Abstract
TPS8555 Background: Adoptive cellular therapy may be practice-changing in relapsed/refractory multiple myeloma (MM). NY-ESO-1 TCR T (GSK3377794) are autologous polyclonal T cells transduced by a self-inactivating lentiviral vector to express an affinity-enhanced TCR capable of recognizing NY-ESO-1 or LAGE-1a antigenic peptides in complex with HLA-A*02. GSK3377794 has shown clinical activity in synovial sarcoma, melanoma, myxoid/round cell liposarcoma, and MM after autologous stem cell transplant. NY-ESO-1 and LAGE-1a are cancer/testis antigens frequently overexpressed in MM and linked to poor clinical outcome. PD-1 expression on CD8 T cells, which has been observed in MM patients previously treated with GSK3377794 as well as with CD19 CAR T-cell therapy, can limit adaptive immune response. We hypothesize that GSK3377794 alone, or in combination with the anti-PD-1 inhibitor pembrolizumab, may result in an antitumor effect in MM. Methods: This is an open-label, pilot study (NCT03168438) of GSK3377794 in patients with relapsed/refractory MM positive for HLA-A*02:01, HLA-A*02:05, ± HLA-A*02:06 and NY-ESO-1/LAGE-1a. Patients (n = 20) who have received ≥3 prior therapies containing ≥1 immunomodulatory imide, proteasome inhibitor, alkylator, CD38 monoclonal antibody, or glucocorticoid will be assigned to either single-infusion GSK3377794 (Arm 1, n = 10) or single-infusion GSK3377794 + pembrolizumab 200 mg IV every 3 weeks (Arm 2, n = 10). Arm 1 enrollment will be completed first. In Arm 2, pembrolizumab will begin in Week 3 (Week 6 if precluded by toxicity). Patients in both arms will provide cells via leukapheresis to manufacture autologous NY-ESO-1–specific T cells, undergo lymphodepletion (fludarabine + cyclophosphamide), and then receive GSK3377794 infusion (1−8x109 transduced T cells). Primary and secondary objectives are to assess safety/tolerability and antitumor activity, respectively, of GSK3377794 (± pembrolizumab). Arm 2 enrollment will pause for a 3-week safety review after 3 patients have received a first dose of pembrolizumab. Efficacy, safety, and biomarkers will be assessed every visit. The treatment phase will last 108 weeks, or until disease progression; follow-up will last ≤15 years. As of January 2020, 3 patients have been treated. Funding: GlaxoSmithKline (208470) Clinical trial information: NCT03168438 .