Safety and efficacy of helminth treatment in relapsing-remitting multiple sclerosis: Results of the HINT 2 clinical trial

Abstract

Background: The hygiene hypothesis suggests that microbial replacement may be therapeutic in allergic and autoimmune diseases. Nevertheless, the results of helminth treatment, including in multiple sclerosis (MS), have been inconclusive.

Objective: To assess safety and brain magnetic resonance imaging (MRI) activity in subjects with relapsing-remitting multiple sclerosis (RRMS) during oral administration of ova from the porcine whipworm, Trichuris suis (TSO).

Methods: A total of 16 disease-modifying treatment (DMT) naive RRMS subjects were studied in a baseline versus treatment (BVT) controlled prospective study. MRI scans were performed during 5 months of screening-observation, 10 months of treatment, and 4 months of post-treatment surveillance.

Results: No serious symptoms or adverse events occurred during treatment. For the cohort, there was a trend consistent with a 35% diminution in active lesions when observation MRIs were compared to treatment MRIs ( p = 0.08), and at the level of individuals, 12 of 16 subjects improved during TSO treatment. T regulatory lymphocytes were increased during TSO treatment.

Conclusion: TSO is safe in RRMS subjects. Potentially favorable MRI outcomes and immunoregulatory changes were observed during TSO treatment; however, the magnitude of these effects was modest, and there was considerable variation among the responses of individual subjects.

Trial registration: ClinicalTrials.gov NCT00645749.

Keywords: Multiple sclerosis; helminth therapy; hygiene hypothesis; phase 1 clinical trial; whipworm.

Conflict of interest statement

Declaration of Conflicting Interests

The authors have nothing to disclose.

Figures

Figure 1

Study Design. The phases of the study are shown for intake and screening (S), no-treatment observation (O), TSO treatment (T), and post-treatment evaluation (P) periods, with each month indicated by a numeral in subscript. Monthly brain MRIs are indicated by thick arrows; during the post-treatment phase only one MRI was mandated per protocol (P2 or P4 month). Clinical assessments (examining neurologist, EDSS; technician, MSFC; and treating neurologist, medical evaluation), standard safety laboratory determinations, and research immunological determinations were performed at the time points indicated by respective dots.

Figure 2. Colonoscopy. Representative images are from subject 122 at month T10 of TSO treatment

A. Colonic mucosa with live, active T. Suis larva with its anterior end embedded in superficial colonic epithelium (arrow) and posterior end free in lumen of colon. B. Colonic biopsy demonstrating to T. Suis larvae in cross section (stars), normal-appearing colonic crypt (straight arrow), and normal-appearing lamina propria (curved arrow) (x 100). The anterior end of the worm has burrowed into the superficial epithelium near the crest of the colonic crypt and is covered by a thin layer consisting of the apical surfaces of epithelial cells. These photographs have not been published previously but were taken from the same subject reported on previously, with permission (Wiley).

Figure 3. Blood Eosinophils and Humoral Responses to T. Suis

3A. Fold change in blood eosinophils expressed relative to subjects’ pretreatment baseline determination. At entry, all HINT 2 subjects had normal absolute blood eosinophil determinations (30–500 cells/ul); during treatment five subjects experienced absolute eosinophilia (range 600–1230 eosinophils per ul of blood. 3B. Trichuris Suis specific serum IgG1 expressed as fold change relative to baseline determination in optical density units (OD 465 nm). 3C. Trichuris Suis specific serum IgE expressed as fold change relative to baseline determination in optical density units (OD 465 nm). The baseline optical density unit determinations for IgG1 and IgE ELISA assays in HINT 2 subjects were indistinguishable from those of control healthy blood donors and thus represent the presumed non-specific background of the assay. The data are represented by mean (histogram height) and one standard deviation (bar) and were analyzed by ordinary one-way ANOVA with values at month S1 as the base for comparison, using GraphPad PRISM version 6.0. Data is not significant unless otherwise stated; significance values are indicate as* p-value ≤ 0.05, ** p-value ≤ 0.01, *** p-value ≤0.001, and **** p-value ≤ 0.0001).

Figure 4. Blood T Regulatory Cells

A. Gating strategy during flow cytometry for FOXP3+, CD25+, CD127−, CD4+ T cells. B. The change in cells with a T regulatory phenotype, relative to baseline determinations. Antibodies employed are listed in Supplementary Material. Data and p-values are analyzed and presented as in Figure 3.

Figure 5. Change in Brain MRI Activity for Individual Subjects Between Baseline and Treatment Study Periods

For each subject, the mean number of GdE on masked readings of double-dose gadolinium-enhanced brain MRI were determined for their 1) baseline period (the set of 5 scans for months S1, O1, O2, O3, O4), and 2) treatment period (the set of 5 scans for months T6, T7, T8, T9, T10). Subsequently, the difference between mean GdE at baseline and mean GdE during treatment (BVT difference) was determined for each subject. Determinations for each individual are indicated by a dot and are expressed such that a positive BVT difference indicates worsening (i.e., more GdE during treatment), and a negative BVT difference value indicates improvement (i.e., less GdE during treatment). Each dot represents the data from ten MRI scans for an individual, as designated by color and subject number in the key.