Abstract LB-083: Phase I study of T cells redirected to EGFRvIII with a chimeric antigen receptor in patients with EGFRvIII+ glioblastoma

• Published in: Cancer research (Chicago, Ill.) Ill.), 2016-07, Vol.76 (14_Supplement), p.LB-083-LB-083
• Main Authors: O’Rourke, Donald M., Nasrallah, MacLean P., Morrissette, Jennifer, Melenhorst, Jan J., Lacey, Simon F., Mansfield, Keith, Martinez-Lage, Maria, Desai, Arati, Brem, Steven, Maloney, Eileen, Mohan, Suyash, Wang, Sumei, Verma, Gaurav, Navenot, Jean-Marc, Shen, Angela, Zheng, Zhaohui, Levine, Bruce L., Okada, Hideho, June, Carl H., Maus, Marcela V.
• Format: Article
• Language: English
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM2016-LB-083

We initiated a Phase I study of intravenous delivery of autologous T cells re-directed to the EGFR variant III mutation by means of a lentiviral vector encoding a chimeric antigen receptor (CAR). Patients with recurrent glioblastoma (GBM) have their tumors screened for the presence of the EGFRvIII mutation by a next-generation sequencing based assay. Eligible patients undergo leukapheresis for collection of autologous T cells, which are genetically modified ex vivo to express the EGFRvIII CAR, expanded, and then cryopreserved for infusion. We report results on the nine patients we have treated. We targeted a challenging subset of GBM patients, with multi-focal residual, progressive disease refractory to standard and experimental therapies, including temozolomide, bevacizumab, and radiation. To date, we have found that infusion of 1-5×10⁁8 CART-EGFRvIII cells is feasible to manufacture and infusion is safe, without evidence of off-tumor toxicity or cross-reactivity to wild type EGFR. No clinical or laboratory signs of systemic cytokine release syndrome have been observed, though elevations in serum IL-6 occur concurrently with CART-EGFRvIII expansion in the peripheral blood. One patient developed non-convulsive status epilepticus nine days after CART-EGFRvIII infusion, which resolved with standard treatment and anti-cytokine therapy. All patients have had significant expansion of CART-EGFRvIII cells between 7-10 days post-infusion, as measured by flow cytometry and quantitative PCR in peripheral blood samples. Five patients have undergone surgical resection of tumor between 6-120 days after infusion, and pathologic evaluation has demonstrated infiltration of activated CAR T cells, recruitment of new T cells (as assessed by next generation T cell receptor deep sequencing), and specific EGFRvIII target antigen loss in GBM cells in some cases. These findings provide evidence that CART-EGFRvIII cells are safe, without evidence of off-target toxicity or cytokine release syndrome, and are immunologically active. The data also suggest a mechanism of antigen editing by activated CART-EGFRvIII cells that track to specific EGFRvIII GBM cells. Citation Format: Donald M. O’Rourke, MacLean P. Nasrallah, Jennifer Morrissette, Jan J. Melenhorst, Simon F. Lacey, Keith Mansfield, Maria Martinez-Lage, Arati Desai, Steven Brem, Eileen Maloney, Suyash Mohan, Sumei Wang, Gaurav Verma, Jean-Marc Navenot, Angela Shen, Zhaohui Zheng, Bruce L. Levine, Hideho Okada, Carl H. June, Ma