Biologic Drugs: Benefits Outweigh Risks
Biologic drugs, which impact the immune system, carry certain risks, but they are manageable.
Treatment for rheumatoid arthritis changed dramatically more than 20 years ago with the advent of the disease-modifying antirheumatic drug (DMARD) methotrexate. Over the past 15 years, new types of DMARDs, called biologics, have continued to revolutionize treatment. Even newer ones are under development.
All of these drugs target parts of the immune system that drive the inflammation that is responsible for rheumatoid arthritis. This slows the process that would otherwise damage joints. The inevitable disability that was once common with rheumatoid arthritis can now be avoided for most people.
Effect on Immune System
While each class of biologic drug has its own array of possible side effects, they all share a few. By attacking the immune system, all of the drugs increase a person’s risk for infections and cancer, which is a concern for many people.
“They hit parts of the immune system that might sense the presence of infections and fight them,” says Cleveland Clinic rheumatologist Matthew Bunyard, MD. As worrisome as that sounds, Dr. Bunyard explains that only about one-fourth to one-third of people who take these medications get more frequent infections, and they tend to be common and mild ones, such as colds, the flu, bronchitis and sinusitis. Life-threatening infections, such as tuberculosis, histoplasmosis (a fungal infection), and serious bacterial infections, are rare.
The drugs don’t wipe out the immune system. They actually are quite targeted. Each class of biologic drugs attacks different components of the immune system. One drug, rituximab, targets a particular type of cell (B cells), while the others interfere with the way cells signal to one another. They block cytokines, which are molecules that trigger inflammation.
What is important to know is that there are measures you and your doctor can take to minimize the chances of any serious problems. “Each person has a pre-existing risk that needs to be thought about before starting one of these medications,” says Dr. Bunyard.
Therefore, your doctor will assess your individual risk based on any medical conditions you have, as well as your history of infections (including hepatitis) and cancer.
Everyone will be screened for tuberculosis and hepatitis. Annual immunization against the flu and other vaccinations appropriate for your age are also recommended. It is safe to use killed vaccines, which do not have live organisms. Some immunizations, such as shingles, should be given before starting a biologic medication.
The increased risk for cancer is another scary potential side effect. Dr. Bunyard explains that when these drugs first came on the market, the studies showed an increased risk for lymphoma and other cancers. But now that they have been used for several years by hundreds of thousands of patients, it appears that the cancer risk is lower than first thought.
The warning is still there, so it continues to be something to look out for. “The risk will vary based on the state of each person’s immune system,” says Dr. Bunyard. Cancer screenings appropriate for your age and sex are recommended.
Injection and Infusion Reactions
Other possible risks include adverse reactions to the injection or infusion. Some of the drugs are delivered by injection, and it’s relatively common to have a painful, red, raised area at the site where you’ve given yourself the shot. “It can be annoying, but it’s not dangerous and will go away after several days,” says Dr. Bunyard.
Some biologic drugs are delivered by intravenous infusion. Rare but dangerous reactions can occur with these, which is why they are delivered at a healthcare facility.
“Ultimately, these are extremely powerful medications, and for most people the benefits far outweigh the risks,” says Dr. Bunyard.