Pharma M&A Roundup: Merck to Acquire Terns Pharmaceuticals, Shionogi to Acquire 50% of Apnimed’s Ownership of Shionogi-Apnimed Sleep Science

Key Takeaways

• Merck pays $6.7B, 31% premium for Terns.
• TERN-701 targets resistant CML with favorable safety.
• Deal closes Q2 2026, adds oncology asset.
• Shionogi spends $150M to own SASS fully.
• AD109 aims to treat OSA pharmacologically.

Summary

Merck announced a $6.7 billion cash deal to acquire Terns Pharmaceuticals, paying a 31% premium and targeting the oral BCR::ABL1 inhibitor TERN‑701 for treatment‑resistant chronic myeloid leukemia. The transaction, slated to close in Q2 2026, adds an orphan‑drug‑designated oncology asset to Merck’s pipeline. Meanwhile, Shionogi agreed to purchase Apnimed’s 50% stake in the Shionogi‑Apnimed Sleep Science joint venture for $100 million upfront plus a $50 million milestone, making SASS wholly owned and freeing Apnimed to focus on its AD109 OSA candidate. Both deals close in the second quarter of 2026 and signal strategic bets on high‑unmet‑need therapeutic areas.

Pulse Analysis

Merck’s purchase of Terns underscores a renewed focus on differentiated oncology assets as the company seeks to offset slowing growth in its traditional blockbuster drugs. TERN‑701, an allosteric BCR::ABL1 inhibitor, offers a potential solution for patients who have exhausted existing tyrosine‑kinase inhibitors, and its orphan‑drug status could accelerate regulatory pathways. By paying a sizable premium, Merck signals confidence in the drug’s ability to generate deep molecular responses, which could translate into premium pricing and a durable revenue stream in the competitive CML market.

Shionogi’s move to fully acquire the Shionogi‑Apnimed Sleep Science venture reflects the pharmaceutical industry's pivot toward addressing the massive unmet need in obstructive sleep apnea (OSA). With roughly 80 million Americans affected, OSA remains dominated by mechanical devices, leaving a lucrative gap for oral therapeutics. AD109, a once‑daily combination of aroxybutynin and atomoxetine, targets the neuromuscular cause of airway collapse, differentiating it from existing treatments. The $150 million transaction not only consolidates Shionogi’s R&D capabilities but also provides Apnimed capital to accelerate AD109’s development, potentially reshaping the OSA therapeutic landscape.

These parallel deals illustrate a broader trend of large pharma leveraging M&A to acquire niche, high‑potential assets rather than building them internally. Investors should watch the integration progress, especially Merck’s ability to navigate CML regulatory hurdles and Shionogi’s execution of late‑stage trials for AD109. Successful outcomes could boost earnings guidance and set precedents for future acquisitions targeting rare‑disease designations and underserved patient populations.