Hematopoietic stem cell (HSC) self renewal and lineage commitment depend on complex interactions with the microenvironment. The ability to maintain or expand HSCs for clinical applications or basic ...research has been substantially limited because these interactions are not well defined. Recent evidence suggests that HSCs reside in a low-perfusion, reduced-nutrient niche and that nutrient-sensing pathways contribute to HSC homeostasis. Here we report that suppression of the mTOR pathway, an established nutrient sensor, combined with activation of canonical Wnt-β-catenin signaling, allows for the ex vivo maintenance of human and mouse long-term HSCs under cytokine-free conditions. We also show that the combination of two clinically approved medications that together activate Wnt-β-catenin and inhibit mTOR signaling increases the number (but not the proportion) of long-term HSCs in vivo.
CRISPR-Cas9 gene editing provides a powerful tool to enhance the natural ability of human T cells to fight cancer. We report a first-in-human phase 1 clinical trial to test the safety and feasibility ...of multiplex CRISPR-Cas9 editing to engineer T cells in three patients with refractory cancer. Two genes encoding the endogenous T cell receptor (TCR) chains, TCRα (
) and TCRβ (
), were deleted in T cells to reduce TCR mispairing and to enhance the expression of a synthetic, cancer-specific TCR transgene (NY-ESO-1). Removal of a third gene encoding programmed cell death protein 1 (PD-1;
), was performed to improve antitumor immunity. Adoptive transfer of engineered T cells into patients resulted in durable engraftment with edits at all three genomic loci. Although chromosomal translocations were detected, the frequency decreased over time. Modified T cells persisted for up to 9 months, suggesting that immunogenicity is minimal under these conditions and demonstrating the feasibility of CRISPR gene editing for cancer immunotherapy.
Acute graft-versus-host disease (GVHD) is treated with systemic corticosteroid immunosuppression. Clinical response after 1 week of therapy often guides further treatment decisions, but long-term ...outcomes vary widely among centers, and more accurate predictive tests are urgently needed. We analyzed clinical data and blood samples taken 1 week after systemic treatment of GVHD from 507 patients from 17 centers of the Mount Sinai Acute GVHD International Consortium (MAGIC), dividing them into a test cohort (n = 236) and 2 validation cohorts separated in time (n = 142 and n = 129). Initial response to systemic steroids correlated with response at 4 weeks, 1-year nonrelapse mortality (NRM), and overall survival (OS). A previously validated algorithm of 2 MAGIC biomarkers (ST2 and REG3α) consistently separated steroid-resistant patients into 2 groups with dramatically different NRM and OS (P < .001 for all 3 cohorts). High biomarker probability, resistance to steroids, and GVHD severity (Minnesota risk) were all significant predictors of NRM in multivariate analysis. A direct comparison of receiver operating characteristic curves showed that the area under the curve for biomarker probability (0.82) was significantly greater than that for steroid response (0.68, P = .004) and for Minnesota risk (0.72, P = .005). In conclusion, MAGIC biomarker probabilities generated after 1 week of systemic treatment of GVHD predict long-term outcomes in steroid-resistant GVHD better than clinical criteria and should prove useful in developing better treatment strategies.
•Biomarker scores generated after 1 week of steroid treatment of GVHD are prognostic.•Biomarkers reflect prognosis better than early clinical response to GVHD treatment.
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Chimeric antigen receptor (CAR) T cells have demonstrated promising efficacy, particularly in hematologic malignancies. One challenge regarding CAR T cells in solid tumors is the immunosuppressive ...tumor microenvironment (TME), characterized by high levels of multiple inhibitory factors, including transforming growth factor (TGF)-β. We report results from an in-human phase 1 trial of castration-resistant, prostate cancer-directed CAR T cells armored with a dominant-negative TGF-β receptor (NCT03089203). Primary endpoints were safety and feasibility, while secondary objectives included assessment of CAR T cell distribution, bioactivity and disease response. All prespecified endpoints were met. Eighteen patients enrolled, and 13 subjects received therapy across four dose levels. Five of the 13 patients developed grade ≥2 cytokine release syndrome (CRS), including one patient who experienced a marked clonal CAR T cell expansion, >98% reduction in prostate-specific antigen (PSA) and death following grade 4 CRS with concurrent sepsis. Acute increases in inflammatory cytokines correlated with manageable high-grade CRS events. Three additional patients achieved a PSA reduction of ≥30%, with CAR T cell failure accompanied by upregulation of multiple TME-localized inhibitory molecules following adoptive cell transfer. CAR T cell kinetics revealed expansion in blood and tumor trafficking. Thus, clinical application of TGF-β-resistant CAR T cells is feasible and generally safe. Future studies should use superior multipronged approaches against the TME to improve outcomes.
In the phase III COMFORT-I study, the Janus kinase 1 (JAK1)/JAK2 inhibitor ruxolitinib provided significant improvements in splenomegaly, key symptoms, and quality-of-life measures and was associated ...with an overall survival benefit relative to placebo in patients with intermediate-2 or high-risk myelofibrosis. This planned analysis assessed the long-term efficacy and safety of ruxolitinib at a median follow-up of 149 weeks. At data cutoff, approximately 50% of patients originally randomized to ruxolitinib remained on treatment whereas all patients originally assigned to placebo had discontinued or crossed over to ruxolitinib. At week 144, mean spleen volume reduction was 34% with ruxolitinib. Previously observed improvements in quality-of-life measures were sustained with longer-term ruxolitinib therapy. Overall survival continued to favor ruxolitinib despite the majority of placebo patients crossing over to ruxolitinib hazard ratio 0.69 (95% confidence interval: 0.46-1.03); P = 0.067. Exploratory analyses suggest that crossover may have contributed to an underestimation of the true survival difference between the treatment groups. Ruxolitinib continued to be generally well tolerated; there was no pattern of worsening grade ≥ 3 anemia or thrombocytopenia with longer-term ruxolitinib exposure. These longer-term data continue to support the efficacy and safety of ruxolitinib in patients with myelofibrosis. The study is registered at clinicaltrials.gov: NCT00952289.
To describe long-term outcomes of anti-CD19 chimeric antigen receptor T (CART) cells in patients with relapsed or refractory chronic lymphocytic leukemia (CLL).
Between January 2013 and June 2016, 42 ...patients with relapsed or refractory CLL were enrolled in this study and 38 were infused with anti-CD19 CART cells (CART-19). Of these, 28 patients were initially randomly assigned to receive a low (5 × 10
) or high (5 × 10
) dose of CART-19, and 24 were evaluable for response assessment. After an interim analysis, 10 additional patients received the selected (high) dose and of these, eight were evaluable for response. Patients were followed for a median 31.5 months (range, 2 to 75 months).
At 4 weeks, the complete and overall responses for the 32 evaluable patients were 28% (90% CI, 16% to 44%) and 44% (90% CI, 29% to 60%), respectively. The median overall survival (OS) for all patients was 64 months; there was no statistically significant difference between low- and high-dose groups (
= .84). Regardless of dose, prolonged survival was observed in patients who achieved a CR versus those who did not (
= .035), with median OS not reached in patients with CR versus 64 months in those without CR. The median progression-free survival was 40.2 months in patients with CR and 1 month in those without a CR (
< .0001). Toxicity was comparable in both dose groups.
In patients with advanced CLL, a 5 × 10
dose of CART-19 may be more effective than 5 × 10
CART-19 at inducing CR without excessive toxicity. Attainment of a CR after CART-19 infusion, regardless of cell dose, is associated with longer OS and progression-free survival in patients with relapsed CLL.
The randomized, double-blind, placebo-controlled, phase 3 COMFORT-I trial evaluated the JAK1/JAK2 inhibitor ruxolitinib in patients with intermediate-2/high-risk myelofibrosis. The primary and ...planned 3-year analyses of COMFORT-I data demonstrated that ruxolitinib-the first myelofibrosis-approved therapy-reduced splenomegaly and prolonged overall survival versus placebo. Here, we present the final 5-year results.
Patients managed in Australia, Canada, and the USA were randomized centrally (interactive voice response system) 1:1 to oral ruxolitinib twice daily (15 or 20 mg per baseline platelet counts) or placebo. Investigators and patients were blinded to treatment. The secondary endpoints evaluated in this analysis were durability of a ≥35% reduction from baseline in spleen volume (spleen response) and overall survival, evaluated in the intent-to-treat population. Safety was evaluated in patients who received study treatment.
Patients were randomized (September 2009-April 2010) to ruxolitinib (n = 155) or placebo (n = 154). At termination, 27.7% of ruxolitinib-randomized patients and 25.2% (28/111) who crossed over from placebo were on treatment; no patients remained on placebo. Patients randomized to ruxolitinib had a median spleen response duration of 168.3 weeks and prolonged median overall survival versus placebo (ruxolitinib group, not reached; placebo group, 200 weeks; HR, 0.69; 95% CI, 0.50-0.96; P = 0.025) despite the crossover to ruxolitinib. The ruxolitinib safety profile remained consistent with previous analyses. The most common new-onset all-grade nonhematologic adverse events starting <12 versus ≥48 months after ruxolitinib initiation were fatigue (29.0 vs 33.3%) and diarrhea (27.8 vs 14.6%). New-onset grade 3 or 4 anemia and thrombocytopenia both primarily occurred within the first 6 months, with no cases after 42 months. The most common treatment-emergent adverse event-related deaths in the ruxolitinib-randomized group were sepsis (2.6%), disease progression (1.9%), and pneumonia (1.9%).
The final COMFORT-I results continue to support ruxolitinib as an effective treatment for patients with intermediate-2/high-risk MF.
ClinicalTrials.gov, NCT00952289.
Advanced systemic mastocytosis comprises rare hematologic neoplasms that are associated with a poor prognosis and lack effective treatment options. The multikinase inhibitor midostaurin inhibits KIT ...D816V, a primary driver of disease pathogenesis.
We conducted an open-label study of oral midostaurin at a dose of 100 mg twice daily in 116 patients, of whom 89 with mastocytosis-related organ damage were eligible for inclusion in the primary efficacy population; 16 had aggressive systemic mastocytosis, 57 had systemic mastocytosis with an associated hematologic neoplasm, and 16 had mast-cell leukemia. The primary outcome was the best overall response.
The overall response rate was 60% (95% confidence interval CI, 49 to 70); 45% of the patients had a major response, which was defined as complete resolution of at least one type of mastocytosis-related organ damage. Response rates were similar regardless of the subtype of advanced systemic mastocytosis, KIT mutation status, or exposure to previous therapy. The median best percentage changes in bone marrow mast-cell burden and serum tryptase level were -59% and -58%, respectively. The median overall survival was 28.7 months, and the median progression-free survival was 14.1 months. Among the 16 patients with mast-cell leukemia, the median overall survival was 9.4 months (95% CI, 7.5 to not estimated). Dose reduction owing to toxic effects occurred in 56% of the patients; re-escalation to the starting dose was feasible in 32% of those patients. The most frequent adverse events were low-grade nausea, vomiting, and diarrhea. New or worsening grade 3 or 4 neutropenia, anemia, and thrombocytopenia occurred in 24%, 41%, and 29% of the patients, respectively, mostly in those with preexisting cytopenias.
In this open-label study, midostaurin showed efficacy in patients with advanced systemic mastocytosis, including the highly fatal variant mast-cell leukemia. (Funded by Novartis Pharmaceuticals and others; ClinicalTrials.gov number, NCT00782067.).
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