Background: We evaluated the effects of low doses of the tyrosine kinase Abelson (Abl) inhibitor Nilotinib, on safety and pharmacokinetics in Parkinson’s disease dementia or dementia with Lewy bodies.Objectives: The primary outcomes of this study were safety and tolerability; pharmacokinetics and target engagement were secondary, while clinical outcomes were exploratory.Methods: Twelve subjects were randomized into 150 mg (n = 5) or 300 mg (n = 7) groups and received Nilotinib orally every day for 24 weeks.Results: This study shows that 150 mg and 300 mg doses of Nilotinib appear to be safe and tolerated in subjects with advanced Parkinson’s disease. Nilotinib is detectable in the cerebrospinal fluid (CSF) and seems to engage the target Abl. Motor and cognitive outcomes suggest a possible beneficial effect on clinical outcomes. The CSF levels of homovanillic acid are significantly increased between baseline and 24 weeks of treatment. Exploratory CSF biomarkers were measured.Conclusions: This small proof-of-concept study lacks a placebo group and participants were not homogenous, resulting in baseline differences between and within groups. This limits the interpretations of the biomarker and clinical data, and any conclusions should be drawn cautiously. Nonetheless, the collective observations suggest that it is warranted to evaluate the safety and efficacy of Nilotinib in larger randomized, double-blind, placebo-controlled trials.

IMPORTANCE This study evaluated nilotinib safety and its effects on biomarkers as a potential disease-modifying drug in Parkinson disease.OBJECTIVES To assess nilotinib effects on safety and pharmacokinetics and measure the change in exploratory biomarkers in patients with moderately severe Parkinson disease. DESIGN, SETTING, AND PARTICIPANTSThis was a single-center, phase 2, randomized, double-blind, placebo-controlled trial with 300 patients approached in clinic; of these, 200 declined to participate, 100 were screened, 25 were excluded, and 75 were randomized 1:1:1 into placebo; nilotinib, 150-mg; or nilotinib, 300-mg groups. Recruitment started on May 17, 2017, and ended April 28, 2018, and follow-up ended August 10, 2019. Parkinson disease was confirmed according to the UK Brain Bank diagnostic criteria and symptoms were stabilized with use of optimal levodopa and/or dopamine agonists and other medications used in Parkinson disease.INTERVENTIONS Nilotinib vs placebo, administered orally once daily for 12 months followed by a 3-month washout period.MAIN OUTCOMES AND MEASURES It was hypothesized that nilotinib is safe and can be detected in the cerebrospinal fluid, where it alters exploratory biomarkers via inhibition of Abelson tyrosine kinase and potentially improves clinical outcomes. RESULTSOf the 75 patients included in the study, 55 were men (73.3%); mean (SD) age was 68.4 (8.2) years. Doses of 150 or 300 mg of nilotinib were reasonably safe, although more serious adverse events were detected in the nilotinib (150 mg: 6 [24%]; 300 mg: 12 [48%]) vs placebo (4 [16%]) groups. The 150-mg nilotinib group showed an increase in cerebrospinal fluid levels of the dopamine metabolites homovanillic acid (159.80nM; 90% CI, 7.04-312.60nM; P = .04) and 3,4-dihydroxyphenylacetic acid (4.87nM; 90% CI, 1.51-8.23nM; P = .01), and the 300-mg nilotinib group showed an increase in 3,4-dihydroxyphenylacetic acid (7.52nM; 90% CI, 2.35-12.69nM; P = .01). The nilotinib 150-mg but not the nilotinib 300-mg group demonstrated a reduction of α-synuclein oligomers (−0.04 pg/mL; 90% CI, −0.08 to 0.01 pg/mL; P = .03). A significant reduction of hyperphosphorylated tau levels was seen in the nilotinib 150-mg (−10.04 pg/mL; 90% CI, −17.41 to −2.67 pg/mL; P = .01) and nilotinib 300-mg (−12.05 pg/mL; 90% CI, −19.21 to −4.90 pg/mL; P = .01) groups.CONCLUSIONS AND RELEVANCE In this study, nilotinib appeared to be reasonably safe and detectable in the cerebrospinal fluid. Exploratory biomarkers were altered in response to nilotinib. Taken together, these data will guide the development of a phase 3 study to investigate the effects of nilotinib therapy in patients with Parkinson disease. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT02954978

Nilotinib is a broad‐based tyrosine kinase inhibitor with the highest affinity to inhibit Abelson (c‐Abl) and discoidin domain receptors ( DDR 1/2). Preclinical evidence indicates that Nilotinib reduces the level of brain alpha‐synuclein and attenuates inflammation in models of Parkinson's disease ( PD ). We previously showed that Nilotinib penetrates the blood‐brain barrier ( BBB ) and potentially improves clinical outcomes in individuals with PD and dementia with Lewy bodies ( DLB ). We performed a physiologically based population pharmacokinetic/pharmacodynamic (pop PK / PD ) study to determine the effects of Nilotinib in a cohort of 75 PD participants. Participants were randomized (1:1:1:1:1) into five groups (n = 15) and received open‐label random single dose ( RSD ) 150:200:300:400 mg Nilotinib vs placebo. Plasma and cerebrospinal fluid ( CSF ) were collected at 1, 2, 3, and 4 hours after Nilotinib administration. The results show that Nilotinib enters the brain in a dose‐independent manner and 200 mg Nilotinib increases the level of 3,4‐Dihydroxyphenylacetic acid ( DOPAC ) and homovanillic acid ( HVA ), suggesting alteration to dopamine metabolism. Nilotinib significantly reduces plasma total alpha‐synuclein and appears to reduce CSF oligomeric: total alpha‐synuclein ratio. Furthermore, Nilotinib significantly increases the CSF level of triggering receptors on myeloid cells ( TREM )‐2, suggesting an anti‐inflammatory effect. Taken together, 200 mg Nilotinib appears to be an optimal single dose that concurrently reduces inflammation and engages surrogate disease biomarkers, including dopamine metabolism and alpha‐synuclein.