The Beijing Intellectual Property Court (BIPC) has introduced a potentially game-changing approach to assessing polymorph patents in China, signaling a possible shift away from the country's notoriously strict patentability standards. In a landmark ruling involving Chengdu Sino-strong Pharmaceutical Co. Ltd.'s rocuronium bromide patent, the court explicitly considered commercial success as a factor in determining inventiveness, marking a significant departure from established precedents.
New Standard Emerges from Rocuronium Bromide Case
The case centered on patent ZL201911372921.X, which covers Form A of rocuronium bromide, a neuromuscular blocking agent. The patent disclosed that Form A demonstrates "chemical stability markedly superior to that of the prior art," allowing storage in an open container at 25°C for 30 days with minimal impurity changes. This represents a dramatic improvement over prior art forms that required storage below -15°C to -20°C according to European and US pharmacopoeias.
The China National Intellectual Property Administration (CNIPA) had initially invalidated the patent in August 2023, reasoning that improved stability in crystalline versus amorphous forms was predictable based on common knowledge. However, the BIPC overturned this decision in October 2024, establishing what appears to be a more lenient standard.
Court Introduces "Better Technical Effect" Standard
The BIPC's ruling represents a fundamental shift from the traditional "unexpected technical effect" requirement to a more accessible "better technical effect" standard. The court explicitly stated that "if a crystal form achieves a better technical effect than the prior art, it could be recognised as inventive, even if the acquisition of this crystal form is obvious."
This new approach considers the substantial economic investment required for polymorph research and development. As the court noted, "the trial-and-error process leading to its final acquisition and the uncertainty surrounding the viability of acquiring a crystal form aligning with the requirements of the pharmaceutical industry demand considerable economic investment."
Commercial Success as Patentability Factor
Perhaps most significantly, the BIPC explicitly factored the successful marketing of Form A into its inventiveness assessment. The court stated that "if the disclosed technical effect is highly relevant to druggability, and the marketed drug uses the crystal form, it should be recognised that it achieves a beneficial technical effect."
This commercial success consideration represents a stark contrast to traditional Chinese patent law practice, where technical merit alone typically determines patentability.
Contrast with Recent CNIPA Decisions
The BIPC's approach stands in sharp contrast to recent CNIPA invalidation decisions, exemplified by the fruquintinib Crystal Form I case. In that decision, CNIPA maintained its strict standards, invalidating the patent despite acknowledged stability advantages because the patentee failed to provide comparative data against the closest prior art form used in pre-clinical studies.
The fruquintinib decision highlighted several common pitfalls in Chinese polymorph patent prosecution: insufficient comparative data, incremental technical effects, and failures to preempt obviousness challenges. The CNIPA emphasized that "mere identification of a new polymorph, absent comparative data against the closest prior art form or unpredicted technical leaps, cannot satisfy inventiveness requirements."
Implications for Pharmaceutical IP Strategy
The divergent approaches between the BIPC and CNIPA create uncertainty for pharmaceutical companies developing polymorph patent strategies in China. While the BIPC decision offers hope for more lenient treatment, it remains unclear whether this represents an isolated ruling or the beginning of a broader shift in Chinese patent law.
The decision could prove particularly beneficial for companies that have successfully commercialized their polymorph inventions, as commercial success may now serve as evidence of inventiveness. However, companies must still demonstrate that their polymorphs achieve specific beneficial properties relevant to druggability, such as improved purity, melting point, or hygroscopicity.
Uncertain Future for Polymorph Patents
Despite the BIPC's innovative approach, significant uncertainty remains. The decision has not been reviewed by the Intellectual Property Court of the Supreme People's Court, and the Supreme People's Court has not commented publicly on the ruling. The established precedent from Boehringer v CNIPA (2011), which required "unexpected technical effects," has guided Chinese patent practice for over a decade.
The contrast between the BIPC's more permissive approach and CNIPA's continued strict enforcement suggests that polymorph patent outcomes in China may increasingly depend on the specific forum and circumstances of each case. Companies pursuing polymorph protection in China should prepare for both scenarios, ensuring robust comparative data while also documenting commercial success and druggability benefits where applicable.
