Which baseline laboratory tests are required before initiating ixekizumab (Taltz) and what monitoring schedule should be followed after starting therapy?

Baseline Laboratory Testing and Monitoring for Taltz (Ixekizumab)

Before initiating Taltz, you must evaluate for tuberculosis infection; no other routine laboratory tests are mandated by FDA labeling, though baseline inflammatory markers and screening for hepatitis B are reasonable in clinical practice. 1

Pre-Treatment Requirements

Mandatory Screening

• Tuberculosis evaluation is the only FDA-mandated pre-treatment assessment 1
  • Do not administer to patients with active TB
  • Initiate treatment of latent TB prior to starting Taltz
  • Consider anti-TB therapy in patients with past history of latent or active TB where adequate treatment cannot be confirmed

Additional Baseline Considerations (Not FDA-Mandated but Clinically Prudent)

While the FDA label does not require routine laboratory monitoring 1, the AAD-NPF guidelines for biologics in psoriasis suggest baseline screening practices that can be extrapolated to IL-17 inhibitors 2:

• Hepatitis B screening (HBsAg, anti-HBc, anti-HBs) - particularly important given infection risk
• Complete blood count (CBC) - to establish baseline
• Pregnancy test in women of childbearing potential - safety during pregnancy is unknown 2

Ongoing Monitoring Schedule

There is no FDA-mandated laboratory monitoring schedule for Taltz after initiation 1. This distinguishes IL-17 inhibitors from agents like methotrexate that require regular liver function monitoring.

Clinical Monitoring Focus

Instead of routine labs, monitoring should focus on:

• Signs and symptoms of infection - upper respiratory infections, oral candidiasis, conjunctivitis, and opportunistic infections occur more frequently 1
• Active TB surveillance - monitor closely for signs/symptoms during and after treatment 1
• Gastrointestinal symptoms - abdominal pain, diarrhea, hematochezia, or weight loss may indicate inflammatory bowel disease, which can occur within the first 6 months (median onset 4 months) 3
• Eczematous eruptions - severe cases have been reported from days to months after first dose 1

Key Clinical Pitfalls

Common Misconceptions

Unlike traditional DMARDs, Taltz does not require routine CBC or liver function monitoring - this is a critical distinction from methotrexate protocols that many clinicians reflexively apply to all systemic therapies 1.

High-Risk Scenarios Requiring Vigilance

• Inflammatory bowel disease risk: Patients with gastrointestinal symptoms or family history of IBD should be carefully evaluated before starting therapy 3. During treatment, new-onset abdominal pain, diarrhea, or hematochezia warrants immediate evaluation and potential discontinuation 1
• Infection susceptibility: If serious infection develops or patient is not responding to standard therapy, discontinue Taltz until infection resolves 1

When to Consider Laboratory Testing During Treatment

While not mandated, consider checking inflammatory markers (CRP) if:

• Assessing disease activity in axial spondyloarthritis patients 4
• Evaluating potential infection or inflammatory bowel disease complications
• Patient develops unexplained systemic symptoms

Practical Algorithm

Before First Dose:

1. TB screening (mandatory) 1
2. Hepatitis B panel (prudent)
3. Pregnancy test if applicable
4. Rule out active infection
5. Screen for IBD history/symptoms 3

During Treatment:

• No routine laboratory monitoring required 1
• Clinical assessment at each visit for infection, GI symptoms, skin reactions
• Laboratory testing only if clinically indicated by symptoms

This streamlined approach reflects the favorable safety profile of IL-17 inhibitors compared to other immunosuppressive agents, though vigilance for specific complications remains essential.