Study of SIRPant-M in Participants With Relapsed or Refractory Non-Hodgkin's Lymphoma

This is an open-label phase 1 study of SIRPant-M studied in serial cohorts either alone (monotherapy), or combined with low-dose focal external-beam radiotherapy (XRT) in patients with relapsed- or refractory Non-Hodgkin's lymphoma (NHL). Both B-cell and certain T-cell NHL (select PTCL; CTCL) are eligible. The primary objective of the study is to assess the safety and tolerability of autologous SIRPant-M, delivered by 3 intra-tumoral injection, given either alone or combined with 2.5 Gy focal XRT. A course (cycle) of SIRPant-M (RB-1355) is prepared from a single mononuclear apheresis, and comprises 3 equal ITI doses, administered at 2-day intervals. A low dose (90x10\^6 cells split over 3 injections), an intermediate dose (300x10\^6 cells split over 3 injections) and a high dose (600x10\^6 cells split over 3 injections) of SIRPant-M are evaluated. In cohorts receiving supplemental radiation, each cell injection will be followed by 2.5 Gy radiation directed at the injected tumor site (7.5 Gy total). At the highest dose level only, alternate day IT-dosing (Day 1, 3, 5) will be compared with Weekly IT-dosing (W1, 2, 3). Patients with PR or sustained clinical benefit (at least SD) after 1 cycle may receive a 2nd cycle of treatment, using cells prepared and frozen following the initial apheresis. Dose escalations will be staggered using the 3+3 Phase 1 design, and safety will be monitored by the Safety Review Committee (SRC). The SRC may direct additional- or intermediate dose levels to be evaluated, as guided by emerging data.