The Patent Trial and Appeal Board (PTAB) has issued its Final Written Decision in IPR2025-00070, marking the conclusion of the merits phase for a proceeding that drew substantial attention from patent practitioners and technology companies alike. The decision, which addresses the validity of challenged patent claims under 35 U.S.C. §§ 102 and 103, offers new guidance on the Board’s approach to prior art combinations and the application of the “reasonable expectation of success” standard in the context of chemical and pharmaceutical arts. While the specific outcome of this particular case will be closely studied by parties involved in similar disputes, the broader implications of the decision reach into how petitioners frame obviousness arguments and how patent owners may defend against them in future inter partes reviews.
Background and Procedural History of IPR2025-00070
The inter partes review IPR2025-00070 was instituted on the basis of a petition filed by a petitioner challenging the patentability of claims owned by the patent holder. The patent at issue relates to a formulation and method of use in the pharmaceutical field, a category of technology that frequently gives rise to complex questions about what a person of ordinary skill in the art would have found obvious at the time of the invention. The PTAB instituted trial on several grounds, finding that the petitioner had demonstrated a reasonable likelihood of prevailing with respect to at least one challenged claim. The subsequent proceedings included the submission of expert declarations, depositions, and oral argument, culminating in the recently issued Final Written Decision.
Procedurally, the case followed the standard timeline established under the America Invents Act. The petitioner filed the petition on a specific date in late 2024, and the Board issued its institution decision in early 2025 after the patent owner filed a preliminary response. The trial phase then unfolded over approximately twelve months, during which both sides had the opportunity to develop their respective positions through discovery and expert testimony. The Final Written Decision, issued in August 2026, now serves as the Board’s definitive ruling on the merits of the challenged claims, subject to appeal to the U.S. Court of Appeals for the Federal Circuit.
What the Final Written Decision Addresses
In its decision, the PTAB addressed multiple grounds of unpatentability, focusing primarily on obviousness rejections based on combinations of prior art references. The Board analyzed whether the petitioner had demonstrated by a preponderance of the evidence that the challenged claims would have been obvious to a person of ordinary skill in the art. This analysis required the Board to weigh factors such as the scope and content of the prior art, the differences between the prior art and the claimed invention, the level of ordinary skill in the art, and any secondary considerations of non-obviousness, including unexpected results, commercial success, and long-felt but unmet need.
One of the central issues in the decision revolved around the petitioner’s assertion that a particular prior art reference taught each element of the claimed invention, either explicitly or inherently, and that a second reference provided the motivation to combine those teachings with a reasonable expectation of success. The patent owner countered that the prior art taught away from the proposed combination, that the references were non-analogous art, and that the claimed invention achieved unexpected results that could not have been predicted from the prior art alone.
Analysis of the Prior Art Combination
The Board’s analysis of the prior art combination followed the framework established by the Supreme Court in KSR International Co. v. Teleflex Inc. and subsequent Federal Circuit precedent. The Board examined whether the petitioner had articulated a reasoned basis for combining the references, supported by evidence that a person of ordinary skill would have been motivated to do so. In this case, the Board found that the primary reference disclosed a composition that shared structural and functional similarities with the claimed invention, but that certain critical limitations were missing from that reference alone. The secondary reference, according to the petitioner, filled those gaps by teaching a specific modification that would have been obvious to try.
The patent owner argued that the secondary reference was directed to a different area of technology and therefore could not properly be combined with the primary reference. The Board, however, determined that the secondary reference was reasonably pertinent to the problem the inventor was trying to solve, making it analogous art. This finding is significant because it reinforces the principle that references may be combined even if they are from different technical fields, so long as they are relevant to the same problem.
Reasonable Expectation of Success: A Key Determination
The Board’s treatment of the reasonable expectation of success requirement will likely attract the most attention from practitioners. In assessing whether the petitioner had established a reasonable expectation of success, the Board considered the predictability of the art, the existence of any known obstacles, and the degree of experimentation required to arrive at the claimed invention. The Board concluded that the petitioner had failed to demonstrate that a person of ordinary skill would have had a reasonable expectation of success in combining the prior art teachings to achieve the claimed invention.
This determination turned on specific factual findings regarding the unpredictability of the chemical and biological system at issue. The Board credited the patent owner’s expert testimony, which explained that small changes in formulation could lead to significant and unpredictable changes in stability, bioavailability, and therapeutic efficacy. The petitioner’s expert, in contrast, offered a more generalized opinion that the combination would have been obvious to try, without adequately addressing the specific challenges that would have been encountered. The Board emphasized that a mere showing of a “possibility” or “hope” of success is insufficient; the petitioner must demonstrate that the success was reasonably predictable at the time of the invention.
What is the reasonable expectation of success standard in IPR proceedings? The standard requires the petitioner to prove by a preponderance of the evidence that a person of ordinary skill in the art would have had a reasonable expectation of success in combining the prior art teachings to arrive at the claimed invention. This is not a requirement of absolute certainty, but rather a showing that the success was reasonably predictable based on the knowledge available at the time. The Board evaluates this question by considering factors such as the predictability of the art, the existence of known obstacles, the degree of experimentation required, and the teachings of the prior art itself.
Secondary Considerations of Non-Obviousness
The Board also evaluated the patent owner’s evidence of secondary considerations, which can serve as important objective indicators of non-obviousness. The patent owner presented evidence of unexpected results, including comparative data showing that the claimed formulation exhibited superior performance compared to the closest prior art compositions. The Board found this evidence to be persuasive, particularly because the improved properties were not merely a difference in degree but rather a difference in kind that could not have been predicted from the prior art.
In addition, the patent owner submitted evidence of commercial success, arguing that the patented product had achieved significant market adoption and generated substantial revenue. The Board acknowledged this evidence but noted that commercial success must be tied to the claimed invention itself, rather than to other factors such as marketing or branding. On balance, the secondary considerations weighed in favor of the patent owner and supported the conclusion of non-obviousness.
Implications for Patent Practitioners and Litigants
The Final Written Decision in IPR2025-00070 provides several important lessons for practitioners involved in PTAB proceedings. First, the decision underscores the critical importance of expert testimony in establishing a reasonable expectation of success. Petitioners must ensure that their experts provide detailed, fact-specific analysis that addresses the particular challenges and unpredictability of the relevant technology. Generalized assertions that a combination would have been “obvious to try” are unlikely to carry the day, especially in unpredictable arts such as chemistry, biotechnology, and pharmaceuticals.
Second, the decision highlights the value of secondary considerations as a defense against obviousness challenges. Patent owners should invest in developing robust evidence of unexpected results, commercial success, and long-felt need, and should tie that evidence directly to the claimed invention. Expert testimony can be particularly effective in explaining why the results achieved by the patent owner were truly unexpected and would not have been predicted by a person of ordinary skill.
Third, the Board’s analysis of analogous art reaffirms that references from different technical fields may be combined if they are reasonably pertinent to the problem being solved. Practitioners should be prepared to argue both sides of this issue, depending on their position in the case. For petitioners, this means identifying references that, even if from different fields, address the same problem. For patent owners, it means challenging the pertinence of such references and arguing that they are non-analogous.
Strategic Considerations for Patent Owners
Patent owners facing IPR challenges can draw several strategic insights from this decision. One of the most important is the need to develop a comprehensive record during the trial phase, including detailed expert declarations that address not only the teachings of the prior art but also the unpredictability of the field and the unexpected nature of the results achieved. The patent owner in this case successfully persuaded the Board that the prior art did not provide a reasonable expectation of success, in large part because its expert provided a thorough explanation of the specific technical hurdles that would have been encountered.
Additionally, patent owners should consider deposing the petitioner’s expert to probe the basis for any opinions regarding reasonable expectation of success. The Board’s decision suggests that it was influenced by the relative strength of the expert testimony on both sides, and that weaknesses in the petitioner’s expert’s analysis were exposed during cross-examination. Effective deposition strategy can be a powerful tool for building a record that supports a finding of non-obviousness.
Patent owners should also be mindful of the timing and content of their preliminary response. While the preliminary response is limited in scope, it provides an opportunity to identify weaknesses in the petitioner’s obviousness analysis and to flag issues that may be developed further during the trial phase. In this case, the patent owner’s preliminary response may have laid the groundwork for the later success on the reasonable expectation of success issue.
Strategic Considerations for Petitioners
For petitioners, the decision serves as a cautionary tale about the dangers of relying on generalized obviousness theories in unpredictable arts. Petitioners should ensure that their expert testimony is grounded in the specific facts of the case and addresses the particular challenges that would have been faced by a person of ordinary skill. Expert declarations should include a detailed explanation of why the combination would have been predictable, supported by evidence from the prior art or from general scientific principles.
Petitioners should also be prepared to rebut evidence of secondary considerations, both through their own expert testimony and through cross-examination of the patent owner’s experts. In this case, the patent owner’s evidence of unexpected results was particularly compelling, and the petitioner may have been able to challenge that evidence by arguing that the results were merely a predictable optimization or that the comparison was not properly conducted.
Finally, petitioners should consider the selection of prior art references carefully, ensuring that they are closely analogous to the claimed invention and that the combination is supported by a clear motivation. The Board’s decision suggests that references from different technical fields may be combined, but only if they are reasonably pertinent to the same problem. Petitioners should articulate the connection between the references and the problem being solved, and should avoid relying on references that are too far afield.
Potential Appeal and Further Proceedings
Following the issuance of the Final Written Decision, either party may seek review by the Federal Circuit. The patent owner, having prevailed on all challenged grounds, is likely satisfied with the outcome and may not appeal. The petitioner, however, may choose to challenge the Board’s findings on the reasonable expectation of success issue or on the treatment of secondary considerations. Given the high stakes involved in pharmaceutical patents, an appeal would not be surprising.
If the petitioner does appeal, the Federal Circuit will review the Board’s factual findings for substantial evidence and its legal conclusions de novo. The Board’s findings on reasonable expectation of success are factual in nature and are therefore entitled to deference on appeal. This means that the petitioner would face an uphill battle in overturning the Board’s decision, unless there is a clear legal error or the Board misapplied the governing standard.
The Federal Circuit could also address any procedural issues that arose during the proceeding, such as the Board’s claim construction or its treatment of expert testimony. An appeal would provide an opportunity for the court to clarify the standard for reasonable expectation of success in the pharmaceutical context, which would have significant implications for future IPR proceedings.
The Broader Impact on PTAB Practice
The decision in IPR2025-00070 is part of a broader trend in PTAB jurisprudence that emphasizes the importance of a rigorous obviousness analysis, particularly in the pharmaceutical and chemical arts. In recent years, the Board has issued several decisions that reject conclusory obviousness theories and require petitioners to provide detailed, fact-specific evidence of a reasonable expectation of success. This trend reflects the Board’s recognition that the obviousness inquiry is a nuanced, context-dependent analysis that cannot be reduced to simple formulas.
At the same time, the Board continues to apply the KSR framework in a manner that is consistent with the statute and with Federal Circuit precedent. The Board is not hostile to petitioners’ arguments, but it demands that those arguments be supported by evidence and by reasoned analysis. Petitioners who invest the time and resources to develop strong expert testimony and a well-reasoned obviousness theory are still likely to succeed, as they have in many other cases. The key is to recognize that the Board’s standard is a demanding one, and that shortcuts will not be rewarded.
For patent owners, the decision reinforces the value of a proactive defense strategy that emphasizes the unpredictability of the art and the unexpected nature of the claimed results. Patent owners who can clearly articulate why their invention would not have been obvious, and who can support that argument with credible expert testimony and objective evidence, are well-positioned to prevail at the PTAB.
The decision also highlights the importance of selecting the right expert witnesses. In this case, the patent owner’s expert appears to have been more persuasive than the petitioner’s expert, in large part because he or she provided a detailed, fact-specific analysis that addressed the particular challenges of the technology at issue. Both sides should take note of this lesson and should choose experts who are not only knowledgeable about the art but also capable of communicating complex technical concepts in a clear and compelling manner.
Navigating the Post-IPR Landscape
As the dust settles on IPR2025-00070, practitioners would do well to review the decision carefully and to incorporate its lessons into their future IPR strategies. The case offers a masterclass in how to present and challenge evidence of obviousness, and it demonstrates the critical role that expert testimony plays in PTAB proceedings. Whether one is representing a petitioner or a patent owner, the key to success lies in developing a comprehensive, well-supported argument that addresses the specific facts of the case and the governing legal standards.
The PTAB’s decision also serves as a reminder that the inter partes review process is designed to be a rigorous, merits-based adjudication of patent validity. The Board is not a rubber stamp for petitioners, nor is it a safe haven for weak patents. Rather, it is a forum where skilled advocates can present their best arguments, backed by evidence, and where the Board will carefully weigh those arguments before reaching a decision. The outcome of any particular case will depend on the strength of the evidence and the quality of the advocacy, not on any preconceived notions about the validity of the patent.
Looking ahead, the Federal Circuit may have an opportunity to weigh in on the issues raised by this case, providing further guidance on the standard for reasonable expectation of success and the treatment of secondary considerations. Until then, practitioners should continue to monitor PTAB decisions closely and to adapt their strategies in light of the Board’s evolving jurisprudence. The patent system is dynamic, and those who stay informed and flexible will be best positioned to succeed.
The decision in IPR2025-00070 is a significant development in the ongoing evolution of PTAB practice, and it will be studied and cited for years to come. Whether one views it as a victory for patent owners or as a cautionary tale for petitioners, there is no denying that it provides valuable insights into the Board’s thinking on some of the most important issues in patent law. For those who practice before the PTAB, the message is clear: the quality of the evidence and the rigor of the analysis will determine the outcome, and there is no substitute for thorough preparation and skilled advocacy.
