Sequential Intranodal Immunotherapy (SIIT) Combined With Anti-PD1 (Pembrolizumab) in Follicular Lymphoma

Patients with advanced stage follicular lymphoma, untreated and relapsed are eligible for this study. Staging includes PET/CT, CT and bone marrow specimens. Lymphoma nodes must be available for surgical biopsy, radiation and intranodal treatment. Additionally, there must be evaluable lesions for measuring systemic effects. The patient undergo leukapheresis for collection of monocytes then cultured ex vivo to obtain immature dendritic cells (DC). The treatment targets single lymphoma nodes with radiation (single fraction of 8 Gy), ultrasound-guided injections of autologous DCs , low-dose rituximab (5 mg) and GM-CSF sc. This sequential intranodal immunotherapy (SIIT) is repeated three times, targeting different lymphoma nodes. Anti-PD1 monoclonal antibody (Pembrolizumab) is given iv at each cycle of SIIT and then every third week for a total of 11 cycles. Patients are evaluated for clinical response with PET/CT, CT and bone marrow analysis. CD8 and CD4 T cell responses against autologous tumor cells are measured in blood after treatment by flow cytometry. The primary aims are to induce systemic clinical responses and correlated T cell responses which may prolong time to next standard therapy.