Chemical genetic control of cytokine signaling in CAR-T cells using lenalidomide-controlled membrane-bound degradable IL-7.

CAR-T cell therapy has emerged as a breakthrough therapy for the treatment of relapsed and refractory hematologic malignancies. However, insufficient CAR-T cell expansion and persistence is a leading cause of treatment failure. Exogenous or transgenic cytokines have great potential to enhance CAR-T cell potency but pose the risk of exacerbating toxicities. Here we present a chemical-genetic system for spatiotemporal control of cytokine function gated by the off-patent anti-cancer molecular glue degrader drug lenalidomide and its analogs. When co-delivered with a CAR, a membrane-bound, lenalidomide-degradable IL-7 fusion protein enforced a clinically favorable T cell phenotype, enhanced antigen-dependent proliferative capacity, and enhanced in vivo tumor control. Furthermore, cyclical pharmacologic combined control of CAR and cytokine abundance enabled the deployment of highly active, IL-7-augmented CAR-T cells in a dual model of antitumor potency and T cell hyperproliferation.

Anti-TACI single and dual-targeting CAR T cells overcome BCMA antigen loss in multiple myeloma.

Chimeric Antigen Receptor (CAR) T cells directed to B cell maturation antigen (BCMA) mediate profound responses in patients with multiple myeloma, but most patients do not achieve long-term complete remissions. In addition, recent evidence suggests that high-affinity binding to BCMA can result in on-target, off-tumor activity in the basal ganglia and can lead to fatal Parkinsonian-like disease. Here we develop CAR T cells against multiple myeloma using a binder to targeting transmembrane activator and CAML interactor (TACI) in mono and dual-specific formats with anti-BCMA. These CARs have robust, antigen-specific activity in vitro and in vivo. We also show that TACI RNA expression is limited in the basal ganglia, which may circumvent some of the toxicities recently reported with BCMA CARs. Thus, single-targeting TACI CARs may have a safer toxicity profile, whereas dual-specific BCMA-TACI CAR T cells have potential to avoid the antigen escape that can occur with single-antigen targeting.