Chiesi to Buy KalVista for $1.9 Billion in Its Biggest-Ever Deal, Wrapping the First Oral HAE Pill Into a Growing Rare Disease Portfolio
Italian drugmaker Chiesi will pay $27 a share for KalVista Pharmaceuticals to acquire Ekterly, the first oral on-demand treatment for hereditary angioedema, in a deal expected to close in the third quarter.
Overview
Chiesi Farmaceutici, the Italian privately held drugmaker, said it will acquire KalVista Pharmaceuticals for about $1.9 billion, the largest acquisition in the company’s nearly 100-year history. The centerpiece of the deal is Ekterly (sebetralstat), the first oral, on-demand therapy approved for hereditary angioedema, a rare genetic swelling disorder long managed with injectables.
Under terms announced on April 29, Chiesi will pay $27 per share in cash for KalVista, according to BioPharma Dive. The offer represents a 36% premium to KalVista’s share price on April 28, FiercePharma reported. Bloomberg reported the same headline price benchmarked against KalVista’s 30-day volume-weighted average. The transaction is expected to close in the third quarter of 2026, FiercePharma reported.
What We Know
- Deal mechanics. Chiesi will buy out KalVista at $27 per share in cash, valuing the U.S.-listed biotech at roughly $1.9 billion, BioPharma Dive reported. STAT characterized the offer as a roughly 40% premium to KalVista’s Tuesday closing price, while FiercePharma reported the 36% figure benchmarked against the April 28 closing price. Both metrics describe the same headline price.
- The asset at the center. Ekterly (sebetralstat) is a plasma kallikrein inhibitor — a small molecule that blocks the protein driving the swelling cascade in hereditary angioedema attacks, FiercePharma reported. The U.S. Food and Drug Administration approved Ekterly in July 2025 as the first oral on-demand treatment for acute HAE attacks in adults and adolescents aged 12 and older, FiercePharma reported.
- Commercial traction. Ekterly generated $49 million in 2025 sales over roughly half a calendar year on the market following its July approval, FiercePharma reported. BioPharma Dive noted the drug captured roughly 20% of the U.S. patient population by February and that uptake exceeded analyst expectations, citing notes from Stifel and RBC Capital Markets.
- Acquirer profile. The asset will be folded into Chiesi Global Rare Diseases, the company’s existing business unit focused on orphan conditions, FiercePharma reported. Chiesi has set a strategic revenue target of €6 billion by 2030, and Ekterly is expected to contribute meaningfully toward it, FiercePharma reported.
Why It Matters
Hereditary angioedema is a genetic disorder that produces unpredictable, sometimes life-threatening attacks of swelling in the airway, abdomen, and extremities. Until Ekterly, on-demand acute therapy required injection or infusion — a meaningful obstacle for patients managing sudden episodes. BioPharma Dive reported that Ekterly distinguishes itself from prophylactic injectables such as CSL Behring’s Andembry and Ionis Pharmaceuticals’ Dawnzera by treating attacks once they begin rather than preventing them.
The acquisition arrives as the broader HAE treatment landscape is being reshaped by next-generation modalities. BioPharma Dive noted that Pharvaris and Intellia Therapeutics are advancing competing approaches, with Pharvaris’s deucrictibant — a bradykinin B2 receptor antagonist — meeting Phase 3 endpoints for on-demand treatment ahead of an expected NDA filing. Intellia, as previously reported, released positive Phase 3 data on April 27 for lonvo-z, an in vivo CRISPR therapy that could ultimately offer a one-time edit instead of repeat dosing.
For Chiesi, a family-controlled company headquartered in Parma, the deal extends a multi-year buildout of its rare disease franchise and represents the company’s largest deal in its nearly 100-year history, FiercePharma reported. Adding Ekterly gives Chiesi a commercial product with active growth — and a foothold in the kallikrein-bradykinin pathway that has become one of the more competitive corners of rare disease drug development.
What We Don’t Know
- Closing risk. BioPharma Dive reported the close is targeted for the third quarter, but no definitive date has been disclosed and neither company has detailed potential antitrust hurdles given Chiesi’s existing rare disease footprint.
- Pediatric label expansion. Public reporting has not detailed a regulatory timeline for expanding Ekterly’s label to younger patients, beyond noting Ekterly’s current indication starts at age 12, per FiercePharma.
- Pipeline integration. Public reporting on the deal has focused on Ekterly. Details on KalVista’s earlier-stage programs, and how Chiesi plans to fund or prioritize them after closing, have not been disclosed.
- Long-term competitive pressure. Whether Chiesi can sustain Ekterly’s pricing and uptake against an evolving HAE market — including a possible one-time gene-editing therapy from Intellia — will likely shape the deal’s eventual return on investment, but neither company has commented on the long-term competitive thesis.