Pharmacoeconomics Expert’s Pricing Opinions Admitted
Posted on January 7, 2026 by Expert Witness Profiler
This is an antitrust action filed by Plaintiffs CareFirst of Maryland, Inc., Group Hospitalization and Medical Services Inc., and CareFirst Bluechoice Inc. (collectively, “CareFirst”) alleging that Defendants Johnson & Johnson and Janssen Biotech, Inc. (collectively, “J&J”) used monopoly power to unlawfully delay the introduction of biosimilar competitors for their drug ustekinumab (sold under the brand name “Stelara”).
J&J filed a motion to exclude the testimony of Plaintiffs’ expert Dr. Aaron S. Kesselheim. J&J sought to exclude both of Kesselheim’s opinions on the grounds that they are unreliable or unhelpful to the jury.
Pharmacoeconomics Expert Witness
Aaron Seth Kesselheim, M.D., J.D., M.P.H., is a Professor of Medicine at Harvard Medical School and a faculty member in the Division of Pharmacoepidemiology and Pharmacoeconomics in the Department of Medicine at Brigham and Women’s Hospital.
He is also a Visiting Professor of Law at Yale Law School, and has practiced internal medicine at Brigham and Women’s Hospital for over 20 years. Kesselheim holds an M.D. and J.D. from the University of Pennsylvania as well as an M.P.H. from Harvard. Kesselheim assisted in founding the Center for Bioethics at Harvard Medical School and has published over seven hundred scholarly articles.
Discussion by the Court
Kesselheim’s expert report provides background information and two opinions related to the pricing of pharmaceutical drugs. J&J sought to exclude both opinions on reliability and relevancy grounds as well as background information Kesselheim provided regarding certain “life cycle management” strategies employed in the pharmaceutical industry.
A. Kesselheim’s First Opinion
Kesselheim’s first opinion discussed the historical impacts of “biosimilar competition on the market for biologic drugs” since the passage of the Biologics Price Competition and Innovation Act (BPCIA). Specifically, Kesselheim opined that, in the fifteen years since BPCIA’s passage, “[b]iosimilar competition has an impact on pricing.” Kesselheim bases his first opinion “largely” on two studies he co-authored in 2021 and 2024, which examined two non-Stelara biologies and studied “how market structures altered by the BPCIA affected prices for biologies subject to biosimilar competition.”
J&J argued that Kesselheim’s first opinion regarding biosimilar competition generally should be excluded because it merely repeats findings from his two studies on other biologic drugs and makes no effort to reliably extrapolate those findings to Stelara.
The Court held that Kesselheim’s first opinion is grounded in fifteen years of research and peer-reviewed studies examining how biological drug markets respond to biosimilar competition, and Kesselheim clearly applies those industry patterns to a hypothetical but-for scenario. J&J argued that Kesselheim should have performed an analysis beyond repeating the findings of his studies or ran “new regression models” more specific to Stelara. However, Kesselheim’s role is to explain market behavior based on consistent historical experience and thus is not required to have performed new quantitative analysis. Accordingly, any alleged gaps in Kesselheim’s analysis go to weight and can be addressed on cross-examination.
Additionally, Kesselheim’s first opinion is helpful for the jury because it bears directly on what would have happened to Stelara prices absent the alleged anticompetitive conduct. Kesselheim’s first opinion situates Stelara within the broader context of a competitive biologies market, including comparator biologies such as Humira and J&J’s own Remicade. Thus, Kesselheim provided the jury with a framework for understanding how a competitive biologies market typically functions.
B. Kesselheim’s Second Opinion
Kesselheim’s second opinion discussed the likely “effects of biosimilar competition on the ustekinumab market if one or more biosimilars launched in or around September 25, 2023.” Kesselheim opined that if one or more biosimilars launched at that time, “there would have been a meaningful lowering of spending related to this drug by all different categories of payors in the U.S.”
J&J sought to exclude Kesselheim’s second opinion on the grounds that it is unreliable and unhelpful speculation. J&J argued that Kesselheim utilized no specific methodology or analysis to draw his conclusions. According to J&J, Kesselheim’s conclusions rest on analogies to other drugs such as Humira, ignore available evidence from actual biosimilar entry, and amount to impermissible ipse dixit.
Kesselheim’s conclusion that earlier biosimilar entry would have led to a meaningful reduction in Stelara’s net price is grounded in reliable, peer-reviewed research as well as consistent historical experience across biologic drug markets. Kesselheim’s conclusions are not merely speculation, as J&J contended. Rather, in his report, Kesselheim synthesized data from multiple biosimilar launches and explained why Stelara shares salient market characteristics with comparator drugs such as Humira. This is not only reliable expert testimony but also relevant context for the jury to understand how biosimilar entry affects biologic pricing.
Furthermore, the Court is not persuaded by J&J’s argument that Kesselheim’s opinion is faulty because he did not specifically examine the data following the entry of a biosimilar drug to ustekinumab in January 2025. Given the timing of the events in this litigation, such data simply was not available when Kesselheim prepared his report in March 2025.
C. Kesselheim’s Discussion of Life Cycle Management Strategies
Kesselheim opined on how “life cycle management” strategies in the pharmaceutical industry are an important factor affecting biosimilar availability. Kesselheim opined that “life cycle management” strategies is a “broad term” describing “drug manufacturers’ strategic efforts to extend their drugs’ market exclusivities, prolong commercial viability, or strengthen their competitive positions in a market.” J&J sought to exclude these observations on the grounds that they are “not grounded in the facts of this case” and are unhelpful to a jury. J&J argued that these “generalized musings” are untethered to either of CareFirst’s theories of liability in this case and thus would risk misleading the jury by introducing irrelevant industry practices that CareFirst does not allege are unlawful.
The Court held that Kesselheim appropriately draws on his specialized knowledge of industry practices and incentives to provide context for why J&J’s alleged conduct fits within established industry patterns. J&J’s objections that Kesselheim “was not even aware of the biologic manufacturing patents at issue” and “did not review any of the settlements that J&J entered with biosimilar manufacturers” went to the weight, not admissibility.
Held
The Court denied J&J’s motion to exclude the testimony of Dr. Aaron Kesselheim.
Key Takeaway
Kesselheim’s observations on pharmaceutical life cycle management are admissible as reliable and relevant testimony. Kesselheim’s opinions on this issue are grounded in specific academic research examining how branded drug manufacturers use secondary patents and related strategies to extend market exclusivity and delay biosimilar competition. This type of experiential expert testimony does not need to rest on quantitative analysis specific to Stelara to be reliable.
Please refer to the blog previously published about this case:
Marketing Expert’s Testimony on Patent-Related Barriers Admitted
Case Details:
| Case Caption: | Carefirst Of Maryland, Inc., Et Al. V. Johnson & Johnson |
| Docket Number: | 2:23cv629 |
| Court Name: | United States District Court, Virginia Eastern |
| Order Date: | December 23, 2025 |
