How helpful are biological deposits at the EPO?

In our article about biological deposits under the Budapest Treaty, we explored the deadlines and formalities for depositing microorganisms so that the deposit can be referenced in a patent application. For the present article, we reviewed the prosecution history of over 45 cases at the European Patent Office (EPO)[1]. We found that, when made correctly, a reference to a deposited microorganism can be very helpful in overcoming a range of objections from the EPO’s examiners.

We found that amending the independent claims to reference the deposited strain was pivotal in achieving allowance in approximately 50% of the granted cases that we reviewed. On the other hand, in cases that had not yet granted, a substantial minority (approximately 10%) were refused or withdrawn after the EPO alleged that “the deposit was made by a person other than the applicant and that the declaration required by Rule 31(1)(d) EPC was not made by the deadline”. (As explained in our aforementioned article, deposits can be made by a person other than the applicant, but if so, the applicant must provide evidence that the depositor has authorised the deposit to be referenced in the patent application and has given unreserved, irrevocable consent to the deposited material being made available to the public.)

In cases where allowance followed amendment of the independent claims to refer to a deposited strain, the amendment appeared to help overcome objections of various categories. In some cases, the EPO examiners had alleged that the original claims were insufficiently disclosed or unclear. In such cases, the straightforward strategy of focusing the claims on one or more deposited strains was used by some applicants to secure allowance.

In other cases, novelty and/or inventive step issues were addressed by focusing the claims on one or more deposited strains. This strategy was effective in several cases where the EPO identified prior art that was allegedly very ‘close’ to the claimed invention (e.g., disclosing closely related microorganisms).

However, specifying a deposited microorganism is not automatically enough to establish patentability at the EPO. In general, the EPO wants to see that the claimed invention achieves an “unexpected technical effect”, and this also applies to inventions involving microorganisms. In cases where an unexpected technical effect was shown to be associated with the deposited microorganisms, an inventive step was readily acknowledged. In contrast, when an unexpected technical effect had not been demonstrated, the EPO is often reluctant to acknowledge an inventive step. In one case, the examiner acknowledged novelty but denied inventive step, saying “there is nothing magical about a deposit per se…”.

As noted above, we have identified several cases where sufficient disclosure of the invention required a reference to a deposit, but where the applicant had not submitted evidence that the (third party) depositor “has authorised the applicant to refer to the deposited biological material in the application and has given his unreserved and irrevocable consent to the deposited material being made available to the public”. These cases did not achieve allowance, showing that failing to file this evidence can be fatal. However, while the deadline for submitting this evidence is 16 months from the filing or priority date, we have seen some cases where the EPO has shown some leniency around the 16 month deadline for filing it.

In summary, we have seen that referring to a biological sample deposited under the Budapest Treaty can be instrumental in addressing a range of objections from EPO examiners. This underlines the importance of correctly making the deposit before filing the patent application and correctly referencing it in the application.




  1. IPquants was used to search EPO cases that were pending or granted between 2020-2023 based on the keywords “strain” in the claims, and “bacterial ~3 AND viral ~3 AND fungal ~3” in the description”. This returned over 150 cases. The claims of these cases were then filtered for the keyword “deposit*” and “accession”. We reviewed publicly available case files on the EP register of the cases of interest.