What are Biosimilars and Generics: A Detailed Guide for Patients

When a doctor prescribes medication, pharmacies often offer several options: the original drug, its generic, or a biosimilar. The price difference can be significant, which raises many questions for patients. What are these drugs? Are they safe? Can they be trusted?

Let's break down these concepts in simple terms. Understanding the difference will help you make the right choice without compromising the quality and effectiveness of your treatment.

What is an Original Drug?

This is the first drug that was developed, underwent all clinical trials, and received a patent. The developing company spent years and billions of dollars on research to prove its efficacy and safety. Original drugs are expensive because their price includes all the costs of their creation.

What is a Generic Drug?

After the patent for an original drug expires, other pharmaceutical companies can produce its analogues—generics. These are medications that contain the exact same active substance in the same dosage and form as the original drug.

Key Features of Generics:

• Identical Chemical Composition: A generic is essentially a "copy" of the original drug. If the original drug, for example, has an active substance named "X", the generic will also contain "X".
• Proven Bioequivalence: To be approved for sale, a generic must demonstrate that it works in the body in the same way as the original. This is called "bioequivalence."
• Lower Price: Generic manufacturers do not spend money on development and large-scale clinical trials, so their products are significantly cheaper.

For example, a drug for nephrology with the active substance "Y" might be produced by different companies under different brand names, but it is fundamentally the same generic drug.

What is a Biosimilar?

With the advancement of biotechnology, "biological drugs" have emerged. They are not produced through chemical synthesis, but with the help of living cells. For example, these can be monoclonal antibodies used in chemotherapy for solid tumors.

A biosimilar is an analogue of such a biological drug. However, unlike chemical generics, a biosimilar cannot be an **absolute** copy of the original. This is due to the complexity of the living organisms involved in production.

Key Features of Biosimilars:

• Similar, but not Identical: A biosimilar is very similar in structure to the original drug, but it may have minor differences that do not affect its safety or effectiveness.
• Clinical Trials: To gain approval, biosimilars undergo more rigorous studies than generics. They must prove not only bioequivalence but also clinical similarity to the original.
• Efficacy and Safety: Once approved by regulatory authorities, a biosimilar is considered as safe and effective as its original counterpart.

Biosimilars are widely used in modern medicine, including in hematology and for treating multiple sclerosis, making expensive drugs more accessible.

Key Differences in a Table