Recent amendments to the Patent Trial and Appeal Board’s (PTAB) inter partes review (IPR) and post-grant review (PGR) procedures have introduced challenges for petitioners, particularly in the biologics sector. These changes have led to a notable shift towards ex parte reexaminations as an alternative strategy for contesting patent validity.
Historically, IPRs have been the preferred method for biosimilar applicants under the Biologics Price Competition and Innovation Act (BPCIA) to challenge patents efficiently. However, increased scrutiny and higher denial rates have made this route less predictable, potentially prolonging patent disputes and delaying biosimilar market entry. Recent analyses indicate that while IPR institution rates have shown a slight uptick, they remain below the historical average of approximately 67%.
In contrast, ex parte reexaminations have emerged as a viable alternative. Unlike the adversarial nature of IPRs, ex parte reexaminations involve a review between the patent owner and a USPTO examiner, initiated by a third-party request. The USPTO grants approximately 95% of these requests, compared to a 63% institution rate for IPRs. However, the claim cancellation rate in ex parte reexaminations is lower, with only 14% of cases resulting in all claims being canceled. Notably, about 62% of patents undergoing reexamination experience modified or canceled claims.
Data from the USPTO indicates a significant increase in ex parte reexamination filings. In the first quarter of fiscal year 2026, over 200 requests were filed, compared to 495 in the entire fiscal year 2025. This surge aligns with the declining institution rates of IPRs, suggesting that stakeholders are increasingly considering ex parte reexaminations as a strategic option.
For legal professionals in the biologics industry, these trends underscore the importance of evaluating all available avenues for patent challenges. While ex parte reexaminations offer a higher likelihood of initiation and a less adversarial process, they may result in lower claim cancellation rates. Therefore, a comprehensive assessment of each case’s specifics is essential to determine the most effective strategy for challenging patent validity.