FDA Accepts Tezepelumab Biologics License Application and Grants Priority Review

Tezepelumab, a novel human monoclonal antibody that blocks thymic stromal lymphopoietin (TSLP), was granted Priority Review for the treatment of asthma from the US food and Drug Administration (FDA) today, according to statements from codevelopers AstraZeneca and Amgen. The Priority Review was in response to a Biologics License Application (BLA) submitted on May 10, 2021.

TSLP is an epithelial-cell–derived cytokine that sits upstream of many inflammatory cascades. The cytokine is essential in the initiation and persistence of allergic, eosinophilic, and other types of airway inflammation associated with severe asthma.

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Severe asthma, which affects approximately 10% of asthma patients, places them at increased risk of mortality and at twice the risk of asthma-related hospitalizations vs patients with persistent asthma, according to company statements. Approximately two-thirds of patients with severe asthma have type 2- (T2) inflammation-driven asthma which includes eosinophilic asthma. These patients typically exhibit elevated levels of inflammatory biomarkers, including blood eosinophils, serum IgE and fractional exhaled nitric oxide. They remain uncontrolled despite use of inhaled controller medications, available biologic therapies, and oral corticosteroids (OCS).

Drivers of inflammation in severe asthma may be unclear and patients may not respond well to or qualify for current biologics. Severe asthma is characterized by frequent exacerbations, decreased lung function, and impaired quality of life, according to company statements.

"Severe asthma is a challenging, complex disease for physicians and millions of patients and has a high unmet medical need," said David M. Reese, M.D., executive vice president of Research and Development at Amgen, in the company statement. "We are proud to advance an innovative, first-in-class monoclonal antibody that targets the top of the inflammatory cascade and represents a potentially transformative treatment option for a broad population of patients with severe asthma.”

In a statement, Mene Pangalos, executive vice president, BioPharmaceuticals R&D for AstraZeneca, explained: “Tezepelumab has demonstrated reductions in exacerbations irrespective of blood eosinophil counts, allergy status and fractional exhaled nitric oxide, and has the potential to transform treatment for a broad population of severe asthma patients.”

Results from the PATHFINDER clinical trial program laid the foundation for the BLA with pivotal findings reported from the NAVIGATOR phase 3 trial. Participants in NAVIGATOR had severe uncontrolled asthma and were receiving standard of care (SOC) treatment with medium- or high-dose inhaled corticosteroids (ICS) plus at least one additional controller medication with or without OCS. When added to SOC, tezepelumab demonstrated superiority across all primary and key secondary endpoints vs placebo.

The NAVIGATOR trial population included approximately equal proportions of patients with high (≥300 cells/µL) and low (<300 cells/µL) blood eosinophil counts. In the subgroup of patients with baseline eosinophil counts <300 cells/cells/µL, the trial met the primary endpoint, with tezepelumab demonstrating a statistically significant and clinically meaningful reduction in annualized asthma exacerbation rate (AAER).

Importantly, similar reductions in AAER were seen in the subgroup of patients with baseline eosinophil counts <150 cells/µL, a group not currently well served by existing treatments for severe asthma which are approved for patients with eosinophilic, vs non-eosinophilic, asthma.

Investigators reported no clinically meaningful differences in safety results between the tezepelumab and placebo groups in NAVIGATOR. The most frequently reported adverse events with tezepelumab were nasopharyngitis, upper respiratory tract infection and headache.8

Results from the NAVIGATOR Phase 3 trial were published in the New England Journal of Medicine in May 2021.

Tezepelumab was granted an FDA Breakthrough Therapy Designation for patients with severe asthma without an eosinophilic phenotype in September 2018.