RT Journal Article SR Electronic T1 Combined Regulatory T-Lymphocyte and IL-2 Treatment Is Safe, Tolerable, and Biologically Active for 1 Year in Persons With Amyotrophic Lateral Sclerosis JF Neurology - Neuroimmunology Neuroinflammation JO Neurol Neuroimmunol Neuroinflamm FD Lippincott Williams & Wilkins SP e200019 DO 10.1212/NXI.0000000000200019 VO 9 IS 6 A1 Jason R. Thonhoff A1 James D. Berry A1 Eric A. Macklin A1 David R. Beers A1 Patricia A. Mendoza A1 Weihua Zhao A1 Aaron D. Thome A1 Fabio Triolo A1 James J. Moon A1 Sabrina Paganoni A1 Merit Cudkowicz A1 Stanley H. Appel YR 2022 UL http://nn.neurology.org/content/9/6/e200019.abstract AB Background and Objectives In a phase 1 amyotrophic lateral sclerosis (ALS) study, autologous infusions of expanded regulatory T-lymphocytes (Tregs) combined with subcutaneous interleukin (IL)-2 were safe and well tolerated. Treg suppressive function increased and disease progression stabilized during the study. The present study was conducted to confirm the reliability of these results.Methods Participants with ALS underwent leukapheresis, and their Tregs were isolated and expanded in a current Good Manufacturing Practice facility. Seven participants were randomly assigned in a 1:1 ratio to receive Treg infusions (1 × 106 cells/kg) IV every 4 weeks and IL-2 (2 × 105 IU/m2) injections 3 times/wk or matching placebo in a 24-week randomized controlled trial (RCT). Six participants proceeded into a 24-week dose-escalation open-label extension (OLE). Two additional participants entered directly into the OLE. The OLE included dose escalation of Treg infusions to 2 × 106 cells/kg and 3 × 106 cells/kg at 4-week intervals.Results The Treg/IL-2 treatments were safe and well tolerated, and Treg suppressive function was higher in the active group of the RCT. A meaningful evaluation of progression rates in the RCT between the placebo and active groups was not possible due to the limited number of enrolled participants aggravated by the COVID-19 pandemic. In the 24-week OLE, the Treg/IL-2 treatments were also safe and well tolerated in 8 participants who completed the escalating doses. Treg suppressive function and numbers were increased compared with baseline. Six of 8 participants changed by an average of −2.7 points per the ALS Functional Rating Scale–Revised, whereas the other 2 changed by an average of −10.5 points. Elevated levels of 2 markers of peripheral inflammation (IL-17C and IL-17F) and 2 markers of oxidative stress (oxidized low-density lipoprotein receptor 1 and oxidized LDL) were present in the 2 rapidly progressing participants but not in the slower progressing group.Discussion Treg/IL-2 treatments were safe and well tolerated in the RCT and OLE with higher Treg suppressive function. During the OLE, 6 of 8 participants showed slow to no progression. The 2 of 8 rapid progressors had elevated markers of oxidative stress and inflammation, which may help delineate responsiveness to therapy. Whether Treg/IL-2 treatments can slow disease progression requires a larger clinical study (ClinicalTrials.gov number, NCT04055623).Classification of Evidence This study provides Class IV evidence that Treg infusions and IL-2 injections are safe and effective for patients with ALS.AALS=Appel ALS Rating Scale; AE=adverse event; ALS=amyotrophic lateral sclerosis; ALSFRS-R=ALS Functional Rating Scale–Revised; cGMP=current Good Manufacturing Practice; FDA=Food and Drug Administration; FVC=forced vital capacity; HMH=Houston Methodist Hospital; IL=interleukin; IP=infusion product; IRB=Institutional Review Board; MGH=Massachusetts General Hospital; MIP=maximal inspiratory pressure; OLE=open-label extension; OLR1=oxidized low-density lipoprotein receptor 1; ox-LDL=oxidized low-density lipoprotein; RCT=randomized controlled trial; SAE=serious adverse event; TEAE=treatment-emergent adverse event; UTHealth=University of Texas Health Science Center at Houston