⚠ Four Established Asthma BiologicsModerate threat

Amgen (AMGN) — threat to the moat

TEZSPIRE competes with four established asthma biologics, one of them sold by its own international partner.

Severe asthma was treated with biologics long before TEZSPIRE arrived. The 10-K names four: DUPIXENT, FASENRA, NUCALA and XOLAIR1. Each has years of prescribing experience behind it, and each targets a particular type of asthma, which lets a doctor choose a drug for a specific patient.

Severe asthma biologics named by AmgenTEZSPIREAmgen; AstraZeneca abroadDUPIXENTRegeneron and SanofiFASENRAAstraZenecaNUCALAGSKXOLAIRGenentech and NovartisTEZSPIRE, 2025 sales$1,478MAmgen Form 10-K FY2025; FY2025 results release
Five drugs, one class.

TEZSPIRE's case is its mechanism, acting on the airway epithelium where inflammation starts2. That case has taken it to $1,478 million in 20253 and $486 million in the second quarter of 20264. But a mechanism is an argument, and the incumbents answer with their own clinical data and with rebates to the benefit managers who decide formulary positions.

The partnership complicates the picture. AstraZeneca sells TEZSPIRE outside the United States5 and also sells FASENRA, one of the drugs TEZSPIRE competes with6. A partner with a competing product has mixed incentives in every country where it decides which drug its sales force emphasises.

TEZSPIRE is widening its own use: it is now approved for nasal polyps as well as asthma7. A drug with more indications has more to offer a benefit manager, and the incumbents are playing the same game.

The measure that would confirm this threat is a sharp slowdown in TEZSPIRE's growth outside the United States, where AstraZeneca controls the selling. If international growth lags American growth by a wide margin, the partner will be favouring its own drug, and TEZSPIRE's reach will be limited to the market Amgen sells itself.

References
  1. ReportedThe 10-K names four: DUPIXENT, FASENRA, NUCALA and XOLAIR.
    Amgen Form 10-K for fiscal 2025 - Item 1 patents, biosimilars and competitors. — FY2025 · publ. 13 February 2026 · source ↗
  2. ReportedTEZSPIRE's case is its mechanism, acting on the airway epithelium where inflammation starts.
    Amgen Form 10-K for fiscal 2025 - Item 1 business: products, collaborations, staff and pipeline. — FY2025 · publ. 13 February 2026 · source ↗
  3. ReportedThat case has taken it to $1,478 million in 2025 and $486 million in the second quarter of 2026.
    Amgen fourth-quarter and full-year 2025 results release, Form 8-K exhibit 99.1 - product sales for 2024-2025, non-GAAP EPS and 2026 guidance. — FY2025 · publ. 3 February 2026 · source ↗
  4. ReportedThat case has taken it to $1,478 million in 2025 and $486 million in the second quarter of 2026.
    Amgen second-quarter 2026 results release, Form 8-K exhibit 99.1 - product sales performance: inflammation, rare disease and established products, and sales by region. — Q2 2026 · publ. 4 August 2026 · source ↗
  5. ReportedAstraZeneca sells TEZSPIRE outside the United States and also sells FASENRA, one of the drugs TEZSPIRE competes with.
    Amgen Form 10-K for fiscal 2025 - Item 1 business: products, collaborations, staff and pipeline. — FY2025 · publ. 13 February 2026 · source ↗
  6. ReportedAstraZeneca sells TEZSPIRE outside the United States and also sells FASENRA, one of the drugs TEZSPIRE competes with.
    Amgen Form 10-K for fiscal 2025 - Item 1 patents, biosimilars and competitors. — FY2025 · publ. 13 February 2026 · source ↗
  7. ReportedTEZSPIRE is widening its own use: it is now approved for nasal polyps as well as asthma.
    Amgen Form 10-K for fiscal 2025 - Item 1 business: products, collaborations, staff and pipeline. — FY2025 · publ. 13 February 2026 · source ↗
Sources
Generated September 28, 2026