🧾 What This Document Is

This is a 6-K filing, which is a report foreign companies (like Swiss-based AC Immune) file with the SEC to share major news with U.S. investors. This specific filing contains a press release announcing an amendment to a major partnership.

👉 In simple terms: AC Immune is updating investors on its deepening collaboration with drug giant Eli Lilly to develop treatments for Alzheimer's and similar diseases.

🏢 What The Company Does

AC Immune SA is a clinical-stage biopharmaceutical company. This means they are focused on developing new drugs but are not yet selling any commercial products.

👉 In simple terms, they are a research company trying to invent and test new medicines for brain diseases like Alzheimer's and Parkinson's. Their work centers on fixing "misfolded proteins" that are believed to cause these diseases.

🤝 The Deal With Lilly

The big news is an amendment to a 2018 license and collaboration agreement with Eli Lilly. The original deal was to develop small molecule drugs (called Morphomers) that target a protein called Tau, which forms toxic clumps in the brains of Alzheimer's patients.

The amendment now:

• Reflects "growing excitement" in the field for targeting Tau inside brain cells.
• Allows the partnership to develop new lead candidates and back-up compounds.
• Kicks off the final stage of preclinical work, with IND-enabling studies set to start in the first half of 2026. An IND (Investigational New Drug) application is required to begin human clinical trials.

💰 The Financial Terms

This amendment comes with immediate cash for AC Immune and outlines a huge future payday if the drug succeeds.

Upfront & Short-Term Cash:

• CHF 10 million upfront payment (Swiss Francs, ≈ USD $11.2 million as of April 2026).
• An additional milestone payment will be due when the drug first doses a patient in a Phase 1 clinical trial.

Long-Term Potential Value (if all goes well):

• Over CHF 1.7 billion (≈ USD $1.9 billion) in potential future development, regulatory, and commercial milestone payments.
• Tiered royalty payments in the low double digits on any future sales of the drug.

👉 Why it matters: This deal provides AC Immune with critical non-dilutive funding (cash without selling stock) to fund its research. The huge potential milestone payments show how valuable this single program could become.

🚀 Key Moves & Strategic Signal

The major move here is deepening a partnership with a top-tier pharmaceutical company. By amending the agreement, Lilly is signaling its continued belief in AC Immune's science and technology.

Why this matters:

• It validates AC Immune's Morphomer platform technology.
• It keeps a major, well-funded partner committed to advancing a key program.
• The CEO's comment suggests they are now even more confident that targeting Tau inside cells could "slow or even completely halt" the disease, moving from treatment to prevention.

📅 Key Dates & What's Next

The most immediate next step is clear:

• H1 2026 (First half of 2026): IND-enabling studies are set to commence. These are the final animal studies and lab work required by regulators before a drug can be tested in humans.

This is a critical near-term milestone that will move the candidate closer to human trials.

📦 Company Context & Pipeline

AC Immune isn't a one-trick pony. This Lilly deal is part of a broader portfolio.

• They have two technology platforms: SupraAntigen® (for vaccines and diagnostics) and Morphomer® (for small molecule drugs like the Tau inhibitors here).
• Their pipeline includes programs in Phase 2 and Phase 3 development.
• They have a history of partnerships, with >$4.5 billion in potential total milestones and royalties across all their deals.

⚖️ Big Picture: Strengths & Risks

Strengths (👍):

• Deepening Partnership: Having Lilly, one of the world's largest drug companies, double down is a major vote of confidence.
• Significant Non-Dilutive Funding: CHF 10 million now, with potential for billions later.
• Targeting a Critical Need: Alzheimer's disease has massive unmet medical need. A drug that works could be a blockbuster.

Risks (⚠️):

• Long Development Timeline: The drug won't even start human trials until at least late 2026 or later. It will be many years before we know if it works and is safe.
• High Failure Rate: Neurodegenerative disease drug development is notoriously difficult, with a very high failure rate in clinical trials.
• Dependency: A significant portion of AC Immune's value and funding is tied to the success of its partnership deals.

🧠 The Analogy

This is like a promising university startup (AC Immune) that invented a brilliant new engine technology (Morphomer). A major car manufacturer (Lilly) licensed the tech years ago and has now seen such promising lab results that it's signing a new, bigger contract and immediately funding the next step: building a full prototype to test on the track (IND-enabling studies). The startup gets paid now and stands to earn royalties if the engine ever goes into millions of cars.

🧩 Final Takeaway

AC Immune secured an immediate CHF 10 million cash infusion and reaffirmed its high-value partnership with Lilly to advance a promising Tau-targeting Alzheimer's drug into the final stage of testing before human trials, highlighting both the potential and the long road ahead in neurodegenerative drug development.

For further information, please contact: SVP, Investor Relations & Corporate Communications Gary Waanders, Ph.D., MBA AC Immune Phone: +41 21 345 91 91 Email: [email protected]

International Media Chris Maggos Cohesion Bureau Phone: +41 79 367 6254 Email: [email protected]