Biosion USA started a Phase IIa clinical trial to investigate BSI-045B in patients with atopic dermatitis (AD).

BSI-045B will be evaluated as a monotherapy and an add-on therapy with Dupixent (dupilumab), co-developed by Sanofi and Regeneron.

BSI-045B is a humanised monoclonal antibody that targets thymic stromal lymphopoietin (TSLP), a cytokine that is involved in the pathogenesis of AD.

The open-label Phase IIa trial (NCT05932654) will evaluate the efficacy, safety, tolerability, immunogenicity, pharmacokinetics (PKs) and pharmacodynamics (PDs) of BSI-045B. According to the ClinicalTrials.gov registry, Biosion plans to enrol 80 participants with moderate to severe AD.

According to the company’s website, the trial will be conducted in the US.

Participants will be enrolled into four cohorts that will investigate 300mg and 480mg doses of BSI-045B as a monotherapy and an add-on therapy with Dupixent.

Dupixent was first approved in 2017 and is used as a treatment for AD, asthma, sinusitis, and eosinophilic oesophagitis.

Patients in each cohort will be treated with a loading dose of BSI-045B administered every week for three weeks. Afterwards, patients will receive the assigned dose every two weeks through week 24.

The primary endpoints of the trial will measure the proportion of patients with Eczema Area and Severity Index 75 (EASI75) at week 12 and BSI-045B’s safety profile. According to the trial registry, the estimated study completion date is November 2024.

In April, Biosion opened an investigational new drug (IND) application following a review by the US Food and Drug Administration (FDA).

Development of BSI-045B

The drug candidate was previously studied in a Phase I trial (NCT05114889). The randomised, double-blind, placebo-controlled study evaluated the single ascending dose and multiple ascending doses of BSI-045B in 56 healthy volunteers and 12 patients with AD.

According to Biosion, the results from the Phase I trial demonstrated BSI-045B to be a first-in-class treatment for AD due to the single dose activity in the AD cohort, as well as favourable PK and safety profiles.

BSI-045B is co-developed with China-based CTTQ, which has rights to the development and commercialisation of the drug candidate in China. CTTQ is currently conducting a Phase II trial in patients with severe uncontrolled asthma in China.