Fasenra Insurance Denied? How to Appeal Your Benralizumab Asthma Denial

Fasenra (benralizumab) is a biologic antibody that targets the IL-5 receptor on eosinophils, causing rapid and near-complete depletion of blood and tissue eosinophils. FDA-approved for severe eosinophilic asthma, Fasenra dramatically reduces exacerbation rates and can eliminate the need for oral corticosteroids in many patients. Yet insurance denials for Fasenra are common, with patients often caught in battles over step therapy and biomarker requirements. Here's how to fight back.

What Fasenra Treats and Why Patients Need It

Fasenra is approved as an add-on maintenance treatment for severe asthma with an eosinophilic phenotype in adults. Unlike anti-IL-5 antibodies that simply neutralize the cytokine, benralizumab binds directly to the IL-5 receptor alpha chain on eosinophils and basophils, triggering antibody-dependent cell-mediated cytotoxicity (ADCC) — essentially causing the immune system to destroy eosinophils directly.

Clinical results from the SIROCCO and CALIMA trials showed:

• Approximately 50% reduction in annual exacerbation rates compared to placebo
• Significant reduction in oral corticosteroid use in OCS-dependent patients
• Rapid near-complete depletion of blood eosinophils after first injection

Fasenra has a convenient every-8-week dosing schedule after initial monthly doses, which improves adherence compared to some competitor biologics.

Why Insurers Deny Fasenra

Step therapy / preferred biologic requirements: Plans frequently mandate a trial of a different asthma biologic before approving Fasenra. Nucala (mepolizumab), Dupixent (dupilumab), or Xolair (omalizumab) may be required first depending on the plan's formulary preferences.

Eosinophil count threshold not documented: Most plans require blood eosinophils ≥150 or ≥300 cells/µL for asthma biologic approval. If this isn't documented with a recent CBC with differential, the PA is typically denied.

Severity not documented: Plans require evidence of uncontrolled severe asthma — typically ≥2 exacerbations in the prior 12 months requiring systemic corticosteroids, or OCS dependence — and this must be clearly stated in the PA documentation.

Not the preferred anti-IL-5 agent: Some plans prefer Nucala (mepolizumab) over Fasenra, and may deny coverage with a recommendation to switch.

Missing clinical documentation: Prior Authorization Denied: How to Appeal" class="auto-link">Prior authorization applications missing key information (eosinophil count, exacerbation history, current medications) are routinely denied automatically.

Step-by-Step: How to Appeal a Fasenra Denial

Step 1: Get the denial in writing and identify the specific reason. Know whether you're fighting step therapy, a threshold issue, or severity documentation.

Step 2: Pull your most recent CBC with differential. Your blood eosinophil count is the cornerstone of eligibility for Fasenra. Ensure the most recent value is available.

Step 3: Compile your exacerbation history. Document dates of all systemic steroid bursts, ER visits, urgent care visits, and hospitalizations for asthma in the past 12–24 months.

Step 4: Document your current asthma regimen. Show that you're on optimized high-dose ICS/LABA therapy. Include any LAMA, leukotriene modifier, or theophylline use.

Step 5: Have your pulmonologist or allergist write a Letter of Medical Necessity addressing your eosinophil count, exacerbation frequency, prior treatments, and clinical rationale for selecting Fasenra specifically over competitor biologics.

Step 6: Submit your internal appeal with complete documentation and request peer-to-peer review.

Step 7: File an external appeal if needed.

What to Include in Your Fasenra Appeal Letter

• Policy number, member ID, and claim reference
• Fasenra (benralizumab) prescribed dose and frequency
• Blood eosinophil count with test date (CBC with differential)
• Pulmonary function testing results if available (FEV1, FEV1/FVC)
• Asthma exacerbation history with dates and severity
• Current asthma medications (ICS, LABA, LAMA, OCS if applicable)
• OCS daily dose and duration if patient is OCS-dependent
• Prior biologic trials if any (name, duration, response)
• Letter of Medical Necessity from pulmonologist or allergist
• SIROCCO and CALIMA trial citations
• GINA severe asthma management guidelines citation
• Request for peer-to-peer review

Success Tips for Fasenra Appeals

Emphasize your eosinophil count. Fasenra is designed for eosinophilic asthma. A count ≥300 cells/µL is the strongest qualifier and correlates with the most dramatic clinical response in trials. Highlight this number prominently.

Document OCS burden. If you're on daily or frequent oral corticosteroids, the medical and cost argument for Fasenra is compelling. OCS-dependent asthma patients face serious long-term risks from steroid use, and Fasenra has demonstrated the ability to eliminate OCS in many patients.

Challenge the preferred biologic substitution. If your plan wants to substitute Nucala for Fasenra, your physician should document whether there's a clinical reason to prefer benralizumab — such as prior experience with mepolizumab with suboptimal response, or preference for the every-8-week dosing schedule.

Request your plan's specific prior auth criteria. Match your documentation point-by-point to the plan's requirements. This methodical approach is far more effective than a general appeal letter.

Fight Back With ClaimBack

Severe eosinophilic asthma can cause serious, life-threatening attacks. You deserve access to the biologic your pulmonologist prescribed. ClaimBack helps you build a compelling, complete appeal so you can get the medication you need.

Start your Fasenra appeal at ClaimBack

Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Common Reasons Insurance Claims Are Denied