The unmet need driving alarmin biology investment
Severe asthma affects an estimated 10–15% of the approximately 315 million asthma patients worldwide, and as many as 60% of those patients have inadequately controlled disease despite maximal inhaled corticosteroid (ICS) and long-acting beta-agonist (LABA) regimens, according to patent filings from Amgen and MedImmune. This treatment gap—tens of millions of patients with no adequate pharmacological option—is the commercial and scientific engine behind the alarmin-targeting biologic wave now visible across patent databases.
The inflammatory heterogeneity of severe asthma—spanning eosinophilic, non-eosinophilic, and corticosteroid-dependent phenotypes—has made a single biologic solution elusive. Biologics targeting downstream effectors such as IL-5 or IgE leave non-eosinophilic patients without options. The field has consequently moved upstream, toward the epithelial alarmins—TSLP, IL-33, and IL-25—that sit at the apex of both innate and adaptive immune activation and are released in response to environmental triggers including allergens, viruses, and pollutants.
According to WHO estimates, asthma is among the most common chronic diseases globally, and the economic burden of severe, uncontrolled disease is disproportionate. The patent landscape analyzed here reflects a field in which multiple large pharmaceutical companies—Amgen, AstraZeneca/MedImmune, Regeneron, Sanofi, Novartis, and Genentech/Roche—are simultaneously prosecuting IP across overlapping molecular targets, indicating both the scale of the commercial opportunity and the intensity of competitive pressure.
As many as 60% of severe asthma patients—estimated from a global pool of approximately 315 million asthma patients—have inadequately controlled disease despite maximal ICS and LABA therapy, according to patent filings from Amgen and MedImmune reviewed in a PatSnap patent dataset analysis.
The three canonical alarmins—TSLP, IL-33, and IL-25—and their cognate receptors (TSLP-R/IL-7Rα, ST2/IL1RL1, and IL17RB respectively) constitute the full alarmin receptor network identified across TH2 pathway patents from Genentech/Roche and University of California-based academic filings. Each alarmin operates at a distinct node of the airway epithelial injury response, and their combined activity explains why single-target blockade may be insufficient in a subset of patients.
Tezepelumab and the TSLP IP fortress
Tezepelumab, the anti-TSLP monoclonal antibody co-developed by Amgen and MedImmune (AstraZeneca), represents the most extensively prosecuted single alarmin target in the patent dataset analyzed. Its core IP—rooted in PCT/US2018/027271 with a priority date of April 12, 2017—spans active or pending filings across at least nine jurisdictions: US, WO, AU, CA, IL, JP, TN, and IN, indicating a deliberate strategy to establish broad international protection before generic or biosimilar competition emerges.
TSLP (thymic stromal lymphopoietin) is an epithelial-derived upstream alarmin that activates dendritic cells, drives naïve T cell differentiation into Th2 cells, and promotes cytokine secretion from mast cells, eosinophils, and macrophages. Because it acts before the Th2 cascade initiates, blocking TSLP can suppress both eosinophilic and non-eosinophilic inflammatory phenotypes—a mechanistic advantage over downstream biologics.
The mechanistic rationale for anti-TSLP therapy, as described consistently across Amgen and MedImmune filings, centers on blocking TSLP before it can activate dendritic cells and initiate downstream Th2 cascades. This upstream positioning enables efficacy across both eosinophilic and non-eosinophilic phenotypes—a population not served by anti-IL-5 or anti-IgE biologics—and is explicitly claimed in retrieved filings. A Japanese-jurisdiction Amgen patent states that tezepelumab reduces exacerbations in both low-EOS and high-EOS patients and may enable steroid-free disease control.
“Tezepelumab’s upstream mechanism enables efficacy across both eosinophilic and non-eosinophilic severe asthma phenotypes—a population not served by anti-IL-5 or anti-IgE biologics.”
The most recent MedImmune filings (WO 2024, AU 2025, CN 2026) specifically address corticosteroid-dependent severe asthma, claiming methods for anti-TSLP antibody use in OCS-dependent patients. These filings claim priority to US provisional applications filed in 2023, suggesting ongoing or completed clinical studies in the OCS-dependent population. This represents a lifecycle management strategy: expanding the tezepelumab label from broad severe asthma into a more refractory, steroid-dependent segment where unmet need is particularly acute.
Novartis AG holds a separate cluster of anti-TSLP filings (WO 2021/152488 and national phase entries in CA, AU, IL, JP, CN) that extend anti-TSLP antibody coverage to COPD and inflammatory/obstructive airway disease more broadly. These filings appear to cover a distinct anti-TSLP antibody program from tezepelumab, signaling that the TSLP target is being pursued by at least two major companies with potentially differentiated molecules and indications.
Map the full tezepelumab patent estate and identify white-space opportunities across alarmin targets.
Explore TSLP Patent Data in PatSnap Eureka →IL-33 antagonists: a crowded and contested axis
The IL-33/ST2 axis has attracted at least three major pharmaceutical programs—MedImmune/AstraZeneca (tozorakimab), Regeneron/Sanofi (itepekimab), and a third program referenced via etokimab—making it the most competitively crowded single target in the alarmin space. Each program is pursuing differentiation through distinct patient populations, dosing regimens, and, increasingly, genomic stratification criteria.
A MedImmune JP-jurisdiction patent explicitly references Phase 2 clinical trial NCT03469934, in which a single IV dose of etokimab (an anti-IL-33 antibody) in uncontrolled moderate-to-severe asthma patients produced significant FEV1 improvement and blood eosinophil reduction versus placebo.
Tozorakimab (MedImmune Limited/AstraZeneca) is described in WO and AU jurisdiction filings as a human IgG1 monoclonal antibody binding human IL-33 with high affinity, blocking interaction with both soluble ST2 (sST2) and membrane-bound ST2 (IL1RL1). A separate MedImmune WO 2025 filing describes a randomized double-blind placebo-controlled trial evaluating tozorakimab in adults with uncontrolled moderate-to-severe asthma, while a patient-stratification filing from the same year selects specific subgroups based on defined clinical criteria—signaling that the tozorakimab program is moving toward precision indication claims.
Itepekimab (Regeneron/Sanofi) is covered by filings across SG, TW, MX, WO, and CN jurisdictions, with priority dates tracing to 2019 US provisional applications. Notably, multiple Regeneron filings explicitly claim combination regimens pairing anti-IL-33 (itepekimab) with anti-IL-4R (dupilumab)—targeting both the upstream alarmin trigger and the downstream Th2 effector pathway simultaneously. This combination strategy, if validated clinically, could represent a meaningful differentiation from single-alarmin approaches, according to NIH-registered trial frameworks for combination biologics in severe asthma.
A particularly forward-looking signal in the IL-33 IP cluster is the emergence of genomic patient stratification. A MedImmune JP 2026 filing introduces treatment selection based on IL33 risk allele genotypes (IL1RL1 polymorphisms), while a Regeneron CN 2024 filing describes using IL-33 polygenic risk scores (PRS) to identify patients likely to respond to IL-33 antagonists, IL-4Rα antagonists, or IL-13 receptor antagonists. These filings signal that the field is generating IP not only for molecules but for their companion biomarker-defined indications—a trend with significant competitive implications.
Bispecific and multi-alarmin blockade: the next frontier
Bispecific molecules simultaneously targeting two alarmins or an alarmin plus a downstream effector represent the most nascent but strategically significant IP cluster in this dataset. The rationale is straightforward: if 40–50% of severe asthma patients fail single-alarmin targeting, simultaneous blockade of two nodes in the alarmin cascade may deliver additive or synergistic efficacy.
Sanofi’s lunsekimig (SAR443765) is the most clinically advanced bispecific alarmin-related agent in the dataset. This Nanobody molecule targets both IL-13 and TSLP—the upstream initiator of the airway response and a downstream mediator and enhancer, respectively. Sanofi’s 2024 WO and 2026 WO filings describe the dual-blockade rationale explicitly: TSLP inhibition suppresses the initiation of the asthmatic response, while IL-13 blockade prevents amplification. Clinical biomarker data cited in patent filings include FeNO reduction of at least 18 ppb versus placebo and blood eosinophil reduction of at least 30%—consistent with pharmacodynamic proof-of-concept. The 2026 WO filing introduces a precision indication: “high-risk asthma” defined by elevated FeNO and elevated blood eosinophil count simultaneously.
Sanofi’s lunsekimig (SAR443765), a Nanobody molecule targeting both IL-13 and TSLP, showed FeNO reduction of at least 18 ppb and blood eosinophil reduction of at least 30% versus placebo in proof-of-concept data cited in Sanofi’s WO 2024 and WO 2026 patent filings.
Sinomab Bioscience Limited represents an emerging entrant with WO 2023 and CL 2024 filings covering bispecific binding proteins (bsBp) capable of neutralizing two different alarmins among TSLP, IL-33, and IL-25. The Sinomab filings describe methods for treating moderate-to-severe asthma and atopic dermatitis, reducing oral corticosteroid dosage, suppressing innate lymphoid cell (ILC) proliferation, and compromising both Type 1 and Type 2 immune responses. The explicit claim that alarmins exhibit functions beyond Th2 immunity—encompassing Type 1 inflammatory subtypes—positions pan-alarmin blockade as potentially superior to monospecific approaches for heterogeneous severe asthma.
Multiple patent filings—from Sinomab and Sanofi—explicitly frame bispecific alarmin blockade as addressing both Type 1 and Type 2 immune responses in asthma. Sinomab’s filings cover all three canonical alarmins (TSLP, IL-33, IL-25) in combination, while Sanofi’s lunsekimig targets TSLP plus the downstream effector IL-13. This multi-node approach is positioned as potentially superior to monospecific strategies for the heterogeneous severe asthma population.
A mechanistically distinct approach appears in CSL Innovation’s WO 2024 filing, which targets CD131 (the beta-common chain receptor) to simultaneously inhibit both IL-5 and GM-CSF signaling in severe asthma. This strategy does not rely on the alarmin axis but represents emerging interest in dual cytokine blockade via shared receptor components—a signal that the severe asthma IP landscape extends beyond the TSLP/IL-33/IL-25 triad identified in most alarmin-focused filings.
The bispecific and multi-alarmin category aligns with broader trends in respiratory biologics documented by EMA and FDA in their guidance frameworks for combination biologic development, where simultaneous pathway blockade is increasingly recognized as a clinically rational strategy for diseases with heterogeneous inflammatory drivers.
Identify bispecific alarmin patent white spaces and track emerging competitors with PatSnap Eureka’s AI-powered drug pipeline analysis.
Analyse Bispecific Alarmin Patents in PatSnap Eureka →Companion diagnostics and precision patient selection
Patient stratification is rapidly becoming an independent IP asset in the alarmin biologics space, with multiple companies filing patents that define specific biomarker-based patient populations as claims—not merely as clinical trial inclusion criteria. This shift represents a maturation of the field from broad indication claims toward precision medicine positioning.
The stratification landscape across the dataset encompasses four distinct approaches. Genentech/Roche uses periostin (POSTN) as a biomarker for Th2-high asthma patient selection across multiple active patents in HK, CN, and EP jurisdictions, with FeNO, IgE, and other Th2 biomarkers also claimed as stratification tools. MedImmune Limited’s JP 2026 filing introduces genomic stratification based on IL33 risk allele genotypes (IL1RL1 polymorphisms) for tozorakimab patient selection. Regeneron’s CN 2024 filing describes IL-33 polygenic risk scores (PRS) to select patients likely to respond to IL-33 antagonists, IL-4Rα antagonists, or IL-13 receptor antagonists—a single stratification tool potentially applicable across multiple biologic classes. Sanofi’s WO 2026 filing for lunsekimig defines a “high-risk asthma” indication by the combination of elevated FeNO and elevated blood eosinophil count.
“The field is generating IP not only for molecules but for their companion biomarker-defined indications—early movers in stratified-indication patents may establish significant competitive barriers.”
The emergence of polygenic risk scores as patient selection tools is particularly notable. According to research frameworks published by Nature journals covering precision medicine in respiratory disease, PRS-based approaches can identify patients with genetic predispositions to specific inflammatory endotypes—enabling pre-treatment patient triage that could substantially improve clinical trial success rates and post-approval prescribing precision.
MedImmune Limited’s JP 2026 patent filing introduces genomic patient stratification for IL-33 antagonist therapy based on IL33 risk allele genotypes (IL1RL1 polymorphisms), representing an emerging IP category in which companion diagnostic criteria are claimed alongside the therapeutic molecule.
For drug developers and IP strategists, this trend has a direct competitive implication: companies that establish IP rights over specific biomarker-defined patient subpopulations may be able to protect market share even after core molecule patents expire, by tying the most responsive patient segments to proprietary companion diagnostic workflows. The Genentech periostin patents—active across HK, CN, and EP—are an early example of this strategy in the Th2 biologic space.
Strategic implications for drug developers and IP teams
The alarmin biologic landscape in severe asthma presents a set of distinct strategic opportunities and risks that differ depending on whether an organization is a molecule developer, an IP licensor, or a clinical-stage biotech seeking to position against established programs.
TSLP: lifecycle management, not greenfield
Amgen and MedImmune’s anti-TSLP portfolio is the most extensively prosecuted in this dataset, with active or pending status across at least nine jurisdictions, multiple continuation filings (the latest US continuation pending in 2025), and expansion into OCS-dependent asthma. New entrants targeting TSLP with monospecific antibodies face a dense IP landscape and a well-established clinical benchmark. Differentiation would need to come from formulation (e.g., subcutaneous vs. intravenous), dosing interval, pediatric populations, or COPD indications where Novartis is also active.
IL-33: differentiation through precision
The IL-33/ST2 axis is crowded at the IP level, with MedImmune, Regeneron/Sanofi, and related programs all holding active filings. Differentiation is being sought through patient stratification (IL33 risk alleles, polygenic risk scores), specific dosing regimens, and combination strategies with anti-IL-4R. Companies entering this space without a distinct patient stratification or combination rationale face significant freedom-to-operate challenges and limited commercial differentiation.
Bispecifics: early-stage but rapidly filing
Both Sinomab and Sanofi are pursuing simultaneous dual-target alarmin blockade. This strategy may address the subset of severe asthma patients who fail single-alarmin targeting, and represents an early-stage but rapidly emerging IP frontier. The Sinomab WO 2023 and CL 2024 filings covering all three canonical alarmins (TSLP, IL-33, IL-25) in bispecific format are the broadest claims in this category and merit close monitoring by competitors.
Non-eosinophilic severe asthma: a persistent gap
Retrieved filings from Amgen and MedImmune explicitly differentiate tezepelumab’s efficacy across eosinophilic and non-eosinophilic phenotypes, while IL-17 antagonist filings from Novartis target a low-IgE, non-eosinophilic population. Drug developers targeting steroid-resistant non-type-2 severe asthma (neutrophilic, paucigranulocytic) may find limited overlap with alarmin-based strategies and should assess alternative targets including CD6, IL-17, PDE4, and CD131—the latter appearing in CSL Innovation’s WO 2024 filing for dual IL-5/GM-CSF blockade.
For a comprehensive view of the alarmin IP landscape—including freedom-to-operate analysis, assignee monitoring, and clinical pipeline tracking—the PatSnap Eureka platform provides AI-powered access to over 2 billion data points across 120+ countries, enabling drug developers and IP teams to navigate this complex, multi-assignee space with precision.