The present disclosure is directed, at least in part, to disease-modifying treatments for neurodegenerative disorders. In one embodiment, a method of delaying worsening of one or more symptoms and/or progression of a neurodegenerative disorder is provided. In one embodiment, a method of treating or ameliorating one or more symptoms of a neurodegenerative disorder is provided. In one embodiment, the methods of the present invention comprise administering to a subject in need thereof, a compound having the structure of Formula (1a); Formula (1a); and/or a pharmaceutically acceptable salt thereof. In one embodiment, the the compound of (1a) and/or a pharmaceutically acceptable salt thereof is administered in combination with one or more pharmacologically active agents.