Acquisition · Pharmaceuticals (sleep medicine)
Shionogi buys out Apnimed's half of their sleep medicine venture for $100 million
- Buyer
- Shionogi (Osaka)
- Target
- Shionogi-Apnimed Sleep Science (Apnimed's 50%), Massachusetts
- Value
- $100M upfront (about ¥15.95B), plus a $50M milestone payment and royalties
- Status
- Agreed March 24, 2026; expected to close in April 2026.
- Date
- 2026-03-24
Shionogi agreed to buy Apnimed's 50% of Shionogi-Apnimed Sleep Science (SASS), the joint venture the two set up in 2023 to develop drugs for sleep apnea and other sleep disorders. Shionogi pays $100 million upfront, another $50 million if SASS-002 (sulthiame) hits a development milestone, and royalties on future sales. Shionogi said running the venture alone would speed up decisions and launch.
Why it matters
Sleep apnea is common and mostly treated with breathing machines, so medicines for it are a large opportunity; Shionogi now owns this pipeline outright.
The joint venture
Shionogi and Apnimed, a Massachusetts drug developer, set up SASS in 2023, pairing Shionogi's small-molecule drug discovery with Apnimed's clinical research skills. Shionogi already appointed several of its directors. SASS has two main programs, SASS-001 and SASS-002, plus several early discovery projects.
About sulthiame
Apnimed licensed sulthiame from Germany's Desitin in 2024. The once-daily pill is already approved for other illnesses in several countries outside the US, and it has finished two mid-stage trials in more than 300 European patients with obstructive sleep apnea. Apnimed keeps its own lead drug, AD109, which is not part of the deal.
Sources
Kakehashi M&A News home
