Journal: mAbs
Article Title: Targeting IL-7Rα with PNU-159682 antibody–drug conjugates in acute lymphoblastic leukemia: translational implications
doi: 10.1080/19420862.2026.2663639
Figure Lengend Snippet: Enhanced anti-tumor activity of IL-7Rα-targeting ADCs with novel payload PNU-159682. (a) Schematic representation of the conjugation process for generating PNU-159682-linked ADCs. Antibodies were partially reduced with 20 mM 2-mercaptoethylamine (2-MEA) for 0.5 hours at 37 °C, followed by conjugation with 10 mM Mal–PEG4–VC–PAB–DMEA–PNU-159682 for 16 hours at 4 °C, yielding a drug-to-antibody ratio of 3–4. (b) In vitro cytotoxicity of 577-PNU, 577-MMAE, isotype control IgG–PNU, and free PNU-159682 in NALM6 cells. Cell viability was measured using the WST-8 assay 72 hours after treatment. Data are shown as mean ± SEM. (c) Comparison of IC 50 values between 577-MMAE and 577-PNU in NALM6 cells, calculated from nine independent experiments performed on separate days; IC 50 values analyzed after log10 transformation; paired t-test (two-tailed), p < 0.0001; geometric mean ratio (MMAE/PNU) = 85.3 (95% CI 57.7–126.0). (d) In vivo anti-tumor efficacy of each treatment in NALM6 xenografts (subcutaneous model). Mice were treated with a single dose of 577-MMAE (10 mg/kg; n = 4), 577-PNU (0.5 mg/kg; n = 5), isotype control IgG–PNU (0.5 mg/kg; n = 4), free PNU-159682 (17 µg/kg, the dose of PNU equal to 0.5 mg/kg 577-PNU; n = 3), or phosphate-buffered saline (PBS) vehicle ( n = 5). Tumor volumes were measured twice weekly. (e) Complete response (CR) rate on day 28 following treatment with 577-MMAE (10 mg/kg; n = 4) or 577-PNU (0.5 mg/kg; n = 5). Two-sided Fisher’s exact test comparing groups: p = 0.0476. (f) Relative body weight change (%) during treatment. Data are presented as mean ± SEM; n = 3–5 per group. * p < 0.05; **** p < 0.0001.
Article Snippet: His-tagged recombinant human IL-7Rα ectodomain (R&D Systems, Minneapolis, MN, USA, Cat. No. 10758-IR) was captured on the active flow cell to approximately 50 response units (RU).
Techniques: Activity Assay, Conjugation Assay, In Vitro, Control, Comparison, Transformation Assay, Two Tailed Test, In Vivo, Saline