RADIANT-AD: Rademikibart Effective Over 52 Weeks in Atopic Dermatitis, With Cheng Zhou, MD

Rademikibart treatment of adults and adolescents living with moderate-to-severe atopic dermatitis leads to rapid and clinically significant improvements, new data suggest, with many improvements sustaining through 52 weeks.1,2

These data were the result of a phase 3 study of rademikibart presented in the late-breaking research session at the 2026 American Academy of Dermatology (AAD) Annual Meeting in Denver, Colorado. To discuss the findings in depth, as well as their significance, the HCPLive team spoke in a Q&A interview with Cheng Zhou, MD, of Peking University People’s Hospital.

Zhou, an investigator in the RADIANT-AD trial from which these data were drawn, spoke about these results in detail. His written responses are transcribed here:

HCPLive: Can you walk us through the top-line results from the phase 3 trial — what did rademikibart actually show?

Zhou: The phase 3 RADIANT‑AD trial showed that rademikibart produced rapid, clinically meaningful improvements in adults and adolescents with moderate‑to‑severe atopic dermatitis, with responses that continued to deepen and were sustained through 52 weeks.

At Week 16, rademikibart significantly outperformed placebo across all major efficacy endpoints, and importantly, patients continued to improve over time rather than reaching an early plateau. By one year, a large majority of patients achieved near‑maximal skin clearance and sustained itch control, supporting both the durability and consistency of response.

HCPLive: What were the primary endpoints, and were they met?

Zhou: The study had two co‑primary endpoints: the proportion of patients achieving an Investigator’s Global Assessment score of 0 or 1 with at least a 2‑point reduction, and the proportion achieving at least a 75% improvement in EASI score at Week 16. Both endpoints were met with strong statistical significance.

At Week 16, 47.4% of patients treated with rademikibart achieved IGA 0/1, compared with 17.6% on placebo, while 74.2% achieved EASI‑75 versus 34.4% with placebo (both p<0.001). Importantly, these responses continued to improve over time, with IGA 0/1 and EASI‑75 rates rising to 87.1% and 96.6%, respectively, by Week 52, underscoring the durability of the treatment effect.

HCPLive: How did the drug perform on itch and quality of life measures, not just skin clearance?

Zhou: Rademikibart demonstrated rapid and sustained improvement in itch, a major driver of quality of life in atopic dermatitis. By Week 16, 54.7% of patients treated with rademikibart achieved a clinically meaningful ≥3‑point reduction in pruritus score, compared with 27.5% on placebo (p<0.0001), with responses continuing to deepen over time; by Week 52, 91.2% of patients achieved this level of itch improvement. Importantly, clinicians often view a ≥4‑point reduction as an even more stringent and clinically meaningful benchmark, and analyses using this higher threshold showed a similar pattern of robust and durable separation from placebo.

While broader quality‑of‑life and other patient‑reported outcome measures have not yet been fully reported and will be presented separately, the magnitude and durability of itch reduction observed are strongly aligned with meaningful day‑to‑day functional benefit for patients.

HCPLive: What did the safety profile look like, and were there any findings that stood out to you?

Zhou: Overall, rademikibart demonstrated a safety profile comparable to placebo through Week 16 and consistent with long‑term IL‑4/IL‑13 pathway inhibition through Week 52. Rates of serious adverse events, treatment discontinuations, and injection‑site reactions were low, and no new safety signals emerged over one year of treatment. One finding of particular interest was the low and placebo‑comparable rate of conjunctivitis (3.9% vs 3.1%), which is a known concern for dermatologists using existing therapies in this class.

HCPLive: Were there any side effects that clinicians should be aware of when thinking about this drug?

Zhou: The side effects observed with rademikibart were generally consistent with what clinicians would expect for biologic therapies targeting type 2 inflammation, with most events being mild to moderate in severity. Conjunctivitis occurred at low rates and was comparable to placebo, and treatment‑related discontinuations were rare. As with any systemic biologic therapy, clinicians should remain attentive to overall tolerability and routine safety monitoring, but no unexpected or treatment‑limiting adverse effects were identified in this trial.

HCPLive: What questions does this trial leave unanswered, and what would you want to see studied next?

Zhou: While the phase 3 RADIANT‑AD trial clearly establishes strong and rapid efficacy and one‑year durability, important questions remain regarding the broader patient experience and longer‑term use. Ongoing and planned analyses of patient‑reported outcomes and quality‑of‑life measures will help further contextualize the depth and clinical relevance of the benefits observed with rademikibart. In addition, longer follow‑up beyond one year will be important to better characterize the impressive durability of response and long‑term safety, as well as to understand how these results translate across the diverse patient subgroups encountered in real‑world dermatology practice.

HCPLive: What is the timeline toward a potential FDA submission?

Zhou: At this time, neither Connect Biopharma nor its partner Simcere has publicly disclosed a specific timeline for an FDA submission in atopic dermatitis. The current RADIANT AD study was conducted by Simcere in China and the results create options outside of China for an active US regulatory filing plan. Any submission would follow completion of full analyses and internal strategic review, but no timing has been announced.

References

1. Results from Phase 3 Study of Rademikibart in Moderate-to-Severe Atopic Dermatitis to be Presented in the Late-Breaking Research Session at the 2026 American Academy of Dermatology (AAD) Annual Meeting. Connect Biopharma Holdings Limited. March 10, 2026. Accessed March 31, 2026. https://investors.connectbiopharma.com/news-releases/news-release-details/results-phase-3-study-rademikibart-moderate-severe-atopic.

2. Early symptom improvement with remibrutinib in chronic spontaneous urticaria: Daily Itch Severity Scores and Hives Severity Scores from phase 3 REMIX-1/-2 studies. Poster presented at: 2026 American Academy of Dermatology Annual Meeting; March 27–31, 2026; Denver, CO.