Biologics Guide for Ankylosing Spondylitis

Biologics Guide — scientific infographic poster

Table of Contents

  1. Why Biologics Are Different from Nonsteroidal Anti-Inflammatory Drugs
  2. When to Start Biologics
  3. The Four Drug Classes in Ankylosing Spondylitis
  4. Tumor Necrosis Factor Inhibitors — First-Line Biologics
  5. IL-17 Inhibitors
  6. JAK Inhibitors — Oral Option
  7. IL-23 Inhibitors — Not Effective for Ankylosing Spondylitis
  8. Picking Your Biologic — Decision Matrix
  9. Cost and Insurance Reality
  10. How to Give Yourself an Injection
  11. What to Expect — Timeline of Response
  12. Side Effects — What to Watch
  13. Pre-Treatment Screening Checklist
  14. Monitoring During Treatment
  15. Stopping or Switching
  16. Combining Biologics with Other Drugs
  17. Key Research Papers
  18. Connections
  19. Featured Videos

1. Why Biologics Are Different from Nonsteroidal Anti-Inflammatory Drugs

When your rheumatologist says “we’re going to start a biologic,” they are talking about a fundamentally different class of drug than the nonsteroidal anti-inflammatory drugs (NSAIDs) you have probably been taking. Nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen, celecoxib, indomethacin) manage pain and inflammation by blocking cyclooxygenase enzymes. They help you function. They do not, in any meaningful way, change the long-term course of ankylosing spondylitis.

Biologics block specific cytokines — the molecular messengers driving the disease. In ankylosing spondylitis (AS) these are primarily tumor necrosis factor-alpha, IL-17, and, in the case of JAK inhibitors, the intracellular signaling pathway (JAK-STAT) that many cytokines use to deliver their messages. Turning off these pathways can slow or halt spinal fusion when started early, before syndesmophytes (bony bridges between vertebrae) form.

The trade-off is real. Biologics mean injections or infusions instead of pills. They suppress parts of the immune system. They cost thousands of dollars a month. They involve insurance battles, prior authorizations, specialty pharmacies, and baseline infectious-disease screening. For the right patient — especially a young person with active inflammation — the trade-off is worth it. For someone with mild disease well-controlled on nonsteroidal anti-inflammatory drugs, it usually is not.

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2. When to Start Biologics

The 2019 ACR/SAA/SPARTAN guidelines (American College of Rheumatology / Spondylitis Association of America) recommend moving to a biologic after failing 2 or more nonsteroidal anti-inflammatory drugs at adequate doses for 2–4 weeks each. “Failure” means active disease despite full anti-inflammatory dosing. For the details of what counts as an adequate nonsteroidal anti-inflammatory drug (NSAID) trial, see nonsteroidal anti-inflammatory drug Strategy.

But there are several situations where rheumatologists push to start a biologic earlier:

The reason rheumatologists give for not waiting months on nonsteroidal anti-inflammatory drugs in these situations: time with inflamed vertebrae is time in which fusion that does not reverse can build.

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3. The Four Drug Classes in Ankylosing Spondylitis

Four cytokine/pathway-targeted drug classes are relevant to ankylosing spondylitis, and only three of them actually work for the axial (spine) disease:

  1. Tumor necrosis factor inhibitors (TNFi) — first-line biologic. Block tumor necrosis factor-alpha.
  2. IL-17 inhibitors (IL-17i) — second-line or first-line with specific comorbidities.
  3. JAK inhibitors (JAKi) — oral pills; block intracellular signaling. Approved (drug labels) for people who had too little response to, or could not tolerate, one or more TNF inhibitors.
  4. IL-23 inhibitors — effective in psoriatic arthritis and psoriasis, but not in axial ankylosing spondylitis. Not used for ankylosing spondylitis (see section 7).

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4. Tumor Necrosis Factor Inhibitors (TNFi) — First-Line Biologics

Tumor necrosis factor inhibitors are the oldest, best-studied, and usually the first biologic class offered for ankylosing spondylitis. They work in about two-thirds of patients.

Adalimumab

40 mg subcutaneous every 2 weeks. The most prescribed biologic in the world. Self-injected at home as either a pre-filled pen or syringe. Refrigerated shipping, shelf-stable at room temperature for up to 14 days.

Etanercept

50 mg subcutaneous weekly. Self-injected. Etanercept is a soluble tumor necrosis factor receptor fusion protein (slightly different mechanism from the monoclonal antibodies). Important caveat: etanercept is not effective for inflammatory bowel disease, and the 2019 American College of Rheumatology guideline favors TNF-inhibitor monoclonal antibodies over other biologics for people with ankylosing spondylitis plus Crohn’s or UC.

Infliximab

5 mg/kg intravenous (IV) infusion at weeks 0, 2, and 6, then every 6 weeks (the label’s ankylosing spondylitis schedule). Requires an infusion center — roughly a 2-hour appointment each time. No self-injection. The label’s wording on raising the dose (up to 10 mg/kg every 8 weeks, or as often as every 4 weeks) is in its rheumatoid arthritis section, not its ankylosing spondylitis section. Excellent evidence in ankylosing spondylitis + inflammatory bowel disease and ankylosing spondylitis + uveitis.

Certolizumab pegol

400 mg subcutaneous at weeks 0, 2, and 4, then 200 mg every 2 weeks or 400 mg every 4 weeks. Certolizumab is pegylated and lacks the Fc portion of a normal antibody — which means it does not actively cross the placenta. This makes it the safest TNFi in pregnancy. See Pregnancy and ankylosing spondylitis.

Golimumab

50 mg subcutaneous monthly (the injected form), or intravenous 2 mg/kg at weeks 0 and 4, then every 8 weeks (the infusion form). Monthly dosing is a selling point for patients who hate weekly or bi-weekly injections.

Biosimilars for TNFi

Biosimilars are U.S. Food and Drug Administration-approved, near-identical copies of the originator biologic — comparable to generic drugs for small molecules, although the regulatory pathway is different.

Biosimilars are often cheaper and have equivalent efficacy in head-to-head studies. Insurance companies may force a switch to whichever biosimilar they contract with this year — this is annoying but usually clinically fine.

TNFi Response and Structural Effects

In the main adalimumab trial (ATLAS, 2006), 45.2% of patients on adalimumab reached a BASDAI 50 response (at least 50% improvement in the disease activity score) at week 12, against 15.9% on placebo. Long-term studies show slower spinal fusion with sustained TNFi use, especially when started before significant syndesmophyte formation.

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5. IL-17 Inhibitors (IL-17i) — When TNFi Fails or for Specific Comorbidities

IL-17 is a cytokine central to the spondyloarthritis disease process. Blocking it works well in ankylosing spondylitis and psoriasis, and somewhat less well in inflammatory bowel disease (where it can actually cause trouble).

Secukinumab

150 mg subcutaneous at weeks 0, 1, 2, 3, and 4, then every 4 weeks (or 150 mg every 4 weeks without the loading doses). The label lists 300 mg every 4 weeks for people whose ankylosing spondylitis is still active.

Ixekizumab

160 mg subcutaneous (two 80 mg injections) at week 0, then 80 mg every 4 weeks (the label’s ankylosing spondylitis schedule; the 80 mg doses at weeks 2, 4, 6, 8, 10, and 12 belong to the plaque-psoriasis schedule).

Bimekizumab

Newer. Targets both IL-17A and IL-17F (where secukinumab and ixekizumab only target IL-17A). 160 mg subcutaneous every 4 weeks, with no loading dose, in the label’s ankylosing spondylitis schedule. Early data suggest higher response rates than single-target IL-17i.

When to Prefer IL-17i Over TNFi

IL-17i CAUTION in Inflammatory Bowel Disease

This is crucial. Secukinumab and ixekizumab can trigger or worsen Crohn’s disease and ulcerative colitis flares. The secukinumab label reports inflammatory bowel disease flares, in some cases serious, in its clinical trials, and the 2019 American College of Rheumatology guideline favors TNF-inhibitor monoclonal antibodies (such as adalimumab or infliximab) over other biologics for people with ankylosing spondylitis plus inflammatory bowel disease. See ankylosing spondylitis and inflammatory bowel disease Overlap.

IL-17i Side Effects

Most characteristic: increased rate of candidiasis (oral thrush, vaginal yeast infections). Also injection site reactions and upper respiratory infections. Typically manageable; in the secukinumab label’s psoriasis trials, candida infections of the skin and mouth occurred in 1.2% of treated people against 0.3% on placebo.

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6. JAK Inhibitors (JAKi) — Oral Option

JAK inhibitors are small molecules, not biologics in the strict sense, but they occupy the same therapeutic niche and are often grouped with biologics in clinical conversation.

Tofacitinib

5 mg twice daily. U.S. Food and Drug Administration (FDA) approved for ankylosing spondylitis in 2021.

Upadacitinib

15 mg once daily. U.S. Food and Drug Administration approved for ankylosing spondylitis. Many rheumatologists prefer upadacitinib for its once-daily dosing and slightly more selective JAK1 inhibition.

Advantages of JAKi

Disadvantages of JAKi

The U.S. Food and Drug Administration has placed a boxed warning on all oral JAKi for serious infections (including tuberculosis), mortality (death), malignancy, MACE (major adverse cardiovascular events), and thrombosis. The warning is based on the ORAL-SURVEILLANCE trial, which was conducted in rheumatoid arthritis patients over age 50 with at least one cardiovascular risk factor. Whether the same risk applies to younger ankylosing spondylitis patients is debated, but the warning stands.

A baseline cardiovascular risk assessment is done before starting a JAKi. Both labels approve them for adults with ankylosing spondylitis who had too little response to, or could not tolerate, one or more TNF inhibitors; the labels set no IL-17-inhibitor step. They are also an option for people who cannot do injections.

Cost and Monitoring

JAKi require quarterly lab monitoring: complete blood count (CBC), LFTs, and lipid panel. JAK inhibitors reliably raise low-density lipoprotein (LDL) cholesterol and occasionally suppress neutrophil or lymphocyte counts.

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7. IL-23 Inhibitors — Currently NOT Effective for Ankylosing Spondylitis

Ustekinumab blocks IL-12 and IL-23, and risankizumab blocks IL-23, a cytokine upstream of IL-17 in the inflammatory cascade. They work beautifully in psoriasis and, to a lesser degree, peripheral psoriatic arthritis. Randomized trials in ankylosing spondylitis showed no efficacy for axial disease. This was a genuine surprise to the field given the mechanistic logic.

The 2019 American College of Rheumatology guideline states that treatment with ustekinumab (like rituximab, abatacept, or interleukin-6 inhibitors) is not recommended in ankylosing spondylitis, even when TNF inhibitors cannot be used, due to lack of effectiveness. These drugs are used for psoriatic arthritis with peripheral joint disease, not axial spondyloarthritis.

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8. Picking Your Biologic — Decision Matrix

How other conditions (comorbidities) shape the choice of drug:

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9. Cost and Insurance Reality

These drugs are expensive.

Insurance coverage is usually available with prior authorization. The PA packet typically requires: documented nonsteroidal anti-inflammatory drug failure (2+ nonsteroidal anti-inflammatory drugs for 2–4 weeks each), a BASDAI score, C-reactive protein or erythrocyte sedimentation rate results, and in some cases imaging. Many rheumatology offices have a PA coordinator who prepares this packet.

Manufacturer copay assistance programs dramatically reduce out-of-pocket costs for commercially-insured patients:

Patient assistance programs provide free drug to uninsured patients meeting income criteria — typically up to 400–500% of the federal poverty level. Applications go directly through the manufacturer.

Specialty pharmacy is required for most biologics — a few large national specialty pharmacies fill most of them. Retail pharmacies generally cannot fill these drugs. Expect monthly phone calls to confirm each shipment.

Switching biologics: insurance often enforces step therapy — a cheaper TNFi has to fail first before the plan will pay for an IL-17i or JAKi. Carefully documented failures make appeals go more smoothly.

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10. How to Give Yourself an Injection

If you have never given yourself a shot, the first one is nerve-wracking. After three or four, it’s boring. Points that injection nurses commonly teach:

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11. What to Expect — Timeline of Response

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12. Side Effects — What to Watch

Common and usually manageable:

Boxed warning: every TNF-inhibitor label (adalimumab, etanercept, infliximab, certolizumab, golimumab) carries a boxed warning for serious infections that can lead to hospitalization or death, including tuberculosis (TB), bacterial sepsis and invasive fungal infections, and for malignancy — lymphoma and other cancers, some fatal, have been reported in children and teenagers treated with TNF blockers.

Serious but rare:

Cancer risk: TNFi use is associated with a slightly increased risk of lymphoma — roughly a doubling of baseline risk, but because baseline risk is very low the absolute numbers remain small. Non-melanoma skin cancers are more common; annual skin checks are the usual practice.

Vaccines:

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13. Pre-Treatment Screening Checklist

Screening usually done before the first dose:

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14. Monitoring During Treatment

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15. Stopping or Switching

The 2019 American College of Rheumatology guideline recommends against stopping a biologic in people whose disease is stable; the observational studies it cites found relapses in 60–74% of patients after a TNF inhibitor was stopped, sometimes within a few weeks to months. Biologics can be paused for surgery — typically one dosing interval before and held until wounds are healed, often 1–2 weeks post-op — with low risk of losing response. Longer pauses (months) can cause loss of response that may require re-titration or a switch.

Switching within a class is common and often works: adalimumab to certolizumab, secukinumab to ixekizumab. Switching across classes (TNFi to IL-17i, IL-17i to JAKi) is the standard move after primary or secondary failure.

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16. Combining Biologics with Other Drugs

For non-pharmacologic adjuncts, see Exercise and PT Protocol — exercise remains foundational no matter which biologic you’re on.

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Key Research Papers

  1. van der Heijde D, et al. 2016 update of the ASAS-EULAR management recommendations for axial spondyloarthritis. Annals of the Rheumatic Diseases. 2017. — doi:10.1136/annrheumdis-2016-210770
  2. Ward MM, et al. 2019 Update of the ACR/SAA/SPARTAN recommendations for the treatment of axial spondyloarthritis. Arthritis & Rheumatology. 2019. — doi:10.1002/art.41042
  3. Baeten D, et al. Secukinumab, an interleukin-17A inhibitor, in ankylosing spondylitis (MEASURE 1 and MEASURE 2). New England Journal of Medicine. 2015. — doi:10.1056/NEJMoa1505066
  4. van der Heijde D, et al. Ixekizumab, an interleukin-17A antagonist in radiographic axial spondyloarthritis (COAST-V). Lancet. 2018. — doi:10.1016/S0140-6736(18)31946-9
  5. van der Heijde D, Kivitz A, Schiff MH, et al. (2006). Efficacy and safety of adalimumab in patients with ankylosing spondylitis: results of a multicenter, randomized, double-blind, placebo-controlled trial. Arthritis and Rheumatism — PubMed PMID: 16802350

PubMed Topic Searches

Curated PubMed topic searches — each link opens a live query so you always see the most recent literature.

  1. PubMed: Ankylosing spondylitis biologic therapy
  2. PubMed: TNF inhibitor ankylosing spondylitis
  3. PubMed: Secukinumab ankylosing spondylitis
  4. PubMed: Ixekizumab axial spondyloarthritis
  5. PubMed: Tofacitinib ankylosing spondylitis
  6. PubMed: Upadacitinib ankylosing spondylitis
  7. PubMed: Biosimilar spondyloarthritis

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Connections

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