Anti-TNF Biologics

Anti–tumor necrosis factor (anti-TNF) biologics are advanced medicines for moderate to severe Crohn’s disease and ulcerative colitis. They block TNF, a key immune signal that drives gut inflammation. This class includes infliximab, adalimumab, certolizumab pegol, and golimumab. They can induce remission, heal the bowel lining, and reduce hospitalizations. Careful screening, vaccination, and monitoring help keep treatment safe.

Key takeaways

• Anti-TNFs calm inflammation by blocking the TNF protein.

• Infliximab is an infusion, others are self-injections.

• Most people see benefit within 2 to 8 weeks.

• Screening for tuberculosis and hepatitis B is required before starting.

• Infections, skin reactions, and antibody formation are the main risks.

• Drug levels can guide dosing when response fades.

What are anti-TNFs and how do they work?

Tumor necrosis factor (TNF) is a chemical messenger that helps the immune system respond to threats. In IBD, TNF is overactive and keeps the gut inflamed. Anti-TNF biologics are lab-made antibodies that attach to TNF and block its signal. This lowers inflammatory activity, lets the gut heal, and improves symptoms like pain, urgency, and bleeding.

Which medicines are in this class?

Four agents are used in IBD. Choice depends on disease type, severity, access, and patient preference.

Biosimilars of infliximab and adalimumab work the same way as the originators, with comparable safety and effectiveness.

Who benefits from anti-TNFs?

Anti-TNFs are used for moderate to severe disease, steroid dependence, or when 5-aminosalicylates and steroids are not enough. They are helpful for:

• Inducing and maintaining remission in Crohn’s and UC.

• Healing the intestinal lining (mucosal healing).

• Treating perianal fistulizing Crohn’s, often with surgery and antibiotics.

• Reducing steroid use, hospitalizations, and the need for surgery.

How quickly do they work?

Some symptom relief may appear within 2 to 4 weeks, especially with infliximab and adalimumab. Full benefits often build by 8 to 12 weeks. Fistulas can take longer to close. If symptoms persist, drug levels and antibodies can guide adjustments.

Safety: key risks and how to lower them

All anti-TNFs suppress part of the immune response. Most people tolerate them well with routine monitoring. Important safety points include:

• Infections: higher risk of common infections and reactivation of latent infections. Screening for tuberculosis (TB blood test or skin test) and hepatitis B is required before starting. Untreated TB or chronic hepatitis B needs specialist input.

• Infusion or injection reactions: flushing, itching, headache, or low blood pressure during infliximab infusions; redness or swelling at injection sites with the self-injectables. Severe allergic reactions are uncommon.

• Antibodies to the drug: the immune system can form antibodies that lower effectiveness or cause reactions. This risk may be reduced by consistent dosing and, in selected cases, combining with a low-dose immunomodulator. Combination therapy has added risks, so it is individualized.

• Less common risks: psoriasis-like rashes, lupus-like symptoms, demyelinating disease, and worsening congestive heart failure. Providers avoid anti-TNFs in significant heart failure and are cautious in people with prior demyelination.

• Cancer: overall risk is low. There may be a small increase in some skin cancers. Sun protection and regular skin checks are sensible. The risk of lymphoma is mainly discussed with combination therapy, and absolute risk remains low.

Call the care team urgently for fever above 101°F, severe abdominal pain, shortness of breath, chest pain, or heavy rectal bleeding.

Vaccination and infection prevention

• Complete needed vaccines before treatment when possible. Give non-live vaccines at any time, including flu, COVID-19, Shingrix, and pneumonia vaccines.

• Avoid live vaccines during therapy. Household members can receive most vaccines safely.

• Annual skin exams and routine cancer screening are recommended.

• Practice food and travel hygiene, and seek early care for infections.

Dosing, monitoring, and therapeutic drug monitoring (TDM)

• Baseline: TB and hepatitis B screening, review of vaccines, complete blood count (CBC), and liver tests.

• During treatment: regular CBC and liver tests, plus stool calprotectin or C-reactive protein to track inflammation.

• TDM: measuring trough levels and anti-drug antibodies helps when response is incomplete or lost. Options include increasing the dose, shortening the interval, addressing antibodies, or switching within or outside the class.

Practical tips for use

• Infusions: infliximab infusions take several hours, with observation afterward. Pre-medication is sometimes used for prior reactions.

• Injections: adalimumab, certolizumab, and golimumab are stored in the refrigerator. Let the pen or syringe warm to room temperature before use, rotate sites, and dispose of sharps safely.

• Missed doses: contact the clinic for guidance. Do not double up without advice.

• Travel: carry medicines in a cooler bag, and bring documentation for security checks.

Special situations: pregnancy, pediatrics, and surgery

• Pregnancy: maintaining remission is the priority. Infliximab and adalimumab cross the placenta mostly in the third trimester. Certolizumab crosses less. Pediatric teams plan infant vaccines carefully after birth. Live vaccines for the infant are generally delayed if exposed in late pregnancy, and timing is individualized.

• Pediatrics: infliximab and adalimumab are widely used in children and teens with moderate to severe disease. Growth and nutrition are monitored closely.

• Surgery: anti-TNFs often continue up to surgery for IBD. Decisions depend on the procedure type and infection risk, and are coordinated with the surgeon.

FAQs

How are anti-TNFs different from steroids?

Steroids calm inflammation quickly but are not for long-term control. Anti-TNFs are designed for long-term remission and healing, with a safer profile over time.

What if an anti-TNF stops working?

The team will check symptoms, inflammation markers, and drug levels. Options include dose adjustment, treating antibodies, or switching to another biologic class.

Can people switch to a biosimilar?

Yes. Biosimilars are highly similar in structure, function, safety, and effectiveness. Many people switch without problems.

Do anti-TNFs increase COVID-19 risk?

Serious COVID-19 is influenced by many factors. Staying in remission, keeping vaccines up to date, and following public health advice remain important.