Biologic DMARDs

01Purpose and principlesWhat the treatment does and how it fits into care.

Biologic DMARDs are monoclonal antibodies or receptor fusion proteins. They include TNF inhibitors, IL-6 receptor inhibitors, B-cell depletion, T-cell co-stimulation modulation and IL-17, IL-12/23 or IL-23 inhibitors. They are not ranked by novelty. The best choice is the licensed and commissioned option that treats the active domains while fitting infection, bowel, eye, heart, neurological, malignancy and reproductive factors.

Treatment begins only after diagnostic and activity confirmation. In rheumatoid arthritis, NICE uses treat-to-target conventional-DMARD therapy before biologic eligibility and applies disease-activity and previous-treatment criteria. Psoriatic disease requires assessment of peripheral joints, entheses, digits, spine and skin. Axial spondyloarthritis requires active inflammatory disease rather than pain from fixed damage or fibromyalgia. A biologic should not compensate for an uncertain diagnosis or unmeasured adherence.

Pre-treatment screening is an active risk-management process. Ask about recent or recurrent infection, TB exposure or residence, viral hepatitis, HIV, zoster and varicella, travel, dental and skin infection, bronchiectasis, urinary devices, wounds, vaccines, malignancy and pregnancy. Obtain FBC, liver and renal profiles and class-specific tests. A negative IGRA is less reliable during immunosuppression; combine it with exposure history and chest imaging when indicated.

TNF is central to granuloma maintenance, explaining tuberculosis reactivation and other intracellular infection risk. Adalimumab, etanercept, infliximab, certolizumab and golimumab differ in structure, route, licensed diseases and placental transfer. A standard adalimumab rheumatoid, psoriatic or axial regimen is 40 mg subcutaneously every other week. Biosimilars share the reference product's clinical licence but require clear device training and brand traceability.

Tocilizumab blocks the IL-6 receptor and can rapidly reduce CRP, fever and inflammatory symptoms. In rheumatoid arthritis, the adult subcutaneous regimen is 162 mg weekly; giant-cell-arteritis schedules may use weekly or every-other-week treatment according to the product and clinical need. Monitor neutrophils, platelets, ALT or AST and fasting lipids. Diverticulitis, abdominal pain or peritonism needs urgent imaging because gastrointestinal perforation may occur without the expected CRP rise.

Rituximab is given as two 1000 mg IV infusions two weeks apart for rheumatoid arthritis, with methotrexate, after appropriate previous treatment; retreatment is based on response and is not given sooner than 16 weeks. Infusion premedication and observation are required. Measure immunoglobulins before each course because repeated depletion can cause persistent hypogammaglobulinaemia and infection. Late-onset neutropenia and rare progressive multifocal leukoencephalopathy are important delayed hazards.

IL-17 inhibitors such as secukinumab treat psoriasis, psoriatic arthritis and axial spondyloarthritis. A common adult psoriatic-arthritis regimen with significant psoriasis is 300 mg subcutaneously at weeks 0, 1, 2, 3 and 4, then every four weeks; other phenotypes use 150 mg and product-specific escalation. Assess candidiasis and inflammatory bowel disease before and during treatment. Active IBD often favours a monoclonal TNF inhibitor or another bowel-effective class.

Class choice also uses extra-articular disease. Recurrent uveitis or active inflammatory bowel disease tends to favour a monoclonal TNF antibody over etanercept. Severe psoriasis may favour IL-17 or IL-23 pathway treatment. Previous lymphoma may lead the multidisciplinary team toward rituximab in rheumatoid arthritis. A history of solid malignancy requires oncology-informed timing and recurrence-risk discussion rather than a universal waiting period.

Key points

A biologic DMARD is a protein therapeutic targeting a cytokine, receptor or immune cell; choice follows diagnosis, prior DMARD response, NICE eligibility, dominant disease domain, comorbidity and patient preference.
Do not start during active serious infection. Before treatment, screen for tuberculosis, hepatitis B with HBsAg, anti-HBc and anti-HBs, hepatitis C and HIV, and update vaccination.
TNF inhibitors treat rheumatoid, psoriatic and axial spondyloarthritis but need special caution with latent TB, demyelination and heart failure; adalimumab is contraindicated in NYHA class III or IV heart failure.
IL-6 inhibitors can normalise CRP and suppress fever while infection or bowel perforation evolves; monitor neutrophils, platelets, transaminases and lipids as well as symptoms.
Rituximab depletes CD20-positive B cells. Screen every patient for hepatitis B core antibody as well as surface antigen, measure immunoglobulins and plan vaccines before infusion.
IL-17 inhibition is effective for axial and psoriatic disease but can increase mucocutaneous candidiasis and may worsen or unmask inflammatory bowel disease; the bowel phenotype influences selection.
Never combine two biologic DMARDs or a biologic with a JAK inhibitor routinely because serious infection rises without an established benefit.
Inactivated vaccines are safe but response may be weaker; avoid live vaccines during biologic immunosuppression and time them before treatment when possible.
Hold treatment through a serious infection or major surgery according to the drug-specific plan; restart only when recovery and wound status are satisfactory.
Pregnancy and infant-vaccine planning is molecule- and trimester-specific. Some TNF inhibitors are compatible, but placental transfer late in pregnancy can require deferral of infant live vaccines.

02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.

Expected treatment response

Reduced synovitis, stiffness, enthesitis, skin activity, inflammatory markers and disability within the class-specific assessment window supports continuation under NICE criteria.

Serious or opportunistic infectionRed flag

Focal symptoms, weight loss, zoster, dyspnoea, confusion or functional decline may be more informative than fever or CRP during biologic immunosuppression.

TNF-specific toxicity

New heart failure, demyelination, lupus-like rash or paradoxical psoriasiform disease during TNF inhibition requires targeted assessment and possible class switch.

IL-6 masked emergencyRed flag

Severe abdominal or infectious symptoms with a low CRP on tocilizumab remain urgent because IL-6 blockade directly suppresses acute-phase signalling.

Rituximab immune deficiency

Recurrent sinopulmonary infection, low IgG, late neutropenia or poor vaccine response after repeated courses indicates clinically important B-cell depletion.

IL-17 bowel or fungal signal

New chronic diarrhoea, bloody stool, abdominal pain or recurrent oral or genital candida may indicate a class-specific complication or previously occult bowel disease.

Red flags requiring action

Fever, rigors, hypotension, confusion, hypoxaemia, focal neurological change or rapidly progressive infection requires immediate biologic interruption and emergency sepsis assessment.
Persistent cough, weight loss, night sweats, lymphadenopathy or unexplained systemic illness can represent tuberculosis or another opportunistic infection despite a negative pre-treatment screen.
Jaundice or transaminase rise in an HBsAg-positive or anti-HBc-positive patient may represent hepatitis B reactivation, especially after rituximab.
New or worsening dyspnoea, oedema or reduced ejection fraction during TNF inhibition requires heart-failure assessment and specialist withdrawal review.
New optic neuritis, sensory level, focal neurological deficit or demyelinating syndrome during a TNF inhibitor requires urgent neurology and rheumatology review.
Severe abdominal pain, fever or peritonism on an IL-6 inhibitor may indicate gastrointestinal perforation even when CRP is low.
Painful red photophobic eye, active inflammatory bowel disease or recurrent candidiasis during an IL-17 inhibitor can change class suitability and needs coordinated specialty review.

03Assessment before treatmentTests and checks that guide safe selection.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line baseline infection screenFirst stepFirst line
Why
Exclude active infection and identify reactivation risks before the first biologic dose.
Interpretation and limitations
Take TB exposure history and IGRA with chest imaging when indicated; obtain HBsAg, anti-HBc, anti-HBs, HCV antibody with reflex RNA and HIV testing, and investigate any active focus.
02
Baseline FBC, renal and liver profiles
Why
Confirm organ reserve and create class-specific monitoring baselines.
Interpretation and limitations
Cytopenia or transaminase abnormality may alter IL-6 or other treatment; renal and liver status affects infection risk, concomitant DMARDs and procedural safety even when the biologic itself is not renally cleared.
03
Disease activity and phenotype measurement
Why
Prove treatment eligibility and select a target appropriate to the dominant domain.
Interpretation and limitations
Use DAS28 for relevant rheumatoid pathways and validated joint, axial, skin or bowel measures where applicable; separate inflammatory activity from damage and widespread pain.
04
Immunoglobulins before rituximab
Why
Identify low IgG and quantify infection risk before B-cell depletion or retreatment.
Interpretation and limitations
A low or falling IgG requires infection history, vaccine review and specialist risk-benefit decision; severe recurrent infection may need immunology input and replacement consideration.
05
Class-specific serial laboratory tests
Why
Detect cytopenia, liver injury and metabolic change during biologic exposure.
Interpretation and limitations
Tocilizumab requires neutrophil, platelet, transaminase and lipid monitoring; other biologics follow their product and concomitant-DMARD schedule rather than one universal panel.
06
Symptom-directed cultures and imaging
Why
Diagnose infection or organ toxicity rapidly when new symptoms develop.
Interpretation and limitations
Obtain samples before antimicrobials when safe, but do not delay sepsis treatment; low CRP on IL-6 blockade and negative baseline TB testing do not exclude serious infection.
07
Pregnancy and infant-vaccine record
Why
Align biologic timing with maternal control and neonatal live-vaccine safety.
Interpretation and limitations
Document exact agent, gestational last dose and planned postpartum restart; communicate any live-vaccine deferral directly to maternity, neonatal and primary-care records.

04Treatment approachPreparation, options, escalation and aftercare.

01Eligibility and selectionConfirm target, then choose classFirst stepActive rheumatic disease remains above target after the required conventional therapy or has a pathway-specific indication.

1Verify diagnosis, inflammatory activity, adherence and NICE criteria and document peripheral, axial, skin, eye and bowel domains plus the patient's priority.
2Compare classes against TB and hepatitis risk, recurrent infection, heart failure, demyelination, IBD, uveitis, malignancy, pregnancy, route and monitoring burden.
3Choose one biologic with an objective response window and a predefined plan for non-response, secondary failure and adverse effects.

02Pre-treatment safetyScreen, vaccinate and assign ownershipA specific biologic has been selected and initiation is planned.

1Exclude active infection and complete TB, triple-marker hepatitis B, hepatitis C and HIV assessment, adding dental, skin, chest or urine investigation only when clinically indicated.
2Update inactivated vaccines and give any necessary live vaccine before immune suppression at the Green Book and product-specific interval.
3Record baseline bloods, pregnancy and contraception, class-specific hazards, sick-day contacts and which team will monitor, withhold and authorise restart.

03Serious-infection branchWithhold first and find the sourceSystemic illness or significant bacterial, viral, fungal or mycobacterial infection occurs during treatment.

1Withhold the biologic and urgent doses, obtain appropriate cultures and imaging and begin sepsis or infection treatment without relying on fever or CRP.
2Look for opportunistic and reactivation syndromes shaped by the class, including TB and hepatitis B, and involve infection or hepatology expertise.
3AlternativeRestart only after clinical recovery, source control and an explicit specialist decision that accounts for organism, residual focus and alternative class options.

04Inadequate responseSwitch rather than combineThe predefined disease target is not reached or is lost after an initial response.

1Reconfirm inflammatory activity, injection technique, adherence, infection, immunogenicity, structural damage and coexisting osteoarthritis or fibromyalgia.
2Stop the ineffective agent and switch within or between mechanisms according to disease guideline, comorbidity and commissioning rules.
3Do not overlap two biologics or add a JAK inhibitor routinely; coordinate washout and flare control using pharmacology and infection risk.

05Pregnancy and infant planningChoose disease control with a neonatal planConception, pregnancy or breastfeeding occurs before or during biologic treatment.

1Use the BSR agent-specific compatibility table and prefer a proven pregnancy-compatible option rather than stopping effective control without a replacement.
2If an Fc-containing TNF inhibitor continues late, record the last dose and any need to defer infant live vaccines; certolizumab has minimal placental transfer.
3Coordinate postpartum restart, wound or infection assessment and breastfeeding compatibility with rheumatology, maternity and primary care.

05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.

A monoclonal TNF inhibitor with activity across synovial, axial, entheseal, skin, eye and bowel disease, selected through the relevant NICE pathway.

Adalimumab

Give 40 mg subcutaneously every other week for adult rheumatoid arthritis, psoriatic arthritis or axial spondyloarthritis; some licensed skin and bowel indications use loading or weekly regimens and must follow their own product schedule.

Do not use with active serious infection or NYHA III or IV heart failure; screen TB and hepatitis B and review demyelination, live vaccines, malignancy and pregnancy timing.

IL-6 receptor inhibition for eligible rheumatoid arthritis and selected giant-cell arteritis pathways, including monotherapy when methotrexate is unsuitable.

Tocilizumab

For adult rheumatoid arthritis, give 162 mg subcutaneously once weekly; giant-cell-arteritis treatment can be 162 mg weekly or every other week according to the product and clinical need, while intravenous regimens differ.

Monitor neutrophils, platelets, transaminases and lipids; investigate infection and abdominal pain despite low CRP, and review diverticulitis, bowel perforation risk and CYP-normalisation interactions.

CD20 B-cell depletion for severe active rheumatoid arthritis after appropriate prior DMARD or TNF-inhibitor treatment under NICE criteria.

Rituximab for rheumatoid arthritis

Give 1000 mg intravenously on days 1 and 15 with methotrexate and infusion premedication; assess retreatment from clinical response, with no repeat course sooner than 16 weeks.

Screen HBsAg and anti-HBc, measure immunoglobulins and vaccines, avoid active infection, monitor infusion reactions, late neutropenia and rare PML, and use the product reproductive interval.

IL-17A inhibition for psoriasis, psoriatic arthritis and axial spondyloarthritis where skin and musculoskeletal domains support this target.

Secukinumab

For adult psoriatic arthritis with significant psoriasis, give 300 mg subcutaneously at weeks 0, 1, 2, 3 and 4, then every four weeks; many non-severe-skin or axial regimens use 150 mg with product-defined escalation.

Exclude active serious infection and review recurrent candidiasis and inflammatory bowel disease; avoid live vaccines and use product-specific pregnancy and contraception advice.

Pegylated Fab TNF inhibitor with minimal Fc-mediated placental transfer, useful when an effective TNF inhibitor is needed through pregnancy.

Certolizumab pegol

Give 400 mg subcutaneously at weeks 0, 2 and 4, then 200 mg every two weeks or 400 mg every four weeks for adult rheumatoid or psoriatic arthritis and axial spondyloarthritis.

Screen infection, TB and hepatitis B and review heart failure or demyelination; compatibility does not remove maternal infection monitoring or routine newborn assessment.

06Complications, monitoring and follow-upAdverse effects, response and longer-term review.

Measure the exact disease and domain response at the NICE-defined continuation interval, including function and steroid requirement; stop or switch treatment that fails its objective target.
At every contact ask about infection, TB symptoms, zoster, new travel or exposure, wounds, dental infection, neurological change, heart-failure symptoms, bowel symptoms and pregnancy plans.
Check agent-specific bloods: combine the biologic schedule with concomitant methotrexate monitoring, and add neutrophil, platelet, liver and lipid surveillance for IL-6 blockade.
Before each rituximab course, review infections, total IgG and hepatitis B prevention, and time vaccines far enough before infusion to generate a response when disease allows.
Record brand and batch for every biologic, inspect injection technique and storage and investigate adherence or immunogenicity before declaring pharmacological failure.
Maintain a shared written plan for serious infection, surgery, pregnancy, infant live vaccines and restart so that primary, emergency and specialty teams do not make conflicting decisions.

07Special situationsVariants, exceptions and circumstances that change the usual approach.

A low CRP can be pharmacological

IL-6 blockade interrupts hepatic acute-phase signalling, so serious infection and perforation must be judged from symptoms, physiology and imaging.

Anti-HBc matters without HBsAg

Resolved hepatitis B can reactivate after B-cell depletion, making the core-antibody result essential before rituximab.

Monoclonal TNF differs from receptor fusion

Adalimumab and infliximab are effective for bowel disease and uveitis patterns in which etanercept is a poorer strategic fit.

Biosimilar traceability is clinical

Recording brand and batch allows adverse-event attribution and prevents confusion when devices or supply change despite equivalent active treatment.

Secondary failure has several causes

Antidrug antibodies, missed doses, infection, weight, structural damage and a new pain syndrome can all mimic loss of target effect.

Placental transfer depends on Fc

Certolizumab lacks an Fc region and transfers minimally, whereas Fc-containing antibodies cross increasingly later in pregnancy and can alter infant live-vaccine timing.

08Common pitfallsFrequent interpretation and management errors.

01
Selecting a biologic from the joint diagnosis alone while ignoring active bowel disease, recurrent uveitis, heart failure, demyelination or pregnancy.
02
Screening for hepatitis B with surface antigen alone and missing an anti-HBc-positive patient before rituximab.
03
Using a low CRP to exclude sepsis or bowel perforation in a patient receiving tocilizumab.
04
Combining two biologics or a biologic and JAK inhibitor to rescue partial response without evidence or infection justification.
05
Continuing an ineffective biologic because laboratory results are normal while the agreed disease target remains unmet.
06
Failing to communicate late-pregnancy biologic exposure to the team scheduling infant rotavirus or BCG vaccination.