Patent enablement requirements are provided under Article 102 of Vietnam’s Law on Intellectual Property (IP Law). In particular, a patent specification must “fully and clearly disclose the nature of the invention to such an extent that, based on the specification, a person having ordinary skill in the relevant art can implement the invention.” In pharmaceutical and biotechnology patents, this requirement is more complicated and subject to more rigorous assessment.

The Patent Examination Guidelines (Guidelines) of the Intellectual Property Office of Vietnam (IP Office) were amended in March 2026 to introduce Annexes III and IV for the pharmaceutical and biotechnology sectors, in which Annex III provides detailed guidelines on the assessment of specification requirements. These amendments were made under a project for strengthening capacity in industrial property examination between the Japan International Cooperation Agency (JICA) and the IP Office.

Annex III provides detailed instructions on how examiners assess enablement in a pharmaceutical or biotechnology application, and offers examples of acceptable and unacceptable descriptions with regard to the enablement aspect.

Enablement Requirements in Pharma and Biotech Patents

Article 12.7 of Circular 10/2026/TT-BKHCN (Circular 10) adds to the requirements of Article 102 of the IP Law that the description must demonstrate the novelty, inventive step, and industrial applicability of the technical solution. For pharmaceutical composition subject matters, Article 12.9 of Circular 10 sets out that the description must present the results of clinical trials and/or the pharmacological effects of the claimed pharmaceutical composition, and must include at least the following information:

• Substance/mixture used.
• Testing method (system) employed.
• Information on the test results.
• Correlation between the pharmacological effects obtained from the tests and the application of the pharmaceutical product in the prevention, diagnosis, and treatment of diseases.

The Guidelines note that pharmacological study results should be presented in a quantified manner, and pharmacological study systems include clinical studies, animal experiments, and in vitro studies. In cases where the description does not include pharmacological study results, or where it provides such results for a compound but does not clearly identify the specific compound used in the study, the invention may be considered as not meeting the requirements for sufficient disclosure, enablement, and clarity.

Accordingly, in cases where the application only claims the active ingredient, any addition of claims directed to a pharmaceutical composition must take into account the description requirements applicable to pharmaceutical inventions. Not all additions of pharmaceutical composition claims will be acceptable. Support for pharmaceutical claims is also included in the mentioned requirements.

For biotechnology inventions such as genes, polypeptides, and proteins, Annex III clarifies that these products must be defined by their structural features, such as their particular sequences, to meet the enablement requirements. The Guidelines also suggest that, where it is not possible to describe these subject matters by structural features, they may be defined by the process by which they are produced (product-by-process). This explains the objections of the IP Office when a biological product subject matter is defined in the claim only by its properties, such as antigen-binding ability or immunogenic capability.

In addition, Article 12.10 of Circular 10 requires that for descriptions that include a sequence listing, the sequence listing must be presented in accordance with the WIPO ST.26 standard as a separate part and placed at the end of the description. In practice, the usual XML format is not submittable to the online filing system of the IP Office. Therefore, an ST.26 sequence listing must be converted into PDF format, which is not feasible for search purposes, for submission and for page-fee determination. This practice leads to a waste of resources in cases where sequences included in the description must still be reproduced for the issuance of a physical patent in ST.26 format, and it also increases the fee burden on applicants, since page fees may be counted twice for the sequences. However, the IP Office has not yet adopted any measures to change this practice.

For inventions relating to Markush groups, the Guidelines require that the description must include at least one illustrative example of the preparation method for each group of compounds. The number of examples must be sufficient to enable a person having ordinary skill in the relevant art to implement the invention and to assess that the invention achieves the intended effect across the entire scope defined by the claims. It can be interpreted that the number of examples must be adequate to represent all the embodiments covered by the claims. The IP Office has issued objections where the examples in the description are considered insufficient to represent or demonstrate the effect across all claimed embodiments. In such cases, the applicant needs to submit additional data demonstrating the effect, and show that such data are sufficient to be representative and/or to narrow the scope of the claims.

Disclaimer

The principles governing the acceptance of disclaimers, as explained in the Guidelines, are also the general principles applicable to amendments—namely, that a disclaimer must not add a new technical subject matter and/or alter the nature of the subject matter, or extend beyond the content disclosed in the original description. This appears to be stricter than the regulations in other jurisdictions, as it seems that disclaimers are only accepted when they have been disclosed in the original specification.

However, Annex III also provides an example in which a disclaimer is acceptable even though it is not disclosed in the original description. In this example, the exclusion of humans from mammals is accepted, even though the exclusion of humans is not originally disclosed, because an invention covering a subject matter involving humans is considered contrary to morality and public order. (This situation may correspond to the EPO’s acceptance of a disclaimer relating to a subject matter that is excluded from patentability for non-technical reasons.)

There are few examples provided of acceptable and unacceptable disclaimers. The IP Office appears to remain very strict in examining this matter.

Post-Filing Experimental Data

The principles set out in Annex III for submitting supplementary data are as follows:

• Supplementary experimental data are not considered part of the description and are only accepted as evidence;
• The description must comply with the requirements of sufficiency of disclosure, clarity, and enablement; and
• Such supplementary experimental data are intended only to clarify or substantiate the technical effect already described in the original specification, in comparison with the technical effect disclosed in the cited prior art for the purpose of demonstrating inventive step.

From these principles, it can be seen that there is no requirement for the supplementary data to have been available before the filing date. As long as such data demonstrates the same technical effect that has already been clearly disclosed in the original specification, it may be accepted for the purpose of supporting the inventive step of the claimed subject matter.

Based on the examples provided in this section, it should be noted that both the technical effect to be demonstrated and the experimental methods must already have been disclosed in the original specification. Supplementary data serves only, as its name suggests, to supplement what has already been disclosed. Vietnamese examiners may adopt a very strict approach when assessing post-filing data.

Conclusion

Although the Patent Examination Guidelines of the IP Office do not provide explicit tests for assessing enablement of the patent specification, nor for disclaimers or post-filing experimental data in a general sense, the principles and examples set out in Annex III are quite extensive and closely aligned with situations encountered in practice. They help align the examination approach of the IP Office with the understanding and handling of such issues by applicants. This document serves not only as guidance for IP examiners in conducting examination, but is also highly useful for applicants and IP practitioners in drafting specifications and making amendments.

In the future, it is expected that additional issues and practices that remain unclear will be further clarified by the IP Office through updates to the Patent Examination Guidelines.