Merck Serono SA v The Comptroller-General of Patents, Designs, and Trade Marks

A Court of Appeal decision applying assimilated EU law binds a later Court of Appeal where it has applied the relevant CJEU authority as part of its ratio. The later court cannot use its statutory power to depart from assimilated EU case law unless a recognised exception to the ordinary rule of precedent applies.

For supplementary protection certificates, Regulation (EC) No 469/2009 treats the product as the active ingredient or combination of active ingredients. A later marketing authorisation for a new therapeutic use is not the first authorisation under article 3(d) if the same product was previously authorised for another therapeutic use. The court would in any event have declined to depart from the CJEU decision establishing that rule.

Merck applied for a supplementary protection certificate for cladribine. Its basic patent concerned use of cladribine to treat multiple sclerosis, and its application relied on a 2017 marketing authorisation for MAVENCLAD.

Earlier marketing authorisations had authorised cladribine for treating hairy cell leukaemia. The Hearing Officer refused the application in decision BL O/0484/23, applying Santen. The Patents Court dismissed Merck’s appeal. Merck did not pursue its separate legitimate-expectation ground.

Before the Court of Appeal, Merck contended that Santen was wrongly decided and that the court should instead apply the approach in Neurim. The central issues were whether the court was bound by its earlier decision in Newron, which had applied Santen, and, if not, whether it should depart from Santen.

1. Appeal dismissed. The court was bound by Newron. Under section 6 of the European Union (Withdrawal) Act 2018 and paragraphs 4 and 5 of the European Union (Withdrawal) Act 2018 (Relevant Court) (Retained EU Case Law) Regulations 2020, the Court of Appeal could depart from assimilated EU case law only if it was not bound by binding post-transition domestic authority which had applied it.

2. Newron had applied Santen as part of its ratio. Its conclusion depended on accepting Santen's strict distinction between the identity of a product and its manner of use. The difference between article 3(b), considered in Newron, and article 3(d), considered here, did not prevent that binding effect.

3. The recognised Young v Bristol Aeroplane exceptions did not apply. A prior Court of Appeal decision is not per incuriam merely because counsel did not advance an argument that the court should depart from assimilated EU law. Per incuriam requires ignorance of binding authority or a statutory provision which would necessarily have produced a contrary result.

4. In any event, the court would not have departed from Santen. Departure under the [1966] 1 WLR 1234 Practice Statement requires more than a view that the earlier decision was wrong. Particular caution is required for statutory interpretation and for an instrument intended to operate uniformly across jurisdictions. Santen restored coherence after the uncertainty created by Neurim, respected the wording and balanced objectives of the SPC regime, and retained a simple and predictable system for patent offices.

5. Accordingly, article 3(d) of Regulation (EC) No 469/2009 did not permit Merck to treat the 2017 authorisation as the first marketing authorisation. A new therapeutic application does not create a distinct product where the same active ingredient was already authorised for another therapeutic application.

• Court of Appeal (Civil Division): Appeal dismissed in [2025] EWCA Civ 45. The court held that it was bound by Newron and could not depart from Santen.
• Patents Court: The appeal from the Hearing Officer was dismissed by Michael Tappin KC, sitting as a Deputy Judge of the High Court. No citation was stated.
• UK Intellectual Property Office: The Hearing Officer refused the SPC application in BL O/0484/23, applying Santen.