Argo Biopharma will present updated Phase II results for BW-20805, its investigational siRNA therapy for hereditary angioedema, at the European Association of Allergy & Clinical Immunology Congress 2026 in Istanbul, Türkiye.
The programme addresses an unmet need in hereditary angioedema, a rare genetic disorder characterised by sudden swelling attacks that can become life-threatening when the airway is affected. Current preventive treatments may require frequent dosing, creating a need for longer-acting prophylactic options that reduce treatment burden.
BW-20805 targets prekallikrein, a validated therapeutic target in hereditary angioedema. By inhibiting hepatic prekallikrein mRNA, the investigational therapy is designed to reduce prekallikrein production and support long-lasting prevention of HAE attacks.
The updated Phase II analysis includes 18 randomised and dosed participants across three treatment groups. Time-normalised HAE attack rates were reduced by 99 percent in the 600 mg every-24-week group, 93 percent in the 300 mg every-24-week group and 95 percent in the 300 mg every-12-week group. Attack-free rates ranged from 60 percent to 83 percent across the groups.
The study also showed rapid and sustained plasma prekallikrein reduction, with mean reductions exceeding 94 percent in pooled 300 mg groups and 96 percent in the 600 mg every-24-week group on Day 85. Among participants completing 169 days, mean prekallikrein reductions remained above 90 percent across all three groups.
BW-20805 was reported to be well tolerated, with no drug-related severe adverse events, serious adverse events, discontinuations or deaths. The most common adverse event was mild and transient injection-site reaction.
The data support further evaluation of a once-every-six-months dosing regimen. If confirmed in later-stage studies, this dosing interval could represent a meaningful convenience advantage in long-term prophylaxis for HAE.
