radial-mobility-cytotoxic-function-retroviral-replicating-vector

Radial Mobility and Cytotoxic Function of Retroviral Replicating Vector Transduced, Non-adherent Alloresponsive T Lymphocytes

We report a novel adaptation of the Radial Monolayer Cell Migration assay, first reported to measure the radial migration of adherent tumor cells on ...

UCLA David Geffen School of Medicine

Despite new additions to the standard of care therapy for high grade primary malignant brain tumors, the prognosis for patients with this disease is still poor. A small contingent of clinical researchers are focusing their efforts on testing the safety, feasibility and efficacy of experimental active and passive immunotherapy approaches for gliomas and are primarily conducting Phase I and II clinical trials. Few trials have advanced to the Phase III arena. Here we provide an overview of the cellular therapies and vaccine trials currently open for patient accrual obtained from a search of http://www.clinicaltrials.gov. The search was refined with terms that would identify the Phase I, II and III immunotherapy trials open for adult glioma patient accrual in the United States. From the list, those that are currently open for patient accrual are discussed in this review. A variety of adoptive immunotherapy trials using ex vivo activated effector cell preparations, cell-based and non-cell-based vaccines, and several combination passive and active immunotherapy approaches are discussed.

Cellular and vaccine therapeutic approaches for gliomas.

We are accruing patients to a Phase I dose escalation cellular therapy trial (www.clinicaltrials.gov, NCT01144247) involving intratumoral placement of alloreactive cytotoxic T lymphocytes (alloCTL) for recurrent gliomas. The trial is being conducted to confirm the findings of a prior pilot study that indicated this adjuvant therapy may be beneficial in extending survival of recurrent WHO grade III gliomas. To reduce costs of the cellular therapy, we tested a number of synthetic tissue culture media and found the AIM-V growth medium superior for their growth. We also moved the production of the alloCTL from artificial capillary systems to less expensive tissue culture bags. To standardize alloCTL infusates used for therapy, release criteria of ≥60% CD3+ and ≥60% viability were established that consistently translated to a 4 hr cytotoxicity of ≥30% at a 30:1 effector to target ratio. To allow time for completion of quality control testing and transport to the infusion site, we determined that 30,000 IU of human recombinant Interleukin-2 in the cellular infusates sufficiently retained cell viability and cytotoxicity to allow a 10 hr expiration time to be placed on the infusates. We identified a cytotoxic T cell subset, CD3+/CD8+/CD69+, that demonstrated upregulated IFN-γ production upon exposure to relevant target cells. The phenotypic identification of this T cell subset was indicative of robust in vitro cytotoxic function and thus will be followed to determine if it correlates with patient immune response to treatment. Finally, other therapeutic agents routinely used for glioma treatment were integrated into an analysis of alloCTL cytotoxic functionality. Temozolomide and bevacizumab do not adversely affect cytotoxic function of the alloCTL in the short-term, thus providing rationale for further investigating combinatorial chemo-immunotherapy for gliomas.

Implementing preclinical study findings to protocol design: translational studies with alloreactive CTL for gliomas.

Individual or combined strategies of cellular therapy with alloreactive CTLs (alloCTL) and gene therapy using retroviral replicating vectors (RRV) encoding a suicide prodrug activating gene were explored for the treatment of breast tumors metastatic to the brain.

Colin C. Malone

Department of Neurosurgery

UCLA David Geffen School of Medicine

Radial Mobility and Cytotoxic Function of Retroviral Replicating Vector Transduced, Non-adherent Alloresponsive T Lymphocytes