Chiesi strengthens rare disease portfolio with US$1.9B acquisition of KalVista

ITALY—Italian pharmaceutical company Chiesi Farmaceutici has announced the largest acquisition in its 90-year history, agreeing to acquire KalVista Pharmaceuticals in a deal valued at approximately US$1.9 billion.

The transaction marks a major strategic step for Chiesi as it strengthens its position in the rare disease treatment market.

Under the terms of the agreement, Chiesi will purchase KalVista at US$27 per share, representing a 36% premium over KalVista’s closing stock price on April 28.

The acquisition is expected to close in the third quarter of 2026, subject to regulatory approvals and customary closing conditions.

The move reflects Chiesi’s growing focus on rare diseases, an area the company has increasingly prioritised as part of its long-term global growth strategy.

This acquisition significantly expands the capabilities of Chiesi Global Rare Diseases, the company’s specialist business unit dedicated to developing and commercialising therapies for underserved patient populations.

Ekterly at the centre of the deal

At the heart of the acquisition is Ekterly, KalVista’s oral treatment for hereditary angioedema (HAE).

The drug received approval from the U.S. Food and Drug Administration in June 2025 and has since emerged as a notable innovation in the treatment landscape for the rare genetic disorder.

Ekterly offers a distinct advantage because patients can take it on demand after symptoms begin, providing an alternative to existing preventive therapies.

This differentiates it from Orladeyo from BioCryst Pharmaceuticals, which requires daily administration to prevent attacks.

Hereditary angioedema is a rare inherited condition caused by a deficiency or dysfunction of C1 esterase inhibitor (C1INH), a protein that regulates inflammation and immune system activity.

Without sufficient functional C1INH, patients experience sudden episodes of severe swelling in different parts of the body, including the face, abdomen, limbs, and airways.

In severe cases, swelling in the throat can become life-threatening if left untreated.

Changing treatment landscape for HAE

For many years, HAE treatment relied heavily on injectable therapies designed either to stop attacks once they started or to prevent them altogether.

However, the treatment landscape has evolved rapidly in recent years.

In 2025, the FDA approved two additional injectable therapies for HAE: Andembry from CSL Behring and Dawnzera from Ionis Pharmaceuticals.

These approvals ended a four-year period without new HAE treatment approvals in the US market.

Against this backdrop, Ekterly has gained considerable attention because it provides a non-injectable option that offers both convenience and speed of administration during acute episodes.

The treatment has already secured approvals in the UK, Europe, and Japan. In 2025, it generated US$49 million in sales, highlighting its early commercial momentum and market potential.

Strategic growth for Chiesi

Chiesi said the acquisition will support its ambition to expand its rare disease business and help achieve its 2030 revenue target of €6 billion (US$7 billion).

Giacomo Chiesi, Executive Vice President of Chiesi Global Rare Diseases, described the transaction as a strong strategic fit for the company’s portfolio.

He said the acquisition reinforces Chiesi’s commitment to people living with rare conditions and strengthens its presence in rare immunology.

He also noted that patients with hereditary angioedema continue to face significant unmet medical needs, adding that KalVista’s innovation introduces a differentiated on-demand treatment option that could reshape disease management.

Part of a broader wave of pharma deal-making

The KalVista acquisition comes during an active period of major pharmaceutical dealmaking across the global healthcare industry.

Earlier this week, Sun Pharmaceutical Industries announced its US$11.75 billion acquisition of Organon.

Meanwhile, Eli Lilly and Company agreed to acquire Ajax Therapeutics for US$2.3 billion, underscoring continued investor confidence in innovative therapeutic assets and specialised drug portfolios.