Mabwell’s anti-ST2 antibody enters U.S. trials: Can 9MW1911 reshape immunotherapy for COPD?

Mabwell (688062.SH) has secured Investigational New Drug (IND) clearance from the United States Food and Drug Administration for its investigational anti-ST2 monoclonal antibody, 9MW1911, enabling a Phase IIa study in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD). The clearance marks Mabwell’s first U.S.-sanctioned trial for this asset, expanding a program that already completed Phase IIa dosing in China and is progressing toward Phase IIb.

The move elevates Mabwell into an exclusive tier of Chinese biotechs exporting novel biologics into the U.S. clinical pipeline. With IL-33/ST2 signaling long considered an untapped inflammatory axis in COPD, Mabwell is now betting that its differentiated immunologic targeting can rival or complement existing treatment approaches—especially in exacerbation-prone subgroups underserved by standard-of-care bronchodilators and corticosteroids.

How does 9MW1911’s mechanism of action target a key inflammation pathway in COPD?

9MW1911 is a humanized monoclonal antibody that binds with high affinity to the ST2 receptor, acting as an antagonist to the IL-33/ST2 axis. This pathway has been implicated in a range of inflammatory diseases, including asthma, atopic dermatitis, and COPD, with IL-33 released by stressed epithelial cells acting as an upstream alarmin that amplifies immune activation.

Unlike therapies focused on downstream cytokines or T-helper cell polarization, 9MW1911’s upstream targeting of ST2 aims to suppress multiple downstream effectors—offering a broad anti-inflammatory effect without broadly suppressing host defense. The dual potential to reduce exacerbations while avoiding systemic immunosuppression has placed ST2 in a promising but clinically unvalidated category.

Mabwell’s 9MW1911 appears to be the first domestic anti-ST2 antibody to reach the clinic in China and among the few globally to advance into mid-stage trials. While the IL-33/ST2 axis has drawn interest from players like AstraZeneca and Regeneron in asthma and dermatologic conditions, COPD remains an underexplored territory for this target.

What did Mabwell learn from its China-based Phase IIa study, and how credible is the early efficacy signal?

The recently completed Phase IIa study in China enrolled 80 patients with moderate-to-severe COPD and administered escalating doses of 9MW1911 versus placebo (N=20). Mabwell reported that the drug was well tolerated across all arms, with adverse event rates of 70 percent in the treatment groups versus 85 percent for placebo—suggesting a clean safety signal so far. Importantly, no anti-drug antibodies were detected, and no new safety concerns emerged.

From a pharmacokinetic standpoint, the data supported a linear exposure-response relationship, with Mabwell stating that an initial model for dose-effect calibration could be derived. This model is expected to inform Phase IIb optimization and ultimately guide registrational trial design.

Efficacy-wise, the most compelling data point was a dose-dependent reduction in annualized COPD exacerbation rates. At the recommended Phase IIb dose (RP2D, N=30), Mabwell reported a greater than 30 percent reduction in moderate-to-severe exacerbations and a more than 40 percent drop in severe exacerbation rates relative to placebo. The proportion of patients experiencing severe episodes dropped from 35 percent in the placebo group to 13.3 percent in the treatment arm.

These are not trivial findings. While the trial was small and not powered for definitive outcomes, these directional signals align with Mabwell’s mechanistic rationale and validate ST2 as a potentially druggable inflammatory node in COPD. The Phase IIb trial now underway will test this hypothesis more rigorously.

What are the next regulatory and clinical milestones for 9MW1911—and what does this imply for Mabwell’s strategy?

Mabwell initiated its China-based Phase IIb trial in July 2025, with plans to enroll a significantly larger population and conduct an interim analysis after data from at least 120 patients are collected. The company is aiming to launch a Phase III global trial by the end of 2026, assuming continued safety and a statistically significant reduction in exacerbation endpoints.

The U.S. IND clearance gives Mabwell a two-front development strategy: a China-led efficacy validation and a U.S.-focused regulatory engagement that could eventually anchor a global registration package. This bifurcated approach mirrors a broader trend among Chinese biopharma firms that are maturing from biosimilar producers into innovation-first companies targeting high-bar, high-payoff indications.

For Mabwell, the IND also signals its ability to meet U.S. FDA requirements for CMC (chemistry, manufacturing, and controls) and trial governance—often the Achilles heel for first-time Chinese biologics entering the U.S. pipeline.

Whether 9MW1911 becomes a first-in-class COPD immunotherapy or not, the trial itself positions Mabwell closer to peer innovators such as Innovent Biologics, BeiGene, and Junshi Biosciences, which are all building U.S.-China pipelines with immunologic and oncologic leads.

What does Mabwell’s move say about broader COPD immunotherapy trends and industry sentiment?

COPD remains a treatment-challenged disease despite the high prevalence and economic burden. Most late-stage drugs in the COPD pipeline have failed to outperform existing dual or triple inhaled therapies. The few immunologic approaches—such as anti-IL-5 and anti-TSLP agents—have largely underwhelmed in COPD, even if successful in asthma.

The IL-33/ST2 axis represents a novel anti-inflammatory angle with theoretical superiority in preventing exacerbations driven by epithelial cell stress, viral triggers, and neutrophilic inflammation. If Mabwell’s data hold up, it could pave the way for a new COPD subclassification: one responsive to upstream alarmin blockade.

Institutional sentiment toward Mabwell is already warming as the company pivots from platform expansion toward asset-level differentiation. With its 9MW1911 candidate now visible in the U.S. clinical trial registry, it joins a small but growing group of Chinese-origin biologics with a credible Western development trajectory.

While 9MW1911’s Phase IIb results and the timing of the Phase III launch will ultimately determine Mabwell’s breakout potential in COPD, the IND clearance already boosts the company’s credibility with Western investors and partners scouting for first-in-class assets with global viability.

Key takeaways on Mabwell’s anti-ST2 antibody and its strategic implications for the COPD treatment landscape

• Mabwell received U.S. FDA IND clearance to initiate a Phase IIa trial for 9MW1911, a novel anti-ST2 monoclonal antibody in COPD.

• The candidate has already completed a Phase IIa study in China, showing dose-dependent reductions in exacerbation rates and no new safety signals.

• ST2 is an upstream inflammatory target implicated in COPD exacerbations, representing an emerging class of alarmin-based immunotherapy.

• Mabwell’s dual China-U.S. clinical strategy positions it among a handful of Chinese biotechs expanding into global novel biologic development.

• The IL-33/ST2 pathway could offer new therapeutic options for exacerbation-prone COPD patients underserved by bronchodilator regimens.

• Mabwell aims to launch a pivotal Phase III trial in 2026 based on interim Phase IIb data from at least 120 patients.

• Regulatory progress also reflects Mabwell’s internal manufacturing and clinical operations maturity aligned with FDA expectations.

• Institutional investors may view this as a signal that Mabwell is transitioning from platform building to asset-level differentiation.