Lenalidomide (LMID) Significantly Enhances Circulating Serum Levels of IL-2 and IL-15 Levels, NK Expansion and Activation and NK and LAK Cytotoxicity in Children with Refractory/Recurrent Solid Tumors: A Children’s Oncology Group Phase I Consortium Report

LMID is approved by the FDA for adults with specific subsets of MDS and relapsed multiple myeloma and also has anti-tumor activity in adults with relapsed/refractory NHL (Wiernik, et al, JCO, 2008). Although the exact mechanism of LMID anti-tumor activity is unknown, it appears to be related to its immunomodulatory and anti-angiogenic properities. Bartlett et al (BJC, 2004) demonstrated in adults with advanced cancer that following LMID treatment there were an increased number of NK cells and enhanced NK function presumably through the increased production of immunocytokines secondary to T-cell activation (Bartlett et al, personal communication). IL-2 and IL-15 are critically important immunocytokines in NK cell development and functional activation (Caliguiri, et al, Blood 2006). We evaluated the immunomodulatory effects of LMID in a phase 1 trial of oral LMID administered daily × 21 days, every 28 days at 7 doses ranging from (15–70 mg/m²) in children with advanced cancer. Serum levels of GM-CSF, IL-2, IL-8 and IL-15 were measured by ELISA. NK (CD3⁻/56⁺) and Treg (CD4⁺/25⁺) levels in addition to intracellular granzyme B and the NK activation marker, LAMP-1 (CD107-A) were measured by flow cytometry. NK (K562) and LAK (Daudi) cytotoxicity were measured by europium assay at a 20:1 (E:T ratio). 26 children, median age 16 (5–21), 11M/15F: 1 rhabdomyosarcoma, 6 osteosarcoma, 10 other sarcoma, 2 hepatoblastoma, 7 other were enrolled in this study. Results are expressed as mean ± SD (pre and post LMID). Statistical analyses were performed with INSTAT (Graph Pad, San Diego, CA). The following significant changes in immunomodulatory function across all dose levels are shown in the table below.

Bartlett et al has suggested that there may be a difference in immunomodulatory response by LMID dose. There was a significant trend in the correlation between dose and immunomodulation. These results suggest that LMID has profound immunomodulatory and immune activating effects in children with advanced solid tumors. In particular, the significant increase in serum IL-2 and IL-15 cytokine levels and the increase in NK and LAK cytotoxicity in children with advanced cancer suggest an activation of TH1 and NK immune subsets by LMID. Further studies are required to determine the benefit of LMID immunomodulatory effects in children with specific malignancies.