Connect Biopharma Presents Data Supporting Development of Rademikibart at the American Thoracic Society (ATS) 2025 International Conference

– Rademikibart significantly improved airway function, as measured by FEV₁, within a day and significantly reduced acute exacerbations in patients with inflammation-mediated chronic asthma strongly supporting ongoing Phase 2 acute exacerbation studies in asthma and COPD which are expected to report topline data in 1H26 –

– New preclinical data highlights differentiated structural and molecular dynamics of rademikibart with enhanced interleukin-4 receptor alpha (IL-4Rα) inhibition compared to dupilumab providing a molecular basis for the differentiated efficacy and safety observed with rademikibart presented at this meeting –

SAN DIEGO, May 20, 2025 (GLOBE NEWSWIRE) -- Connect Biopharma Holdings Limited (Nasdaq: CNTB) (Connect Biopharma, Connect or the Company), a clinical-stage biopharmaceutical company focused on transforming acute and chronic care of asthma and chronic obstructive pulmonary disease (COPD), today announced clinical and preclinical data supporting rademikibart, the Company’s next-generation, potentially best-in-class anti-interleukin-4-receptor alpha (IL-4Rα) antibody, which was presented at the American Thoracic Society (ATS) 2025 International Conference, taking place from May 18-21, 2025, in San Francisco.

“We are pleased to share new clinical and preclinical data highlighting rademikibart’s potential as a best-in-class treatment for patients with asthma or COPD experiencing an acute exacerbation,” said Barry Quart, Pharm.D., CEO and Director of Connect Biopharma. “The new analyses from our previously completed Phase 2b study not only demonstrate rademikibart’s rapid onset of action and significant improvement in lung function, but also further differentiate its safety profile, overcoming limitations of existing IL-4Rα inhibitors on the market. Taken together, these data reinforce our confidence in our clinical development plan and provide strong commercial rationale for rademikibart as a potentially superior next-generation IL-4Rα inhibitor.”

Title: Rapid Improvement in Lung Function Observed with Rademikibart in Patients with Moderate-to-Severe Uncontrolled Asthma

• At-home spirometry readings from Connect’s Phase 2b trial of rademikibart for moderate-to-severe uncontrolled asthma were evaluated in a post-hoc analysis to assess rademikibart’s ability to rapidly improve lung function.
• Rademikibart rapidly improved lung function (FEV₁) during the initial week of treatment, and most FEV₁ increase was observed within 24 hours.
• Improvements in self-assessed prebronchodilator FEV₁ were greatest in patients with elevated eosinophil counts (≥300 cells/µL) with or without elevated exhaled nitric oxide (FeNO ≥25 ppb), markers of type 2 inflammation, as compared with the overall population.
• Patients with type 2 inflammatory asthma in this study also showed a significant reduction in acute exacerbations.
• Findings support rademikibart’s potential as an effective therapy for patients with asthma or COPD experiencing an acute exacerbation, providing both fast-acting and sustained improvements in lung function.
  
  

Title: Efficacy of Rademikibart in COPD-like Patients: Sub-analyses From the Phase 2b Trial in Patients with Moderate-to-Severe Asthma

• Results from the Company’s Phase 2b trial of rademikibart in moderate-to-severe asthma were assessed in a post-hoc analysis to determine rademikibart’s efficacy in subgroup of COPD-like patients, defined as asthma onset after 40 years of age and post−bronchodilator FEV₁/FVC ratio <0.7.
• Rademikibart significantly improved prebronchodilator FEV₁ from first assessment and was sustained through 24 weeks of treatment, with greatest improvements in patients with elevated baseline eosinophil counts (≥150 cells/µL and ≥300 cells/µL).
• These results suggest that rademikibart has the potential to improve outcomes for patients with COPD, particularly in patients with eosinophilic-driven COPD.
  
  

Title: Effect of Rademikibart on Blood Eosinophil Counts in Patients with Asthma: Is There an IL-4Rα Class Effect?

• In a post-hoc analysis, eosinophil data from the Company’s Phase 2b trial of rademikibart and from the Phase 3 VENTURE and QUEST trials of dupilumab were indirectly compared to determine whether hypereosinophilia is an IL-4Rα inhibitor class effect following published cases of dupilumab-associated hypereosinophilia.
• Rademikibart treatment groups were associated with substantially lower proportions of patients experiencing high post-baseline eosinophil counts than with dupilumab treatment groups. Proportions of patients with high post-baseline eosinophil counts were comparable in the placebo groups, indicating that differences in the active treatment groups are due to drug effect.
• In the rademikibart treatment groups mean eosinophil counts decreased by approximately 30% at Week 24, compared to a mean eosinophil increase between 50% and 120% for dupilumab during 52 weeks of treatment.
• Based on this analysis, the lack of an increase in eosinophils with rademikibart suggests that increased eosinophil counts observed in published data for dupilumab is unlikely to be an IL-4Rα inhibitor class effect, further differentiating rademikibart’s safety profile as a potentially best-in-class IL-4Rα inhibitor.

Title: Optimized Second-generation IL-4Rα Inhibition: Structural and Molecular Dynamics Properties of Rademikibart Fab-IL-4Rα Complex

• Rademikibart is an optimized next-generation human monoclonal antibody targeting IL-4Rα.
• In this study, Connect evaluated the atomic-resolution 3D structures of rademikibart and dupilumab, that may lead to an understanding of the differences in efficacy and safety between the two drugs.
• The x-ray crystal structure of rademikibart Fab-IL-4Rα complex revealed an ~60° rotation of rademikibart on IL-4Rα compared to dupilumab, optimizing interference with the natural IL-4/IL-13 epitope, while dupilumab binds to IL-4Rα through only domain 1, thereby incompletely engaging the natural IL-4/IL-13 epitope on IL-4Rα.
• Compared to dupilumab, molecular dynamics studies showed rademikibart forms a very strong and stable interaction with IL-4Rα, confirmed structurally by lower B-factors (less motion) and more hydrogen bonds (stronger binding) than dupilumab.
• These results further support previously published data showing that rademikibart demonstrated better inhibition of STAT6 intracellular signaling, provided similar potency in prohibiting both IL-4-induced TARC release and IL-4-induced B cell activation and has more than 2-fold higher binding affinity to IL-4Rα compared to dupilumab.
• These data support the underlying molecular and structural rationale for enhanced IL-4Rα inhibition by rademikibart compared to dupilumab.

The poster presentations will be available on Connect’s website under the .

About Connect Biopharma and Rademikibart

Connect Biopharma is a clinical-stage biopharmaceutical company dedicated to transforming care for asthma and COPD. Headquartered in San Diego, California, the company is advancing rademikibart, a next-generation, potentially best-in-class anti-interleukin-4-receptor alpha (IL-4Rα) antibody. With an initial focus on acute exacerbations—an area with significant unmet need—rademikibart has the potential to also drive chronic utilization in asthma and COPD amongst the approximately 1 million asthma patients and 1.3 million COPD patients in the U.S. who experience acute exacerbations annually. In a Phase 2 trial for asthma, rademikibart demonstrated strong efficacy and safety data, with clinically meaningful reductions in exacerbations and rapid, statistically significant improvements in forced expiratory volume in one second (FEV₁), observed within one week—and in most cases, within 24 hours via home spirometry.

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This press release discusses our product candidate, rademikibart, which is under clinical investigation and has not yet been approved for marketing by the U.S. Food and Drug Administration or by any other regulatory agency. No representation is made as to the safety or effectiveness of rademikibart for the uses for which it is being studied. The trademarks included herein are the property of the owners thereof and are used for reference purposes only.

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