Chiesi in US$1.9bn deal to buy KalVista and its angioedema drug

The Italian pharma group Chiesi has agreed to acquire KalVista Pharmaceuticals for US$27 per share in cash, valuing the US‑based biotech at around US$1.9bn. The deal will significantly deepen Chiesi’s presence in rare and ultra‑rare disease. Under the deal, Chiesi will take full control of KalVista’s lead asset, sebetralstat, an oral, on‑demand therapy for hereditary angioedema (HAE) that the companies describe as the first treatment of its kind in the class.

The transaction structure is a straightforward cash tender offer: Chiesi will pay US$27.00 per share, representing a roughly 36% premium to KalVista’s 30‑day volume‑weighted average share price as of 28 April. A subsidiary of Chiesi will launch the tender for all outstanding KalVista shares. If it succeeds, any remaining shares will be scooped up via a second‑step merger at the same price. At about US$1.9bn in total enterprise value, this is Chiesi’s largest acquisition to date, underscoring how seriously the group is betting on rare‑disease growth.

The move slots neatly into Chiesi Global Rare Diseases, the dedicated business unit within Chiesi Farmaceutici SpA that is charged with developing and commercialising therapies for rare and ultra‑rare conditions. By adding sebetralstat to its rare‑immunology portfolio, the Italian pharma group gains the first oral, on‑demand option for HAE, a rare but life‑altering condition where patients often struggle with infrequent‑dosing, injectable prophylaxis or symptom‑driven acute‑treatment gaps. Strategically, sebetralstat is expected to contribute meaningfully to Chiesi’s €6bn revenue target for 2030, while also giving the company a more solid commercial presence in the US rare‑disease space.

The deal is expected to close in the third quarter of 2026, assuming at least a majority of KalVista shares are tendered and regulatory approvals are in hand. From day one, Chiesi says it will focus on working with the HAE community, physicians and scientific groups to smooth the transition and squeeze as much real‑world value as possible out of sebetralstat. “In HAE, patients continue to face significant unmet needs, and KalVista’s innovation meaningfully expands our presence in rare immunology by adding a differentiated, on-demand treatment option that can bring meaningful advancement in how the disease can be managed,” commented Giacomo Chiesi, Executive Vice President, Chiesi Global Rare Diseases.