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CNIPA: technical features of a dosage regimen have a limiting effect

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Jianhui Li of Wanhuida Intellectual Property explains how China addresses the question of whether the features of an administration process limit a patented product and distinguish it from prior art

In the pharmaceutical field, there are inventions that address newly discovered dosage regimens for known drugs, such as new dosage or administration intervals, rather than new indications.

As to the technical features embodied in claims based on a dosage regimen – such as administration object, method, route, dose, and time interval – the EPO adopts a different approach from the CNIPA.

The EPO explicitly recognises the patentability of use claims that are limited to a dosage regimen, whereas the CNIPA is of the opinion that the distinguishing features of an administration process cannot be used to establish novelty in a use claim. Consequently, it is difficult to patent inventions involving a new dosage regimen in China.

A critical case

In invalidation decision No. 54827, the CNIPA set forth the reasoning and criteria in assessing novelty regarding product claims incorporating the technical features of a dosage regimen in the field of medicine.

Zoetis Services LLC owns an invention patent, No. ZL200780048424.3, which relates to a vaccine for treating canine diseases. Claim 1 of the patent presents a distinguishing technical feature from exhibit 1, which is described as “the vaccine is formulated and administered subcutaneously in a first dose, orally in a second and third dose.” This feature, if interpreted literally, appears to be a description of the drug administration process, which would be categorised as a simple feature of drug use, thus does not have any impact on the drug structure or composition, nor does it limit the scope of the claims.

On November 10 2021, a petitioner launched an invalidity attack against the patent at issue, arguing that adjusting the vaccine dosage form, excipients, and other composition in so far as it adapts to different routes of administration is a conventional technical means in this field, which is common knowledge among technical personnel and is devoid of novelty.

The argument was rejected by the CNIPA, which ascertained the novelty of claim 1 based on the following reasoning: the patented product is a combination of subcutaneous injection formulation and oral formulation, whereas exhibit 1 fails to explicitly disclose the combination product of subcutaneous injection and oral formulations of the vaccine comprising canine distemper virus, canine adenovirus type-2, canine parainfluenza virus and the attenuated strains of canine parvovirus as presented in claim 1. The CNIPA therefore concluded that claim 1 incorporates a distinguishing technical feature and has novelty.

Exploring the CNIPA’s rationale

It is common knowledge in the art that injection and oral dosage forms usually contain different excipients. In the present patent embodiment, the combination of injection and oral dosage forms does indeed produce a good immunological effect, and the substantial contribution of the invention is the combination of the injection and oral dosage forms. Moreover, the petitioner had not raised any objection to the patentee’s interpretation of the scope of protection.

Taking into account various parameters – including the literal interpretation of claim 1, the material contribution of the invention, and the consensus of the parties over the scope of protection of the patent at issue – the CNIPA affirmed that claim 1, in its essence, protects a combination product.

The CNIPA specifically underlined the language in which claim 1 is phrased, “the vaccine is formulated…”, to be exact. The collegial panel opined that the language attests that claim 1 is not a mere feature of the drug administration method but a feature that would indirectly affect the product’s preparation, suggesting that the product is a combination of two dosage forms, namely the injection formulation and the oral formulation, and their respective excipients thereof.

As a result, the CNIPA, in assessing novelty and inventiveness of the patent, focused on ascertaining whether the corresponding combination product was disclosed in the prior art, rather than solely on whether the drug administration method was disclosed.

In China, dosage regimen is generally viewed as a feature of drug administration, which, in principle, does not have a limiting effect on the product. The patent at issue pertains to the improvement of a dosage regimen.

The reason why the CNIPA finds a technical feature of a dosage regimen has a limiting effect could be boiled down to the language employed in drafting the claims. As a matter of fact, the interpretation of the drafting language “the vaccine is formulated…” remains controversial in practice, as it is neither unequivocally correspondent to the administration process, nor entirely unrelated to the pharmaceutical preparation process.

Based on the consensus of both parties over the scope of protection, the CNIPA employed a tactful approach, finding that the subject matter to be protected by the claims is essentially a combination product that involves different administration routes, which may have implicit limitations on the form of drug formulation.

A pivotal determination

In the field of medicine, whether the technical features of a dosage regimen could limit the patented product and distinguish it from the prior art is often at the centre of the debate. Therefore, it is pivotal to determine whether a technical feature embodied in the form of a dosage regimen is a simple feature of drug administration that directly affects the determination of the scope of protection of such claims, as the assessment of novelty and inventive step may hinge on the finding.

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