Chiesi acquires KalVista as pharma deepens rare disease push

Overview

Updated May 31

For decades, people with hereditary angioedema had one option when an attack hit: inject themselves, often in a panic. In this genetic condition, the immune system misfires and swells tissues shut—sometimes fatally, closing the airway. In July 2025, a pill changed that.

On Wednesday, Italian drugmaker Chiesi Farmaceutici agreed to buy KalVista Pharmaceuticals for about $1.9 billion in cash. It was the largest acquisition in Chiesi's 90-year history. Chiesi now owns EKTERLY (sebetralstat), the only oral on-demand therapy for the rare immune disorder.

The deal values KalVista at $27.00 per share, a 36% premium over recent prices. EKTERLY generated $49 million in sales during its first nine months on the US market, with the final quarter at $35 million, nearly double the expected $21 million. The KONFIDENT-KID trial posted positive Phase 3 results for ages 2 to 11 in March 2026, pointing toward a US regulatory filing in the second half of this year that could expand the patient population.

Why it matters

Roughly 1 in 50,000 people inherit a disease that can swell their throat shut—and now there is a pill, owned by a company willing to spend billions to sell it.

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Key Indicators

$1.9B

Deal value

Largest acquisition in Chiesi's history, paid entirely in cash.

36%

Premium paid

Markup over KalVista's recent trading price before the deal was announced.

$27.00

Per-share price

All-cash offer unanimously approved by both boards.

$49M

EKTERLY 2025 revenue

Sales in EKTERLY's first nine months on the US market after its July 2025 launch.

$35M

Q4 2025 EKTERLY sales

Fourth-quarter revenue nearly doubled the $21M analyst consensus, signaling strong commercial uptake.

1 in 50,000

HAE prevalence

Estimated rate of hereditary angioedema, the disease EKTERLY treats.

First

Oral on-demand HAE therapy

Before EKTERLY, attack treatments required injection or infusion.

Q3 2026

Expected close

Subject to KalVista shareholder vote and regulatory review.

Voices

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People Involved

Giuseppe Accogli

Chief Executive Officer, Chiesi Group

Leading the largest deal in company history

Benjamin Palleiko

Chief Executive Officer, KalVista Pharmaceuticals

Selling company after one year of commercial sales

Organizations Involved

Chiesi Farmaceutici

Family-owned pharmaceutical company

Acquirer

Italian drugmaker based in Parma, owned by the founding Chiesi family, with about 7,000 employees and roughly €3 billion in annual revenue.

KalVista Pharmaceuticals

Publicly-traded biotech

Target

US-listed biotech, originally spun out of UK research, focused on plasma kallikrein inhibitors for hereditary angioedema and related conditions.

Timeline

2011 April 2026

8 events Latest: April 29th, 2026 · 4 months ago

Tap a bar to jump to that date

April 2026
Chiesi agrees to acquire KalVista for $1.9 billion
Latest M&A

Italian drugmaker offers $27 per share in cash—a 36% premium—in its largest-ever deal, gaining global rights to EKTERLY. Both boards approve unanimously.
April 29th, 2026
Shareholder law firms open fair-price investigations
Legal

Halper Sadeh LLC and Ademi LLP each announced investigations into whether KalVista's board obtained adequate consideration for shareholders, citing substantial insider change-of-control benefits triggered by the deal. Such probes are routine following biotech acquisitions at a premium and do not, by themselves, block deal completion.
April 29th, 2026
Jones Trading downgrades KALV to hold; analyst sees no antitrust risk
Market

Jones Trading moved KalVista stock to hold after shares surged 39% to $26.67, just below the $27.00 offer price, leaving minimal upside for investors who buy in now. The firm noted it does not anticipate meaningful antitrust risk given Chiesi's limited existing presence in the hereditary angioedema market.
April 29th, 2026
March 2026
KONFIDENT-KID trial posts positive interim Phase 3 results for children aged 2–11
Clinical

KalVista presents interim data from the largest pediatric HAE trial ever conducted at the 2026 Global Angioedema Leadership Conference: 88.9% of attacks were mild or moderate, median time to symptom relief was 1.5 hours, and sebetralstat was well tolerated with no serious adverse events. A US regulatory filing is targeted for Q3 2026.
March 30th, 2026
2025
FDA approves EKTERLY as first oral on-demand HAE therapy
Regulatory

The agency clears sebetralstat for adults and adolescents, ending decades in which the only attack treatments were injections or infusions.
2025
2024
Phase 3 KONFIDENT trial reports positive results
Clinical

Sebetralstat shows it can stop hereditary angioedema attacks faster than placebo when taken as a pill, setting up regulatory submission.
2024
2017
KalVista lists on NASDAQ
Corporate

The biotech becomes publicly traded in the US through a reverse merger, raising capital to push sebetralstat through late-stage trials.
2017
2011
KalVista founded around a single enzyme target
Company History

British scientists launch KalVista to develop drugs blocking plasma kallikrein, an enzyme that drives swelling in hereditary angioedema.
2011

Scenarios

Deal closes on schedule, EKTERLY rolls out worldwide

Likely

Discussed by: Bloomberg, BioSpace, sell-side biotech analysts

KalVista shareholders approve the sale, antitrust reviews in the US and EU clear without conditions, and the deal closes in Q3 2026 as planned. Chiesi uses its established commercial infrastructure across Europe and Asia to launch EKTERLY in markets KalVista could not have reached alone for years. Rare-disease prescription drug sales typically grow slowly but durably, so revenue ramps over multiple years rather than a single launch quarter.

Competing bidder emerges, forces price up

Unlikely

Discussed by: M&A arbitrage desks, biotech deal trackers

A larger pharma player—possibly one already active in rare immunology like Takeda, Sanofi, or CSL—decides EKTERLY's franchise potential is worth more than $1.9 billion and tables a topping bid before the shareholder vote. Chiesi's deal includes a customary breakup fee, but the family-owned company has limited ability to win a bidding war against a multinational with deeper pockets. KalVista shareholders end up with a higher price.

Regulatory review delays close into 2027

Possible

Discussed by: Antitrust attorneys, deal-completion analysts

EU or US antitrust regulators take a closer look at how the combined company would compete in the small hereditary angioedema market, where only a handful of companies—BioCryst, Takeda, CSL, Pharvaris—operate. Chiesi has limited HAE presence today, so substantive overlap concerns are unlikely, but second-request reviews can still push closing dates by months. The deal closes eventually but later than guided.

Commercial launch underperforms expectations under new owner

Uncertain

Discussed by: Pharma industry observers, rare disease patient groups

Once Chiesi takes over, integration friction or pricing pushback from US payers slows EKTERLY's uptake compared to KalVista's pre-deal projections. Rare disease drugs depend heavily on small specialist networks and patient organizations; if Chiesi's commercial team mishandles those relationships, prescriptions plateau. The deal still pays off long-term but takes longer to break even than planned.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

January-March 2018

Sanofi acquires Bioverativ (2018)

French drugmaker Sanofi paid $11.6 billion for Bioverativ, a Biogen spinoff focused on hemophilia. Like KalVista, Bioverativ had a launched product and a clear path in a rare blood disorder market.

Then

Sanofi gained a foothold in rare hematology and immediately started a string of further rare-disease deals, signaling a new strategic direction.

Now

The acquisition is now seen as a successful template for rare-disease M&A: pay a premium for a smaller company with an approved drug and use the buyer's global infrastructure to scale it.

Why this matters now

The structural similarity—mid-size acquirer, focused biotech with a launched orphan drug, premium price, expansion into rare disease—is almost identical to Chiesi-KalVista, just at smaller scale. Demonstrates the deal logic Chiesi is following.

January 2019

Takeda acquires Shire (2019)

Japanese drugmaker Takeda completed a $62 billion takeover of Shire, the Ireland-headquartered rare disease leader behind several hereditary angioedema therapies including Firazyr and Takhzyro. It was the largest overseas acquisition by a Japanese company at the time.

Then

Takeda took on substantial debt to fund the deal and spent years divesting non-core assets. Shire's HAE franchise became a cornerstone of Takeda's rare disease business.

Now

Takeda is now one of the dominant players in hereditary angioedema worldwide, the same therapeutic area Chiesi is entering through KalVista. The Shire deal showed both the appeal and the price tag of HAE leadership.

Why this matters now

Establishes how valuable HAE franchises can be—Takeda paid tens of billions partly for an injection-based portfolio that EKTERLY is now competing against. It also frames who Chiesi will go up against commercially.

December 2020

AstraZeneca acquires Alexion (2020)

AstraZeneca paid $39 billion for Alexion, a Boston-based rare disease specialist whose flagship drug Soliris treated paroxysmal nocturnal hemoglobinuria and other ultra-rare conditions. The deal was AstraZeneca's largest ever and pulled the British-Swedish drugmaker into a category dominated until then by smaller, focused biotechs.

Then

Alexion became AstraZeneca's rare disease division and immediately added high-margin revenue. Investors who had questioned the price came around as Soliris and its successor Ultomiris kept growing.

Now

The deal helped legitimize rare-disease franchises as a strategic acquisition category for big pharma, accelerating subsequent transactions and bidding multiples for orphan-drug companies.

Why this matters now

Same template as Chiesi-KalVista: a larger pharma company buys a smaller specialist with an approved rare-disease drug to gain instant franchise revenue and global launch capacity. The pricing math—premium for a launched product with limited competition—mirrors what Chiesi paid.