In its largest acquisition to date, Chiesi Group is buying Kalvista Pharmaceuticals Inc. for $27 per share, a roughly 40% premium to the previous day’s closing price, putting the total deal value at about $1.9 billion. In return, the Italian pharma firm adds to its rare disease franchise Kalvista’s recently approved hereditary angioedema (HAE) drug, plasma kallikrein inhibitor Ekterly (sebetralstat), which has gotten off to a strong commercial launch as the only orally available, on-demand treatment for HAE.