One Case a Day | China: Determination of Support for Functional Features – "Sustained-Release Drug" Case (2022) No. 56132

Case Introduction
Late at night, let's begin today's case study.

Previous cases discussed the determination of functional features in China and the U.S. Today, we share a Chinese case that focuses on determining whether functional features, when undisputed, can be supported by the specification.

For product claims, it is advisable to avoid using functional features, especially in the chemical field. The standard for functional features to be supported by the specification is very high in China.

If:
① The function/effect defined in the claims is achieved by the specific means described in the embodiments of the specification, and
② A person skilled in the art cannot understand that this function/effect can also be achieved by other alternative means not mentioned in the specification, or
③ The description in the specification does not make it clear to a person skilled in the art what these alternative means are or how to apply them,
then the claims are considered not to be supported by the specification.

In this case, the collegial panel first determined that condition ① applies (some embodiments can achieve the corresponding function, while others cannot) and further argued that condition ③ also holds (the realization of the corresponding function is also controlled by parameters such as coating and preparation methods, and the specification does not clarify the impact of each factor on the function/effect, making it unclear to a person skilled in the art what these alternative means are or how to apply them).

Case Information

• Application Number: 201510599477.0
• Invention Title: Solid Oral Extended-Release Drug Dosage Form
• Internal Case Number: 4W113250
• Decision Information: No. 56132
• Decision Date: May 12, 2022

Key Points of the Decision
If the function/effect defined in the claims is achieved by the specific means described in the embodiments of the specification, and a person skilled in the art cannot understand that this function/effect can also be achieved by other alternative means not mentioned in the specification, or the description in the specification does not make it clear to a person skilled in the art what these alternative means are or how to apply them, then the claims are considered not to be supported by the specification.

For the determination of inventiveness, a use invention of a chemical product is based on discovering new properties of the product and utilizing these properties. If the use to be protected is an inevitable result of known applications in the prior art, then the use invention is considered to lack inventiveness relative to the prior art.

Controversial Focus
Claim 1 of the involved patent, as amended, protects a solid oral extended-release drug dosage form comprising an extended-release matrix preparation, wherein the extended-release matrix preparation comprises a composition containing at least the following components:

(1) At least one polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements; and
(2) At least one active agent selected from opioid analgesics, and

wherein the composition comprises at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements,

wherein, when measured using USP Apparatus 1 at 100 rpm and 37°C in 900 ml of enzyme-free simulated gastric fluid, the dosage form provides a dissolution rate of 12.5 wt% to 55 wt% of the active agent released after 1 hour, 25 wt% to 65 wt% released after 2 hours, 45 wt% to 85 wt% released after 4 hours, and 55 wt% to 95 wt% released after 6 hours.

The controversial focus of this case is: Whether the functional features related to the dissolution amounts of the active ingredient at 1, 2, 4, and 6 hours can be supported by the specification.

Invalidation Decision
1. Article 26, Paragraph 4 of the Patent Law stipulates that the claims shall be supported by the specification and define the scope of patent protection. According to this provision, if:

① The function/effect defined in the claims is achieved by the specific means described in the embodiments of the specification, and
② A person skilled in the art cannot understand that this function/effect can also be achieved by other alternative means not mentioned in the specification, or
③ The description in the specification does not make it clear to a person skilled in the art what these alternative means are or how to apply them,

then the claims are considered not to be supported by the specification.

2. In this case, Claim 1 protects a solid oral extended-release drug dosage form comprising an extended-release matrix preparation, wherein the extended-release matrix preparation comprises a composition containing at least (1) at least one polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements and (2) at least one active agent selected from opioid analgesics. The composition comprises at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements, and when measured..., the dosage form releases the active agent in amounts of 12.5–55 wt%, 25–65 wt%, 45–85 wt%, and 55–95 wt% after 1, 2, 4, and 6 hours, respectively.

3. Claim 1 is a product claim, and its current expression combines product composition features with functional/effect features. For product claims, it is generally advisable to avoid using functional/effect features to define the invention. If a technical feature cannot be defined by structural features or defining it with functional/effect features is more appropriate than using structural features, then the function/effect should be directly and positively verifiable through experiments, operations, or conventional means in the technical field as specified in the specification. For such claims, it should be examined whether this functional/effect limitation can be supported by the specification.

4. The key to whether such functional/effect limitations can be supported by the specification lies in whether a person skilled in the art, based on the description in the specification, can anticipate what the main influencing factors of the function/effect are, thereby determining whether a person skilled in the art, based on the description in the specification, can understand what other alternative means, mentioned or not mentioned in the specification, can be used to achieve this function/effect.

5. The features related to the structure and/or composition of the product in Claim 1 are that the active ingredient is selected from at least one opioid analgesic and that polyethylene oxide with a molecular weight of at least 800,000 constitutes at least 80 wt% of the composition forming the extended-release matrix preparation. If, based on the records in the specification, for the opioid analgesic, when the condition that polyethylene oxide with a molecular weight of at least 800,000 constitutes at least 80 wt% of the composition forming the extended-release matrix preparation is met, the obtained product is highly likely to have the said dissolution properties, then the drafting method of Claim 1 can be considered supported by the specification. Conversely, if, based on the records in the specification, when this condition is met, it is still difficult to determine whether the obtained product has the said dissolution properties, and the records in the specification also cannot determine what means can be used to ensure the dissolution characteristics, then the functional/effect limitation of Claim 1 is considered not to be supported by the specification.

6. The specification of the involved patent provides a total of 31 embodiments. Some embodiments (e.g., Embodiments 1–3, 4.1, 4.4–4.6, 5.1, 5.2, 6, 7.1, 7.2, 8.1, 9–12, 13.1–13.3, 14.1–14.3, 24) meet the matrix preparation defined in Claim 1, i.e., containing at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements. Among them, Embodiments 6 and 9 did not measure the dissolution of the product, and Embodiments 1, 2, and 11 used USP Apparatus 2 (paddle method). Based on common knowledge in the field and the patentee's admission, the choice between the paddle method and the basket method is merely a selection of measurement apparatus and should not substantially affect the dissolution results. Therefore, the dissolution effects of Embodiments 1, 2, and 11 can be considered in light of the dissolution effects defined in Claim 1.

7. However, among these embodiments, the dissolution rates of tablets from Embodiments 1–3 and 11–12, which fall within the scope of Claim 1 (matrix preparations containing at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000), do not meet the active agent release characteristics defined in Claim 1 in some cases. Specifically:

• The dissolution at 4 hours for the untreated whole tablet of Embodiment 1 is 43%, below the lower limit of 45% defined in Claim 1.
• The dissolution at 2 hours for the whole tablet of Embodiment 2.1 is 72%, exceeding the upper limit of 65% defined in Claim 1.
• The dissolution at 1, 2, and 4 hours for the whole tablet of Embodiment 2.2 is 57%, 78%, and 95%, respectively, all exceeding the upper limits defined in Claim 1.
• The dissolution at 2 and 4 hours for the whole tablet of Embodiment 2.3 is 77% and 93%, respectively, both exceeding the upper limits defined in Claim 1.
• The dissolution at 2 and 4 hours for the tablet of Embodiment 3 heat-treated for 14 hours is 69% and 87%, respectively, exceeding the upper limits defined in Claim 1.
• The dissolution at 1 and 2 hours for the tablet of Embodiment 11 is 12% and 19%, respectively, both below the lower limits defined in Claim 1.
• The dissolution at 1, 2, and 4 hours for the tablet of Claim 12.1 does not meet the limitations of Claim 1.
• The dissolution at 4 hours for the tablet of Embodiment 12.2 is 95%, exceeding the upper limit defined in Claim 1.

In other words, based on the embodiments provided in the specification, when the condition that polyethylene oxide with a molecular weight of at least 800,000 constitutes at least 80 wt% of the composition forming the extended-release matrix preparation is met, the obtained dosage form does not necessarily satisfy the dissolution characteristics described in Claim 1.

8. On the contrary, reviewing the embodiments recorded in the specification, for preparations containing at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements, factors such as whether coating is applied, the specific composition of the coating, and preparation methods all have unpredictable effects on the dissolution rate. For example:

• For the same product, changes in preparation methods, such as the duration of heat treatment, alter the dissolution characteristics of the product, making it change from not meeting the dissolution rate requirements to meeting them (see Embodiment 1, Table 1.1) or from meeting the dissolution rate requirements to not meeting them (see Embodiment 3, Table 3).
• When the core tablet and coating material compositions are identical, only differences in coating thickness result in different dissolution characteristics (see paragraphs 0941–0943, Table 12, Embodiments 12.1 and 12.2, and Embodiments 13.1–13.3).

Additionally, the specification provides a large number of embodiments where the content of high molecular weight polyethylene oxide is below 80% but the dissolution meets the requirements (facts from Embodiments 1–25 other than those meeting the requirements), indicating that there is no necessary relationship between dissolution rate and high molecular weight polyethylene oxide content.

9. Therefore, based on the records in the specification, a person skilled in the art cannot ensure that all dosage forms within the protection scope of Claim 1, defined by the compositional feature of containing at least 80 wt% of polyethylene oxide with a molecular weight of at least 800,000 based on rheological measurements, possess the active agent dissolution rate characteristics described in Claim 1. In fact, in light of the specification of the involved patent, it can be seen that the dissolution rate described in Claim 1 is clearly achieved by the specific means described in the embodiments of the specification. Only specific combinations of various preparation conditions can achieve the dissolution rate described in Claim 1. However, the specification of the involved patent does not clarify the impact of each factor on the function/effect, making it unclear to a person skilled in the art what these alternative means are or how to apply them. In other words, the specification does not adequately describe the functional/effect feature, failing to enable a person skilled in the art to generalize what means should be adopted to obtain the said function/effect in the claimed solution. Therefore, Claim 1 is not supported by the specification and does not comply with Article 26, Paragraph 4 of the Patent Law.

...