Sanofi's Bispecific Lunsekimig Has Mixed Readouts in Phase 2

Why It Matters

Successful respiratory data positions lunsekimig as a potential next‑generation therapy for asthma and COPD, while the dermatitis setback underscores the challenges of broad‑indication bispecifics. The outcomes will shape Sanofi’s ability to sustain growth as Dupixent faces patent erosion.

Key Takeaways

• Lunsekimig succeeded in asthma and nasal polyps trials.
• Failed primary endpoint in atopic dermatitis phase 2b study.
• Dual IL‑13/TSLP targeting shows promise for respiratory diseases.
• Sanofi advancing lunsekimig into phase 3 COPD and asthma programs.
• Part of Sanofi’s plan to replace Dupixent revenue

Pulse Analysis

The rise of bispecific antibodies reflects a broader industry shift toward multitargeted immunotherapies, aiming to improve efficacy while simplifying treatment regimens. Lunsekimig’s design—simultaneously neutralizing IL‑13, a key driver of type‑2 inflammation, and TSLP, an upstream epithelial cytokine—offers a mechanistic rationale for tackling complex respiratory disorders. By leveraging this dual blockade, Sanofi hopes to differentiate its pipeline from existing monotherapies and capture market share in asthma and chronic obstructive pulmonary disease, segments projected to exceed $30 billion globally by 2030.

In the AIRCULES phase 2b trial, lunsekimig delivered a statistically significant reduction in asthma exacerbations and measurable gains in forced expiratory volume, outcomes that align with regulatory expectations for late‑stage respiratory candidates. The DUET study echoed these findings in chronic rhinosinusitis with nasal polyps, where patients experienced notable declines in polyp size and symptom burden. However, the VELVET atopic dermatitis trial fell short of its primary EASI improvement goal, highlighting the difficulty of translating respiratory success to skin indications where disease pathways may diverge. The mixed readouts suggest that lunsekimig’s therapeutic window may be narrower than initially hoped, prompting Sanofi to prioritize respiratory programs.

Strategically, lunsekimig is a cornerstone of Sanofi’s plan to offset the looming revenue cliff from Dupixent, which generated nearly $18 billion last year and faces patent expirations in the early 2030s. Advancing lunsekimig into phase 3 COPD (PERSEPHONE) and high‑risk asthma (AIRLYMPUS) trials could secure a new blockbuster, especially if the drug demonstrates superior efficacy or dosing convenience over existing biologics. Moreover, the company’s parallel development of anti‑OX40L amlitelimab and IL‑33 inhibitor itepekimab creates a diversified immunology portfolio, reducing reliance on any single candidate. Investors will watch the upcoming phase 3 data closely, as positive results could reaffirm Sanofi’s leadership in the competitive biologics market and sustain its growth trajectory.