blurred female scientist using a dropper and test tube

Demystifying Biosimilar Development Regulations: Key Considerations for Sponsors

Biosimilars – biological medicines highly similar to another already approved biologic – have emerged in recent years as an area of rapid development activity, especially for Inflammatory bowel diseases (IBD) such as Crohn’s disease (CD) and ulcerative colitis (UC). While these drugs have historically faced the common misconception that they are less safe and less effective compared to the original biologic product, biosimilars undergo very rigorous and extensive testing before receiving regulatory approval, and public perceptions are starting to shift. As these drugs continue to grow in popularity with physicians and patients alike, it is crucial for sponsors to understand what these changes mean for current and future IBD development activity.

In our new white paper, Similar But Different: Regulatory and Operational Considerations for Biosimilar Clinical Development in IBD, we discuss how biosimilars have transformed the treatment landscape for IBD in the past decade, their current therapeutic uses in CD and UC, and global regulatory considerations for running biosimilar clinical trials in IBD. This post reviews some of the regulatory factors that are evaluated for biosimilar medications during the course of a trial. The list of full regulatory requirements varies by country; however, these factors are common parts of the evaluation process by many regulatory bodies.


Even licensed biologics undergo changes in relevant molecular attributes over time.1 In a study of biologics licensed for use in rheumatology, all reported changes to the production process over time, including change of cell culture supplier and modification of the protein purification procedure.2 The original medicines available today are therefore not identical but comparable to those available in previous years. 

Biosimilars must demonstrate clinical comparability with the reference drug (the original biologic) in order to receive regulatory approval. The following table outlines the properties and methods used to demonstrate comparability in a biosimilar for infliximab (IFX).3,4

Properties How was similarity determined? 
Protein structure and production quality  Detailed laboratory analysis of the structural characteristics of different batches of the drug 
Pharmacokinetic, pharmacodynamic and toxicological tests on animals  "In vitro" and "in vivo" tests on different species 
Pharmacokinetic, pharmacodynamic and toxicological tests on humans  Initial clinical trials 
Clinical efficacy and safety  Major clinical trials
Safety in everyday practice  Risk management plan , Post-marketing trials (Phase 4),  Routine reporting of side effects,  Pharmacovigilance 


The initial comparability tests are conducted in the indication and population that are considered the most sensitive to detect clinically significant differences in safety, immunogenicity, and efficacy between the original and biosimilar drug. If the biosimilar product is highly similar to the reference medicine and has comparable safety and efficacy in this therapeutic indication, safety and efficacy data may then be extrapolated to indications already approved for the reference medicine.5

Extrapolation must be supported by all the scientific evidence generated in other comparability studies. In these cases, clinical trials are often not required to be repeated for all indications; instead, changes are approved based on data from quality and in vitro comparability studies. The possibility of extrapolation is dependent on the regulatory landscape of the particular country or countries in which the clinical trial is being conducted. In the EU, which pioneered biosimilar regulation by establishing a solid framework for approval, decisions based on extrapolation are dependent on a number of criteria:5,6

  • Mechanism of action: The mechanism of action of the active substance should be mediated by the same receptor in both the initial and extrapolated indication. If the mode of action is complex, involving multiple receptors or building sites, additional studies may be needed to prove that the biosimilar and reference medication will behave similarly.
  • Study population: Comprehensive comparability studies must demonstrate that the biosimilar is highly similar to the reference medicine in a “key population” in which potential differences can be detected.
  • Clinical setting: Data from one indication may not be directly applicable to an indication within another therapeutic area where the mode of action, posology, or pharmacokinetics may be different. Additional studies may be needed in this case.
  • Safety data: A comparable safety profile for the proposed indication must be established in one therapeutic indication before extrapolation. Comparability must be shown at the structural, functional, pharmacokinetic, and pharmacodynamic levels, and efficacy must be comparable.
  • Immunogenicity data: Extrapolation of immunogenicity data always requires justification as immunogenicity is determined by more than product-related characteristics. Factors relating to patient (age, immune status), disease (comorbidities, concomitant treatments) and treatment-related factors (route of administration, length of exposure) must be considered.

Meet the challenges of your IBD trial with confidence

Understanding each country’s regulatory intricacies of biosimilar development is crucial for the success of your trial. With a network of more than 3,900 global IBD sites, and a regulatory team with local regulation expertise, PSI specializes in delivering studies on time and with quality data.

Discover the full white paper here, or contact us to learn more about running your pivotal Phase 2 and 3 IBD trials with PSI.

1 Schiestl M, Stangler T, Torella C, Cepeljnik T, Toll H, Grau R. Acceptable changes in quality attributes of glycosylated biopharmaceuticals. Nat Biotechnol. 2011;29(4):310-312. doi:10.1038/nbt.1839. https://www.ema.europa.eu/en/human-regulatory/overview/biosimilar-medicines-overview

2 Schneider C. Biosimilars in rheumatology: the wind of change. Annals of the Rheumatic Diseases. 2013;72(3):315-318. doi:10.1136/annrheumdis-2012-202941

3 European Medicines Agency. Assessment report Inflectra. European Medicines Agency. June 27, 2013. https://www.ema.europa.eu/en/documents/assessment-report/inflectra-epar-public-assessment-report_en.pdf

4 Krznarić Ž. Biosimilars in Inflammatory Bowel Disease: From Theory to Practice. Presented at: PSI Internal Training; June 27, 2023.

5 European Medicines Agency, European Commission. Biosimilars in the EU – Information Guide for Healthcare Professionals. European Medicines Agency. 2019. https://www.ema.europa.eu/en/documents/leaflet/biosimilars-eu-information-guide-healthcare-professionals_en.pdf.

6 European Medicines Agency. Biosimilar Medicines: Overview. European Medicines Agency. April 26, 2023. Accessed July 3, 2023. https://www.ema.europa.eu/en/human-regulatory/overview/biosimilar-medicines-overview.

pair of gloved hands drawing up medicine from a vial with a needle

Similar But Different: Regulatory and Operational Considerations for Biosimilar Clinical Development in IBD  

The rise of IBD biosimilars and what comes next

Biosimilars present untapped potential for expanding patient access and improving treatment options in Inflammatory Bowel Disease (IBD) and other therapeutic areas, but these trials also bring unique challenges and regulatory considerations.

In this white paper, you’ll learn how biosimilars have transformed the treatment landscape for IBD in the past decade, their current therapeutic uses in Crohn’s disease and ulcerative colitis, and global regulatory considerations for running biosimilar clinical trials in IBD.

Download our new white paper to learn about:

  • IBD epidemiology and current biosimilar treatment methods
  • Regulatory considerations and other challenges for biosimilar trials
  • Future opportunities for biosimilar therapeutics
radiopharmaceutical molecules, glass-like on an light blue background

Operationalizing Radiopharmaceutical Clinical Trials: Opportunities and Challenges  

When PSI published a blog post on the current state of radiopharmaceutical clinical trials in 2019, we had no way of knowing of the changes that would transform the clinical trial industry – along with every other one on earth – just a few months later.

Of course, managing global nuclear medicine trials has never been easy due to the complexity of regulatory requirements in each country and the necessity for experienced, highly trained sites either within close proximity to the material’s manufacturing site or with the ability to provide at the site level. However, travel restrictions and supply chain challenges have only exacerbated these obstacles. While some of these issues are starting to ease, the need for an experienced, global perspective toward managing these studies has only increased.

Success starts with understanding the risk factors that can impact your radiopharmaceutical trial from startup through the clinical phase. Drawing on our experience as we continue to run radiopharm studies in multiple oncology indications, we’ve highlighted some of the most common challenges to consider below – and how to overcome them.

1. Country-specific Regulatory Requirements for Radiopharmaceutical Agents

As development interest in this new class of agents has continued to grow, so has the complexity of the regulatory landscape. Additional approvals should be considered for studies in both the United States and the United Kingdom, as outlined in the table below:

Country Consideration
USA Radiation Safety Committees approvals typically obtained before submissions to IRBs
UK HRA radiology review prior to submission is needed, as well as approval of Administration of Radioactive Substances Advisory Committee (ARSAC). ARSAC review goes in parallel to the ethics/regulatory review

The European Union’s Clinical Trial Regulation has streamlined the process for submitting clinical trial applications in the EU, but many countries still encourage or require additional approvals. An in-depth understanding of each specific country’s requirements in your trial is essential to proactively anticipate requirements and potential questions that can delay approvals. Drawing on our experience with these studies, PSI maintains a library of country-specific radiopharmaceutical requirements and regulations within VISIONAL™, our machine-learning-powered system for data-driven feasibility and enrollment forecast. This pairing of regulatory expertise and technology allows us to accurately predict timelines and model hundreds of country and site combinations, their budgets, and probability of success within minutes.

2. Site Imaging Qualifications and Other Common Delays in Site Activation

Site qualification can be time-consuming for sites, so sponsors should confirm timelines during the feasibility process and ensure that sites are well-trained and supported with any study-specific calibration or camera requirements. PSI created the role of Site Support Specialist to help support sites in the qualification and camera process as well as during the study, saving them time and frustration. An example of the site imaging qualification process is shown below.

Site Imaging Qualifications

This is a simplified example, and the process can be much lengthier if dosimetry is included as part of the study. We have found having a dedicated Site Support Specialist assigned to work one-on-one with each site during the qualification process significantly decreases delays in site activation due to camera qualification.

Issues with technical transfer, or IND amendments (if the drug will be manufactured on-site), can also lead to delays. In some instances, choosing a central procurement facility may be effective, allowing one facility to execute the contract and technical transfer independent of site startup and activation.

3. Logistical Issues During Clinical Phase

As noted in our previous article, cooperation and coordination are imperative every step of the way for the successful delivery of radiopharmaceutical trials: from the facilities and procedures that produce the nuclear material to their handling and storage to the transportation of the drug and dispensation. Understanding the patient journey and which procedures must be completed at each step, including when the investigational product should be ordered, is recommended as a proactive foundational tool. At PSI, we have developed a detailed and unique visual patient journey utilized at the site and project levels.

In addition, other tools for clinical staff, such as a patient visit and MRI/whole brain PET scan tracker calendar, biopsy procedure schedule, source template, and automatic calculator for time-dependent procedures, will help provide additional clarity and compliance. We also recommend tracking key steps via Interactive Response Technology.

4. Central Radiology Review and Delays in Submitting Scans

It is critical to manage and track all steps in the imaging process at each site, including navigating the technical dialogue between nuclear medicine technologists, nuclear physicians/radiologists, investigators, and other stakeholders. Sponsors should ensure clear communication and receipts from the central reader for all scans received and that the appropriate project team members are copied on any queries to the site. PSI’s Site Support Specialist is key in ensuring every stage is performed accurately and on time, including monitoring site submissions in real time and assisting sites with submissions when needed. This role has also proven beneficial in managing and providing oversight of all site queries, cutting the site team’s time spent on imaging queries in half.

5. Development and Implementation of Site-Specific Enrollment Plans

Solid tumor oncology trials represent one of the most competitive markets in clinical research, with over 3,000 trials ongoing or planned, according to data from clinicaltrials.gov, Citeline, and GlobalData. With additional obstacles presented by sites’ limited proximity to manufacturing centers, sponsors and their partners should have detailed site-specific enrollment plans that consider the patient journey at each site, from identifying prospective patients to scheduling the needed imaging assessments and surgeries or biopsies. Walking through this patient journey helps both the site and the CRA to identify all the involved team members so that potential risk factors can be mitigated. PSI’s dedicated Site Support Specialists may meet with sites as soon as they’re selected by clients to understand this patient journey and put together a tailored site enrollment strategy based on site referral patterns, facilities, capabilities, and other key factors.

Meet the challenge of your radiopharmaceutical pivotal trial with PSI

Every study is different, and there is no one-size-fits-all solution for ensuring success. With an established and proven network of almost 300 global radiopharmaceutical sites, PSI specializes in delivering radiopharm studies on time and with quality data. Seventy-nine percent of PSI CRAs have oncology experience, and PSI has developed therapeutic-specific training and resources for radiopharmaceutical trials to achieve the highest level of quality for your study. In addition, PSI’s Site Support Specialist role has led to a dramatic improvement in site activation and enrollment.

Contact us here to learn more about running your pivotal Phase 2 and 3 radiopharmaceutical trials with PSI.


Inflammatory Bowel Disease: Current Status and Future Perspectives

In today’s crowded IBD clinical trial landscape, it can be difficult to complete your study as quickly and efficiently as possible. Being aware of the unique challenges that come with IBD trials can help you prepare and pivot more effectively when complications arise. In this white paper, Dr. Maxim Kosov, Senior Medical Advisor at PSI, breaks down recent trends in IBD clinical research, including insights into patient recruitment and retention.

Inflammatory Bowel Disease: Current Status and Future Perspectives offers insights into recent trial and research developments that will most impact study design and operationalization for various IBD therapies and indications. Download our new white paper to learn about:

  • IBD epidemiology, patient risk factors, and cost drivers
  • Current diagnostic and treatment methods
  • Common clinical trial challenges and methods for patient enrollment and retention

View a sneak peek below


Executive Summary 

Inflammatory bowel disease (IBD) is an umbrella term that covers several clinical conditions, with two of them being the most common: Ulcerative Colitis (UC), which is limited to the colonic mucosa; and Crohn’s Disease (CD), which potentially affects any segment of the gastrointestinal tract from the mouth to the anus.

Both UC and CD are chronic, lifelong inflammatory diseases with a pattern of flare-ups and remission. While we have learned a lot about the predisposing factors, clinical symptoms, pathways, pathology, and genetics, the exact cause of these diseases remains unknown. The number of clinical trials aimed at the discovery of novel therapeutic options is increasing annually. But with more trials comes increasing complexity and challenges.

As a result, while we have come a long way in developing options to treat the symptoms of the diseases, we do not yet have a definitive treatment or cure. These diseases remain highly debilitating and, while no longer fatal in industrialized countries with the current state of medicine, continue to have a negative impact on the overall quality of life for the patient. This white paper will discuss UC and CD’s respective epidemiology and risk factors, current diagnostic and treatment approaches, and considerations for designing effective clinical trials.

Discover the Latest IBD Insights in our Latest Whitepaper


Maxim Kosov, MD, PH.D.

Maxim Kosov, MD, Ph.D., is a Senior Medical Advisor at PSI CRO AG (USA). He graduated from Pediatric Medical Academy in Saint-Petersburg, Russia, in 1993 and worked as an intensive care physician in neonatal intensive care units of several major hospitals. He completed an international fellowship in neonatology at Albany Medical College, NY, USA, in 1996. In parallel with clinical work, Maxim was an Assistant Professor of the Faculty of Anesthesiology and Intensive Care at Saint-Peterburg Pediatric Medical Academy.

He joined PSI in 2004 and acted as a Medical Monitor in more than 60 clinical trials in various indications. He is the author/co-author of more than 50 publications and presented his research works at numerous international meetings and congresses, including annual European Respiratory Society (ERS) meetings in Berlin (2002), Stockholm (2002), and Drug Information Association (DIA) Congress in Hamburg (2016). He is a member of ASCO.


PSI CRO is a privately-owned, full-service clinical research organization (CRO) operating globally. PSI’s global reach supports clinical trials across multiple countries and continents and specializes in the planning and execution of global pivotal registration clinical trials. With an exceptionally high repeat and referral business rate combined with minimal staff turnover, PSI is committed to being the best CRO in the world as measured by its employees, customers, investigators, and vendors.

Global headquarters are based Switzerland at 113a Baarerstrasse, Zug 6300. www.psi-cro.com

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