Biologic Response Modifiers
In 1998, the FDA approved the first of an entirely new class of drugs to treat some forms of arthritis. Referred to as biologic response modifiers, or more commonly as biologics, the drugs copy the effects of substances naturally produced by the immune system. The biologic drugs are genetically engineered, meaning human genes involved in the production of natural immune proteins in the human body are used in non-human cell cultures to produce the biologic drug.
The biologic drug can then affect certain specific immune responses, including inflammatory activity.
Current biologic drugs inhibit the actions of cytokines (proteins that serve as chemical messengers between cells). Enbrel (etanercept), Remicade (infliximab), and Humira (adalimumab) block or inhibit the action of TNF-alpha (a cytokine involved in inflammation). Kineret (anakinra) blocks interleukin-1 (IL-1), another protein that plays a role in the inflammation pathway. Orencia (abatacept) is classified as a T-cell costimulation modulator, or simply put, blocks the activation of T-cells. Rituxan (rituximab) selectively targets CD20-positive B-cells for depletion.
The language used to describe these drugs can get very technical and confusing, but the important fact to remember is that two-thirds of rheumatoid arthritis patients have a favorable response to biologics. The drugs that are believed to slow disease progression can remarkably reduce symptoms and even effect a remission in some patients.
Essential
The biologic drugs are expensive. Insurance pre-authorization is required before treatment can begin. The injectable biologic drugs are classified as specialty drugs by prescription drug plans. The biologics that are infused are considered treatments. Be sure you know your share of the cost.
How Are Biologics Different than DMARDs?
Technically speaking, the biologics are considered a subset of DMARDs in that they slow progression of the disease. Though most traditional DMARDs are taken orally, the new biologics are either injected or given intravenously. Though the biologic drugs may take weeks before any benefit is noticed by some patients, others recognize vast improvement after the first or second injection or infusion.
Enbrel — Subcutaneous (under the skin) self-injection once or twice weekly (three or four days apart).
Remicade — Intravenous (into a vein) injection over two to three hours every four to eight weeks.
Humira — Subcutaneous self-injection every other week.
Orencia — Given intravenously over thirty minutes every four weeks.
Rituxan — Intravenous infusion given twice (two weeks apart) and repeated every six to nine months. The first treatment takes six to eight hours. Subsequent treatment may be shorter or longer.
Are Biologic Drugs Suitable for Every Patient?
Biologic drugs shouldn't be used by some patients. Patients who have a previous medical history that includes recurrent infections, tuberculosis, multiple sclerosis, lymphoma, or congestive heart failure may be unsuitable candidates for the biologic drugs.
Generally, the biologic drugs are considered safe for most patients; however, a range of side effects are possible, from common side effects (injection site reactions) to more serious side effects (severe allergic reactions, increased risk of infection, increased risk of lymphoma, neurologic complications). Your doctor will consider and discuss the risk versus benefit with you.
