Chris Viehbacher

Biogen's core multiple sclerosis franchise — once the foundation of the company's profitability — faces generic competition and secular decline. The controversial and ultimately disappointing launch of Aduhelm (an Alzheimer's disease drug with contested efficacy data) damaged the company's reputation and investor confidence. Viehbacher, who previously led Sanofi, is executing a strategic pivot toward new therapeutic areas. Biogen's pipeline and recent acquisitions focus on rare diseases (through the $7.3 billion acquisition of Reata Pharmaceuticals), neuropsychiatry, immunology, and a partnership with Eisai on Leqembi (lecanemab) for early Alzheimer's disease — which has shown more convincing efficacy than Aduhelm. The biosimilar business provides additional revenue diversification. His key decisions involve pipeline execution and portfolio prioritization, Leqembi commercial launch optimization, M&A strategy to build new growth platforms, cost restructuring, and restoring investor confidence after years of strategic drift.