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WHEN CHOICE ARRIVES: Competition & Consequences

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BIOSIMILAR APPROVALS

Articles

Between congressional hearings and executive orders, experts had plenty to draw on when dissecting the barriers to biosimilar access at Festival of Biologics USA to close out April 2025.


Biosimilars Policy Roundup: April 2025

Thriving in the evolving biosimilar market demands bold collaboration, early global partnerships, and a fresh approach to development strategies to overcome uncertainty and drive future success.

Biosimilar Market Development Requires Strategic Flexibility and Global Partnerships

Cameron Santoro is an associate editor for The Center for Biosimilars

Christopher T. Robertson, JD, PhD, reviewed the history and ethical landscape of providing access to drugs before FDA approval, highlighting the crucial role of clinical trials and ethical safeguards at the 2025 Festival of Biologics USA. 

FDA's Expanded Access: From Laetrile to Right to Try, Ethical Debates Over Early Drug Access

A plain language summary for patients explains there were no differences in safety outcomes between adalimumab-adbm and the originator in a pooled analysis of the VOLTAIRE clinical trials.

Clinical Evidence Shows No Safety Gaps Between Biosimilar, Reference Adalimumab

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Ryan Haumschild, PharmD, MS, MBA, director of pharmacy services at Emory Healthcare and Winship Cancer Institute, discusses the growth and continued challenges facing biosimilars used to treat breast cancer.

Dr Ryan Haumschild Draws Link Between Biosimilars, Health Equity in Breast Cancer

Fran Gregory, PharmD, vice president of emerging therapies at Cardinal Health, discusses how specialty pharmacists manage inventory, storage, and handling of biosimilars. 

Dr Fran Gregory Discusses the Unique Requirements for Handling Biosimilars

Fran Gregory, PharmD, vice president of emerging therapies at Cardinal Health, discusses the importance of collaboration between all stakeholders to boost confidence in providing patients with a biosimilar drug. 



Dr Fran Gregory: Providing Patients With High-Quality Biosimilars Is a Collaborative Effort 

Fran Gregory, PharmD, vice president of emerging therapies at Cardinal Health, discusses what the future biosimilars marketplace may look like compared with generics and reference products at Asembia 2023.

Dr Fran Gregory Discusses the Future Landscape of the Biosimilars Marketplace

Fran Gregory, PharmD, vice president of emerging therapies at Cardinal Health, discusses how the use of biosimilars in other countries strengthens the acceptance and approval of these products in the United States. 

Dr Fran Gregory: What Can We Learn From Biosimilar Use in Other Countries? 

Kathy Oubre, MS, CEO of Pontchartrain Cancer Center, discusses the use of biosimilars and how pharmacy benefit managers (PBMs) as well as payers have challenged the biosimilar market.

Kathy Oubre Discusses PBM, Payer Challenges for Biosimilar Adoption

 of safety results from the VOLTAIRE clinical trials described the results of a recent 

 of safety data in patients with rheumatoid arthritis (RA), Crohn disease (CD), and chronic plaque psoriasis, which found no differences in safety outcomes between adalimumab-adbm (Cyltezo) and the reference product (Humira).

The purpose of the summary, according to authors from Boehringer Ingelheim, is to help patients understand the findings and help health care professionals make treatment decisions. The summary included concise explanations of the results and their meaning, the conditions included, study designs, and definitions of biologics, biosimilars, interchangeability, and adverse events. It also provided links to external resources, including the original pooled safety publication and plain language summaries of the individual VOLTAIRE trials.

Biosimilars referencing adalimumab, a monoclonal antibody targeting tumor necrosis factor-α, first entered the US market in 2023, and Cyltezo was the first adalimumab biosimilar to gain the 

The 5 VOLTAIRE clinical trials compared effectiveness and safety of continually receiving the adalimumab originator to switching one or more times between the originator and Cyltezo in patients with RA (VOLTAIRE-RA, VOLTAIRE-RAext), Crohn disease (VOLTAIRE-CD), and chronic plaque psoriasis (VOLTAIRE-X, VOLTAIRE-PsO). Pooled safety results of all five trials were 

 in November 2024. The authors of the summary explained that the data was pooled “to provide a better understanding of the overall safety” of adalimumab-adbm.

Across all VOLTAIRE clinical trials, there were 1368 participants, 645 in VOLTAIRE-RA, 147 in VOLTAIRE-CD, 317 in VOLTAIRE-PsO, and 259 in VOLTAIRE-X. The pooled analysis evaluated total and serious adverse events (AEs), discontinuation of treatment due to AEs, deaths, and AEs of special interest, which included serious infections, cancers, and major adverse cardiac-related events. The researchers also investigated whether there were any differences in safety based on sex or age group.

In the pooled analysis, rates of AEs, serious AEs, and discontinuations were similar in patients with RA and chronic plaque psoriasis, regardless of whether they were treated with Cyltezo or the originator. Patients with CD had “slightly higher” rates of AEs, serious AEs, and discontinuations than the other two conditions in both biosimilar and reference product groups. There were no significant differences in deaths between conditions or between biosimilar and reference product groups. There were also no significant differences in safety outcomes between treatments in patients who were 65 or older, or those who were under 65.

Cancers and major adverse cardiac-related events were only reported in patients with RA and were not significantly different between treatment groups. Serious infections were reported in patients with RA and chronic plaque psoriasis, and there were no significant differences between groups. There were no AEs of special interest observed in patients with CD.

Limitations of the VOLTAIRE trials discussed by the authors included that the participants were predominantly white, thus the results may not be representative of all patients, and that the findings may not be applicable to patients with autoimmune conditions other than those included in the trials. When explaining the meaning of the results, the authors said since there were no differences in safety outcomes between biosimilar and reference product groups across the VOLTAIRE trials, patients with RA, CD, and chronic plaque psoriasis who take Cyltezo can expect similar side effects to those of the reference product.

Cohen S, Bender S, Shaberman A, Vinisko R, McCabe D. A plain language summary of the pooled safety results of adalimumab-adbm from the VOLTAIRE clinical trials in people with rheumatoid arthritis, Crohn's disease, and chronic plaque psoriasis. 

. 2025;25(4):323-329. doi:10.1080/14712598.2025.2476033

Clinical

 Wyost/Jubbonti (denosumab-bddz; GP2411), the first biosimilar to reference Xgeva/Prolia (denosumab) in the US.

 The drugs will be used to treat osteoporosis and hypercalcemia as well as prevent skeletal-related events associated with bone metastases from solid tumors.

The FDA accepted Sandoz’ biologics license application for Wyost/Jubbonti in 

. This approval is also notable in that there are currently no denosumab biosimilars approved in the European Union. The news comes after the same products were approved in Canada 

Similar to the reference products, the biosimilars have the same drug compound (denosumab-bddz) but were approved with 2 brand names that will be used for different indications:

Wyost vs Jubbonti

Jubbonti is interchangeable with Prolia, and Wyost is interchangeable with Xgeva.

Wyost and Jubbonti were also approved with interchangeability designations, allowing them to be substituted for their respective reference product at the pharmacy level without needing to wait for a provider to give permission. It is the ninth biosimilar to receive this label.

"Sandoz has achieved the first FDA approval for biosimilars to denosumab, a medicine that can address primary and secondary bone loss, such as osteoporosis, as well as cancer-related skeletal events, which are disease states that can profoundly reduce quality of life for patients. I am proud that Sandoz continues to pioneer access to these life-changing medicines for the patients who need them most," commented Keren Haruvi, President Sandoz North America, in a statement.

According to Sandoz, over 10 million adults over age 50 in the US have osteoporosis, of whom most (> 80%) are women. It is predicted that 1 in 2 women and 1 in 4 men will experience an osteoporosis-related fracture in their lifetime, which could result in decreased quality of life, disability, and death.

The approval of Wyost/Jubbonti was based on a comprehensive data package containing 

 results that were presented at the American Society of Clinical Oncology annual meeting 2023 and the American Society for Bone and Mineral Research annual meeting 2023, respectively.

Denosumab products are human monoclonal antibodies that bind to the RANKL protein, preventing activation of the RANK receptor on the surface of osteoclasts and preventing osteoclastic bone resorption.

The phase 1 study evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) of denosumab-bddz compared with the reference product (EU authorized and US licensed) in 499 healthy participants (mean [SD] age, 64.6 [6.1] years; White, 90.9%).

 The double-blind, 3-arm, parallel-group analysis was conducted at 2 German centers. Participants were randomized 1:1:1 to receive the biosimilar or the EU- or US-sourced reference agents.

Participants were between 28 and 65 years old and weighed between 50 and 90 kg. PK end points were measured by area under the serum concentration-time curve measured from the time of dosing and extrapolated to infinity (AUC

), or to the last measurable concentration (AUC

), and maximum observed serum concentration (C

). PD end points were measured by the area under the effect-time curve of the percentage change from baseline (AUEC %CfB) in serum carboxy-terminal crosslinked telopeptide of type I collagen (CTX) and CTX and procollagen I N-terminal propeptide (PINP) serum concentration per visit.

Results showed that the treatment arms (biosimilar vs EU-sourced reference product; biosimilar vs US-sourced reference product) showed statistically similar values for AUC

 (1.02; 1.00), and AUEC %CfB in CTX (1.01; 1.01). Changes from baseline to Week 39 in serum concentrations of CTX and PINP were also similar between groups.

The international, double-blind, parallel group phase 3 trial (ROSALIA study; 

) looked at the clinical efficacy, safety, and tolerability of denosumab-bddz compared with the reference product through 52 and 78 weeks.

 Postmenopausal women with osteoporosis aged 55 to 80 years who had bone mineral density (BMD) T-scores between 2.5 and 4.0 at the lumbar spine were eligible for participation.

In total, 527 patients were randomized 1:1 to receive a 60-mg dose of Wyost or the EU-authorized reference product on day 1 and at week 26. Prior to the third dose at week 52, patients who were receiving the reference product were rerandomized to remain on the reference product or switch to the biosimilar.

Overall, 502 patients received a third dose (biosimilar to biosimilar, n = 253; reference to reference, n = 125; reference to biosimilar, n = 124). The mean age of the participants was 64.6 (6.15) years, and most (91.3%) were White.

No clinically meaningful differences between the groups regarding new vertebral fractures were observed. Switching from the reference product to the biosimilar did not affect the incidence or severity of treatment-emergent adverse events (TEAEs). Immunogenicity profiles were similar between groups.

Most TEAEs were grade 1 or 2, most of which were not considered treatment related, and no treatment discontinuations occurred as a result. The most common TEAEs reported were hypocalcemia, COVID-19 infection, and nasopharyngitis.

The majority of antidrug antibodies had very low, nonreportable titers (< 20 mg/mL), were nonneutralizing, and transient.

In its company statement, Sandoz declined to comment on a launch timeline due to ongoing litigation issues with the reference product manufacturer (Amgen).

I think they are excited for these biosimilars to come to market and are ready to prescribe them to patients.

I think they will wait for more real-world data with these products before prescribing them.

I think they will need more education on the safety and efficacy on these products before feeling comfortable prescribing them.

Sandoz receives FDA approval for first and only denosumab biosimilars. News release. Sandoz; March 5, 2024. Accessed March 5, 2024. 

https://www.marketscreener.com/quote/stock/SANDOZ-GROUP-AG-160016887/news/Sandoz-receives-FDA-approval-for-first-and-only-denosumab-biosimilars-46097288/

2. Vogg B, Poetzl J, El Galta R, Fuhr R, Schwebig A, Sekhar S. Pharmacokinetics and pharmacodynamics of proposed denosumab biosimilar and reference denosumab in healthy male subjects. Presented at: 2023 ASCO Annual Meeting; June 2-6, 2023; Chicago, IL. Poster SAT-436.

3. Jeka S, Dokoupilová E, Kivitz A, et al. Pharmacokinetics and pharmacodynamics of proposed denosumab biosimilar and reference denosumab in postmenopausal osteoporosis: the ROSALIA study. Presented at: ASBMR 2023 Annual Meeting; October 13-16, 2023; Vancouver, Canada. Poster P303.

Sandoz’ Wyost/Jubbonti (denosumab-bddz) references Prolia and Xgeva and can be used to treat osteoporosis and hypercalcemia as well as prevent skeletal-related events associated with bone metastases from solid tumors.

Business & Practice

Approvals Launches

FDA Approves First Denosumab Biosimilars

The House of Representatives has approved the bipartisan 21st Century Cures legislation, which includes funding for innovative research and provisions to speed up the drug approval process.

By a vote of 392-26, the House approved the 21st Century Cures Act. The House had passed an earlier version of the bill in July 2015 but continued to revise and update it, releasing the most recent draft of the bill last week. These updates included provisions for mental health, substance abuse, and child and family services.

Members of both political parties have been vocal in their support of the legislation, often citing its passage as a top priority during the lame-duck Congressional session. Prior to the election, Senate Majority Leader Mitch McConnell, R-Kentucky, had said it “could end up being the most significant piece of legislation we pass in the whole Congress." 

House of Representatives Approves Bipartisan 21st Century Cures Legislation

People with Crohn disease (CD) or ulcerative colitis (UC) who switched to the infliximab biosimilar CT-P13 had higher treatment persistence (84% and 91%) than those new to infliximab (66% and 53%), with no new safety concerns.

 (ReFLECT) investigated treatment persistence with the infliximab biosimilar CT-P13 (Inflectra) in patients with inflammatory bowel disease (IBD) who were either infliximab-naive or were switching from the reference product (Remicade) or biosimilar SB2. Overall, treatment persistence was 72% in patients with Crohn disease and 64% in ulcerative colitis at 2 years, and the rate of persistence was higher in switched patients compared to infliximab-naive patients. No new safety signals were observed.

CT-P13 was the first biosimilar monoclonal antibody approved by the European Medicines Agency in 2013, and the first biosimilar to Remicade, an inhibitor of tumor necrosis factor (TNF)- α. Its approval in Europe and extrapolation to all the indications of the reference product were based on randomized controlled trials in patients with rheumatoid arthritis and ankylosing spondylitis. More recently, large randomized controlled trials have established efficacy and safety of switching to CT-P13 from the originator in IBD. Although the safety and efficacy of CT-P13 has been demonstrated by these randomized controlled trials, the authors said, few real-world studies have reported CT-P13 persistence in IBD with follow-up duration longer than 1 year.

The ReFLECT study was a prospective, observational cohort study conducted across multiple centers in France to evaluate real-world effectiveness and safety of intravenous CT-P13. The adult population with IBD included 530 patients with CD (71%), including 327 with no prior infliximab exposure, and 221 patients with UC (29%), including 152 who were infliximab-naive. The primary outcome of the study was persistence on CT-P13 after a 2-year follow-up period. Secondary outcomes included biochemical parameters, disease activity, and safety.

In patients with CD, the estimated persistence rate was 81.5% (95% CI, 76.7-86.6) at 1 year and 71.7% (95% CI, 66.7-77.0) at 2 years. Treatment persistence was higher in switched patients (83.7%; 95 % CI, 78.0-89.9) compared to infliximab-naive patients (65.7%; 95% CI, 58.6-73.7) with CD. In UC, the estimated CT-P13 persistence rate was 73.4 % (95% CI, 64.8-83.0) after 1 year and 63.7 % (95% CI, 55.3-73.3) after 2 years. Treatment persistence was also higher in switched patients with UC (91.2%; 95% CI, 81.7-100.0) compared to infliximab-naive patients with UC (53.4%; 95% CI, 43.0-66.2). The most common reasons for discontinuing CT-P13 treatment were treatment failure and intolerance in CD, and treatment failure, intolerance, and remission in UC.

Disease activity, indicated by Harvey Bradshaw Index, in CD, decreased over the follow-up period for infliximab-naive patients and remained stable for switched patients. In UC, Mayo score decreased over time in infliximab-naive patients, and decreased following the first CT-P13 administration, then remained stable in switched patients. In both CD and UC, C-reactive protein decreased over the follow-up period in infliximab-naive patients and remained stable in switched patients.

About half of patients (49.5%) reported at least 1 adverse event (AE). Serious AEs occurred in 13% of patients, and AEs with a possible relationship to CT-P13 treatment occurred in 18% of patients. Adverse events were “consistent with those from other prospective observational studies of CT-P13 in patients with IBD,” the authors wrote.

The authors said that their findings, consistent with previous observational studies, demonstrated maintained effectiveness of CT-P13 in more than 80% of switched patients over 2 years and “improved disease activity with sustained clinical benefit” in infliximab-naive patients.

Laharie D, Bouhnik Y, Vuitton L, et al. Real-world effectiveness and safety of CT-P13, an infliximab biosimilar, for inflammatory bowel diseases: A prospective national observational cohort study (ReFLECT study). Clin Res Hepatol Gastroenterol. 2024;48(10):102483. doi:10.1016/j.clinre.2024.102483

People with inflammatory bowel disease (IBD) who switched to the infliximab biosimilar CT-P13 had higher treatment persistence (84% and 91%) than those new to infliximab (66% and 53%), with no new safety concerns.

Patients With IBD Maintain Therapy 2 Years Post Switching to Infliximab Biosimilar

Paul Hahn on AMD biosimilars

Retina specialists have been cautious about adopting ranibizumab biosimilars, not due to efficacy concerns but because of cost-driven mandates like step therapy, raising fears that biosimilars will be forced upon them rather than remaining a choice. However, with growing experience, the field is adjusting.

According to Paul Hahn, MD, PhD, FASRS, a retina specialist and vitreoretinal surgeon at NJ Retina and a board member of the American Society of Retina Specialists, the upcoming aflibercept biosimilars may face a smoother integration, especially as insurance and cost considerations push patients away from branded Eylea.

Although real-world data confirm biosimilars' safety and effectiveness, the main concern is whether specialists will retain autonomy in treating age-related macular degeneration (AMD) and other retinal diseases. As more anti–vascular endothelial growth factor (VEGF) biosimilars enter the market, ongoing clinical experience will be key to building physician confidence.

This transcript has been edited for clarity; captions were auto-generated.

Based on your experience, how do retinal specialists perceive the ranibizumab biosimilars currently available on the market, and how appropriate do they consider them for treating patients with wet AMD?

People, and doctors in particular, are often very resistant or wary of change. When there's a new option on the market, if it doesn't fit their profile of what they're looking for, such as a new mechanism of action or a specific advantage, doctors may be a little bit wary of what that means, such as the case with biosimilars.

I think when biosimilars first became part of a consideration in the retinal armamentarium, there was a lot of hesitation around these. I think that exists because biosimilars are now here, not because of efficacy; they don't work better than our reference products. But it's a cost consideration, and many of us as doctors are used to not thinking about what costs less for the patient, but rather we're used to thinking about what works best for our patient. It's a different mindset.

Along the same lines, I think there's concern from a physician standpoint about how these biosimilars will be forced upon us as physicians. Right now, we like to treat our patients according to what medicine we think is best for them, but more and more, there are insurance mandates that require us to use what is often the cheaper medicine first. What we call step therapy, or what some people have referred to as a fail-first approach, allowing us to only use other therapies if they fail the less expensive drugs first.

With that history of step therapy mandates, I think there's a lot of hesitation to incorporating biosimilars because of this concern that it's going to be something that's forced upon us.

What are your thoughts on the upcoming entry of multiple aflibercept biosimilars into the US market, and how do you think they will impact access to care for patients with AMD ?

The entry of ranibizumab biosimilars has accustomed many retina specialists to the fact that biosimilars are now here, and aflibercept biosimilars may have an easier time at being incorporated. Certainly, many patients are on the aflibercept reference product, Eylea, and as patients need to be transitioned away from Eylea, either because of cost considerations, insurance mandates, or for whatever other reason, I think those aflibercept biosimilars are going to be one of the options. Again, I think for biosimilars in general, there's always going to be a cost consideration and a concern for retina specialists that cost is going to trump efficacy in treating patient disease, but I think what we'll all agree is that it's great that we have options for our patients. If biosimilars provide additional options for our patients, I think that's fantastic. 

Right now, in the beginning of 2025, we are seeing a lot of different events come into play, which is limiting access from retina specialists to therapies that they need. Along those same lines, having different options available, including biosimilars, is very important. As with ranibizumab biosimilars, I think the importance is how these biosimilars, including the aflibercept biosimilars, are pushed onto the retina specialists, whether it's something that the retina specialists maintain choice in administering or whether it's something that they are mandated to start first before trying a drug that the retina specialist may think is better for that patient in front of them.

What kind of evidence do you think is needed to make retinal specialists feel comfortable enough to regularly prescribe anti-VEGF biosimilars to their patients with AMD and other retinal diseases?

The burden of approval for biosimilars is different than the reference product. The clinical trial pathway is slightly different. Utilization of these biosimilars and real-world experience identifying that these biosimilars are effective and safe is going to be important, and we've seen that.

With the biosimilars on the market, we have seen that they are effective and that they are safe. In a recent database study that I've recently performed, we saw that in 2023, biosimilars in this database accounted for about 3% of utilization. And in 2024, it increased to about 10% of utilization.

Whether retina specialists are becoming more comfortable using them or whether they're being forced to use them more often is unclear from that study. But certainly, there's increased utilization of biosimilars. With that, as we hopefully learn that they are indeed safe and effective, I think retina specialists will feel more comfortable.

The introduction of biosimilars in the treatment of age-related macular degeneration (AMD) is raising concerns among physicians about cost-driven mandates and the autonomy to choose the best therapies for their patients, according to Paul Hahn, MD, PhD, FASRS, a retina specialist at NJ Retina.

Retina Specialists’ Evolving View on Biosimilars in AMD Treatment

Innovative statistical methods, such as simultaneous CIs and multiplicity-adjusted TOST (MATOST) were explored by researchers to address challenges posed by differing FDA and European Medicines Agency (EMA) regulatory requirements for biosimilar approvals, according to a review published in 

These differences have prompted research into innovative statistical methods for more efficient and accurate biosimilar assessments. When a biosimilar has both US and EU reference products, sponsors must conduct 3 bridging studies comparing the biosimilar product with the US-licensed reference product, the biosimilar product to the EU-approved reference product, and the US-licensed reference product to the EU-approved one.

Despite Europe's greater biosimilar adoption, regulatory disparities and complex US approval processes hinder development, underscoring the need for global harmonization.

The FDA and EMA also differ on foreign-approved comparators; the EMA permits them (with caveats), while the FDA requires 3-way comparisons.

Researchers criticize the conventional 3-way comparison for neglecting variability, underutilizing data, and creating multiple testing issues. This study investigated 2 alternatives, simultaneous confidence intervals and MATOST.

Regulatory Framework for Biosimilar Approval

Both agencies have slightly different definitions for biosimilars. The FDA defines biosimilars as biological products highly similar to the reference product, with no clinically meaningful differences between safety, purity, and potency compared with the reference product. However, the EMA defines biosimilars as biological medicinal products containing the same active substance as the reference product and similar in quality characteristics, biological activity, safety, and efficacy.

The FDA's stepwise approach assesses analytical similarity, investigating the structural and functional characteristics of the biosimilar product based on critical quality attributes at various stages of the manufacturing process. The stepwise approach includes a pharmacokinetics (PK) and pharmacodynamics (PD) similarity assessment, demonstrating PK and PD through human clinical pharmacology studies after passing animal toxicity studies, and a clinical similarity assessment, gathering information on immunogenicity, clinical efficacy, and safety.

Additionally, the main purpose of the 3-way comparison is to ensure the drug substance or product meets product specifications, to demonstrate biosimilarity between the test product and the US-licensed product, and to establish a bridge justifying the use of clinical data generated using the EU-approved reference product as the comparator. Strict requirements on biosimilar products are necessary to ensure the efficacy and safety of biosimilars on the market.

The drug sponsor should provide 3-way bridging evidence when using a non–US-licensed product in a regulatory submission for a biosimilar product. This evidence justifies the use of comparative data from the non–US-licensed product in assessing biosimilarity and bridging to the US-licensed reference product.

Disadvantages, such as underutilizing data collected from the entire study, can impair conventional pairwise comparisons, potentially biasing and misleading results. Since pairwise comparisons do not use the same reference product in each comparison, and each comparison may use a different equivalence acceptance criterion margin, the precision of each equivalence test varies. Multiple comparisons will inflate the type 1 error rate unless some significance-level adjustment approaches are considered. Overall, these pairwise comparisons cannot distinguish the relationship among the biosimilar product, the US-licensed reference, and the EU-approved reference.

Without loss of generality, the US-licensed reference product and the EU-approved reference product are considered as the 2 reference products, with the US-licensed reference as the primary reference.

Comparative Analysis of Statistical Approaches

The simultaneous CI method in a parallel study design used fiducial probabilities to perform pairwise equivalence tests. The simulation study used 4 methods for pairwise comparison and included 3 simultaneous CI methods with different assumptions and 1 conventional approach. The results found all approaches can maintain desired power when the sample size per arm is larger than 20. The simultaneous CI method under equal variability has the best performance among all the methods and can achieve similar statistical power to the conventional approach. The study found that the simultaneous CI method works well in parallel study design.

Among simulation results, the Holm and Bonferroni method were very conservative, and TOST was more likely to fail to reject the null hypothesis to control type 1 error inflation. In a crossover design with multiple formulations, especially within the Williams design, the MATOST method is not favorable since it may lead to an unrealistically large sample size, though it can control the type 1 error rate.

Addressing Challenges in Equivalence Testing

The FDA requires sponsors submitting biosimilar products for regulatory approval to conduct a 3-way pairwise comparison when both US-licensed and EU-approved reference products exist. Determining equivalence margins in the equivalence tests is crucial. Using sample estimation in the hypothesis setting is unnecessary because it does not consider the variability of the estimation.

Generalizing the CI method will allow researchers to determine equivalence margins by sampling standard deviations and considering the variability of the estimation. Researchers need to propose another method for controlling type 1 error inflation specifically for crossover designs to reduce the large sample size required for conducting a biosimilar study.

“For future research, it is possible to consider further utilization of fiducial inference under crossover designs and generalize the simultaneous CI method...,” the authors concluded. “Generalizing the simultaneous CI method can help researchers in determining equivalence margins by sampling standard deviations and taking the variability of estimation into consideration.”

Pong A, Chow S, Chow SC. Comparison of innovative and conventional methods in biosimilar bridging studies with multiple references. 

. 2024;18:377-387. doi:10.2147/btt.s470182

Jeremias S. Improving biosimilar access through global regulatory convergence. The Center for Biosimilars

. January 15, 2025. Accessed February 24, 2025. 

https://www.centerforbiosimilars.com/view/improving-biosimilar-access-through-global-regulatory-convergence

The FDA and European Medicines Agency (EMA) mandate high similarity between biosimilars and reference products, but their regulatory processes differ, especially with multiple reference products.

Pearl Steinzor

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