Key Points TCM-derived CD19 CAR T–cell therapy is safe for treatment of poor-risk NHL patients undergoing autologous HSCT. Addition of a CD28 costimulatory domain to the CAR, plus changes to T-cell product manufacturing, resulted in improved T-cell expansion.

Numerous stem cell-based therapies are currently under clinical investigation, including the use of neural stem cells (NSCs) as delivery vehicles to target therapeutic agents to invasive brain tumors. The ability to monitor the time course, migration, and distribution of stem cells following transplantation into patients would provide critical information for optimizing treatment regimens. No effective cell-tracking methodology has yet garnered clinical acceptance. A highly promising noninvasive method for monitoring NSCs and potentially other cell types in vivo involves preloading them with ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) to enable cell tracking using magnetic resonance imaging (MRI). We report here the preclinical studies that led to U.S. Food and Drug Administration approval for first-in-human investigational use of ferumoxytol to label NSCs prior to transplantation into brain tumor patients, followed by surveillance serial MRI. A combination of heparin, protamine sulfate, and ferumoxytol (HPF) was used to label the NSCs. HPF labeling did not affect cell viability, growth kinetics, or tumor tropism in vitro, and it enabled MRI visualization of NSC distribution within orthotopic glioma xenografts. MRI revealed dynamic in vivo NSC distribution at multiple time points following intracerebral or intravenous injection into glioma-bearing mice that correlated with histological analysis. Preclinical safety/toxicity studies of intracerebrally administered HPF-labeled NSCs in mice were also performed, and they showed no significant clinical or behavioral changes, no neuronal or systemic toxicities, and no abnormal accumulation of iron in the liver or spleen. These studies support the clinical use of ferumoxytol labeling of cells for post-transplant MRI visualization and tracking.

The phase III trial GEM05MENOS65 randomized 390 patients 65 years old or younger with newly diagnosed symptomatic multiple myeloma (MM) to receive induction with thalidomide/dexamethasone, bortezomib/thalidomide/dexamethasone and Vincristine, BCNU, melphalan, cyclophosphamide, prednisone/vincristine, BCNU, doxorubicin, dexamethasone bortezomib (VBMCP/VBAD/B) followed by autologous stem cell transplantation (ASCT) with MEL-200. After ASCT, a second randomization was performed to compare thalidomide/bortezomib (TV), thalidomide (T) and alfa-2b interferon (alfa2-IFN). Maintenance treatment consisted of TV (thalidomide 100 mg daily plus one cycle of intravenous bortezomib at 1.3 mg/m on days 1, 4, 8 and 11 every 3 months) versus T (100 mg daily) versus alfa2-IFN (3 MU three times per week) for up to 3 years. A total of 271 patients were randomized (TV: 91; T: 88; alfa2-IFN: 92). The complete response (CR) rate with maintenance was improved by 21% with TV, 11% with T and 17% with alfa2-IFN (P, not significant). After a median follow-up of 58.6 months, the progression-free survival (PFS) was significantly longer with TV compared with T and alfa2-IFN (50.6 vs 40.3 vs 32.5 months, P=0.03). Overall survival was not significantly different among the three arms. Grade 2-3 peripheral neuropathy was observed in 48.8%, 34.4% and 1% of patients treated with TV, T and alfa2-IFN, respectively. In conclusion, bortezomib and thalidomide maintenance resulted in a significantly longer PFS when compared with thalidomide or alfa2-IFN. (no. EUDRA 2005-001110-41).

CD19-directed chimeric antigen receptor (CD19CAR) T cell therapy has been successful in treating several B cell lineage malignancies, including B cell non-Hodgkin's lymphoma (NHL). This modality has not yet been extended to NHL manifesting in the central nervous system (CNS), primarily due to concerns for potential toxicity. CD19CAR T cells administered intravenously (IV) are detectable in cerebrospinal fluid (CSF), suggesting that CAR T cells can migrate from the periphery into the CNS, where they can potentially mediate anti-lymphoma activity. Here, we report the outcome of a subset of patients with primary CNS lymphoma (PCNSL; n=5) treated with CD19CAR T cells in our ongoing Phase 1 clinical trial (NCT02153580). All patients developed at least grade 1 cytokine release syndrome and neurotoxicity post-CAR T cell infusion; toxicities were reversible and tolerable, and there were no treatment-related deaths. At initial disease response, 3 of 5 patients (60%, 90%CI [19%,92%]) appeared to achieve complete remission, as indicated by resolution of enhancing brain lesions, and the remaining 2 patients had stable disease. Although the study cohort was small, we demonstrated that using CD19CAR T cells to treat PCNSL can be safe and feasible.