Insider Buys Signal Confidence in Adverum Biotechnologies Braden Michael Leonard, a major shareholder in Adverum Biotechnologies, has purchased 117,941 shares worth $587,574. This move comes as the company's stock surged over 21% last week. Leonard now holds 2.72 million shares. Adverum is also advancing its ARTEMIS Phase 3 trial for a groundbreaking gene therapy targeting wet age-related macular degeneration.12