Japanese drugmaker Shionogi agreed on October 5, 2026 to acquire IntraBio, an Austin, Texas biotech that sells the rare neurological disease drug Aqneursa (levacetylleucine), for $2 billion in cash paid upfront to IntraBio's shareholders.
Shionogi Inc., the company's New Jersey-based US subsidiary, will buy all of IntraBio's outstanding shares, and IntraBio will become a wholly owned subsidiary. The deal still needs regulatory clearance and other customary closing conditions; Shionogi expects it to close before the end of 2026.
The announcement came less than three weeks after the US Food and Drug Administration expanded Aqneursa's label on September 18 to include ataxia in patients with ataxia-telangiectasia, a rare inherited neurodegenerative disorder.
What IntraBio built
IntraBio was founded in 2015 to develop treatments for neurodegenerative diseases. Its scientific co-founders were Grant Churchill, Antony Gallone and Frances Platt of the University of Oxford and Michael Strupp of the University of Munich, who worked on small molecules that act on lysosomal function and calcium signalling inside cells. The company started out in Oxford, England, and moved its headquarters to Austin in 2024.
Its drug, levacetylleucine, is a modified form of the amino acid L-leucine designed to pass through cell membranes, including the blood-brain barrier. The FDA first approved it as Aqneursa in September 2024 for the neurological symptoms of Niemann-Pick disease type C, an inherited disorder that affects how cells handle fats and that strikes about one in a million people in the US. The European Commission approved it for the same disease in early 2026.
The September 2026 label expansion made Aqneursa the first drug approved in the US to treat ataxia in ataxia-telangiectasia patients weighing at least 15 kilograms. A European review of that indication is still underway. The drug label notes that its mechanism of action in both diseases is unknown.
According to figures Shionogi released with the deal, IntraBio recorded net sales of about $67.9 million in 2025, all from Aqneursa, and a net loss of $35.8 million. Fierce Pharma reported that IntraBio is also running a phase 3 study in CACNA1A disorders, a group of conditions caused by mutations in a single gene.
“Bringing Aqneursa to Shionogi after our acquisition of Radicava will deepen our commitment to rare disease communities”
Why Shionogi is buying
The deal is Shionogi's second large rare-disease purchase in about a year. It bought global rights to the ALS drug Radicava (edaravone) from Tanabe Pharma for $2.5 billion plus a potential royalty, which launched its rare-disease business. Shionogi expects Radicava to generate about $700 million in global sales in fiscal 2026.
Shionogi, based in Osaka, earns most of its revenue from royalties on HIV drugs sold by ViiV Healthcare, the GSK-controlled company in which Shionogi raised its stake from 10% to 21.7% earlier this year. Its own rare-disease pipeline has been uneven: zatolmilast, which came with its 2020 purchase of Tetra Therapeutics, failed two phase 3 trials in Fragile X syndrome, as disclosed in May 2026. It also has a Pompe disease candidate licensed from Maze Therapeutics in 2024.
Shionogi said it would assess how the acquisition affects its forecast for the fiscal year ending in March 2027. Its shares on the Tokyo Stock Exchange fell about 4.5% on the day of the announcement and recovered 3.8% the next day, GEN reported.
The funding behind IntraBio
IntraBio stayed private and raised relatively modest sums for a company with an approved drug. It closed a $15 million Series C in April 2023 to fund its pivotal phase 3 trial and prepare filings in the US and Europe. In March 2024, when it moved its headquarters to Texas, it said it had raised more than $40 million in new equity from investors it did not name, to pay for the launch of its Niemann-Pick drug.
Neither IntraBio nor Shionogi disclosed the company's investors or headcount. Kirkland & Ellis advised IntraBio on the sale.
A scarce asset in rare disease
Analysts pointed to the value large drugmakers place on approved rare-disease products. Sumant Kulkarni, a senior biotechnology analyst at Canaccord Genuity, told GEN that companies with approved products for rare indications present significant scarcity value for strategic buyers and investors.
Shionogi has set a 2030 target for its growth plan, which includes expanding into rare-disease markets outside Japan. Once the deal closes, Aqneursa will sit alongside Radicava in its US rare-disease portfolio, together with the COVID-19 drug Xocova and the antibiotic Fetroja.
