CTIM-11. SINGLE-CENTER, OFF-LABEL NEOADJUVANT PEMBROLIZUMAB FOR TREATMENT OF RECURRENT GBM AT UCLA

Abstract Neoadjuvant drug administration provides a window of opportunity for developing novel therapies. Specifically, neoadjuvant pembrolizumab (PD1 checkpoint inhibitor) has the potential improving understanding immunomodulatory effects on tumor microenvironment and treating recurrent GBM. It is known that functional immune deficit exists within T-lymphocyte compartment. As promotes lymphocyte infiltration, it may contribute to antitumor in setting. Our previous randomized clinical trial (RCT) suggested improved survival GBM patients with 1-2 relapses. Here, we sought extend our original findings analyze role off-label multiple recurrences. We identified retrospective 22-patient cohort at UCLA. Every patient had tissue diagnosis, received standard treatment, one five Each surgical resection 7-21 days. Progression-free (PFS) overall (OS) neoadjuvant-treated were calculated as days from compared historical control data RCT (n = 15 neoadjuvant, adjuvant). Results show significantly increased median PFS adjuvant (114 vs 75 days, p 0.03). The OS was 294 192 control. Both not statistically different than (PFSp 0.08, OSp 0.13). Since limited initial recurrences, this suggests more advanced recurrences could also benefit neo-adjuvant therapy. Ongoing work will evaluate microenvironmental genetic signature induced by assess pre-surgical volume so adequate comparisons can be made other trials. believe promising finding offers therapeutic options those