Phase 1 Study of CK0801 in Treatment of Bone Marrow Failure Syndromes.

BACKGROUND: An inflammatory bone marrow microenvironment contributes to acquired bone marrow failure syndromes. CK0801, an allogeneic T regulatory (Treg) cell therapy product, can potentially interrupt this continuous loop of inflammation and restore hematopoiesis. METHODS: In this phase 1 dose-escalation study of CK0801 Treg cells, we enrolled patients with bone marrow failure syndromes with suboptimal response to their prior therapy to determine the safety and efficacy of this treatment for bone marrow failure syndromes. RESULTS: We enrolled nine patients with a median age of 57 years (range, 19 to 74) with an underlying diagnosis of aplastic anemia (n=4), myelofibrosis (n=4), or hypoplastic myelodysplasia (n=1). Patients had a median of three prior therapies for a bone marrow failure syndrome. Starting dose levels of CK0801 were 1 × 106 (n=3), 3 × 106 (n=3), and 10 × 106 (n=3) cells per kg of ideal body weight. No lymphodepletion was administered. CK0801 was administered in the outpatient setting with no infusion reactions, no grade 3 or 4 severe adverse reactions, and no dose-limiting toxicity. At 12 months, CK0801 induced objective responses in three of four patients with myelofibrosis (two had symptom response, one had anemia response, and one had stable disease) and three of four patients with aplastic anemia (three had partial response). Three of four transfusion-dependent patients at baseline achieved transfusion independence. Although the duration of observation was limited at 0.9 to 12 months, there were no observed increases in infections, no transformations to leukemia, and no deaths. CONCLUSIONS: In previously treated patients, CK0801 demonstrated no dose-limiting toxicity and showed evidence of efficacy, providing proof of concept for targeting inflammation as a therapy for bone marrow failure. (Funded by Cellenkos Inc.; Clinicaltrials.gov number, NCT03773393.).

Allogeneic cord blood regulatory T cells decrease dsDNA antibody and improve albuminuria in systemic lupus erythematosus.

Background: Lupus nephritis (LN) constitutes the most severe organ manifestations of systemic lupus erythematosus (SLE), where pathogenic T cells have been identified to play an essential role in 'helping' B cells to make autoantibodies and produce inflammatory cytokines that drive kidney injury in SLE. Regulatory T cells (Tregs), responsible for decreasing inflammation, are defective and decreased in SLE and have been associated with disease progression. We hypothesize that treatment with allogeneic, healthy Tregs derived from umbilical cord blood (UCB) may arrest such an inflammatory process and protect against kidney damage. Methods: UCB-Tregs function was examined by their ability to suppress CellTrace Violet-labeled SLE peripheral blood mononuclear cells (PBMCs) or healthy donor (HD) conventional T cells (Tcons); and by inhibiting secretion of inflammatory cytokines by SLE PBMCs. Humanized SLE model was established where female Rag2-/-γc-/- mice were transplanted with 3 × 106 human SLE-PBMCs by intravenous injection on day 0, followed by single or multiple injection of UCB-Tregs to understand their impact on disease development. Mice PB was assessed weekly by flow cytometry. Phenotypic analysis of isolated cells from mouse PB, lung, spleen, liver and kidney was performed by flow cytometry. Kidney damage was assessed by quantifying urinary albumin and creatinine secretion. Systemic disease was evaluated by anti-dsDNA IgG Ab analysis as well as immunohistochemistry analysis of organs. Systemic inflammation was determined by measuring cytokine levels. Results: In vitro, UCB-Tregs are able to suppress HD Tcons and pathogenic SLE-PBMCs to a similar extent. UCB-Tregs decrease secretion of several inflammatory cytokines including IFN-γ, IP-10, TNF-α, IL-6, IL-17A, and sCD40L by SLE PBMCs in a time-dependent manner, with a corresponding increase in secretion of suppressor cytokine, IL-10. In vivo, single or multiple doses of UCB-Tregs led to a decrease in CD8+ T effector cells in different organs and a decrease in circulating inflammatory cytokines. Improvement in skin inflammation and loss of hair; and resolution of CD3+, CD8+, CD20+ and Ki67+ SLE-PBMC infiltration was observed in UCB-Treg recipients with a corresponding decrease in plasma anti-double stranded DNA IgG antibody levels and improved albuminuria. Conclusions: UCB-Tregs can decrease inflammatory burden in SLE, reduce auto-antibody production and resolve end organ damage especially, improve kidney function. Adoptive therapy with UCB-Tregs should be explored for treatment of lupus nephritis in the clinical setting.

Adjunct Therapy with T Regulatory Cells Decreases Inflammation and Preserves the Anti-Tumor Activity of CAR T Cells.

With greater accessibility and an increased number of patients being treated with CAR T cell therapy, real-world toxicity continues to remain a significant challenge to its widespread adoption. We have previously shown that allogeneic umbilical cord blood-derived (UCB) regulatory T cells (Tregs) can resolve inflammation and treat acute and immune-mediated lung injuries. Allogeneic, cryopreserved UCB Tregs have shown a clinical benefit in patients suffering from COVID-19 acute respiratory distress syndrome. The unique properties of UCB Treg cells include a lack of plasticity under inflammatory micro-environments, no requirement for HLA matching, a long shelf life of cryopreserved cells, and immediate product availability, which makes them attractive for treating acute inflammatory syndromes. Therefore, we hypothesized that adjunct therapy with UCB Tregs may resolve the undesirable inflammation responsible for CAR T cell therapy-associated toxicity. In in vitro analysis, no interference from the addition of UCB Tregs was observed on CD19 CAR T cells' ability to kill CD19 Raji cells at different CAR T: Raji cell ratios of 8:1 (80.4% vs. 81.5%); 4:1 (62.0% vs. 66.2%); 2:1 (50.1% vs. 54.7%); and 1:1 (35.4% vs. 44.1%). In the xenogeneic B-cell lymphoma model, multiple injections of UCB Tregs were administered 3 days after CD19 CAR T cell injection, and no detrimental effect of add-on Tregs was noted on the circulating CD8+ T effector cells. The distribution of CAR T cells in multiple organs remained unaffected by the addition of the UCB Tregs. Specifically, no difference in the overall tumor burden was detected between the UCB Treg + CAR T vs. CAR T alone recipients. No tumor was detected in the liver or bone marrow in CAR T cells + UCB Tregs recipients, with a notable corresponding decrease in multiple circulating inflammatory cytokines when compared to CART alone recipients. Here we show the proof of concept for adjunct therapy with UCB Tregs to mitigate the hyper-inflammatory state induced by CAR T cells without any interference in their on-target anti-tumor activity. Administration of UCB Tregs after CAR T cells allows sufficient time for their synapse formation with tumor cells and exerts cytotoxicity, such that the UCB Tregs are diverted to interact with the antigen-presenting cells at the site of inflammation. Such a differential distribution of cells would allow for a two-pronged strategy of a UCB Treg "cooling blanket" effect and lay the groundwork for clinical study.

Allogeneic cord blood regulatory T cells can resolve lung inflammation.

BACKGROUND AIMS: CD4+CD25+CD127lo regulatory T cells (Tregs) are responsible for maintaining immune homeostasis. Tregs can be rendered defective and deficient as a result of the immune imbalance seen in lung injury, and such dysfunction can play a major role in continued tissue inflammation. The authors hypothesized that adoptive therapy with healthy allogeneic umbilical cord blood (UCB)-derived Tregs may be able to resolve inflammation. RESULTS: Ex vivo-expanded UCB Tregs exhibited a unique phenotype with co-expression of CD45RA+CD45RO+ >80% and lung homing markers, including CD49d. UCB Tregs did not turn pathogenic when exposed to IL-6. Co-culture with increasing doses of dexamethasone led to a synergistic increase in UCB Treg-induced apoptosis of conventional T cells (Tcons), which translated into significantly higher suppression of proliferating Tcons, especially at a lower Treg:Tcon ratio. Multiple injections of UCB Tregs led to their preferential accumulation in lung tissue in an immune injury xenogenic model. A significant decrease in lung resident cytotoxic CD8+ T cells (P = 0.0218) correlated with a sustained decrease in their systemic distribution compared with controls (P < 0.0001) (n = 7 per arm) as well as a decrease in circulating human soluble CD40 ligand level (P = 0.031). Tissue architecture was preserved in the treatment arm, and a significant decrease in CD3+ and CD8+ burden was evident in immunohistochemistry analysis. CONCLUSIONS: UCB Treg adoptive therapy is a promising therapeutic strategy for treatment of lung injury.