Are you risking your entire drug patent strategy with one simple oversight? Dosage regimen patents have become a minefield for pharmaceutical companies, with even the smallest misstep leading to costly rejections. Whether you're struggling to navigate the EPO's inventive step requirements or facing setbacks from clinical trial disclosures, securing a strong dosage patent has never been more challenging. But why are so many companies still getting it wrong? And what crucial strategies are being overlooked in jurisdictions like the UK and US? Keep reading as we reveal the hidden pitfalls and insider tips that could make or break your next dosage regimen patent.
Dosage regimen patents have become a critical area of focus in the pharmaceutical and biotech industries. As regulatory bodies and legal frameworks evolve, the challenges associated with patenting dosage regimens have grown more complex. In this blog post, we dive into key insights from a recent webinar led by Dr. Ulrich Storz, Partner at Michalski Hüttermann & Partner, where he analyzed the patentability issues surrounding dosage regimen patents with an eye on European, UK, and US case law.
1. Understanding Dosage Regimen Patents
Dosage regimen patents protect the specific dosage and/or timing of administering a drug. They form a part of the second-generation patents filed after the active pharmaceutical ingredient (API) patent, alongside second medical use and formulation patents. While formulation patents often leave bypass solutions for generic or biosimilar competition (such as allowing for the exchange of buffers in biosimilars), dosage regimen patents require exact adherence to the dosages specified on the drug’s label, making them more meaningful for generic or biosimilar competition.
2. Dosage Regimen Patents and the Inventive Step Requirement
The Enlarged Board of Appeal at the European Patent Office (EPO) played a pivotal role in determining the patentability of dosage regimen patents with its decision in G2/08. This decision declared dosage regimen patents admissible but stressed that they must pass rigorous tests for inventive step and sufficiency. The concern was raised that allowing patents where the only novel feature is the dosage could lead to undue extensions of patent protection.
As a result, the Enlarged Board of Appeal felt it necessary to emphasize the normal, namely that for dosage patents, too, the whole body of jurisprudence relating to the assessment of novelty and inventive step applies.
For dosage regimen claims being considered to belong to the method of treatment category, the Boards of Appeal typically require that applicants must demonstrate that the claimed dosage regimen is supported by human efficacy data, showing that the claimed regimen results in therapeutic benefit..
3. Patentability Challenges in Europe: Key EPO Case Law
Several decisions from the EPO have highlighted the challenges surrounding dosage regimen patents. For example:
- Case T2440/13: This case concerned a patent for rituximab that was revoked due to "added matter." The applicant had claimed a dosage regimen without specifying the timing of administration, even though the application as filed disclosed a specific timing with 1 week interval. By omitting, in the claims, the timing, the patent proprietor wanted to make the claims compliant to the regulatory label, which provided a 4 weekly interval (better no timing in the claims than the wrong timing!). However, in the view of Board of Appeal the omission of the timing introduced new subject matter, leading to the revocation of the patent. The lesson here: ensure that the dosage regimen in your patent matches the clinical label.
- Case T1592/12: This case involved trastuzumab, where the applicant claimed a modified dosage regimen without providing sufficient human efficacy data. Even though late-filed data suggested efficacy, the Board of Appeal rejvoked the patent because sufficiency must be demonstrated at the filing date. This case underlines the importance of having enabling data upfront when applying for dosage regimen patents.
These examples show that inventive step and sufficiency are common areas where dosage patents face opposition, particularly at the EPO.
4. Clinical Trials and Their Impact on Patentability
Human in vivo data are critical in supporting the sufficiency dosage regimen patents. Typically, these data are obtained from Phase II or Phase III clinical trials, but this creates a conflict. Clinical trial plans must be published before the trials begin, meaning that patentees run the risk of their own prior art being used against them.
Interestingly, while clinical trial plans that disclose only dosage regimens (without results) are generally not considered novelty-destroying, they may still be used as prior art in obviousness attacks. Patentees must therefore a carefully manage the timing of their patent filings to avoid conflicts with publicly available trial data.
5. Case Law from the UK and US: A Comparative View
Dosage regimen patents face different legal standards across jurisdictions. In the UK, courts often apply a stricter standard for inventive step compared to the EPO. A notable example is the Actavis v. ICOS case, where the UK Supreme Court concluded that finding the optimal dosage was within the routine capabilities of the skilled person, thereby rejecting the patent. Similarly, a Tadalafil dosage patent that survived the EPO's opposition proceedings was ultimately revoked in the UK due to lack of inventive step based on the argument that dosage finding was in the routine of the skilled artisan.
In the US, the approach tends to align more with the EPO, but courts have shown some flexibility in assessing inventive step. In Salix Pharmaceuticals v. Norwich Pharma, the Federal Circuit was "hesitant" to conclude that clinical trial plans alone provided sufficient expectation of success. However, the court ruled that when combined with prior art suggesting the respective dosage, the claimed dosage regimen became obvious, leading to the revocation of the patent.
This comparative analysis highlights how different jurisdictions apply varying thresholds for assessing inventive step in dosage regimen patents, particularly when prior art from clinical trials is involved.
6. Practical Strategies for Patentees
For patentees seeking to protect their dosage regimens, a few strategies can help mitigate risks:
- Carefully manage publications: Avoid premature publication of dosage data in clinical trial plans that could be used as prior art.
- In vivo human data are essential: Assay or animal data are insufficient for dosage regimen claims. Patentees should aim to obtain human efficacy data early, potentially through small-scale preclinical studies which need not be published upfront.
- Consider redacting dosage information: Where possible, redact dosage details in clinical trial plans to avoid the creation of own prior art.
These proactive steps can help ensure that dosage regimen patents survive scrutiny during the examination and opposition phases.
7. Practical Strategies for Opponents
For opponents challenging dosage regimen patents, several strategies are worth considering:
- Analyze clinical trial dossiers: Regulatory submissions often contain valuable information that can be used in opposition, particularly if clinical trials disclose similar dosages to the claimed regimen.
- Challenge inventive step and sufficiency: Focus on whether the applicant has provided sufficient evidence of efficacy and whether the claimed dosage regimen would have been obvious to a skilled person based on prior art.
The European Patent Office's decision in G2/08 gives opponents a clear pathway to challenge the inventive step of dosage regimen patents, especially when a reasonable expectation of success can be argued from the closest prior art.
Conclusion
Dosage regimen patents represent a challenging but vital area of pharmaceutical patent law. Their patentability often hinges on demonstrating an inventive step and providing sufficient human efficacy data. With increasing scrutiny from the EPO, UK, and US courts, patentees must carefully manage the timing and content of their clinical trial disclosures to preserve novelty and inventive step.
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