With the aim of securing its dominance in the hereditary angioedema (HAE) market through to 2030, Shire has struck a deal to buy Dyax for approximately US$5.9 B upfront plus a contingent value right worth an additional US$646 M. The principal value driver of the deal is Dyax’s Phase III-ready DX-2930, a plasma kallikrein inhibitor for the prevention of type 1 and type 2 HAE. Phase Ib clinical trial data suggest that DX-2930 offers potentially greater efficacy and more convenient dosing compared to Shire’s prophylactic HAE therapy Cinryze® (C1 esterase inhibitor [human]).