Connect Biopharma Touts Rademikibart’s Edge as SEABREEZE Data Looms in 2026

Key Points

• Connect Biopharma says rademikibart continues to show a differentiated clinical and mechanistic profile, including a modest reduction in eosinophils and rapid airway benefits that the company believes set it apart from other IL-4 receptor alpha antibodies like Dupixent.
• CEO Barry Quart highlighted prior data showing fast onset of action, with FEV1 improvements seen within 24 hours and IV dosing producing airway gains within minutes to hours, supporting the view that rademikibart may have direct bronchodilator effects.
• The key upcoming catalyst is the SEABREEZE readout expected in mid-2026; a positive result could lead to an FDA meeting for a Phase 3 acute asthma program, while the company also pointed to a positive interim safety review with no sample-size change recommended.

Connect Biopharma NASDAQ: CNTB Chief Executive Officer Barry Quart said the company’s rademikibart program continues to show a differentiated clinical and mechanistic profile as the company awaits mid-2026 data from its SEABREEZE study.

Speaking during a fireside chat with H.C. Wainwright analyst Brandon Folkes, Quart said rademikibart, an IL-4 receptor alpha monoclonal antibody, has demonstrated clinical characteristics that differ from what is typically expected from the class. He compared the mechanism category to Dupixent but said rademikibart has shown a different profile, including lowering eosinophils in asthma patients.

Quart said Dupixent has been described as increasing eosinophils in asthma patients, and he characterized that as more than a laboratory abnormality, citing serious adverse events reported to the FDA. By contrast, he said Connect believes rademikibart’s different binding profile and epitope lead to greater internalization of the drug-receptor complex, resulting in faster eosinophil turnover and a “nice modest reduction” in eosinophils.

“It certainly gives a clinician the opportunity to not be worried about using the drug in people who come in with high eosinophils,” Quart said.

Rademikibart Shows Rapid Airway Effects, CEO Says

Quart also highlighted what he described as a rapid onset of effect in a prior chronic asthma study, where rademikibart showed significant improvement in airway function, as measured by FEV1, within less than 24 hours. He said FEV1 improved by about 250 milliliters at one week, with much of that effect observed in home spirometry within the first day.

Connect has been evaluating the biological explanation for that effect. Quart said rademikibart appears to directly produce bronchodilation in lung slices and may resensitize the airway to beta-agonists. He said IL-13 and IL-4 are known to shift the dose-response curve for beta-agonists, making them less effective, and that rademikibart appears to shift the curve back toward normal.

“A very clear difference in bronchodilation effect, and we think that has a great deal to do with this very rapid onset of airway improvement,” Quart said.

IV Data Supports Onset and Durability Observations

Quart discussed intravenous rademikibart data released earlier this year, saying the study was still being cleaned and locked at the time of the discussion. He said the company had not yet fully analyzed which patients responded best or how responses related to baseline characteristics.

The IV experiment was designed to test whether drug levels in the blood were directly related to airway improvement, Quart said. With subcutaneous dosing, the onset of effect appeared to track the time needed for the drug to move out of the subcutaneous space. With IV dosing, drug enters the bloodstream immediately.

“Sure enough, we clearly did see that with fairly dramatic improvements in airway function within minutes to hours,” Quart said.

Asked about the difference between asthma and COPD responses in the IV study, Quart said the company will evaluate baseline characteristics and concomitant medications after unblinding the data. He noted that almost all asthma patients in the study had eosinophil counts between 200 and 250, despite eligibility criteria requiring at least 200 eosinophils. He said the asthma results were largely in line with expectations, while the COPD response was “outstanding.”

Quart said COPD patients may have had greater capacity for improvement, potentially because they entered the study with lower percent-predicted FEV1.

Monthly Dosing Potential and Patient Continuity

Quart said prior studies in atopic dermatitis showed similar results with dosing every two weeks and every four weeks, while prior asthma data suggested rademikibart can work for longer than four weeks. He said subcutaneous dosing may support durability because the drug is released over roughly six days, with a Tmax around day six.

For IV dosing, Quart said durability appeared clear beyond one month despite the lack of a delayed-release effect. He said that supports the SEABREEZE study’s 28-day endpoint and also suggests IV-treated acute patients could potentially be covered for about four weeks.

Asked how the company would manage continuity if IV rademikibart were used acutely and subcutaneous rademikibart chronically, Quart said commercialization would require both hospital and outpatient capabilities, including focus on pulmonologists and allergists. He said clinicians surveyed by the company indicated they would likely want to keep a patient on the same therapy if the patient responded to acute IV treatment.

“It will take a certain amount of commercial horsepower, which is why ultimately we think that the drug should be commercialized by somebody with much deeper pockets,” Quart said.

SEABREEZE Readout Expected Mid-2026

Quart said the SEABREEZE study remains a key upcoming catalyst, with data expected in mid-2026. He said the IV data supports the idea that rademikibart works for a month and reinforces the company’s view that the drug has a direct bronchodilator effect, particularly based on the rapid COPD responses.

However, he cautioned that SEABREEZE patients may differ meaningfully from earlier populations because they are likely receiving large doses of bronchodilators and IV steroids such as prednisone or prednisolone. As a result, he said the magnitude of FEV1 improvement may be smaller than in more stable patients, though he said the company still expects improvement.

If SEABREEZE reads out as expected, Quart said Connect would prepare a briefing document and seek an FDA meeting to discuss the design of a Phase 3 program for the acute indication. He said the company has already discussed Phase 3 chronic asthma trial designs with the FDA.

Quart added that Connect’s partner Simcere is expected to begin a Phase 3 chronic asthma study in China early next year. If that study produces strong results, Connect would like the FDA to accept it as one of two chronic studies.

On SEABREEZE endpoints, Quart said FEV1 will remain a significant focus because it is an accepted regulatory endpoint. He also said symptomatic improvement, hospital length of stay and readmissions will be important measures to evaluate.

Quart also addressed the company’s announcement of a positive interim review from the independent data monitoring committee. He said the committee had no safety concerns and recommended no change to the study’s sample size.

“From this point, it’s just a question of completing the studies,” Quart said.

About Connect Biopharma NASDAQ: CNTB

Connect Biopharma Holdings Ltd. is a clinical-stage biopharmaceutical company focused on the discovery and development of monoclonal antibody therapies for immune-mediated disorders. Headquartered in Singapore with a research and commercial presence in the United States, the company applies proprietary technology platforms to target novel pathways in inflammatory and autoimmune diseases.

The company's lead product candidate, CBP-201, is a fully human monoclonal antibody that antagonizes the interleukin-31 receptor, a key mediator of chronic pruritus in conditions such as atopic dermatitis and prurigo nodularis.

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