Several pharma companies think that targeting a rogue protein known as alpha-synuclein could be the key to halting or reversing neurodegeneration in Parkinson’s disease – but has the industry learned from a string of failures in Alzheimer’s? In the space of a few weeks, Novartis AG and Sanofi AS have signed major deals for molecules targeting misfolded alpha-synuclein, the rogue protein thought to be the root cause of Parkinson’s disease.