Persistence of adoptively transferred T cells with a kinetically engineered IL-2 receptor agonist.

Interleukin-2 (IL-2) is a component of most protocols of adoptive cell transfer (ACT) therapy for cancer, but is limited by short exposure and high toxicities. NKTR-214 is a kinetically-engineered IL-2 receptor ßγ (IL-2Rßγ)-biased agonist consisting of IL-2 conjugated to multiple releasable polyethylene glycol chains resulting in sustained signaling through IL-2Rßγ. We report that ACT supported by NKTR-214 increases the proliferation, homing and persistence of anti-tumor T cells compared to ACT with IL-2, resulting in superior antitumor activity in a B16-F10 murine melanoma model. The use of NKTR-214 increases the number of polyfunctional T cells in murine spleens and tumors compared to IL-2, and enhances the polyfunctionality of T and NK cells in the peripheral blood of patients receiving NKTR-214 in a phase 1 trial. In conclusion, NKTR-214 may have the potential to improve the antitumor activity of ACT in humans through increased in vivo expansion and polyfunctionality of the adoptively transferred T cells.

IND-Enabling Studies for a Clinical Trial to Genetically Program a Persistent Cancer-Targeted Immune System.

PURPOSE: To improve persistence of adoptively transferred T-cell receptor (TCR)-engineered T cells and durable clinical responses, we designed a clinical trial to transplant genetically-modified hematopoietic stem cells (HSCs) together with adoptive cell transfer of T cells both engineered to express an NY-ESO-1 TCR. Here, we report the preclinical studies performed to enable an investigational new drug (IND) application. EXPERIMENTAL DESIGN: HSCs transduced with a lentiviral vector expressing NY-ESO-1 TCR and the PET reporter/suicide gene HSV1-sr39TK and T cells transduced with a retroviral vector expressing NY-ESO-1 TCR were coadministered to myelodepleted HLA-A2/Kb mice within a formal Good Laboratory Practice (GLP)-compliant study to demonstrate safety, persistence, and HSC differentiation into all blood lineages. Non-GLP experiments included assessment of transgene immunogenicity and in vitro viral insertion safety studies. Furthermore, Good Manufacturing Practice (GMP)-compliant cell production qualification runs were performed to establish the manufacturing protocols for clinical use. RESULTS: TCR genetically modified and ex vivo-cultured HSCs differentiated into all blood subsets in vivo after HSC transplantation, and coadministration of TCR-transduced T cells did not result in increased toxicity. The expression of NY-ESO-1 TCR and sr39TK transgenes did not have a detrimental effect on gene-modified HSC's differentiation to all blood cell lineages. There was no evidence of genotoxicity induced by the lentiviral vector. GMP batches of clinical-grade transgenic cells produced during qualification runs had adequate stability and functionality. CONCLUSIONS: Coadministration of HSCs and T cells expressing an NY-ESO-1 TCR is safe in preclinical models. The results presented in this article led to the FDA approval of IND 17471.