Biological medicines have changed the way many serious and long-term diseases are treated. They are used in areas such as cancer, autoimmune diseases, diabetes, and several other complex conditions.
But when people hear terms such as biologics and biosimilars, it is easy to get confused. Are they the same? Is one better than the other? And what does the difference mean for pharmaceutical companies involved in development and manufacturing?
To understand this, we first need to look at what are biologics and what are biosimilars.
Both are biological medicines, but they have different roles in the pharmaceutical market. A biologic is an original biological medicine, while a biosimilar is developed to be highly similar to an already approved biological medicine, known as the reference product. Regulatory authorities require biosimilars to demonstrate high similarity and no clinically meaningful differences from their reference products.
The difference also affects biologic drug development, biosimilar development, manufacturing strategies, regulatory requirements, and investment decisions.
What Are Biologics?
What are biologics? The simplest answer is that they are medicines made using biological sources or living systems.
Unlike many conventional medicines that are produced through relatively straightforward chemical synthesis, biologics are generally much larger and more complex molecules. Many biological medicines contain active substances such as proteins produced using living cells or organisms.
Examples can include:
- Monoclonal antibodies
- Insulin
- Growth hormones
- Certain vaccines
- Blood and plasma-derived products
- Other therapeutic proteins
Because these medicines are produced using biological systems, their manufacturing requires carefully controlled conditions.
Even small changes in the manufacturing process can potentially affect the characteristics of the final product. This makes process control, analytical testing, and quality management extremely important in biologics manufacturing.
What Are Biosimilars?
So, what are biosimilars?
A biosimilar is a biological medicine that is highly similar to an already approved biological medicine called the reference product.
It is important to understand that a biosimilar is not simply a copy of the original biologic in the same way that a generic drug is generally a chemical copy of a small-molecule medicine.
Biological products are complex and are produced using living systems. Because of this complexity, it is generally not possible to make an exact molecular copy.
Instead, biosimilar developers conduct detailed analytical and other comparative studies to demonstrate that their product is highly similar to the reference product and does not have clinically meaningful differences in safety and effectiveness. This makes biosimilar development a highly scientific and data-driven process.
Biosimilars vs Biologics: What Are the Key Differences?
The difference between biosimilars and biologics becomes easier to understand when we look at how they are developed, manufactured, and regulated.
| Parameter |
Biologics |
Biosimilars |
| Basic concept |
Biological medicines developed as original/reference products |
Biological medicines developed to be highly similar to an approved reference product |
| Reference product |
The original product that establishes the reference |
Developed and evaluated against an approved reference product |
| Development approach |
Independent development to establish quality, safety, and efficacy |
Comparative development focused on demonstrating biosimilarity |
| Manufacturing |
Produced using living cells or biological systems |
Produced using biological manufacturing systems and a process designed to achieve consistent product quality |
| Analytical testing |
Characterizes product quality, purity, potency, and consistency |
Extensive comparative analytical characterization against the reference product |
| Clinical evidence |
Clinical development appropriate to establish safety and efficacy |
Comparative evidence designed to demonstrate biosimilarity and no clinically meaningful differences |
| Regulatory focus |
Establish quality, safety, and efficacy of the product |
Demonstrate high similarity to the reference product and no clinically meaningful differences |
| Market role |
Original/reference biological medicine |
Additional biological medicine that can expand treatment options and competition |
The FDA describes a biosimilar as highly similar to its reference product, with no clinically meaningful differences in safety, purity, or potency.
How Are Biologics Different From Conventional Medicines?
The biggest difference is how they are made.
Many conventional medicines are relatively small molecules produced through chemical synthesis. Biologics, on the other hand, are generally larger and more complex and are often produced using living cells or organisms.
For example, a conventional chemical drug may have a relatively well-defined molecular structure that can be reproduced through chemical synthesis.
A biologic may involve a much larger protein structure whose characteristics depend not only on its underlying sequence but also on how it is produced and processed.
This is why biologics manufacturing process development requires careful control of:
- Cell culture conditions
- Raw materials
- Process parameters
- Purification
- Formulation
- Storage
- Analytical testing
The manufacturing process is therefore closely connected to the quality of the final biological product.
How Does Biosimilar Drug Development Differ From Biologics Drug Development?
Both biologic drug development and biosimilar development require significant scientific expertise, but their development strategies are different.
Biologic Drug Development
For an original biologic, the developer needs to establish that the product is safe, effective, and suitable for its intended use.
This involves extensive development work covering product characterization, manufacturing process development, preclinical and clinical studies, quality testing, and regulatory submissions. Together, these activities help demonstrate the biologic’s safety, efficacy, quality, and consistency throughout its development and manufacturing lifecycle.
Biosimilar Development
The approach for a biosimilar starts with an already approved reference product.
The developer performs detailed comparisons between the proposed biosimilar and the reference product.
The comparison can include:
- Molecular structure
- Physicochemical characteristics
- Biological activity
- Purity
- Impurity profile
- Stability
- Pharmacokinetic and pharmacodynamic characteristics
- Immunogenicity
- Clinical performance, where required
The development follows a stepwise comparability approach. The analytical comparison forms the foundation, with additional studies determined based on the evidence generated.
This means the objective is not to independently recreate the entire development history of the reference biologic. Instead, the objective is to demonstrate biosimilarity through a scientifically justified comparative program.
Manufacturing and Regulatory Considerations for Biosimilars and Biologics
Manufacturing is one of the most important parts of both biologic and biosimilar development.
Biologics Manufacturing
The biologics manufacturing process can involve multiple carefully controlled stages:
- Cell line development
- Cell culture or fermentation
- Harvesting
- Purification
- Formulation
- Filling and finishing
- Quality testing
Every stage needs appropriate controls.
Changes in raw materials, equipment, process parameters, or manufacturing conditions can affect product quality. This is why maintaining process consistency is essential.
Biosimilar Manufacturing
The biosimilar manufacturing process also requires highly controlled biological production.
The manufacturer must demonstrate that the resulting product consistently meets its defined quality characteristics and remains highly similar to the reference product.
This makes process development particularly important.
The manufacturer needs to understand:
- Which process parameters influence quality
- Which product attributes are critical
- How impurities are controlled
- How manufacturing consistency is maintained
- How scale-up affects the product
Regulatory Considerations
Regulatory authorities evaluate biosimilars through a comprehensive comparability exercise.
The FDA and EMA both emphasize demonstrating high similarity to the reference product and establishing that there are no clinically meaningful differences in relevant areas such as safety and efficacy.
The exact regulatory requirements vary by market, so manufacturers need strong regulatory planning when developing products for different regions.
How Biosimilars Can Improve Access to Biologic Therapies
Biological medicines can provide important treatment options, but their cost and availability can sometimes create challenges for healthcare systems.
Biosimilars introduce additional competition into the market.
When more approved products become available, pharmaceutical and healthcare systems may have additional treatment options and opportunities for cost savings. The FDA notes that biosimilars may help increase patient access and potentially reduce costs.
For pharmaceutical companies, this creates opportunities to participate in growing markets where demand for biological therapies is increasing.
What Do Biosimilars and Biologics Mean for Pharmaceutical Companies?
For pharmaceutical companies, the choice between developing an original biologic and pursuing a biosimilar program depends heavily on the company's strategy, scientific capabilities, target market, regulatory pathway, and investment objectives.
For Companies Developing Biologics
The focus is on:
- Discovering or developing innovative biological products
- Establishing product quality
- Building manufacturing processes
- Generating safety and efficacy data
- Protecting intellectual property
- Preparing for commercialization
For Companies Developing Biosimilars
The focus shifts toward:
- Selecting an appropriate reference product
- Developing a highly similar biological product
- Advanced analytical characterization
- Comparability studies
- Process development
- Manufacturing consistency
- Regulatory strategy
- Commercial-scale production
Both areas require strong scientific expertise and reliable manufacturing capabilities.
For companies entering the biological medicines market, choosing the right development and manufacturing partner can therefore make a significant difference to timelines, quality, scalability, and regulatory readiness.
Conclusion
Understanding what are biologics and what are biosimilars is important for anyone involved in modern pharmaceutical development.
Biologics are complex biological medicines developed using biological systems, while biosimilars are biological medicines developed to be highly similar to an already approved reference product.
The difference between biosimilars and biologics is therefore not simply about the product itself. It extends to development strategy, analytical characterization, manufacturing, regulatory requirements, and commercialization.
As the biological medicines market continues to expand, both biologic drug development and biosimilar development will remain important areas of pharmaceutical innovation.
For manufacturers, success will depend on strong process understanding, robust quality systems, advanced analytical capabilities, and consistent biologics manufacturing or biosimilar manufacturing processes.
Ultimately, the goal is the same: developing and manufacturing high-quality biological medicines that can meet regulatory requirements and serve the needs of patients and healthcare systems.
FAQs About Biosimilars and Biologics
What Is a Reference Biologic in Biosimilar Development?
A reference biologic, also called a reference product, is an already approved biological medicine against which a proposed biosimilar is compared.
For example, under the FDA pathway, the reference product is the biological product against which the proposed biosimilar is evaluated.
Why Is Comparability Assessment Important for Biosimilars?
Comparability assessment is at the heart of biosimilar development.
It helps demonstrate that the proposed biosimilar is highly similar to the reference product and that there are no clinically meaningful differences in relevant safety and effectiveness characteristics.
What Role Does Analytical Characterization Play in Biosimilar Development?
Analytical characterization provides detailed information about the structure, purity, biological activity, and other quality attributes of the biosimilar.
It is a critical part of the comparative assessment between the biosimilar and its reference product. FDA describes analytical studies as the foundation of the stepwise biosimilar development approach.
Are Biosimilars Interchangeable With Reference Biologics?
Not automatically. A biosimilar and an interchangeable biosimilar are distinct regulatory concepts in the United States. An interchangeable biosimilar must meet additional requirements, and pharmacy-level substitution is subject to applicable state law.
Requirements can differ between countries, so companies should always consider the applicable local regulatory framework.
What Are the Main Manufacturing Challenges for Biosimilars?
Biosimilar manufacturing involves several challenges, including maintaining consistent biological production, controlling critical process parameters, managing product variability, and achieving the required similarity to the reference product. Manufacturers must also control impurities, scale up production efficiently, and maintain consistent quality across batches. This is why a robust biosimilar manufacturing process is essential for ensuring product quality, consistency, and regulatory compliance.
How Does GMP Manufacturing Apply to Biologics and Biosimilars?
GMP principles apply to the manufacturing of biological medicines and biosimilars. Manufacturers need appropriate controls, quality systems, documentation, facilities, personnel, and validated processes to consistently produce products meeting required quality standards.
Why Is Process Consistency Important in Biologics Manufacturing?
Biological products can be sensitive to manufacturing conditions. Changes in the process can potentially affect product characteristics.
Maintaining consistency across the biologics manufacturing process therefore helps ensure consistent product quality and supports regulatory compliance.
What Are the Key Regulatory Considerations for Biosimilar Development?
The key consideration is demonstrating that the proposed biosimilar is highly similar to its reference product and has no clinically meaningful differences in relevant safety and effectiveness characteristics.
The exact evidence and regulatory pathway depend on the product and the regulatory jurisdiction. FDA and EMA both use structured comparability approaches for biosimilar evaluation.
References
https://www.fda.gov/drugs/things-know-about/9-things-know-about-biosimilars-and-interchangeable-biosimilars
https://www.fda.gov/files/drugs/published/Biosimilar-Product-Regulatory-Review-and-Approval.pdf
https://www.ema.europa.eu/en/human-regulatory-overview/marketing-authorisation/biosimilar-medicines-marketing-authorisation
https://www.ema.europa.eu/en/human-regulatory-overview/biosimilar-medicines-overview
https://www.fda.gov/drugs/biosimilars/background-information-list-licensed-biological-products-reference-product-exclusivity-and
