Biologics and Biosimilars: A New Frontier in Therapeutics

By Dr. Supriya Subramanian, Ph.D.Reviewed by Lily Ramsey, LLM

Biologics are medicinal products isolated from various living organisms, including plant or animal cells, bacteria, and yeast. Unlike conventional drugs that are chemically synthesized, composed of small molecules, and impact the whole immune system, biologics are large, complex molecules produced from living cells that target specific immune system components.

Biologics can be personalized depending on a patient’s genetic makeup and have proved to be life-saving drugs in treating previously difficult-to-treat conditions, such as autoimmune diseases, rare genetic disorders, and some cancer types.¹

Biologics are costly and unaffordable for many patients; thus hampering their access to people of all socioeconomic backgrounds. Biosimilars bear structural similarities to the original biologic, with no clinically meaningful differences, offering the same safety, effectiveness, benefits, and side effects.

The manufacturing costs for biosimilars are low, providing high-quality and low-cost treatment alternatives and making healthcare accessible to everyone.¹

Image Credit: maradon 333/Shutterstock.com

Biologics: Foundations and Impact

Biologics target specific cells, proteins, or pathways in the body, such as immune system components or T cells, which modulate the immune response and fight the disease.

This has revolutionized healthcare by providing treatment options for medical conditions, including autoimmune diseases and cancer. There are four classes of biologics: T-cell inhibitors, interleukin (IL) inhibitors, B-cell inhibitors, and tumor necrosis factor (TNF) inhibitors.

As biologics are produced from living organisms, a certain degree of variability exists during manufacturing, leading to minor differences between each batch. However, this variability is strictly maintained within acceptable limits to ensure product efficacy.²

Steps in the Manufacturing Process

• Development of a cell line capable of expressing the desired biologic using techniques such as genetic engineering. The cells are subsequently grown and multiplied in bioreactors containing the desired nutrients and optimal growth conditions to enhance the yield, quality, and purity of the protein of interest.
• Cells are harvested and purified using methods such as centrifugation, filtration, or chromatography to remove contaminants and impurities.
• The final step is drug formulation with excipients to improve the solubility, stability, and shelf-life. Buffer systems and stabilizers are added to maintain optimal pH and prevent degradation or denaturation, respectively.³

Types of Biologics

• Monoclonal antibodies target specific proteins or cells in the body, transforming the treatment of psoriasis and rheumatoid arthritis.
• Vaccines stimulate the immune system to produce antibodies against specific pathogens and prevent infections, including hepatitis B and influenza.
• Cell-based therapies utilize the regenerative properties of stem cells to treat leukemia or certain cancer types.
• Drugs targeting signaling pathways involving cytokines and ILs have demonstrated potential in treating rheumatoid arthritis and inflammatory bowel disease.⁴

Role of Biologics in Disease Treatment

Autoimmune Diseases

Biologics block specific proteins of the body’s defense system that cause inflammation to treat autoimmune diseases.

TNF inhibitors (adalimubab, etanercept, and infliximab) are the most common biologic for treating inflammatory arthritis and can rapidly reduce inflammation within 2–12 weeks and prevent joint damage.

Belimubab is a B-cell inhibitor used alongside conventional treatment (corticosteroids and hydroxychloroquine) for treating lupus or lupus nephritis in adults and children between 5 and 17 years old.

The IL-17 inhibitor secukinumab is used for treating psoriatic arthritis and psoriasis. Abatacept is a T-cell blocker used for treating rheumatoid arthritis when methotrexate provides no relief. Biosimilar of adalimubab and infliximab have also entered the market.⁵

Cancer

Biologics stimulate the immune system to kill cancer cells by slowing tumor growth, preventing metastasis, and aiding the immune system's detection of cancer cells.

Monoclonal antibodies, such as rituximab and its biosimilars and cetuximab, are used to treat chronic lymphocytic leukemia (CLL) and advanced bowel cancer, respectively. They bind to specific proteins on the cancer cell’s surface and stimulate the immune system to kill the cells.

Checkpoint inhibitors (nivolumab, ipilimumab, and pembrolizumab) prevent the binding of the checkpoint proteins, such as CTLA-4 or PD-1, to their respective partner proteins, allowing T-cells to attack and kill cancer cells. They have been used to treat advanced melanoma and various cancers.⁶

Cancer treatment vaccines assist the body’s immune system in detecting tumor-associated antigens present in cancer cells and kill them. Talimogene laherparepvec (T-VEC), an FDA-approved oncolytic therapy derived from herpes simplex virus 1, treats melanoma that cannot be excised with further surgeries.

Sipuleucel-T is used to treat prostate cancer that has metastasized, is ineffective with hormone treatment, or in patients bearing no symptoms.⁷

Rare Genetic Disorders

Gene therapy cures diseases by replacing disease-causing genes with healthy genes, turning off disease-causing genes, or introducing new or modified genes. Roctavian has a modified virus bearing the Factor VIII gene for treating severe hemophilia A in adults.

Once injected, the liver cells receiving the gene produce more factor VIII in the blood, preventing bleeding. Similarly, Hemgenix is a gene therapy for treating hemophilia B caused by factor IX deficiency.⁸

Biosimilars: Mechanisms and Benefits

Biosimilars are developed following the reference biologic’s patent expiry. Although minor differences in some inactive components may exist, the safety, efficacy, purity, and potency are comparable with the reference biologic.

The biosimilar must have the same mechanism of action, dosage form and strength, and route of administration as the reference product for regulatory approval.¹

Manufacturing Biosimilars

• The reference biologic is characterized by quantifying its critical quality attributes (CQAs) using various functional and physiochemical assays that impact its identity, purity, activity, and stability.
• Customized cell lines are generated, and the cell line that demonstrates high similarity with the reference product is selected and expanded to produce a master cell bank. The cells from the master cell bank are used to scale up the production of the desired protein in bioreactors, followed by isolation and purification. CQAs should be rechecked at this point to ensure scaling up the production has no impact on safety and efficacy and that the modifications are within the established limits of variability.⁹

Regulatory Approval for Biosimilars

Biosimilars have an abbreviated approval pathway, aiming to demonstrate similarity with the reference product concerning safety, effectiveness, and quality. Lengthy and costly clinical trials are not required for biosimilar approval, reducing manufacturing costs and time without compromising safety and efficacy.

A biosimilar application includes the following data:

• Analytical studies: Data supporting the structural and functional similarities of the biosimilar to the reference biologic.
• Animal studies: Toxicology or pharmacology data.
• Pharmacology studies: The biosimilar travels through the body similarly and has the same effects as the reference product.
• Immunogenicity assessment: The formation of antidrug antibodies (ADAs) owing to an immune response elicited in response to the biosimilar is evaluated as ADAs reduce treatment efficacy or cause severe adverse events.
• Comparative clinical studies: They are conducted without a validated pharmacodynamic study to confirm that no changes occur in the biosimilar's safety, effectiveness, and quality.¹⁰

Benefits of Biosimilars

Globally, affordable healthcare is important, and biosimilars show immense promise in reducing healthcare costs without compromising quality.

Biosimilars are approximately 80%–85% cheaper than their corresponding biologic, leading to substantial cost savings for patients and healthcare systems and increasing the accessibility of crucial medicines to a wider demographic.

Introducing biosimilars fosters research and innovation as the increase in competition encourages manufacturers to develop novel and advanced therapies, allowing a robust pipeline of affordable medicines that cater to unmet medical needs.¹¹

Techniques for Developing and Studying Biologics and Biosimilars

Recombinant DNA Technology

This method involves the following steps:

• PCR amplification of the DNA fragment
• Insert target DNA into a cloning vector
• Recombinant DNA is subcloned into an expression vector to increase the expression of the recombinant protein and subsequent selection of positive clones.
• Scaling up the production
• Protein isolation and purification

Issues encountered during recombinant protein production

• Unstable vector
• Loss of expression
• Inclusion body formation
• Heterologous gene expression

These issues can be resolved by manipulating the culture conditions using different induction strategies, adding supplements for adequate growth, and optimizing the bioreactor parameters.¹²

Cell Culture Systems

Most biologics have been produced using the mammalian Chinese hamster ovary (CHO; adalimumab, golimumab, rituximab, etc.) or murine myeloma (NS0, Sp2/0; infliximab, belimumab, etc.) cell lines.

CHO cells can produce proteins with post-translational modifications, but a few glycosylation types cannot be produced. CHO cells also produce glycans (α-gal and NGNA) that are not expressed in humans.

Antibodies against these glycans are present in humans, which can increase the immunogenicity and alter the pharmacokinetics of the biologic.

HEK-293 and HT-1080 are the most commonly used human cell lines for manufacturing biologics as they produce human post-translational modifications. Dulaglutide and velaglucerase alfa produced in HEK293 and HT-1080 have been approved for type 2 diabetes and Type 1 Gaucher disease, respectively.

Advantages of human cell lines

• Lack of immunogenic PTMs
• Can be grown in serum-free suspension medium
• Compatible with many transfection methods
• Can attain rapid reproduction

Disadvantages of human cell lines

• Lack of extensive clinical experience
• Susceptible to human viral contamination

Current technological advances have shown improvement in the use of human cell lines to manufacture biologics, and many products have been clinically approved, with several currently in clinical development. Methods such as nanofiltration have demonstrated effective viral clearance.¹³

Analytical Methods

These methods are crucial in the lifecycle of biologics/biosimilars to determine their identity, safety, potency, purity, and quantity.

• Identity: Product identity is determined via western blot, ELISA, peptide mapping, and capillary isoelectric focusing.
• Purity: Separation methods, such as SDS-PAGE, size exclusion chromatography, and capillary electrophoresis-SDS, determine the purity based on size, charge, and hydrophobicity.
• Safety: Samples are collected during various stages of the production process to ensure they are free from microbial contaminants and endotoxins.
• Potency: Animal-and cell culture-based, biochemical, cytotoxicity, or receptor-binding assays are used to determine the biochemical activity of the biologic.
• Quantity: Protein concentration is determined using the Bradford assay, BCA assay, or absorption at 280 nm.¹⁴

Challenges in Manufacturing Biologics/Biosimilars

• Considering biologics/biosimilars are produced from living systems, contamination and product loss are risks.
• Adherence to good manufacturing practices, such as stringent laboratory standards and robust and advanced manufacturing and analytical methods, is crucial to demonstrate equivalence in quality, structure, and clinical performance for regulatory approval.
• Appropriate quality control measures should be implemented throughout manufacturing to ensure product quality and safety.
• Scaling up the manufacturing process and simultaneously maintaining product quality are challenging.

Using disposable bioreactors instead of stainless-steel bioreactors prevents cross-contamination and maintains product integrity.

Automated workflows and closed fluid management systems reduce manual handling and the risk of human error, enhancing cost-effectiveness and reliability.³

Read More on Drug Discovery, Manufacturing and Development

Therapeutic Implications of Biologics and Biosimilars

Personalized Medicine

Personalized therapies involve using a patient’s genetic makeup and environmental and lifestyle factors to design a treatment plan that provides maximum benefit.

Gene polymorphisms can lead to vaccine-associated adverse events and vaccine failure; thus, personalized vaccines for hepatitis B, measles, and influenza are being developed wherein specific genes involved in the immune response to the vaccine are identified.¹⁵

Asthma treatment has become more personalized, catering to the patient’s asthma endotypes, which have been identified using biomarkers.

Biologics that target specific inflammatory pathways (type 2 and non-type 2) have shown promising results in severe asthma treatment. Omalizumab was the first FDA- and EMA-approved biologic (monoclonal antibody) to treat patients (≥12 years) with asthma.¹⁶

Combination Therapy

This emerging therapeutic trend involves the combination of two biologics or a biologic and a chemically synthesized drug that targets several pathogenic pathways, providing a synergistic effect and proving beneficial for patients where monotherapy has failed.

Certain combinations of biologics demonstrate good remission and low adverse event rates for inflammatory bowel disease: vedolizumab + ustekinumab, ustekinumab + TNF, and vedolizumab + TNF.

The VEGA trial demonstrated high remission rates in patients with ulcerative colitis given a combination of guselkumab and golimumab.

Patients with Crohn’s disease in the EXPLORER trial given a combination of vedolizumab, adalimumab, and methotrexate showed clinical and endoscopic remission rates of 54.5% and 34.5%, respectively.^17,18

Future Directions in Biologics and Biosimilars

Biologics are receiving more approvals than small molecule drugs; they are being combined or assessed for new indications.

Imjudo, a CTLA-4 inhibitor, received approval for unresectable liver cancer, and, subsequently, was approved for metastatic non-small-cell lung cancer lacking the epidermal growth factor receptor or anaplastic lymphoma kinase mutations in combination with chemotherapy and durvalumab.

Teplizumab-mzwvm, an anti-CD3 monoclonal antibody, is the first drug approved for type 1 diabetes and has shown delayed onset of stage 3 in clinical trials. Mounjaro, which is approved for type 2 diabetes, is also being considered as an effective anti-obesity drug.¹⁹

Emerging technologies, such as gene editing, RNA interference (RNAi), and cell therapy, have advanced the field of biologics. For example, in RNAi-based treatments, silencing disease-causing genes can address the underlying causes of many diseases.

Continuous advancements in the monitoring and evaluation systems for quality are critical to assess their safety and effectiveness. Fast-track approval and priority review methods should be established to accelerate market entry.²⁰

Physicians and patients are concerned about the switch from a biologic to a biosimilar, particularly if the switch is due to cost.

Launching awareness campaigns to educate physicians and patients that biosimilars are as safe and effective as the original product is crucial to increasing their confidence in using these alternatives. Biosimilars must be integrated into healthcare systems to reduce costs and improve access to life-saving medicines.¹⁰

Conclusion

Biologics have made a significant impact in the treatment of many debilitating diseases. However, biologics are expensive, and biosimilars are a cost-effective alternative. Biosimilars must demonstrate comparable safety, efficacy, purity, quality, and potency as the reference biologic.

Advances in biotechnological methods, manufacturing processes, and regulatory approval pathways have substantially increased the number of biologics/biosimilars in the market.

Biologics are powerful tools in personalized medicine and combination therapies to customize treatments based on patient needs and simultaneously affect multiple pathways for better outcomes.

Introducing biosimilars encourages innovation as pharmaceutical companies are eager to invest in novel and advanced therapies. Thus, more affordable and accessible medications are released in the market.

Finally, pharmaceutical companies, regulatory authorities, and patient advocacy groups should collaborate and ensure these life-saving therapies are available to all patients.

References

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Further Reading

• All Drug Discovery Content
• Exploring the Structure-Activity Relationship (SAR) of Drugs
• Hit to Lead (H2L) Process in Drug Discovery
• Hot Melt Extrusion in the Pharmaceutical and Food Industries
• How is Additive Manufacturing Used in the Pharmaceutical Industry?