Results of a Phase 1 Trial of Gda-201, Nicotinamide-Expanded Allogeneic Natural Killer (NK) Cells in Patients with Refractory Non-Hodgkin Lymphoma (NHL) and Multiple Myeloma

Background: The innate capacity of natural killer (NK) cells to kill tumor targets has been translated into cancer immunotherapy. GDA-201 is a novel allogeneic NK cell product derived from NK cells from healthy donors, expanded ex-vivo with nicotinamide (NAM) and IL-15. We previously reported improved killing function, in vivo proliferation, organ trafficking, and augmented resistance against exhaustion in pre-clinical models. We conducted a phase 1 study of GDA-201 in combination with monoclonal antibodies to enhance NK cell targeting through antibody-dependent cellular cytotoxicity (ADCC). We now report safety data in patients (pts) with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) and multiple myeloma (MM), and report efficacy outcomes in pts with NHL.

Methods: Following donor apheresis, CD3-depleted mononuclear cells were cultured for 14-16 days with NAM (5mM) and IL-15 (20ng/ml), resulting in a 40-fold increase in NK cells and increased expression of CD62L from 2.9% to 21%. GDA-201 contained ~98% NK cells, and CD3 content was maintained at <0.5% (<5x10⁵/kg/dose). Pts with R/R B-cell NHL or MM received lymphodepleting (LD) therapy with cyclophosphamide (400mg/m² IV x 3d) and fludarabine (30 mg/m² /d IV x 3d), followed by GDA-201 (days 0 and 2) and low-dose IL-2 (6 million units sc x 3 doses). Pts with NHL or MM received rituximab (375 mg/m²) or elotuzumab (10 mg/kg), respectively, x 3 weekly infusions.

Results: 30 pts were enrolled:15 with NHL and 15 with MM, in 3 cohorts of escalating GDA-201 dose; 15 pts received the maximum target dose (median dose 12.4 [range 2.0-26.0] x 10⁷ cells/kg). There were no dose limiting toxicities. The most common grade 3/4 adverse events were thrombocytopenia (n=9), hypertension (n=5), neutropenia (n=4), febrile neutropenia (n=4), and anemia (n=3). There were no neurotoxic events, confirmed cytokine release syndrome, graft versus host disease, or marrow aplasia. One patient died of E-coli sepsis.

In pts with NHL, histologies included diffuse large B cell lymphoma (DLBCL) (de novo n=5, transformed n=3), follicular lymphoma (FL) (n=6), and mantle cell lymphoma (n=1). Median age was 64 (range 48-83 years). Pts had a median of 3 lines of prior therapy (range 1-8); most were multiply relapsed or refractory (n=2), and 87% had advanced stage. Median follow-up was 10.8 months (range 4.3-27.5 months). Ten pts had complete response (CR): 6/6 pts with FL and 4/8 with DLBCL; 1 pt had partial response (PR), and overall response rate in pts with NHL was 73.3%. Median duration of response was 8.7 months (range 4.3-25 months). Flow cytometry confirmed the persistence of GDA-201 in peripheral blood for 7-10 days (range 2-92% donor NK cells on day 7), as well as enhanced in vivo proliferation (median Ki 67 99%). Flow cytometry of biopsied tissues at day 4 demonstrated trafficking to bone marrow and lymph nodes. Four pts underwent re-treatment with GDA-201 without LD chemotherapy; GDA-201 cells were detectable in blood after the re-treatment and likely contributed to deepening of response in 2 patients. Post-GDA-201 therapy included allogeneic (n=2) and autologous (n=1) hematopoietic stem cell transplantation. One-year estimates of progression-free survival and overall survival were 66% (95% CI 36-84%) and 82% (95% CI 42-95%), respectively.

Conclusions: Cellular therapy using GDA-201 with monoclonal antibodies to enhance ADCC was well-tolerated, and demonstrated significant clinical activity in heavily pretreated pts with advanced NHL. Data support the future testing of multiple infusions to potentially enhance anti-tumor effect. The omission of lymphodepleting chemotherapy is feasible and contributes to safety of this approach. Phase II studies in aggressive and indolent NHL cohorts are planned.