Expanded autologous regulatory T-lymphocyte infusions in ALS: A phase I, first-in-human study

Abstract

Objective: To determine whether autologous infusions of expanded regulatory T lymphoctyes (Tregs) into patients with amyotrophic lateral sclerosis (ALS) are safe and tolerable during early and later stages of disease.

Methods: Three patients with ALS, with no family history of ALS, were selected based on their differing sites of disease onset and rates of progression. Patients underwent leukapheresis, and Tregs were subsequently isolated and expanded ex vivo. Tregs (1 × 106 cells/kg) were administered IV at early stages (4 doses over 2 months) and later stages (4 doses over 4 months) of disease. Concomitant interleukin-2 (2 × 105 IU/m2/injection) was administered subcutaneously 3 times weekly over the entire study period. Patients were closely monitored for adverse effects and changes in disease progression rates. Treg numbers and suppressive function were assayed during and following each round of Treg infusions.

Results: Infusions of Tregs were safe and well tolerated in all patients. Treg numbers and suppressive function increased after each infusion. The infusions slowed progression rates during early and later stages of disease. Spearman correlation analyses showed that increased Treg suppressive function correlated with slowing of disease progression per the Appel ALS scale for each patient: patient 1: ρ (rho) = -0.60, p = 0.003; patient 2: ρ = -0.71, p = 0.0026; and patient 3: ρ = -0.54, p = 0.016. Measures of maximal inspiratory pressure also stabilized, particularly in 2 patients, during Treg infusions.

Conclusions: These results demonstrate the safety and potential benefit of expanded autologous Treg infusions, warranting further clinical trials in patients with ALS. The correlation between Treg suppressive function and disease progression underscores the significance of using Treg suppressive function as an indicator of clinical status.

Classification of evidence: This study provides Class IV evidence. This is a phase I trial with no controls.

Figures

Figure 1. Treg percentage and suppressive function increased during each round of Treg infusions

Arrows and vertical dotted lines represent Treg infusions. The 1st Treg infusion was administered on week 0 and then every 2 weeks for a total of 4 infusions. The 5th Treg infusion was administered in each patient on weeks 48, 27, and 33, respectively, and then every 4 weeks for a total of 4 infusions. The percentage of CD4+CD25+FOXP3+ Tregs within the total CD4+ cell population is shown for patient 1 (A), patient 2 (B), and patient 3 (C). Treg percentages are shown at baseline (weeks 4.6, 3.0, and 4.9 in each patient, respectively), the days of the 1st and 5th Treg infusions, the day after each Treg infusion, every 2 weeks during each round of infusions, and 1 month after each round. The data point collected the day after the 4th Treg infusion (week 6) in patient 3 was not determined because of a flow staining error. Treg suppressive function is shown on the same time points as the Treg percentages for patient 1 (D), patient 2 (E), and patient 3 (F).

Figure 2. Disease progression slowed during each round of Treg infusions and correlated with increased Treg suppressive function

Arrows and vertical dotted lines represent Treg infusions. Clinical progression is depicted by the ALSFRS-R (white points) and AALS (black points) stages of the disease for patient 1 (A.a), patient 2 (B.a), and patient 3 (C.a). Clinical progression lines during each round of Treg infusions are enlarged in side panels for the early (1) and later (2) stages of disease. Correlation between changes in the AALS and Treg suppressive function is shown for patient 1 (A.b), patient 2 (B.b), and patient 3 (C.b). Lines represent the best fit as determined by linear regression analysis. Data were analyzed by Spearman correlation, and p values <0.05 were considered statistically significant. AALS = Appel Amyotrophic Lateral Sclerosis Rating Scale; ALSFRS-R = revised Amyotrophic Lateral Sclerosis Functional Rating Scale.

Figure 3. Maximal inspiratory pressures stabilized during Treg infusions

Arrows and vertical dotted lines represent Treg infusions. FVC measurements are represented as % predicted values for patient 1 (A), patient 2 (B), and patient 3 (C). Measurements are shown at baseline (weeks 4.6, 3.0, and 4.9 in each patient, respectively), immediately before each Treg infusion, every 2 weeks during each round of infusions, and 1 month after each round. MIP measurements are shown in cm H2O for patient 1 (D), patient 2 (E), and patient 3 (F). MIPs are shown at the same time points as FVC measurements. The MIP values were erroneously not determined for patient 1 immediately before the 5th Treg infusion, and for patient 3, 1 month after the second round of infusions. The solid gray line connects the points between each round of infusions (A-F). FVC = forced vital capacity; MIP = maximal inspiratory pressure.