HG-21: NEXT GENERATION IMMUNOTHERAPY FOR DIFFUSE INTRINSIC PONTINE GLIOMA

In spite of innovative treatment approaches, cure for DIPG is not reached. Based upon preclinical in vitro data on the sensitivity of DIPG cells to Newcastle Disease Virus (NDV) and upon data from NDV treatment of orthotopic E98 xenotransplant tumors, we initiated NDV infusions + loco-regional radiofrequency hyperthermia (LHT) together with dendritic cell (DC) vaccination. DCs were loaded with exosomal tumor antigens obtained from serum after 5 days of NDV + LHT treatment. DCs were matured with cytokines and NDV. Two vaccination cycles were given with 3 weeks pause in between. Afterwards ELISPOT was performed as immunomonitoring. Six children (3 newly diagnosed) were treated, aged median 7.7 years (4.8-9.8). At time of writing, three children (2 newly diagnosed) finished treatment while the other three are under treatment. The treatment is feasible without toxicity. Two patients finished immunomonitoring and showed a positive response against NDV and cross antigens from GBM cell lines. One of them, newly diagnosed in April 2015, is clinically improving with minor response visible on MRI. The second patient with relapse and under therapeutic corticosteroids is clinically and radiologically progressive. The third patient, newly diagnosed in November 2015, finished treatment, remains clinically stable, and waits for immunomonitoring and imaging. Overall, this experience shows a potential novel method to obtain control over disease. Although the clinical/radiological follup-up is very short, the first immunomonitoring data demonstrate the induction of an antitumoral immune response.