Event-Driven Immunoprofiling Predicts Return of Disease Activity in Alemtuzumab-Treated Multiple Sclerosis

Abstract

Background: Alemtuzumab is a highly effective drug for the treatment of multiple sclerosis (MS), characterized by specific patterns of depletion and repopulation. As an induction-like treatment concept, two mandatory infusion courses can inhibit long-term disease activity in the majority of patients, and additional courses can successfully manage subsequent re-emergence of disease activity. Currently, there are no biomarkers to identify patients with re-emergent disease activity requiring retreatment. Methods: In this study, we systematically characterized 16 MS patients commencing alemtuzumab. Clinical parameters, MRI and detailed immunoprofiling were conducted every 3 months for up to 84 months. Results: Alemtuzumab led to significant decrease in clinical disease activity in all evaluated patients. Nine out of 16 patients presented with no evidence of disease activity (NEDA)-3 up to 84 months ("complete-responder"), while 7 patients demonstrated clinical or/and subclinical MRI disease activity and received alemutzumab retreatment ("partial-responder"). In both response categories, all T- and B-cell subsets were markedly depleted after alemtuzumab therapy. In particular, absolute numbers of Th1 and Th17 cells were markedly decreased and remained stable below baseline levels-this effect was particularly pronounced in complete-responders. While mean cell numbers did not differ significantly between groups, analysis of event-driven immunoprofiling demonstrated that absolute numbers of Th1 and Th17 cells showed a reproducible increase starting 6 months before relapse activity. This change appears to predict emergent disease activity when compared with stable disease. Conclusion: Studies with larger patient populations are needed to confirm that frequent immunoprofiling may assist in evaluating clinical decision-making of alemtuzumab retreatment.

Keywords: alemtuzumab; immune cells; immunoprofiling; multiple sclerosis; treatment response.

Figure 1

Clinical characteristics of ATZ treated patients before and after ATZ infusion. (A) ATZ treated patients without ATZ retreatment are depicted (complete-responder, patient 1–9). Clinical disease course including pre-treatment, relapse activity and MRI progress within yearly MRI scans before and after ATZ infusion are shown threw yearly time intervals. After ATZ infusion, follow up evaluation up to 7 years are presented. (B) ATZ treated patients that were retreated with ATZ additionally to two standard ATZ treatments are depicted (partial-responder, patient 10–16). Clinical disease course including pre-treatment, relapse activity and MRI progress within yearly MRI scans before and after ATZ infusion and intervals of ATZ retreatment are shown threw yearly time intervals. After ATZ infusion, follow up evaluation up to 7 years are presented. GA, glatiramer acetate; IFN-beta, interferon-beta; NAT, natalizumab.

Figure 2

Distribution of peripheral lymphocyte subsets of patients with stable disease course after 1st and 2nd ATZ (complete-responder). Distribution of absolute count of lymphocytes (A), CD3+ T cells (B), CD19+ B cells (C), CD4+ T cells (D) and CD8+ T cells (E) before (0 years) and up to 7 years follow up are depicted. Mean values +/− SD of lymphocytes and its subsets at each of the 3 monthly evaluations are shown. Reference ranges are marked by pastel green color and baseline values are highlighted by the dotted line. Additionally, proportion of patients that reached values in reference range (green) vs. not (red) are presented for each individual time point and immune cell subtype. Asterisks indicate a statistically significant difference (*p < 0.05, **p < 0.01, ***p < 0.001).

Figure 3

Distribution of peripheral immune cell subsets of patients with stable disease course after 1st and 2nd ATZ (complete-responder). Distribution of absolute count of peripheral immune cell subsets before (0 years) and up to 7 years follow up are depicted. Mean values +/− SD of absolute count of T cell (A–G), B cell (H–J), and innate immune cell (K,L) subsets are shown. Asterisks indicate a statistically significant difference (*p < 0.05, **p < 0.01, ***p < 0.001).

Figure 4

Distribution of peripheral immune cell subsets of patients with stable disease course after 1st and 2nd ATZ (complete-responder). Distribution of relative count of peripheral immune cell subsets before (0 years) and up to 7 years follow up are depicted. Mean values +/− SD of relative count of T cell (A–G), B cell (H–J), and innate immune cell (K,L) subsets are presented. Arrows indicate ATZ application. Asterisks indicate a statistically significant difference (*p < 0.05, **p < 0.01, ***p < 0.001).

Figure 5

Distribution of peripheral immune cell subsets in patients with reappearance of disease activity after 1st and 2nd ATZ (partial-responder). Distribution of absolute count of peripheral immune cell subsets before (0 years) and up to 7 years follow up are depicted. Mean values +/− SD of absolute count of lymphocytes (A), T cell (B–D, F,G, L–J, N) and, B cell (E,H,K,O), subsets are shown. Reference ranges are marked by pastel green color and baseline values are highlighted by the dotted line. Arrows in black indicate 1st and 2nd ATZ infusions, arrows in gray indicate time point of ATZ retreatment in individual patients. Asterisks demonstrate statistical significance (*p < 0.05, **p < 0.01, ***p < 0.001).

Figure 6

Event-driven immune cell phenotyping before relapse activity and after ATZ retreatment. Distribution of absolute immune cell count of selected T (A,B, G–I) and B cell (C–F) subsets are presented. Black line—partial-responder patients: Immune cell subsets before (baseline, BL) and after 1st and 2nd ATZ infusion 3 monthly up to 24 months follow up (+3, +6, +9, +12, +15, +18, +21, +24) are depicted. Mean values +/− 95%CI of all partial-responder patients are shown. Additionally, distribution of absolute immune cell count before clinical appearance of an acute relapse (RL, red flash) was evaluated in 3 monthly intervals (−12, −9, −6, −3). Mean values +/− 95%CI of 13 relapses are presented. Furthermore, absolute immune cell count before ATZ retreatment (pre RT) and during 3 monthly follow up (+3, +6, +9, +12) are demonstrated. Mean values +/− 95%CI of 10 ATZ retreatments are shown. Gray line—complete-responder patients: Immune cell subsets before (baseline, BL) and after 1st and 2nd ATZ infusion are depicted. In addition, period of stable disease course 24 months after 2nd ATZ infusion are presented. Mean values +/− 95%CI of all complete-responder patients are shown. Arrows indicate ATZ infusion.