In an adult acute myeloid leukemia patient receiving chemotherapy and immunocompromised who has a severe asthma exacerbation, which add‑on biologic—benralizumab (anti‑IL‑5 receptor α) or tezepelumab (anti‑TSLP)—is safer?

Tezepelumab is the Safer Choice for an Immunocompromised AML Patient with Severe Asthma Exacerbation

In an immunocompromised adult with acute myeloid leukemia receiving chemotherapy who develops a severe asthma exacerbation, tezepelumab (anti-TSLP) is the safer biologic choice over benralizumab (anti-IL-5 receptor α) because benralizumab causes complete and rapid depletion of eosinophils within 24 hours, which could further compromise immune defense in an already profoundly immunosuppressed patient. 1, 2

Critical Safety Consideration: Eosinophil Depletion in Immunocompromised Patients

• Benralizumab achieves 100% depletion of blood eosinophils within 24 hours by targeting the IL-5 receptor alpha, resulting in antibody-dependent cell-mediated cytotoxicity (ADCC) that eliminates eosinophils completely. 1, 2

• In an AML patient already receiving chemotherapy with profound immunosuppression, further elimination of eosinophils—which play a role in host defense against certain pathogens—poses additional infection risk that is unacceptable in this clinical context. 3

• Tezepelumab does not cause direct eosinophil depletion but rather modulates upstream inflammatory pathways by blocking thymic stromal lymphopoietin (TSLP), preserving some residual immune function. 4

Mechanism-Based Safety Profile

• Tezepelumab's mechanism is "upstream" of multiple inflammatory pathways, affecting type 2 inflammation without completely ablating specific immune cell populations, making it inherently safer in immunocompromised states. 4, 5

• The reported adverse events for tezepelumab include arthralgia, injection-site reactions, anaphylaxis, and upper respiratory tract infections—none of which involve profound immune cell depletion. 4

• Benralizumab's safety profile includes worsening asthma, nasopharyngitis, and injection site reactions, but the critical concern is the complete eosinophil depletion in a patient who cannot afford further immunosuppression. 2

Efficacy Considerations Support Tezepelumab

• Tezepelumab demonstrates clinical effectiveness in both type 2 and non-type 2 severe asthma phenotypes, providing broad coverage regardless of the underlying inflammatory endotype, which is advantageous when phenotyping may be complicated by AML and chemotherapy. 4, 5

• Clinical improvements with tezepelumab, including reduction in exacerbation frequency and symptom control, can become apparent within a few weeks to several months of initiating therapy. 4

• While benralizumab has been reported to work rapidly in acute exacerbations (even within 24 hours in case reports), this rapid eosinophil depletion is precisely what makes it unsafe in this immunocompromised context. 6

Dosing and Administration

• Tezepelumab is administered as 210 mg subcutaneously every 4 weeks via auto-injector or pre-filled syringe in the abdomen, thigh, or upper arm. 4

• The first two injections should be performed in a hospital setting to allow for patient training and monitoring for potential anaphylactic reactions, which is particularly important in an AML patient with multiple comorbidities. 4, 3

• After initial supervised doses, patients can self-administer subsequent injections, though in an AML patient receiving chemotherapy, continued hospital-based administration may be prudent given the complex medical situation. 4

Critical Pitfalls to Avoid

• Do not use benralizumab in immunocompromised patients where complete eosinophil depletion could compromise remaining immune defenses against opportunistic infections. 1, 2

• Avoid invasive procedures including bronchoscopy during acute AML management due to hemorrhagic and thrombotic complications, which is relevant when considering diagnostic workup before initiating biologic therapy. 3

• Biologics should be added to, not replace, optimized inhaled corticosteroid/long-acting β-agonist therapy, even in the acute setting, though systemic corticosteroids may need careful consideration given infection risk in AML. 1, 2

• Monitor closely for infections given that tezepelumab's adverse event profile includes upper respiratory tract infections, which could be more severe in an immunocompromised host. 4

Supporting Evidence from Guidelines

• Recent 2025 guidelines recommend tezepelumab for both type 2 and non-type 2 asthma, with specific mention that it is appropriate when other biologics may be contraindicated. 3

• The 2024 ISHAM-ABPA guidelines note that biological agents including tezepelumab have been used successfully in complex respiratory conditions, though they emphasize the importance of considering the patient's overall immune status. 3

• All biologics demonstrate favorable safety profiles in immunocompetent patients, but the specific mechanism of benralizumab's complete eosinophil depletion creates unique risk in immunocompromised states that is not present with tezepelumab. 2, 7