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Biologic Agents

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posted in Drugs used in lupus on November 3, 2026 by

Donald Thomas, MD

Updated October 15, 2026

Biologic Agents

Chapter 33 of The Lupus Encyclopedia explains how living cells build these medicines and how we use them in systemic lupus (SLE). Rituximab (Rituxan) and the TNF inhibitors take up most of the chapter. The book calls Benlysta and Saphnelo “biologics FDA-approved for SLE”. Our Saphnelo or Benlysta article compares those two, and our anifrolumab approval article covers Saphnelo. Hydroxychloroquine still belongs beside these drugs in our treatment of lupus guide.


NOTE: Johns Hopkins University Press, publisher of The Lupus Encyclopedia, is a nonprofit publisher. If you purchase JHUP books, like The Lupus Encyclopedia, you support projects like Project MUSE.


“Biologic agents are also called biologic drugs or biologics. They are produced in any living (hence, biologic) system, including microscopic organisms (such as bacteria), animal cells, or plant cells. This contrasts with other drugs produced in a laboratory by mixing chemicals together (called chemical agents).”

Chapter 33, p. 621, The Lupus Encyclopedia

What Biologic Agents Means

How living cells make them

These drugs are also known as “biologic drugs or biologics.” Living systems make them, including “microscopic organisms (such as bacteria), animal cells, or plant cells.” Steroids, immunosuppressants, and antimalarials count as chemical agents here. Moreover, the molecules “tend to be more fragile” than a typical pill. Consequently, factories “must be completely sterile at every step.”

Shots, infusions, and a missed dose

“Stomach acid would destroy the drugs before they could be absorbed,” the book warns. Therefore, we give them through a vein or with a needle under the skin. If you miss a dose, arrange the shot or the infusion as soon as you notice. Then “you need to reset your schedule from that date.”

How Biologic Agents Use Cytokines

Messages that stir immune cells

These messenger particles are called cytokines. Greek roots give us the name: one part for cell, and one part for stirring something up. For example, these cytokines tell lymphocytes to become activated, or “stirred up.” They then “reproduce and move to the area of invasion.”

When inflammation runs high

In SLE, inflammatory cytokines run high while calming ones lag. This chapter asks, “Could doctors control these diseases by decreasing cytokines that cause inflammation or by increasing cytokines that reduce inflammation?” However, “Not all biologics attack cytokines.” Some “interfere with the immune system in other ways.”

TNF Inhibitors, as This Chapter Teaches Them

Why we rarely start these biologic agents

Each TNF inhibitor works “to prevent the cytokine TNF-alpha from attaching to and activating white blood cells.” Inflammatory arthritis “may respond as quickly as a week,” though some people wait several months. Early studies in 2002 and 2003 “showed that TNF inhibitors helped SLE patients.” Infliximab (Remicade) “helped some patients with lupus nephritis (kidney inflammation) and arthritis.” However, “Better drugs are now available,” so we rarely start TNF inhibitors for SLE today.

Checks before the first pen or infusion

Before the first dose, everyone needs a hepatitis B blood test and a tuberculosis test. Also, “Do not use a TNF inhibitor if you have an untreated, active infection.” Uncontrolled heart failure is another stop, “seen mainly with infliximab.” Patients who “have RA overlapping with lupus (rhupus)” may still take one for the arthritis. Others began these drugs in the early 2000s.

Certolizumab and lupus anticoagulant

Researchers are studying certolizumab (Cimzia) “for lupus anticoagulant (LAC) positive SLE patients.” LAC can cause miscarriage and stillbirth. For example, early results “show great promise with significantly more LAC-positive SLE patients having successful births with certolizumab.” TNF inhibitors more broadly are “safe during pregnancy (mainly the first two trimesters) and breast-feeding.”

Rituximab Among Biologic Agents

CD20, the badge on the B-cell

Rituximab belongs with the other biologic agents in this chapter. The book calls CD20 “an identification badge worn by several types of B-cells.” Rituximab “binds to the outer surface of B-cells” on that badge. It then “causes the CD20 B-cells to become inactive or die.” Low platelets “can improve within a few weeks,” while lupus arthritis “may take a few months to begin to improve.”

Dose, then a rare brain infection

A typical dosing schedule is to get 1,000 mg, then a second infusion two weeks later. Doctors often repeat that pair every six months. Infusion centers usually give IV steroids first, to cut the chance of an allergic reaction.

The chapter also names a rare brain infection called PML. It shows up in about 1 out of every 25,000 people with rheumatoid arthritis who receive rituximab. “There have been only a few case reports of its occurring in SLE patients taking rituximab.” Go to the emergency room if confusion or trouble speaking shows up.

Safety Rules for Biologic Agents

Infections

Biologics bring “an increased risk of infections,” as other immunosuppressants do. Therefore, “Make sure not to use biologics during active infection.” The book recommends, “Contact your primary care provider or go to the emergency room immediately if you have infection symptoms.” Moreover, our lupus and infections page lists the daily steps we ask patients to follow.

Vaccines and storage for biologic agents

“Do not get live vaccines (including a Zostavax for shingles) if you are on a biologic.” On rituximab, we time other vaccines “two to five weeks before each cycle’s first rituximab treatment.” Our vaccine recommendations and COVID vaccine timing guide spell out the current schedule. At home, “keep them at 35°F to 46°F,” and skip the crisper because “it could be too cold.” You can keep etanercept and adalimumab at “77°F (out of sunlight)” for up to 14 days.

What Biologic Agents Cost

“Biologics are costly,” from “tens of thousands of US dollars per year” to over “US$100,000 for just one patient.” After a patent ends, another firm can produce a biosimilar. The FDA calls that copy “highly similar” when it has “no clinically meaningful differences” from the approved drug. For example, Infliximab-dyyb (Inflectra) “became the first biosimilar rheumatic drug” in 2016.

Before you begin, bring hepatitis B and tuberculosis results. Mention uncontrolled heart failure, especially if the plan includes infliximab. More Than Lupus explains starting Benlysta, and it also covers newer lupus treatments. Kaleidoscope Fighting Lupus explains monoclonal antibodies in plain language. Ask how a missed dose of these biologic agents resets your calendar before you leave the visit.

For more in-depth information on Biologic Agents:

Read chapter 33 of The Lupus Encyclopedia, edition 2

Look up your symptoms, conditions, and medications in the Index of The Lupus Encyclopedia

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