Klin Padiatr 2015; 227 - A34
DOI: 10.1055/s-0035-1550266

What we learned from bench to bedside with the neuroblastoma targeting CD171-specific CAR

A Künkele 1, AJ Johnson 2, C Berger 3, L Finn 4, J Park 4, MC Jensen 2
  • 1Pediatric Oncology and Hematology, Charité, Berlin, Germany
  • 2Ben Towne Center, Seattle Children's Research Institute, Seattle, USA
  • 3Fred Hutchinson Cancer Research Center, Seattle, USA
  • 4Pediatric Oncology and Hematology, Seattle Children's Hospital, Seattle, USA

Introduction: Despite efficacy of chimeric antigen receptor (CAR) T cell therapy in leukemia and lymphoma patients, similar clinical responses in solid tumor patients is an unrealized objective. We developed a CAR specific for CD171, an antigen expressed in several solid tumors including neuroblastoma.

Methods: Since CD171 is also expressed in healthy tissues, we performed a safety study in non-human primates. Further, we analyzed influence of CAR extracellular spacer and cytoplasmic signaling domain variants on magnitude of cytotoxic CD8+T lymphocyte (CTL) activation for tumor cell cytolysis and cytokine secretion.

Results: CARs displaying the highest in vitro activity displayed the lowest in vivo anti-tumor activity, whereas CARs tuned for moderate signaling potency mediated tumor eradication. Recursively triggering hyperactive CARs rendered CTLs susceptible to activation-induced cell death (AICD), indicating that AICD is a critical parameter for achieving clinical efficacy against solid tumors.

Conclusion: Our results assisted the design of a clinical trial comparing two CARs with different cytoplasmic signaling domains in patients with refractory or relapsed neuroblastoma.