Rademikibart Reduces Treatment Failure by 81% in Phase 2 COPD Exacerbation Study

Connect Biopharma has announced positive preliminary topline results from its global Phase 2 Seabreeze STAT COPD study evaluating rademikibart as an add-on treatment for acute exacerbations in adults with chronic obstructive pulmonary disease (COPD) and type 2 inflammation.

In the randomized, placebo-controlled study, rademikibart reduced the rate of treatment failure by 81% through Week 4 compared with placebo (p=0.0122). The treatment also reduced new moderate-to-severe COPD exacerbations by 85% (p=0.030) and reduced new emergency department visits and hospital admissions associated with COPD exacerbations by 100% (p=0.0137).

Connect said it plans to engage with the U.S. Food and Drug Administration (FDA) regarding a potential Phase 3 registrational development program for rademikibart.

COPD Exacerbations Can Lead to Treatment Failure

Acute exacerbations of COPD can cause worsening respiratory symptoms and may require additional pharmacologic treatment, emergency department care, or hospitalization. The period following an acute exacerbation is therefore an important stage of COPD management.

The Seabreeze STAT COPD study was designed to evaluate whether adding rademikibart to standard of care could reduce treatment failure and other clinical outcomes following an acute exacerbation in patients with evidence of type 2 inflammation.

Rademikibart Targets IL-4Rα Signaling

Rademikibart is a fully human monoclonal antibody targeting interleukin-4 receptor alpha (IL-4Rα), a common receptor subunit for IL-4 and IL-13.

By binding to IL-4Rα, rademikibart is designed to target signaling associated with IL-4 and IL-13 and the broader T helper 2 (Th2) inflammatory pathway. Connect Biopharma is developing the investigational antibody in inflammatory diseases including asthma and COPD.

Rademikibart remains under clinical investigation and has not been approved for marketing by the FDA or any other regulatory agency.

Phase 2 Study Evaluated Treatment Failure After COPD Exacerbation

The Seabreeze STAT COPD study (CBP-201-207; NCT06940154) was a randomized, double-blind, placebo-controlled Phase 2 trial evaluating rademikibart as an adjunct to standard of care.

The study enrolled 159 participants globally with COPD and an eosinophil count of ≥300 cells/μL who had experienced an acute COPD exacerbation. Participants were randomized 1:1 to receive a single subcutaneous dose of rademikibart or placebo in addition to standard of care.

The primary endpoint was treatment failure within 28 days after randomization. Treatment failure included death from any cause, hospital admission or readmission for COPD, an emergency department revisit, an unscheduled medical visit for worsening COPD symptoms, or the need to intensify pharmacologic treatment.

Secondary endpoints included post-bronchodilator FEV1 at Week 1, which was the key secondary endpoint, new moderate-to-severe COPD exacerbations, changes in COPD respiratory symptoms, FEV1 at other time points, and adverse events assessed for eight weeks after dosing.

Rademikibart Reduced Treatment Failure by 81%

Rademikibart significantly reduced the rate of treatment failure by 81% through Week 4 compared with placebo (p=0.0122).

The treatment also reduced the rate of new moderate-to-severe COPD exacerbations by 85% through Week 4 (p=0.030).

In addition, new emergency department visits and hospital admissions for acute COPD exacerbations were reduced by 100% through Week 4 compared with placebo (p=0.0137). These findings formed the principal efficacy results reported by Connect Biopharma from the Phase 2 study.

Rademikibart was also associated with a significant reduction in rescue inhaler use from Week 2 through Week 7 and improved COPD symptoms at Week 2 compared with placebo, with the total symptom score showing p=0.0197.

FEV1 Improved Numerically but Was Not Statistically Significant

Rademikibart produced a 70 mL greater improvement in post-bronchodilator FEV1 at Week 4 compared with placebo.

However, the reported p-value was 0.1607, meaning that this difference did not reach conventional statistical significance. The result should therefore be distinguished from the statistically significant treatment-failure and exacerbation findings.

Safety Profile Was Comparable to Placebo

Rademikibart was well tolerated through the study’s eight-week safety follow-up, with no new safety signals observed.

The company reported that the overall safety profile was comparable to placebo, with lower incidences of adverse events and serious adverse events in the rademikibart group than in the placebo group.

Connect Plans FDA Discussions for Phase 3

Based on the preliminary Phase 2 findings, Connect Biopharma plans to engage with the FDA to seek alignment on a potential Phase 3 registrational development program for rademikibart as an add-on treatment for COPD.

The current findings remain preliminary topline results from a Phase 2 study. Further clinical development will be required to determine whether the observed effects are confirmed in larger and later-stage studies. Rademikibart remains investigational, and the reported findings do not establish its safety or effectiveness for COPD treatment or guarantee regulatory approval.

Reference

Connect Biopharma Announces Positive Preliminary Topline Data from its Global Phase 2 Study of Rademikibart as an Add-on Treatment for Acute Exacerbations in Adults with COPD and Type 2 Inflammation, Connect Biopharma, 30 September 2026

Rademikibart Add-on Treatment of an Acute COPD Exacerbation (Seabreeze STAT COPD), ClinicalTrials.gov ID NCT06940154