Following our earlier analysis of the ingredients and therapies at the heart of PTAB disputes, we now turn to the judges, litigants, and law firms steering these cases. Of the 192 PTAB proceedings involving biologics, a small group of administrative patent judges has overseen a significant share of activity, while a handful of companies—on both the innovator and biosimilar sides—appear repeatedly across the docket. Understanding who’s involved, how often, and in what capacity provides essential context for interpreting trends and anticipating what’s next in this high-stakes forum. Let’s take a look at the data to see who the most active players in the space are.
Q: Which PTAB judges handle the most biologics-related IPRs?
A: A small group of administrative patent judges handles a disproportionate share of biologics-related PTAB proceedings. Of the 189 cases where judge data was available, Robert A. Pollock presided over the most with 54 total cases, followed by Erica A. Franklin (42), Sheridan K. Snedden (37), and Susan L.C. Mitchell (37). These four judges alone were involved in nearly 45% of all tracked proceedings.
Institution and final decision responsibilities are also highly concentrated. Pollock made 25 institution decisions as the presiding judge and issued 6 final decisions in the same role. Franklin led 14 institution decisions and presided over 5 final decisions, while Mitchell directed 25 institution decisions and 1 final decision. Their recurring presence suggests that for many parties litigating biologics at the PTAB, outcomes may hinge on navigating a familiar cast of decision-makers.
Q: Who are the repeat players in this space when it comes to patent owners, petitioners, and their counsel?
A: Broadening the lens beyond judges, we see consistent names among the patent owners and petitioners.
Genentech stands out as the most frequent patent owner at 65 PTAB proceedings, with Morrison & Foerster and WilmerHale frequently associated with these filings. On the petitioner side, Celltrion (30 cases), Regeneron (30), Samsung Bioepis (22), and Mylan (21) appear repeatedly. Top petitioner counsel includes Morrison & Foerster, Irell & Manella, Sidley Austin, and Williams & Connolly, underscoring an ecosystem dominated by established specialists in life‑sciences PTAB practice.
These repeat players—both in-house and in counsel—signal where the center of gravity lies for biologics-related IPR activity, underscoring strategic alignment between familiar firms and deep-pocketed biopharma challengers.
Q: Which patent categories and claims surface most often?
A: Turning to what’s actually being challenged, the vast array of patents spans therapies, manufacturing, and delivery technologies.
| Category | PTAB Cases | District Cases | Patent Count |
| Antibody Engineering / IL Therapies | 205 | 311 | 18 |
| Anti‑TNF Therapies | 114 | 98 | 17 |
| Anti‑VEGF Therapies | 87 | 199 | 11 |
| Drug Delivery Devices | 90 | 62 | 5 |
| Protein Manufacturing / Engineering | 29 | 70 | 11 |
The PTAB docket leans heavily into antibody engineering and IL‑modulating biologics, with anti‑TNF and anti‑VEGF therapies also drawing substantial attention—many times at higher volume than district court filings. The backlog of patent challenges around delivery devices and manufacturing underscores how the PTAB is becoming a sandbox for not just molecule innovation, but for how biologics are made and used.
Q: Which biologics patents are targeted the most?
A: Within each category, specific patents emerged as high-frequency targets.
- US Patent 6,407,213 (methods for making humanized antibodies) was challenged 10 times
- US 7,976,838 (TNF-α inhibitor therapy for autoimmune disease) saw 7 challenges
- US 10,888,601 (VEGF antagonist for eye disorders) appeared 5 times
Delivery device patents also appeared frequently, including US 8,992,486 and US 9,526,844, both covering pen-type injectors. These repeated filings reflect how petitioners zero in on patents that can block biosimilar entry at a formulation, administration, or device level, not just at the molecular level.
Q: What are the most common outcomes in biologics disputes at the PTAB?
A: Of the 188 cases with resolved outcomes, 118 were instituted. Among those, 36 ended with all claims unpatentable, while only 12 resulted in all claims being upheld. Another 27 were settled post-institution, and 10 were dismissed after patent owners disclaimed their claims.
At the institution stage, 40 cases were denied, and another 21 were procedurally dismissed before institution. These numbers reflect both the strength of the petitions being filed and the willingness of patent owners to strategically abandon challenged claims before risking adverse rulings.
Q: What does this mean for biologics strategy at the PTAB?
A: The PTAB has become a central arena in the fight over biologic patent rights. A small group of administrative judges routinely oversees biologics-related cases, while a core set of companies—both innovators and biosimilar challengers—drives the majority of filings. These disputes touch every stage of the product lifecycle, from composition and delivery to formulation and manufacturing.
For patent owners, the PTAB is a critical venue for protecting exclusivity. Nearly 20 percent of instituted cases end with all challenged claims found unpatentable, while many others resolve through settlement or patent disclaimers. Success requires broad patent coverage and a strategy tailored to withstand both procedural and technical scrutiny.
For biosimilar sponsors, the PTAB offers a direct path to market. Inter partes reviews can eliminate blocking patents, shift leverage in settlement negotiations, and accelerate launch timelines. The data shows that both sides are investing heavily in this forum, and future biologic launches will almost certainly face PTAB review alongside traditional litigation.
Contact us to learn more about how WIT’s experts in this sector can help inform your biologics litigation strategy, or if you have any questions or comments about the data presented in this piece.