(2) Subsection (1) above does not apply to an invention consisting of a

substance or composition for use in any such method.”

The Hearing Officer, construing the claim, held that it had two parts: a) one part which related to a substance, namely recombinant nucleic acid; and b) a second part which related to a method that uses that substance. He then held that the method of the second part had two steps: a) expressing in a cell of the dorsal root ganglia in a subject the recombinant nucleic acid; and b) controlling the neural activity of said cell with a light beam to modulate the activity of said light-sensitive protein.

The Hearing Officer applied the decision of the Technical Board of Appeal, T-0566/07. Here the Technical Board of Appeal held that a claim was not patentable for excluded subject matter because there was no ‘causal link’ between the substance in question (composition for staining a retinal membrane) and the surgical method (retinal membrane removal). On the facts of this case, however, the Hearing Officer held that there was a causal link between the substance and method of the claims because the “use of a light beam was directly connected to the administration of the recombinant nucleic acid since only when a light beam is present is the required therapeutic effect achieved”. As such, there was no separate second activity which could be excluded as a method of surgery.

The Hearing Officer then went on to consider if the claim was novel and inventive pursuant to section 4A(4) of the UK Patents Act 1977, concluding that it was.