What is International Preliminary Examination?
International Preliminary Examination (IPE) is an optional phase in the Patent Cooperation Treaty (PCT) process that allows applicants to obtain a detailed examination of their international patent application before entering the national phase. It helps applicants assess and improve the patentability of their invention by addressing issues raised in the International Search Report (ISR) and Written Opinion.
The IPE is conducted by an International Preliminary Examining Authority (IPEA), such as the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), or Japan Patent Office (JPO). Unlike the ISR, which only identifies prior art, the IPE allows applicants to amend claims and provide arguments to strengthen patentability.
Why IPE matters for Businesses and Inventors?
International Preliminary Examination offers several strategic advantages:
- Enhances the chances of national phase success – Allows applicants to address patentability concerns before filing in individual countries.
- Saves time and costs in national prosecution – Reduces the risk of rejection and multiple rounds of examination in different jurisdictions.
- Provides a non-binding preliminary patentability opinion – Helps applicants refine claims and make informed filing decisions.
- Strengthens licensing and investment opportunities – A favorable International Preliminary Report on Patentability (IPRP) can increase confidence in a patent’s validity.
How the IPE Process works?
1. Filing a Demand for IPE
- The applicant must request IPE within 22 months from the priority date or 3 months after receiving the ISR, whichever is later.
- The request (called a “Demand”) is filed with a selected IPEA and requires payment of additional fees.
- The applicant may amend claims, description, and drawings, and submit arguments addressing prior art concerns.
2. Examination by the IPEA
- The IPEA reviews the amended claims and conducts a detailed patentability assessment based on novelty, inventive step, and industrial applicability.
- The applicant may receive written opinions and be allowed to respond with further amendments.
3. Issuance of the International Preliminary Report on Patentability (IPRP)
- The IPEA issues an International Preliminary Report on Patentability (IPRP – Chapter II), which provides:
- A final non-binding opinion on whether the invention meets the criteria for patentability.
- A list of cited prior art affecting the claims.
- An assessment of whether any claims are patentable as amended.
- The IPRP is sent to national patent offices, helping them evaluate the patent application during the national phase.
Example: A biotech company files a PCT application for a new gene-editing technique. The ISR cites prior art that raises doubts about novelty. To improve its chances in the U.S. and Europe, the company requests IPE, submits amendments, and receives a favorable IPRP. This strengthens its position before filing in national patent offices.
IPE vs. ISR vs. National Phase Examination
| Factor | International Search Report (ISR) | International Preliminary Examination (IPE) | National Phase Examination |
| Purpose | Identifies prior art and provides an initial written opinion | Allows applicants to amend and improve patentability before national filings | Determines final patent grant under national laws |
| Timing | Issued within 16 months of priority date | Must be requested within 22 months of priority date | Conducted after national phase entry |
| Binding Effect | Non-binding, advisory only | Non-binding, but persuasive for national offices | Legally determines whether a patent is granted |
| Amendments Allowed? | No | Yes | Yes, but varies by jurisdiction |
| Examining Authority | Conducted by an ISA | Conducted by an IPEA | Conducted by national patent offices |
Challenges in using IPE
While IPE provides strategic benefits, challenges include:
- Additional costs – Requires examination and filing fees, increasing the overall cost of the PCT process.
- Non-binding nature – National offices are not obligated to follow the IPRP, though it influences decision-making.
- Time constraints – Must be requested early in the PCT timeline, requiring quick decision-making.
- Not available in all jurisdictions – Some patent offices may have different rules for recognizing IPE findings.
Strategic business use of IPE
Businesses and inventors use IPE to:
- Improve their patent’s strength before national filings by refining claims and arguments.
- Decide whether to proceed with costly national phase entries based on the IPRP outcome.
- Enhance licensing discussions by demonstrating strong patentability.
- Reduce the risk of rejection in key markets by addressing potential patentability concerns early.
Key takeaways
- International Preliminary Examination is an optional step in the PCT process that allows applicants to amend their application and receive a more detailed patentability opinion.
- The resulting International Preliminary Report on Patentability (IPRP) helps applicants refine claims and prepare for national phase filings.
- While non-binding, a favorable IPRP strengthens a patent’s position before entering national patent offices.
Frequently Asked Questions on International Preliminary Examination
1. What is an International Preliminary Examination?
The International Preliminary Examination is an optional stage in the Patent Cooperation Treaty (PCT) process, where a patent application undergoes a more detailed substantive review. It assesses whether the invention meets the criteria of novelty, inventive step, and industrial applicability before entering the national phase.
2. Who conducts the International Preliminary Examination?
The International Preliminary Examining Authority (IPEA)—such as the EPO, USPTO, or JPO—reviews the application. The applicant selects an IPEA after receiving the International Search Report (ISR).
3. What are the benefits of requesting an IPE?
The IPE provides a detailed legal opinion on the likelihood of patentability, allowing applicants to amend claims before entering the national phase. A positive International Preliminary Report on Patentability (IPRP) can strengthen the patent application in different countries.
4. Does a positive IPE result guarantee a granted patent?
No, national patent offices still conduct independent examinations. However, a favorable IPRP can persuade national offices to grant a patent faster and may reduce examination costs by minimizing rejections.