Chiesi Group has agreed to acquire KalVista Pharmaceuticals in a $1.9 billion all-cash transaction, marking the largest acquisition in the Italian biopharmaceutical company’s history and significantly expanding its presence in rare diseases.
Under the agreement, Chiesi will pay $27 per share for KalVista, representing a 36% premium to the company’s 30-day volume-weighted average share price as of April 28, 2026. The boards of both companies have unanimously approved the deal, which is expected to close in the third quarter of 2026 subject to regulatory approvals and customary closing conditions.
The acquisition gives Chiesi control of EKTERLY (sebetralstat), the first approved oral, on-demand treatment for acute hereditary angioedema (HAE) attacks. The therapy, developed by KalVista, is already approved in the United States, European Union, United Kingdom, Japan, and other international markets. Following its U.S. launch in July 2025, the drug generated $49 million in revenue during 2025, reflecting rapid uptake among patients and physicians.
HAE is a rare genetic disorder that causes recurrent and potentially life-threatening swelling attacks. Existing acute treatments typically require injection or infusion, making sebetralstat’s oral formulation a notable innovation in the market. Clinical studies are also underway to expand the therapy’s use to children aged 2 to 11.
For Chiesi, the transaction strengthens its rare immunology portfolio and advances its strategy of building a leading global rare disease business through its Chiesi Global Rare Diseases unit. The company said sebetralstat is expected to contribute meaningfully toward its goal of reaching €6 billion in revenue by 2030, while also supporting expansion of its U.S. commercial infrastructure.
KalVista’s board said the transaction followed a review of strategic alternatives and delivers substantial value to shareholders while ensuring broader global access to sebetralstat through Chiesi’s international platform.
The acquisition reflects continued dealmaking momentum in the rare disease sector, where pharmaceutical companies are increasingly pursuing targeted therapies with strong pricing power and limited competition. For Chiesi, the purchase of KalVista represents a transformative step in its long-term expansion strategy and deepens its commitment to rare and ultra-rare disease treatments.
If completed, the transaction will further position Chiesi among the more significant privately held players in the global rare disease market.
