Understanding Biologic Drugs

Biologics are a relatively new class of medications that target specific parts of the immune system and have revolutionized the treatment of many chronic illnesses. A number of such agents are currently approved by the United States Food and Drug Administration (FDA) for one or more indications, including etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), ustekinumab (Stelara), anakinra (Kineret), rituximab (Rituxan), trastuzumab (Herceptin) and others. As their name implies, biologics are proteins that are derived from living sources, such as humans, animals or microorganisms.

Biologics represent a class of medications that is distinct from conventional drugs. As described by the FDA, most drugs are synthesized in the laboratory through one or more chemical reactions, and their molecular structure is thus well established. Biologics on the other hand, are complex proteins that cannot be readily created from a series of chemical reactions. Instead, they are produced genetically, by culturing proteins from the synthesis machinery that exists in all living cells. These medications represent the forefront of biomedical research; they have evolved owing to biotechnological, molecular biological, genetic and other laboratory techniques, to provide therapy for a variety of medical conditions.

Although the class of medications that we now refer to as “biologics” is comprised primarily of protein-based drugs, biologics can be composed of one or more components, including sugars, proteins, or nucleic acids. Some of the oldest biological products were directly extracted from living systems and have existed for decades, such as vaccines, organ and tissue transplants, and blood products. Since the late 1990s the FDA has approved newer biologic medications, which are administered via injection or infusion and target specific chemicals in the immune system that are characteristically overactive in different disease states. Biologic agents were first approved for the treatment of rheumatoid arthritis, but their use has now expanded to include not only rheumatology, but also dermatology, gastroenterology, oncology, cardiology, neurology and other medical specialties.

In dermatology, biologics have revolutionized the treatment of moderate-to-severe psoriasis and psoriatic arthritis, among other conditions. Many of the traditional drugs used to treat psoriasis impact the entire immune system. Specific immune cells (called T cells) and proteins (such as TNF-alpha and interleukins 12 and 23), however, have been shown to play a major role in the development of psoriatic disease.

Biologics are able to preferentially target these factors, there- by reducing inflammation and disease activity in psoriasis. As a result, they may offer the most effective means to treat psoriasis that is otherwise too severe or refractory to other therapies. Although biologics are a promising advance in the treatment of psoriasis and other chronic dermatological diseases, they are unfortunately associated with side effects as well, including but not limited to injection site reactions and an increased risk of infections. It is important to discuss possible risks and side effects with your doctor before starting any new medication.

Monica Enamandram 1Monica Enamandram is a fourth- year medical student at Harvard Medical School. She earned bach- elor degrees in biology and Spanish at Yale University. She is interested in patient education and clinical research in dermatology and is excited to develop successful preventive measures and treatment regimens for eczema.