(Reuters) – Swiss biotech firm AC Immune SA filed with U.S. regulators on Tuesday to raise up to $50 million in an initial public offering of common stock. AC Immune, backed by German billionaire Dietmar Hopp, said it plans to use proceeds from the IPO to develop products, including Alzheimer’s drug crenezumab. Crenezumab, which AC Immune licensed to Roche Holding AG’s Genentech division in 2006, targets protein plaques found in brains of patients with Alzheimer’s. The company told the U.S Securities and Exchange Commission in a preliminary prospectus that Credit Suisse, Jefferies and Leerink Partners were underwriting the IPO.