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Page 10 of 15 Gururangan et al. Neuroimmunol Neuroinflammation 2018;5:45 I http://dx.doi.org/10.20517/2347-8659.2018.44

autoimmune encephalitis to demonstrate the safety and efficacy of ttRNA pulsed DCs in mediating potent
antitumor immune responses and regression of established tumor that has prolonged survival in treated
animals without causing inflammatory reactions in the CNS [65,66] . Our group has previously demonstrated
the efficacy of adoptive cell therapy employing tumor-specific T cells generated from bone marrow-derived
[99]
DCs pulsed with ttRNA against intracranial glioma .

Phase 1 study in pediatric patients with recurrent medulloblastoma and primitive neuroectodermal
tumors (reMATCH trial, NCT01326104)
Using a strategy similar to adoptive T-cell therapy pioneered by Dr. Rosenberg at the National Cancer
Institute in patients with metastatic melanoma, we recently completed a phase I study of ttRNA - pulsed
DC vaccine + ttRNA-xALT following MA or NMA conditioning in 10 patients with recurrent PNET and
[104]
GBM (medulloblastoma 8, pineoblastoma 1, and GBM 1) . All patients had tumor resection/biopsy to
confirm recurrence and obtain tissue for vaccine preparation. PBMCs were collected following surgical
recovery for DC preparation and T-cell expansion. Patients then received either NMA conditioning with
cyclophosphamide + fludarabine (n = 9) or MA conditioning with carboplatin + thiotepa + etoposide with
7
6
PBSC support (n = 1) followed by xALT in one of two dose levels; 3 × 10 cells/kg (n = 3) and 3 × 10 cells/kg
7
(n = 7). All patients received at least 3 doses of ttRNA DCs once every 2 weeks at a 1 × 10 /kg per dose. The
median number of vaccines given was 3 (range, 3-9). Of 8 evaluable patients for dose-limiting toxicity by
receiving ttRNA x-ALT and at least one dose of ttRNA DC, there were no dose limiting toxicities associated
with ttRNA DCs + ALT. Toxicities that were possibly attributable to immunotherapy included grade I rash
(n = 1) and a transient grade III elevation of serum alkaline phosphatase (n = 1) 3 months after the 3rd dose
of ttRNA DC. Median time to progression in 9 patients from 1st ttRNA DC + x-ALT administration was 5
months (range, 2-24) and median survival 13 months (range, 2-46+ months). In a recurrent tumor with a
dismal prognosis, 5 patients survived for > 20 months following first dose of ttRNA DC + x-ALT. Three of 10
patients are currently alive; 2 patients who relapsed 12 and 24 months respectively following immunotherapy
but currently alive following additional salvage therapies at 45+ and 46+ months. One additional patient with
Gorlin’s syndrome and recurrent medulloblastoma is currently alive 42+ months following immunotherapy
(received a total of 9 doses of ttRNA DCs) and never received radiotherapy either at diagnosis or at relapse.
Measurement of inflammatory cytokines (IFN-γ, TNF, IL-6, IL-8, and IL-17A) was elevated in general
following MA or NMA chemotherapy. Lymphocyte recovery occurred in all patients at variable intervals.
Using next-generation sequencing (NGS) we evaluated TCR-vβ clones in the PBMC samples from all patients
at baseline and at regular intervals during and post immunotherapy. Clonal diversity during recovery was
higher in patients with prolonged survival (> 20 months; n = 5). Clonal hyper-expansion and persistence
appeared to be higher in patients with prolonged survival and reached significance at day 7 following x-ALT
administration. One patient who received MA conditioning prior to x-ALT and 3 ttRNA DCs and is a long-
term survivor at 46+ months, experienced massive and selective expansion of 4 tumor-reactive TCR Vβ
[99]
clones in the peripheral blood up to four months (16 weeks) post-treatment (Flores et al. , 2018, submitted
for publication). T-cells from one of these clones was tested for anti-tumor function against patient’s
ttRNA DCs. IFN-γ secretion was measured to indicate recognition of cognate tumor antigen and found
to be elevated compared to control ovalbumin-RNA containing DCs. This data suggests that expansion of
productive frequency of TCR Vβ family is potentially predictive of T cell clonal expansion within the larger
family. Analysis of TCR Vβ family expansion in peripheral blood of treated patients could be predictive of
response to adoptive immunotherapy. We have subsequently enrolled 23 subjects (screened 34) in an ongoing
multi-institutional phase II study in which our institution serves as the central GMP manufacturing facility
for autologous cellular products.

Ongoing phase I studies in newly diagnosed malignant glioma and diffuse pontine glioma
We have also initiated two additional upfront phase I clinical trials in children with newly diagnosed
malignant glioma (ACTION trial, NCT03334305) and diffuse brain stem glioma (BRAVO trial,