Patent decision

BL number

O/980/22

Concerning rights in

GB1900893.7

Hearing Officer

Dr L Cullen

Decision date

9 November 2022

Person(s) or Company(s) involved

Sistemic Scotland Ltd

Provisions discussed

Patents Act 1977 - section 1(1)(b); section 3

Keywords

Inventive step

Related Decisions

None

Summary

This application relates to methods of detection of residual undifferentiated pluripotent stem cells (PSCs) in a sample of differentiated cells.

The presence of PSCs in a sample of cells intended for use in the clinical environment can lead to the formation of tumours and teratomas, and so the method of the invention provides a sensitive assay for the detection of these cells. Quantitative PCR, digital PCR or droplet digital PCR are used to detect the presence of one or more microRNAs, specifically, hsa-miR-302a-3p, hsa-miR-302b-3p, hsa-miR-302c-3p, and hsa-miR-302d-3p, which are expressed in undifferentiated PSCs but not in differentiated cells. The sensitivity of the available assay methods is such that they can detect ten or fewer residual undifferentiated PSCs in a sample of one million differentiated cells.

In followingWindsurfing/Pozzoli, the Hearing Officer (HO) identified the skilled person as a team comprising a molecular biologist and a doctor concerned with cell therapy treatments derived from PSCs. Having carefully considered the common general knowledge of this team and analysed the prior art, the HO found that the skilled person, seeking to improve on the assay of D1 would, in light of the disclosure of any of D2-D6, be motivated to substitute Lin28 with a member of the miR-320 cluster, namely hsa-miR-302a-3p, hsa-miR-302b-3p, hsa-miR-302c-3p or hsa-miR-302d-3p. In doing so, and following the method of D1, they would assay a sample of the PSC-derived population by measuring the levels of the miRNAs: hsa-miR-302a-3p, hsa-miR-302b-3p, hsa-miR-302c-3p or hsa-miR-302d-3p; using qRT-PCR.

The HO, reviewing all the claims, concluded that independent claims 1, 15, 17 and 19 all lacked an inventive step and the application was refused under section 18(3).

Full decisionO/980/22  382Kb