Letter to Investors

May 4, 2020

Dear Investor,

2020 continues to be an important and eventful year for AC Immune and the entire field of neurodegenerative diseases, even in the context of the challenges posed by the Covid-19 pandemic.

With publication of our Q1 2020 results, we have again confirmed our strong cash position of CHF 277.9 million, which provides the Company with a solid foundation and a cash runway extending through at least Q1 2024, without including any potential future milestone payments from partnerships. Moving forward, we remain on track to meet multiple value-creating milestones this year, with five clinical readouts expected. Of these readouts, we are particularly excited about the expected announcement of the first Phase 2 proof-of-concept data for semorinemab, an anti-Tau antibody, achieved through our partnership with Genentech, a member of the Roche group.

Our core financial stability and strength reflects that, as with our research strategy, we have always taken a long-term, informed approach. As a result, we are in the best position possible to manage the extraordinary situation presented by Covid-19 thanks, in large part, to the revenues generated by our transformative industry partnerships bolstering our financial outlook. For example, in 2019, our partnership with Eli Lilly and Company on the small molecule Morphomer™ Tau aggregation inhibitor program went from strength to strength. Earlier this year we received a CHF 10 million milestone payment in Q1, the second milestone payment since the deal was penned, and added a new CHF 60 million potential milestone payment to the Lilly agreement.

The solid foundation we have built allows us to drive other proprietary programs forward by executing clinical and preclinical development of additional candidates through multiple potential value inflection points. We ex-pect to drive further growth in 2020 and beyond by expanding our pipeline with additional industry-leading mol-ecules against multiple new cutting edge targets and continue to pioneer our precision medicine approach to neurodegenerative diseases. These activities will further reinforce our position as one of the most influential biotechnology companies targeting neurodegenerative diseases.

As you would expect, AC Immune has always maintained a robust business continuity plan. Every provision is being made to protect the health of patients, staff and investigators, as well as the productivity and integrity of our clinical development during the Covid-19 outbreak. Importantly, the Company currently remains on track to deliver on our clinical readouts expected in 2020, owing largely to the fact that many of our key trials were al-ready fully enrolled when the crisis hit, and patient follow up is continuing virtually, as planned. Additional con-siderations related to Covid-19 include the fact that we plan to conduct the 12-month interim data analysis for our amyloid-beta-targeted vaccine, ACI-24, in Alzheimer's disease as planned, though on a reduced patient da-ta-set. We also continue to prepare for initiation of a Phase 2 study of ACI-24 in people with Down syndrome in the second half of 2020, and expect to initiate the study in line with public health guidance at that time. Finally, our clinical partner Roche notes that dosing of participants in the Phase 2 Colombian Alzheimer's disease pre-vention initiative (API) study has been temporarily interrupted by the countrywide stay at home order. While the ultimate duration of the dosing interruption is not yet known, participants are receiving crenezumab or placebo for at least five years as part of the long-term prevention study, and we continue to expect data from the study in 2022.

There are positive signs that countries, including Switzerland, are beginning to ease restrictions. AC Immune remains in continuous contact with its partners and other important stakeholders, including the Swiss govern-ment, trial investigators and contractors. At this stage, the Company is maintaining its previous guidance with respect to the multiple clinical and preclinical data readouts anticipated this year. AC Immune will keep the market apprised of any new developments or information that may impact clinical timelines.

Thanks to the support of our highly respected investors and partners, as well as our strong balance sheet, AC Immune is in an excellent position to deliver on our exciting plans and make a significant difference for patients with neurodegenerative diseases.

As always, please don't hesitate to get in touch should you have any questions.

We wish you and your family good health and a speedy recovery for the global community.

Best wishes,

Andrea Pfeifer
CEO, AC Immune