G-CSF prevents the progression of structural disintegration of white matter tracts in amyotrophic lateral sclerosis: a pilot trial

Abstract

Background: The hematopoietic protein Granulocyte-colony stimulating factor (G-CSF) has neuroprotective and -regenerative properties. The G-CSF receptor is expressed by motoneurons, and G-CSF protects cultured motoneuronal cells from apoptosis. It therefore appears as an attractive and feasible drug candidate for the treatment of amyotrophic lateral sclerosis (ALS). The current pilot study was performed to determine whether treatment with G-CSF in ALS patients is feasible.

Methods: Ten patients with definite ALS were entered into a double-blind, placebo-controlled, randomized trial. Patients received either 10 µg/kg BW G-CSF or placebo subcutaneously for the first 10 days and from day 20 to 25 of the study. Clinical outcome was assessed by changes in the ALS functional rating scale (ALSFRS), a comprehensive neuropsychological test battery, and by examining hand activities of daily living over the course of the study (100 days). The total number of adverse events (AE) and treatment-related AEs, discontinuation due to treatment-related AEs, laboratory parameters including leukocyte, erythrocyte, and platelet count, as well as vital signs were examined as safety endpoints. Furthermore, we explored potential effects of G-CSF on structural cerebral abnormalities on the basis of voxel-wise statistics of Diffusion Tensor Imaging (DTI), brain volumetry, and voxel-based morphometry.

Results: Treatment was well-tolerated. No significant differences were found between groups in clinical tests and brain volumetry from baseline to day 100. However, DTI analysis revealed significant reductions of fractional anisotropy (FA) encompassing diffuse areas of the brain when patients were compared to controls. On longitudinal analysis, the placebo group showed significant greater and more widespread decline in FA than the ALS patients treated with G-CSF.

Conclusions: Subcutaneous G-CSF treatment in ALS patients appears as feasible approach. Although exploratory analysis of clinical data showed no significant effect, DTI measurements suggest that the widespread and progressive microstructural neural damage in ALS can be modulated by G-CSF treatment. These findings may carry significant implications for further clinical trials on ALS using growth factors.

Trial registration: ClinicalTrials.gov NCT00298597.

Conflict of interest statement

Competing Interests: Armin Schneider is an employee of SYGNIS Bioscience and is an inventor on a patent application claiming the use of G-CSF for the treatment of diseases of the central nervous system. Patent Cooperation Treaty WO04058287, Patent Number: 274597, is licensed to the treatment of amyotrophic lateral sclerosis with G-CSF. All other authors reported no financial disclosure and no conflicts of interest. The mentioned conflicts had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript and this does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

Figures

Figure 1. Consort Flowchart.

Figure 2. Voxel based analysis of DTI data.

SPM “glass brain” representation (left) and slices of voxels (right) with a significant decrease in fractional anisotropy (FA) of patient compared to the healthy controls (ANOVA, p<0.001, uncorrected; 50 contiguous voxels). Statistical FA-maps were superimposed on an averaged FA template of the control group. Colored bars represent t-values; display threshold is set at t value >3.16. Upper row: Cross-sectional comparison of 10 ALS patients when compared to 32 healthy controls (Visit 1). FA of the ALS patients were significantly reduced in WM areas covering widespread parts of the brain, most prominent in the corticospinal tracts, in subcortical WM of the precentral gyrus, and it's connecting fibres in the corpus callosum. Anatomic pattern of FA changes did not alter significantly when both ALS groups were compared separately to the control group. Lower and middle row: Clusters of FA decreases from Visit 1 to Visit 2 in ALS patients treated with G-CSF (middle row) and in the ALS-control group (lower row). ALS patients treated with G-CSF showed small regions of decreased FA, mainly affecting bilateral subcortical WM of the precentral gyrus, whereas the placebo group showed a greater and more widespread decline in FA during the study period. The localization was similar to the clusters of decreased FA in the initial voxel-wise analysis (upper row). Hence, white matter tracts that were initially detected as deficient continued to lose fibre integrity over time.

Figure 3. Longitudinal interaction between VISIT and GROUP.

Placebo-treated ALS patients showed a greater and more widespread decline in FA over time, compared to ALS patients treated with G-CSF (shown in orange;p<0.005, uncorrected; 50 contiguous voxels). These FA changes mainly involved the corticospinal tracts, frontal WM including connecting fibres of the frontal corpus callosum, and temporal WM. Anatomical distribution of decreased FA values in ALS patients treated with G-CSF relative to untreated ALS patients over time are shown in blue (p<0.005, uncorrected; 50 contiguous voxels). These clusters were much less widespread, mainly encompassing posterior thalamic regions. Slice positions are indicated in the MNI coordinates.

Figure 4. Hematological parameters during the study period.

Error bars indicate standard errors of the mean (SEM); *  =  significant difference between the G-CSF and placebo group.