If you see a rheumatologist for your rheumatoid arthritis, there’s a good chance you’re taking a medication called a biologic response modifier. About 40 to 45 percent of patients that rheumatologists treat for RA take one of these drugs. They’re called biologics because they’re made from a living organism, rather than being produced from chemicals in a lab. And although they don’t cure RA, they are highly effective in controlling the symptoms and preventing further joint damage. They produce a response in about two-thirds of the people who take them, often sending their disease into remission. However, because they work by changing the way your immune system works, they do pose some serious risks. Since biologic agents were first approved to treat RA in the late 1990s, doctors have learned a lot about who’s most prone to these adverse effects and how to minimize them, says James R. O’Dell, MD, a rheumatologist and professor at the University of Nebraska Medical Center in Omaha and president of the American College of Rheumatology. Understanding these threats—and working with your doctor to watch out for them—can help you safely get the benefits of these medications. Infection Risk Though there are several types of biologic agents that work in slightly different ways, they all change the way your immune system responds to perceived threats inside your body. “We all know the immune system is supposed to protect us from infections,” says Dr. O’Dell. “So if we modify it too much, we have to be concerned about infections.” Bacterial, viral, and fungal infections may be more common among people taking a type of biologic called a tumor necrosis factor (TNF) inhibitor. These medications, which include adalimumab (Humira) and infliximab (Remicade), work by blocking the action of TNF, a compound in the body that causes inflammation. Other types of biologic agents have been linked to different infections. For example, people may be prone to hepatitis when taking rituximab (Rituxan). This drug binds to and destroys parts of the immune system known as T cells. Your doctor will probably test you for these diseases before prescribing a biologic agent. Be sure to tell him or her if you have a history of serious lung, skin, or other type of infection; if you commonly develop skin ulcers or sores; if you live or have ever lived in areas where severe fungal infections are more common; or if you frequently travel to countries where tuberculosis and similar illnesses are common. Cancer Risk The immune system plays another important role in our bodies—that of surveillance system against malignancy. “All of us produce cells that could become cancers, but for the most part our immune system gets rid of them before anything bad happens,” says Dr. O’Dell. So when doctors first began testing biologic agents, they were concerned that people taking them would be at higher risk for cancer. If you have RA, you already have an elevated risk for certain types of lymphomas, or cancers of the immune system. Your odds may increase again when you first began taking a biologic agent, particularly a TNF inhibitor. However, with time your risk goes back down and may even decrease, Dr. O’Dell says. There also appears to be a slightly increased risk of skin cancer in some patients and lung cancer in patients who have other risk factors for the disease. These include smoking, exposure to hazardous chemicals, or previous radiation therapy. “Other more common malignancies—such as breast cancers and colon cancers—have not been a major concern,” Dr. O’Dell says. Discuss the Risks with Your Doctor Make sure you understand the potential risks of biologic agents before adding them to your treatment plan. Your doctor may suggest you take certain precautions before you begin taking these drugs. For instance, because vaccines that contain live viruses are risky for people with altered immune systems, you might get shots for diseases such as shingles before taking a biologic agent. After you begin taking biologic agents, you should report fevers, chills, or other signs of infection to your rheumatologist. He or she will probably tell you to stop taking the drug until your infection is cured, Dr. O’Dell says. In addition, call your doctor immediately if you experience any of these side effects: Changes to your skin, including paleness, hives, rashes, red patches, or pus-filled bumps Shortness of breath Coughing that won’t stop, or trouble breathing or swallowing Weight loss or gain Burning during urination, or an urgent need to urinate Swollen eyes, face, lips, tongue, or throat Numbness or tingling Vision problems Tightness or pain in your chest or abdomen Weakness in your legs Dizziness Unusual bruising or bleeding These potential side effects may sound frightening, but most are rare. Not only have doctors learned how to match each patient to the biologic agent that’s best for him or her, they’ve found that most risks for side effects decrease the longer you take these medications, Dr. O’Dell says. Key Takeaways Biologics are highly effective in controlling RA symptoms and preventing further joint damage. They produce a response in about 2/3 of people who take them. Because biologics change the way your immune system works, they do pose some serious risks. Some people taking biologics may have a higher risk for infections such as tuberculosis and hepatitis. Others may have a higher risk for certain types of cancer. Your doctor may suggest you take certain precautions before starting these drugs.