Attorney-Client Privilege in Patent Matters

A Patchwork of Legal Protections

But in international patent matters, that expectation may not hold up because this protection is not applied uniformly across jurisdictions, which can pose serious risks, especially in cross-border IP litigation.

While common law countries like the United States and United Kingdom offer strong privilege protections, many others, especially in Europe, do not.

Discovery and Privilege in Common Law Countries

In common law countries, discovery procedures are frequently used in litigation and are considered a crucial part of the process. They are designed to allow parties to gather information from each other before trial, helping to prepare for trial, evaluate the case, and potentially facilitate settlement.
Different methods like depositions, interrogatories, and requests for documents may be used in the discovery procedures. In the case of requests for documents, parties have to disclose internal documents unless they are specifically protected by privilege.

So, even within the U.S., communications with in-house IP teams may lose protection if they aren’t clearly legal in nature.

Weak and Inconsistent Protection in Europe

In contrast, most European jurisdictions lack general discovery procedures and offer inconsistent recognition of attorney-client privilege, depending on national laws.

While many professions such as doctors, criminal lawyers, priests, and journalists benefit from legally recognized professional secrecy, patent attorneys are not always clearly included in these protections.
This creates a real legal risk: confidential emails and early-stage discussions could be exposed in court, especially during cross-border litigation.

For example, if in an email the inventor used wording like “not novel” or “not inventive,” these statements can be interpreted and used in litigation against the applicant to invalidate the granted patent.

The Case for Global Privilege Standards 

If privilege were consistently applied worldwide, companies could speak freely with their advisors, reducing legal uncertainty and avoiding damaging disclosures.

It would also streamline litigation and promote more open, effective innovation strategies across borders.

International Discussions, Slow Progress

To address this inconsistency, the World Intellectual Property Organization (WIPO) has been discussing, since 2013, the possibility of a binding international agreement to establish a minimal and consistent level of privilege for communications between clients and intellectual property advisors concerning patent law.

However, no such agreement has been finalized, and no definitive timeline for its adoption has been announced.

Rule 153 EPC: A Partial Solution

In Europe, some steps have been taken toward standardized protection. Since 2007, Rule 153 of the European Patent Convention (EPC) has provided a legal basis for recognizing privilege before the European Patent Office (EPO).

This rule protects communications with authorized patent professionals in specific legal contexts, such as assessing patentability, prosecuting applications, or giving opinions on infringement.

Here is the exact wording of Rule 153 EPC:

1. Where advice is sought from a professional representative in their capacity as such, all communications between the professional representative and their client or any other person, relating to that purpose and falling under Article 2 of the Regulation on discipline for professional representatives, are permanently privileged from disclosure in proceedings before the European Patent Office, unless such privilege is expressly waived by the client.
2. Such privilege from disclosure shall apply, in particular, to any communication or document relating to:
   (a) the assessment of the patentability of an invention;
   (b) the preparation or prosecution of a European patent application;
   (c) any opinion relating to the validity, scope of protection or infringement of a European patent or a European patent application.

However, this protection only applies to proceedings before the EPO and does not extend to national courts, leaving a significant gap in cross-jurisdictional litigation.

Early-Stage Communication: A Legal Risk

This lack of uniformity becomes particularly problematic when dealing with early-stage communications. If such communications are not clearly protected under privilege, as explained above, they may later become discoverable and potentially damaging in litigation.

Complexity in the U.S.: In-House Counsel Under Scrutiny

Further complexity arises in the United States, where communications by in-house IP staff may not be privileged unless the individual is acting specifically in their capacity as a legal advisor and not in a business or managerial role.

Courts often scrutinize the nature of these communications, and protection may be denied if the person was not a qualified patent attorney at the time or was primarily acting in a business capacity.

The Need for International Harmonization

An international harmonization on Attorney-Client Privilege remains crucial to promote legal certainty, protect innovation, and foster trust across borders.

Efforts toward harmonization have been slow due to deep-rooted differences between common law and civil law systems, lack of consensus on who qualifies as a legal advisor eligible for privilege, political concerns about misuse and fairness, and a general lack of urgency or incentive for reform in some countries.

A Call for Action

With patience and sustained advocacy, like other international IP norms (e.g., TRIPS), incremental steps toward international harmonization on Attorney-Client Privilege are both realistic and meaningful.
We call on legislators to accelerate the development of clear and consistent laws regarding Attorney-Client Privilege in intellectual property matters.

EP&C’s Approach: Protecting Confidentiality Today

At EP&C, we feel the urge for clear guidelines regarding Attorney-Client Privilege. We are not waiting for a universal framework to be established — instead, we proactively implement internal practices to protect confidentiality.

It is important to mitigate risks by always assuming that communications and documentation may become discoverable. Therefore, they should be drafted with care, clearly marked as privileged where appropriate, and not shared without first consulting your patent attorney.

In case of doubt, we recommend scheduling a meeting or a phone call with a qualified patent advisor. EP&C takes confidentiality seriously. That’s why we explicitly advise our clients not to send sensitive or strategic information by email, but to discuss such matters over the phone or in a secure setting.
This proactive approach helps minimize legal risk and ensures better protection of confidential information.

We believe that your patent attorney should be someone you can trust without question. We are in your corner, and the knowledge we hold should never — under any circumstance — be used against you.