Fig. 4: IL-2Rα expression in ALCL patients correlates with survival and represents potential therapeutic target.

a OS of pediatric ALCL, ALK⁺ patients (NHL-BFM cohort, n = 88), and b EFS and OS of adult ALCL, ALK⁻ patients without SCT (n = 34) having low (staining intensity, SI = 0–2) or high (SI = 3) IL-2Rα expression. Kaplan–Meier curves of individual groups were compared using two-tailed log-rank statistics. c Indicated 9 ALCL cell lines and 2 T-cell leukemia-derived control cell lines were incubated for 96 h with different concentrations of PDB dimer linked antibodies targeting either IL-2Rα (ADCT-301) or, as a non-binding control, the glycoprotein gp120 of HIV (B12-SG3249) to determine the LD₅₀. Means ± SD of biological triplicates are shown. d In vivo anti-tumor efficacy of ADCT-301 in murine xenograft models of Mac-2A (ALK⁻) or TLBR-1 (BIA) ALCL cell lines. For each cell line, mice were randomized into three groups to receive a single dose of either vehicle (PBS, n = 4), control ADC (B12-SG3249, 0.5 mg/kg, n = 5), or ADCT-301 (0.5 mg/kg, n = 5) intravenously at day 1 (indicated by an arrow). Tumor volumes were measured with caliper over time and are shown as means ± SEM. P values were determined by two-tailed unpaired Student’s t test. e Schematic illustration of the proposed mechanism.