NP001 regulation of macrophage activation markers in ALS: a phase I clinical and biomarker study

Abstract

This is a phase I, placebo-controlled, single ascending dose safety and tolerability study of NP001 in patients with ALS. NP001 is a novel regulator of inflammatory macrophages and monocytes. As ALS progression is thought to be related to neuroinflammation, an additional objective of the study was to assess the effects of NP001 administration on monocyte activation markers. Thirty-two ALS patients were enrolled and received either placebo (eight) or one of four (six at each dose) ascending single i.v. doses (0.2, 0.8, 1.6 and 3.2 mg/kg NP001). Patients were monitored for safety, and blood monocyte immune activation markers CD16 and HLA-DR were assessed pre- and 24 h post-dosing. Changes from baseline were calculated. Results showed that NP001 was generally safe and well tolerated. Importantly, a single dose of NP001 caused a dose-dependent reduction in expression of monocyte CD16, a marker of monocyte activation/inflammation. Additionally, monocyte HLA-DR expression was also decreased in those patients with elevated values at baseline. In conclusion, these data indicate that NP001 has an acute effect on inflammatory monocytes in ALS patient blood. The potential for modulation of inflammation in the context of ALS disease progression will require further study with long-term follow-up.

Keywords: ALS; NP001; inflammation; macrophage; monocyte.

Conflict of interest statement

Declaration of interest: Gilbert Block is Chief Medical Officer at Neuraltus Pharmaceuticals. Vidhya Gopalakrishnan is Vice President, R&D Operations at Neuraltus Pharmaceuticals. Michael S. McGrath is Founder and consultant of Neuraltus Pharmaceuticals.

The authors alone are responsible for the content and writing of the paper.

Figures

Figure 1

Relationship between baseline monocyte inflammatory activation related markers and the historic rate of ALS disease progression. Levels of activation marker at baseline (y-axis) are plotted against disease progression rate (ALS/FRS-R score lost/month) (X-axis). Figure 1A. Levels of baseline monocyte activation defined by CD14 coexpression of HLA-DR was directly related to the rate of ALS disease progression (r = 0.4310, p = 0.0138; n = 32). Figure 1B. Positive correlation was observed between baseline levels of CD16 expression on the CD16 bright subset of monocytes and disease progression rate in ALS (r = 0.4499, p = 0.0098; n = 32).

Figure 2

NP001 treatment changes CD14 monocyte expression of HLA-DR as a function of the degree of monocyte HLA-DR expression at baseline. The x-axis represents the baseline values of the geometric mean fluorescence intensity of monocyte HLA-DR expression (Geo MFI CD14/HLA-DR). The y-axis represents the percent change from baseline in total monocyte HLA-DR expression. The red line represents the mean percentage change of HLA-DR expression on monocytes from eight placebo patients; the black boxes and line represent the actual individual change from placebo group (r = −0.07721, p = 0.8558; n = 8). The blue triangles and line represent the change in monocyte HLA-DR expression after NP001 independent of dose (r = −0.4967, p = 0.0135; n = 24).

Figure 3

Comparison of NP001 treatment response between ALS patients with elevated levels of baseline monocyte HLA-DR and those with lower range of baseline monocyte HLA-DR. Patients treated with NP001 were divided into two groups based on the median value of baseline monocyte HLA-DR (Geo MFI CD14/HLA-DR = 1200) from the entire group of all 32 patients enrolled in the phase I clinical study. Baseline Geo MFI CD14/HLA-DR was clustered into two groups as shown on the x-axis (Geo MFI CD14/HLA-DR > 1200, n = 12; Geo MFI CD14/HLA-DR < 1200, N = 12). The y-axis represents the percent change in monocyte geometric mean levels of HLA-DR at 24 h compared to baseline. Positive values show an increase in HLA-DR expression and negative values show a relative decrease in HLA-DR expression.

Figure 4

Greatest change in monocyte levels of HLA-DR in ALS patients with the highest rate of disease progression. Patients in the phase I trial were clustered into subgroups based on their historic rate of ALS disease progression, assessed by average monthly change on ALSFRS-R (DP Rate n = 8). DP rates were clustered into three groups as shown on the x-axis (DP Rate < 0.5, n = 8; DP Rate between 0.5 and 1, n = 11; DP Rate ≥ 1, n = 5). The y-axis represents the percent change in monocyte geometric mean levels of HLA-DR at 24 h compared to baseline. Positive values show an increase in HLA-DR expression and negative values show a relative decrease in HLA-DR expression. R 2 = 0.2310, p = 0.0058, one-way ANOVA followed by post-test for linear trend.

Figure 5

NP001 induced changes from baseline on CD16 levels expressed on a CD16 bright subset of monocytes in a dose-dependent manner. ALS patients treated with a single dose of NP001 or placebo had baseline values of monocyte CD16 expression compared with the same measurement obtained 24 h after dosing. The percent change in CD16 level expressed on a CD16 bright subset of monocytes 24 h after dosing is plotted on the y-axis. Placebo (n = 8) and dose levels (n = 6 for each dose) are plotted on the x-axis. R 2 = 0.1958, p = 0.0085, one-way ANOVA followed by post-test for linear trend.

Figure 6

Comparison of CD16 expression on monocyte CD16 bright subset in patients receiving 1.6-mg/kg dose NP001 relative to healthy controls. The left and middle bars represent mean levels of CD16 expression on ALS patient CD16 bright monocytes at baseline (left) and 24 h after NP001 infusion (middle) (n = 6). The bar on the right represents mean level of CD16 expression typically seen in healthy controls (n = 7).