New Phase 2 Data Analysis for Crenezumab Presented at Global Alzheimer's Conference Provides Strong Evidence for Engagement of the Principle Abeta Target

• Crenezumab significantly reduces Abeta oligomers in cerebrospinal fluid (CSF) in patients with Alzheimer's disease
• Strong evidence for principal target engagement of Abeta oligomers, the most neurotoxic species of the Abeta cascade
• New exploratory Phase 2 data analysis presented at the AAIC^© in a late-breaking session in Chicago

AC Immune SA (NASDAQ: ACIU), a Swiss-based, clinical-stage biopharmaceutical company focused on neurodegenerative diseases, today announced that important data on its product candidate crenezumab - currently in two Phase 3 clinical trials conducted by Genentech, a member of the Roche Group, were presented in a late-breaking session at the Alzheimer's Association International Conference (AAIC^© 2018). The conference is the largest international meeting dedicated to advancing dementia science and takes place in Chicago, US, from July 22-26, 2018.

The data presented were from 98 subjects treated in the ABBY and BLAZE Phase 2 trials for mild-to-moderate Alzheimer's disease (AD). The data showed:

• Treatment with crenezumab was associated with a consistent decrease in Abeta oligomer levels in the CSF
• 86% of IV patients and 89% of SC patients had lower levels of Abeta oligomers at week 69 than at baseline (p<0.01 for IV and p<0.001 for SC vs. placebo)
• The median change was -43% (p=0.01) in those treated intravenously (IV) and -48% (p=0.001) in those treated subcutaneously (SC), with 20% (IV) and 14% (SC) of patients falling below the LLoQ after treatment, respectively

Andrea Pfeifer, CEO, AC Immune, said: "These first of their kind data are very promising as they support the proposed mechanism of action of crenezumab to preferentially bind to and promote removal of neurotoxic oligomers, a form of Abeta. We are excited about the potential of crenezumab, as a disease-modifying therapy, given its distinct differentiation from other beta-amyloid antibodies in terms of target specificity and safety."

Dennis J Selkoe, MD, Vincent and Stella Coates Professor of Neurologic Diseases Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA, commented: "These results are encouraging as they strongly suggest principal target engagement of crenezumab with Abeta oligomers, which adds confidence to the notion that crenezumab is well positioned to test the Abeta oligomer hypothesis."

About Crenezumab

Crenezumab is an anti-Abeta antibody discovered by AC Immune using its SupraAntigen^TM technology platform and out-licensed to Genentech, a member of the Roche group, in 2006 as a potential therapy for Alzheimer's disease. Crenezumab is a fully humanized IgG4 monoclonal antibody that binds all forms of misfolded Abeta proteins, but especially to Abeta oligomers, to prevent and break up Abeta aggregation and promote Abeta disaggregation. The IgG4 subclass has reduced effector function, allowing microglia to clear Abeta from the brain while minimizing an inflammatory response.

Roche/Genentech is currently evaluating the clinical efficacy and safety of crenezumab in two Phase 3 clinical trials, CREAD 1 and 2, in 750 participants each trial with prodromal or mild Alzheimer's disease, which started in the first quarter of 2016 and first quarter of 2017, respectively. CREAD 1 was fully recruited in the fourth quarter of 2017 and CREAD 2 completed global recruitment in July 2018. In addition, crenezumab was chosen by an international panel of experts, including the US National Institutes of Health, for use in a first-ever prevention trial in Alzheimer's disease in a large extended family in Colombia (API ADAD) in 2012.