We supported the preclinical development of the TDL clinical protocol (P.I. Michael Bishop;07-C-0064) by establishing the feasibility of expanding TDL in cultures through the use of anti CD3/anti CD8 beads, resulting in a product with high viability, donor origin and T cell content, very low residual B cell numbers, free of endotoxin or contamination;In this process, we developed methods for viably dissociating cells and culturing them under good manufacturing process (GMP) standards. Furthermore we supported the clinical approval process by developing the necessary documentation of standard operating procedures and certificates of analysis for product release, assembling GMP reagents lists, and providing links to established investigational new drug (IND) protocols for manufacture of an clinical product suitable for infusion into patients. Following the approval of this protocol, we have continued to assess T cell expansion and clearance of B cell lymphoma and Hodgkins disease populations in the TDL expansion cultures in the first nine patients. We have characterized the TDL product from both preclinical test cultures and from the first clinical trial cultures, using multiparameter flow cytometry and cytokine production assays. We have demonstrated that the TDL expansion cultures result in the disappearance of lymphoma cells and a marked decline in the frequency of regulatory T cells found in the original tumor population. The final product contains more than 90% T cells, primarily T-Bet+ Th1/Tc1 cells, that have elevated expression of effector molecules including CD40L, NKG2D, and perforin, and produce primarily IFN-gamma on stimulation. These assays will form the basis for tests of efficacy and specificity of anti-tumor activity that will be used to optimize the TDL product. Furthermore we have supported a clinical initiative to make this therapy available to a broader patient population by demonstrating the feasibility of using patient bone marrow (rather than surgically excised lymphoma nodules) as a basis for generating TDL in patients with marrow-resident tumor populations. We have successfully expanded replicate cultures from patient marrow collected following allogeneic transplant, demonstrating significant expansion of donor-derived T cells that meet criteria for T cell numbers and viability, donor chimerism, removal of tumor cells and microbial standards. These tests have supported submission of a protocol amendment providing for use of marrow. Furthermore preclinical studies on marrow form patients with relapsed acute myeloid leukemia are continuing in order to support expansion of this therapy to these patients. Finally we have initiated development of alternative culture conditions to optimize not only the numerical expansion of donor-derived T cells from the lymphoma tissue, but also anti-tumor activity and persistence in vivo after re-infusion. We have shortened the culture and are examining alterations in the cytokine milieu of the culture to enhance retention of activated CD8 effectors. As part of this trial, we are evaluating changes in the peripheral blood following infusion of the TDL product and have been preserving aspirates of tumor sites after TDL therapy to assess molecular changes indicative of donor anti lymphoma activity. These flow cytometric and molecular monitoring studies have been extended to the first of additional planned trials of immune therapies for relapse. In this trial (09-C-0224, P.I.: Nancy Hardy) donor lymphocyte infusions (a standard method of immune therapy) are infused following irradiation of selected tumor sites. Monitoring focuses on whether the irradiation process has produced activation and trafficking of antigen presenting cells into the tumor and subsequent in anti-tumor immune activation. Finally, ongoing clinical trials (04-C-0055, 08-C-0088: P.I. Daniel Fowler) have utilized expanded donor-derived CD4 Type 2 T helper cells grown in rapamycin (Th2rapa). Our support for these efforts has included scaling up research laboratory products into clinical size expansion cultures using GMP materials and practices, preparing Standard Operating Protocols for generation of cultures, developing release criteria for products and providing documentation of these procedure for clinical IND. These efforts have supported the continued development of Th2rapa therapy for B cell malignancies and renal cell carcinoma.
