Ixekizumab (Taltz)
ixekizumab — humanized anti-interleukin-17A monoclonal antibody (IgG4)
Approved Indications & Off-Label Uses
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Moderate-to-severe plaque psoriasis | Patients ≥6 years; candidates for systemic therapy or phototherapy | Monotherapy | FDA Approved |
| Active psoriatic arthritis | Adults | Monotherapy or with conventional DMARDs (e.g., MTX) | FDA Approved |
| Active ankylosing spondylitis | Adults | Monotherapy | FDA Approved |
| Active non-radiographic axial spondyloarthritis | Adults with objective signs of inflammation | Monotherapy | FDA Approved |
Ixekizumab is the second IL-17A inhibitor approved in the United States (March 2016, after secukinumab in January 2015). It can be used as a first-line biologic for plaque psoriasis, PsA, AS, and nr-axSpA without requiring prior TNF inhibitor failure. In PsA, ixekizumab may be given with or without methotrexate. Unlike secukinumab, ixekizumab uses a more intensive every-2-week induction for psoriasis and has no IV formulation.
Palmoplantar pustulosis: Open-label data support use; Evidence quality: Low.
Reactive arthritis: Case series suggest benefit; Evidence quality: Very low.
Hidradenitis suppurativa: Phase II data available; secukinumab (not ixekizumab) has the FDA approval for this indication. Evidence quality: Low.
Dosing by Clinical Scenario
Subcutaneous Dosing — All Indications
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Plaque psoriasis — adults | 160 mg (2×80 mg) at Week 0 | 80 mg Q2W (Wk 2–12), then 80 mg Q4W | 80 mg Q4W | Intensive Q2W induction ×12 weeks provides rapid skin clearance Steady-state trough ~9.3 μg/mL achieved by Week 8 during Q2W phase |
| Plaque psoriasis — pediatric ≥6 yrs, >50 kg | 160 mg (2×80 mg) at Week 0 | 80 mg Q4W | 80 mg Q4W | No Q2W induction in pediatrics Weight-based: 25–50 kg = 80/40 mg; <25 kg = 40/20 mg |
| Psoriatic arthritis — adults | 160 mg (2×80 mg) at Week 0 | 80 mg Q4W | 80 mg Q4W | Use PsO dosing (Q2W induction) if coexistent moderate-severe PsO May be used with or without methotrexate |
| Ankylosing spondylitis — adults | 160 mg (2×80 mg) at Week 0 | 80 mg Q4W | 80 mg Q4W | Single loading dose followed by monthly maintenance |
| Non-radiographic axial spondyloarthritis | 80 mg Q4W (no loading) | 80 mg Q4W | 80 mg Q4W | No loading dose for nr-axSpA — this differs from all other indications The only ixekizumab indication without a loading dose |
Ixekizumab uses a more intensive Q2W induction for plaque psoriasis (7 doses in 12 weeks), reflecting its shorter half-life (~13 days vs ~27 days for secukinumab). This achieves rapid PASI responses — more than 40% of patients reached PASI 100 by week 12 in pivotal trials. For PsA and AS, ixekizumab uses a single 160 mg loading dose (vs secukinumab’s weekly loading over 5 weeks). For nr-axSpA, ixekizumab uniquely has no loading dose at all.
Pharmacology & Mechanism of Action
Mechanism of Action
Ixekizumab is a humanized IgG4 monoclonal antibody that selectively binds to the pro-inflammatory cytokine interleukin-17A (IL-17A) with high affinity. It also binds the IL-17A/F heterodimer, but does not bind IL-17B, IL-17C, IL-17D, IL-17E, or IL-17F homodimer. By neutralising IL-17A, ixekizumab prevents its interaction with the IL-17 receptor complex (IL-17RA/IL-17RC), blocking downstream signalling that drives keratinocyte proliferation, neutrophil chemotaxis, and pro-inflammatory gene expression in the skin, synovium, and entheses. The IgG4 subclass was selected to minimise Fc-mediated effector functions such as complement activation and antibody-dependent cellular cytotoxicity, which are not relevant to the therapeutic mechanism of cytokine neutralisation.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | SC: Tmax ~4 days; bioavailability 60–81% (injection site-dependent: thigh > abdomen > arm); steady state by Week 8 with Q2W dosing | Thigh injection yields highest exposure; Q2W induction achieves therapeutic levels rapidly for psoriasis |
| Distribution | Vss 7.11 L; limited extravascular tissue distribution typical for IgG4 mAb; clearance and Vd increase with body weight | Vd close to plasma volume; weight-based dosing used in pediatrics but not adults |
| Metabolism | Expected catabolic degradation to amino acids and small peptides via intracellular proteolysis; no CYP enzyme involvement; no active metabolites | Extremely low pharmacokinetic drug interaction potential; no hepatic metabolism concerns |
| Elimination | CL 0.39 L/day; t½ ~13 days (geometric mean; CV 40%); linear PK over 5–160 mg dose range | Shorter half-life than secukinumab (~13 vs ~27 days) necessitates the Q2W induction in PsO; Q4W maintenance adequate at steady state |
Side Effects & Adverse Reactions
Data below are from pooled Phase III placebo-controlled plaque psoriasis trials (TALTZ Q2W N=1167 vs placebo N=791) through 12 weeks, supplemented by 60-week and long-term open-label data (FDA PI, revised 08/2024).
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Injection site reactions | 17% | Most common AE; primarily erythema and pain; mild-moderate; rarely leads to discontinuation (vs 3% placebo) |
| Upper respiratory tract infections | 14% | Includes nasopharyngitis and rhinovirus infection (vs 13% placebo — marginal increase) |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Nausea | 2% | Generally mild and transient (vs 1% placebo) |
| Tinea infections | 2% | Reflects IL-17A role in cutaneous antifungal immunity; includes tinea pedis, corporis, cruris (vs <1% placebo) |
| Oral candidiasis | <1% | IL-17A blockade impairs mucosal Candida defence; most mild and treatable with standard antifungals |
| Conjunctivitis | <1% | Occurred more frequently than placebo; generally mild |
| Urticaria | <1% | Hypersensitivity-related |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Serious infections | 0.4% through 12 weeks; 0.7% through 60 weeks (0.02/subject-year) | Any time during treatment | Discontinue until infection resolves; postmarketing reports of serious opportunistic bacterial, viral, and fungal infections |
| Inflammatory bowel disease (Crohn’s / UC) | CD 0.1%; UC 0.2% (through 12 weeks vs 0% placebo) | Variable; weeks to months | Discontinue ixekizumab and initiate appropriate IBD management; monitor closely if pre-existing IBD |
| Neutropenia (Grade ≥3, ANC <1000) | 0.2% through 12 weeks | Early treatment; incidence decreases after Week 12 | Overall neutropenia (all grades) in 11% vs 3% placebo through 60 weeks; majority Grade 1-2 and transient; no associated serious infections in most cases |
| Anaphylaxis / angioedema | Each ≤0.1% (clinical trials); additional cases reported postmarketing | Any injection | Discontinue permanently; initiate emergency therapy |
| Severe eczematous eruptions (postmarketing) | Rare (postmarketing) | Days to months after first dose | May need to discontinue; includes atopic dermatitis-like eruptions, dyshidrotic eczema, erythroderma; some patients managed while continuing therapy |
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| Injection site reactions | Uncommon despite high prevalence | Most were mild-moderate and tolerable; erythema and pain predominate |
| Infections | Uncommon | Serious infections at similar rates to placebo through 12 weeks |
| IBD | Rare | Both new-onset and exacerbation of pre-existing IBD; FDA label mandates discontinuation if IBD develops |
Injection site reactions are the most distinguishing adverse effect of ixekizumab compared to other IL-17 inhibitors and affect approximately 1 in 6 patients during the Q2W induction phase. The reactions are predominantly local erythema and pain, are generally mild-to-moderate, and tend to diminish over time as the dosing frequency transitions to Q4W. Rotating injection sites and allowing the prefilled syringe/autoinjector to reach room temperature (30 minutes) before injection can reduce discomfort. Reassure patients that these reactions rarely require treatment discontinuation.
Drug Interactions
Ixekizumab is an IgG4 monoclonal antibody eliminated by intracellular catabolism. No formal drug interaction studies have been conducted. IL-17A and ixekizumab are not known to interact with CYP enzymes. The main interactions are pharmacodynamic.
Monitoring Parameters
- TB ScreeningBaseline
RoutineEvaluate for latent/active TB before initiating. Do not administer to patients with active TB. Initiate treatment for latent TB prior to starting ixekizumab. Monitor for TB signs/symptoms during treatment. - Signs of InfectionEvery visit
Trigger-basedMonitor for fever, cough, skin infections, fungal infections (tinea, oral candidiasis). Overall infection rate was 27% vs 23% placebo. Serious opportunistic infections reported postmarketing. Discontinue for serious infections until resolved. - IBD SymptomsEvery visit
Trigger-basedMonitor for new or worsening abdominal pain, diarrhoea, bloody stools. Crohn’s disease and UC exacerbations occurred more frequently with ixekizumab than placebo. If IBD develops, discontinue ixekizumab per FDA PI guidance. - Injection Site ReactionsFirst few months
Routine17% incidence; monitor for erythema, pain, swelling. Generally diminish over time as Q2W transitions to Q4W dosing. Ensure proper injection technique and rotation. - Skin ExaminationPeriodic
Trigger-basedMonitor for eczematous eruptions (postmarketing: atopic dermatitis-like, dyshidrotic eczema, erythroderma). Onset variable (days to months). May require discontinuation. - ImmunisationsBaseline
RoutineComplete age-appropriate vaccinations before initiating. Avoid live vaccines during treatment. Inactivated and recombinant vaccines may be given.
Contraindications & Cautions
Absolute Contraindications
- Known serious hypersensitivity to ixekizumab or any excipient — anaphylaxis reported in clinical trials and postmarketing
- Active tuberculosis infection — initiate latent TB treatment before starting ixekizumab
Relative Contraindications (Specialist Input Recommended)
- Active inflammatory bowel disease — ixekizumab increased Crohn’s and UC frequency vs placebo; FDA PI mandates discontinuation if IBD develops
- Active serious infection — do not initiate until infection is controlled
Use with Caution
- Chronic or recurrent infections — higher infection rate observed vs placebo (27% vs 23%)
- Pre-existing IBD or IBD history — monitor closely; IL-17A inhibition has worsened IBD in clinical settings
- Pregnancy — limited human data; neonatal deaths observed in monkey studies at high doses; use only if benefit justifies risk; pregnancy registry available (1-800-284-1695)
- Lactation — ixekizumab detected in animal milk; unknown in human milk; weigh benefit-risk
- Combination with other biologics — not studied and not recommended
In clinical trials, Crohn’s disease (0.1%) and ulcerative colitis (0.2%) occurred more frequently in the ixekizumab group than placebo (0%) during the 12-week placebo-controlled period. The FDA label states: during treatment, monitor for onset or exacerbation of IBD and if IBD occurs, discontinue ixekizumab and initiate appropriate medical management. Exercise caution when prescribing to patients with IBD or IBD risk factors.
Patient Counselling
Purpose of Therapy
Ixekizumab is a biologic medicine that targets a specific protein called IL-17A, which drives the inflammation that causes skin plaques, joint pain, and spinal stiffness. By blocking IL-17A, it reduces inflammation and helps clear skin plaques, relieve joint symptoms, and improve mobility.
How to Take
Ixekizumab is given as an injection under the skin using a prefilled autoinjector pen or syringe. For psoriasis, an initial higher dose is given on day 1, followed by an injection every 2 weeks for the first 3 months, then every 4 weeks thereafter. For joint or spinal conditions, a loading dose is given on day 1 followed by a monthly injection. Patients or caregivers can learn to self-inject at home. Rotate injection sites (thigh, abdomen, or upper arm) and allow the pen/syringe to reach room temperature (30 minutes) before injecting.
Sources
- TALTZ (ixekizumab) [prescribing information]. Indianapolis, IN: Eli Lilly and Company; Revised 08/2024. FDA Label (PDF)Primary regulatory source for all dosing, indications, adverse reactions, warnings, and PK data cited in this monograph.
- European Medicines Agency. Taltz (ixekizumab): EPAR — Product information. EMA Product PageEU regulatory perspective; provides complementary pregnancy/lactation data and injection-site bioavailability details.
- Gordon KB, Blauvelt A, Papp KA, et al. Phase 3 trials of ixekizumab in moderate-to-severe plaque psoriasis. N Engl J Med. 2016;375(4):345-356. doi:10.1056/NEJMoa1512711UNCOVER-2 and UNCOVER-3 pivotal trials demonstrating superiority of ixekizumab over etanercept and placebo in PsO; source for primary adverse reaction data (Table 2).
- Griffiths CEM, Reich K, Lebwohl M, et al. Comparison of ixekizumab with etanercept or placebo in moderate-to-severe psoriasis (UNCOVER-3): results from a phase 3, randomised, double-blind study. Lancet. 2015;386(9993):541-551. doi:10.1016/S0140-6736(15)90138-3UNCOVER-3 Phase 3 trial confirming rapid PASI 75/90/100 responses with ixekizumab; long-term extension data available.
- Mease PJ, van der Heijde D, Ritchlin CT, et al. Ixekizumab, an interleukin-17A specific monoclonal antibody, for the treatment of biologic-naive patients with active psoriatic arthritis: results from the 24-week randomised, double-blind, placebo-controlled and active (adalimumab)-controlled period of the phase III trial SPIRIT-P1. Ann Rheum Dis. 2017;76(1):79-87. doi:10.1136/annrheumdis-2016-209709SPIRIT-P1 trial demonstrating ixekizumab non-inferiority to adalimumab in biologic-naive PsA patients on ACR20/50 endpoints.
- Nash P, Kirkham B, Okada M, et al. Ixekizumab for the treatment of patients with active psoriatic arthritis and an inadequate response to tumour necrosis factor inhibitors: results from the 24-week randomised, double-blind, placebo-controlled period of the SPIRIT-P2 study. Lancet. 2017;389(10086):2317-2327. doi:10.1016/S0140-6736(17)31429-0SPIRIT-P2 trial in TNF-IR PsA patients; demonstrated efficacy of ixekizumab 80 mg Q4W on joints, skin, enthesitis, and dactylitis.
- Deodhar A, van der Heijde D, Gensler LS, et al. Ixekizumab for patients with non-radiographic axial spondyloarthritis (COAST-X): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2020;395(10217):53-64. doi:10.1016/S0140-6736(19)32971-XCOAST-X trial establishing ixekizumab 80 mg Q4W (no loading) efficacy in nr-axSpA; ASAS40 primary endpoint met at weeks 16 and 52.
- van der Heijde D, Cheng-Chung Wei J, Dougados M, et al. Ixekizumab, an interleukin-17A antagonist in the treatment of ankylosing spondylitis or radiographic axial spondyloarthritis in patients previously untreated with biological disease-modifying anti-rheumatic drugs (COAST-V): results of a phase 3, randomised, double-blind, active-controlled and placebo-controlled trial. Lancet. 2018;392(10163):2441-2451. doi:10.1016/S0140-6736(18)31946-9COAST-V trial demonstrating ixekizumab efficacy in biologic-naive AS patients; significant ASAS40 improvement vs placebo at week 16.
- Gossec L, Kerschbaumer A, Ferreira RJO, et al. EULAR recommendations for the management of psoriatic arthritis with pharmacological therapies: 2023 update. Ann Rheum Dis. 2024;83(6):706-719. doi:10.1136/ard-2024-225531Most current EULAR PsA guidelines; positions IL-17 inhibitors as first-line biologic options alongside TNF inhibitors.
- Ramiro S, Nikiphorou E, Sepriano A, et al. ASAS-EULAR recommendations for the management of axial spondyloarthritis: 2022 update. Ann Rheum Dis. 2023;82(1):19-34. doi:10.1136/ard-2022-223296ASAS-EULAR 2022 update recommends IL-17 inhibitors as first-line biologics for axial SpA.
- Gaffen SL, Jain R, Garg AV, Cua DJ. The IL-23–IL-17 immune axis: from mechanisms to therapeutic testing. Nat Rev Immunol. 2014;14(9):585-600. doi:10.1038/nri3707Foundational review of the IL-23/IL-17 axis; explains why IL-17A blockade is effective across psoriatic disease and spondyloarthritis.
- Langley RG, Kimball AB, Nak H, et al. Long-term safety profile of ixekizumab in patients with moderate-to-severe plaque psoriasis: an integrated analysis from 11 clinical trials. J Eur Acad Dermatol Venereol. 2019;33(2):333-339. doi:10.1111/jdv.15242Integrated long-term safety analysis across 11 PsO trials; provides exposure-adjusted rates of infections, neutropenia, IBD, and candidiasis with extended follow-up.
- Zhu B, Edson-Heredia E, Cameron GS, et al. Early clinical response as a predictor of subsequent response to ixekizumab treatment: results from a phase II study of patients with moderate-to-severe plaque psoriasis. Br J Dermatol. 2013;169(6):1337-1341. doi:10.1111/bjd.12610Early-phase data characterising ixekizumab dose-response and early clinical response kinetics that informed pivotal trial dosing.