Pembrolizumab-induced Remission After Failure of Axicabtagene Ciloleucel: Case Report and Literature Review

Background Failure after CD19-directed chimeric antigen receptor (CAR) T-cell therapy for patients with large B-cell B non-Hodgkin lymphoma, especially when it happens early, is an emerging clinical problem. There are no specific recommendations and therefore treatment of these patients remains empiricaI. Immune checkpoint inhibitors are becoming a therapeutic option for these patients. Case report We present a case of a primary mediastinal large B-cell lymphoma who experienced relapse 3.5 months after axicabtagene-ciloleucel therapy and received pembrolizumab. After four cycles of pembrolizumab, complete metabolic response was confirmed. Treatment was discontinued after the sixth cycle due to immune checkpoint inhibitor-related pneumonitis. The disease remains in remission 8 months after the last pembrolizumab dose. We propose mechanisms of action and optimal duration of pembrolizumab treatment in this setting. Finally, we review the existing literature on the sequential administration of CD19-directed CAR T-cell therapy and immune checkpoint inhibitors. Conclusion Immune checkpoint inhibitors are a promising treatment option for patients after failure of CD19-directed CAR-T cell therapy.