ABL1 and Cognitive impairment: However, in clinical practice, nilotinib at the maximal permissible dose for 1 to 6 months has limited penetration into the CNS, resulting in minimal improvement in symptoms and no improvement in cognitive impairment in PD patients.624 In contrast, a more specific c-Abl inhibitor, K0706, has shown higher affinity with c-Abl in vitro than nilotinib.