An Innovative High-Throughput Ex Vivo Drug Assay Incorporating the Native Microenvironment Reveals a Novel Mechanism of Action of Idelalisib in CLL

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2485-2485
Author(s):  
Joan Ballesteros ◽  
Lydia Scarfo ◽  
Mattias Mattsson ◽  
Aliki Xochelli ◽  
Pamela Ranghetti ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Viability ◽  
B Cell ◽  
High Throughput ◽  
Dose Response ◽  
Research Funding ◽  
Ex Vivo ◽  
Response Curves ◽  
Ex Vivo Assay

Abstract The microenvironment (ME) critically promotes progression of chronic lymphocytic leukemia (CLL), favoring leukemic cell survival and proliferation as well as inducing drug resistance. We aimed at reproducing the effects of ME stimuli for the development and optimization of an ex vivo assay that would enable to predict in vivo drug efficacy for agents interfering with ME protective effects e.g. the novel BCR inhibitors. To this purpose, we exploited the following 2 new approaches: 1) the Exvitech® proprietary automated flow cytometry-based platform by Vivia Biotech that enables evaluation of up to 20.000 wells and conditions per sample, and 2) Viviaxs Precision Medicine Native Environment approach that utilizes the whole blood sample rather than isolated leukocytes. We present this assay optimization using primary CLL samples and its validation when exposing CLL cells to the registered PI3Kd inhibitor, Idelalisib, for which only a weak pro-apoptotic effect has been reported, besides the known tissue mobilization activity in vivo. Cryopreserved peripheral blood (PB) mononuclear cells were provided from CLL patients in need of treatment. In order to more closely reproduce the complexity of the in vivo ME, the following elements were evaluated in different combinations: (i) 3 backbone stimulations, previously reported to improve, to different extent, CLL viability and proliferation: CD40L+CpG, CD40L+IL21, CpG+IL2; (ii) "Native Environment", defined as the plasma & erythrocyte/granulocyte fraction of a Ficoll gradient, already shown to improve ex vivo drug testing (Bennet et al. Clin Lymphoma Myeloma Leuk. 2014;14:305-18): the two fractions were added to thawed CLL samples and were obtained from fresh samples of normal donor PB or bone marrow as well as from CLL patients at different stages of disease; (iii) the stroma cell line H5S, added at different ratios (1:10 or 1:100); (iv) both human and bovine fetal serum (at 10 or 20% total volume); (v) stimulatory B cell factors, including IL-21, soluble CD40L, BAFF, and B cell receptor stimulation (anti-IG). CLL cell viability and proliferation was then tested and, although CLL cells from PB are notorious for a low proliferative index and tend to die quickly ex vivo by apoptosis, we achieved a median of 30±3% proliferation (assessed by the CFDA dye) and 60±5% viability (assessed by Annexin V staining) in cryopreserved progressive CLL samples. These results were obtained with the combination of the following assay conditions: CpG+IL2, HS5 (at 1:100 ratio), human serum 10%, and "native environment" from PB of CLL samples (pooled samples to prevent interpatient variability). We then tested the dose responses of Idelalisib in 16 cryopreserved progressive CLL samples and found little effect on the non-proliferative CLL fraction (Fig, 1A), suggesting a limited direct pro-apoptotic activity of the drug. In contrast, potent inhibition of proliferation with median potency (EC50) of 14 nM was observed (Fig 1B). The efficacy was nearly complete leaving a median of 5% resistant CLL cells that proliferated at the highest doses of Idelalisib. In conclusion, we report a novel ex vivo assay that enables high-throughput pharmacological characterization of compounds and combinations, optimized for CLL cells by incorporating ME stimuli and thereby more accurately simulating in vivo interactions. The increased cell viability and proliferation achieved with this innovative assay offers improved opportunities for ex vivo pharmacology, in particular unraveling a hitherto unknown anti-proliferative mode of action for Idelalisib, a drug interfering with the interaction of CLL cells with the ME. Figure 1. Dose response curves of Idelalisib incubated for 96 h with 16 CLL samples in the new Microenvironment Native Environment assay. The effect on non-proliferative (A) and proliferative (B) CLL cells identified using flow cytometry as subpopulations with different CFDA staining is shown. Figure 1. Dose response curves of Idelalisib incubated for 96 h with 16 CLL samples in the new Microenvironment Native Environment assay. The effect on non-proliferative (A) and proliferative (B) CLL cells identified using flow cytometry as subpopulations with different CFDA staining is shown. Disclosures Ballesteros: Vivia Biotech: Employment. Primo:Vivia Biotech: Employment. Robles:Vivia Biotech: Employment. Gorrochategui:Vivia Biotech: Employment. Munugalavadla:Gilead Sciences: Employment. Stamatopoulos:Gilead Sciences: Research Funding; Janssen Pharmaceuticals: Research Funding. Quéva:Gilead Sciences: Employment, Equity Ownership. Ghia:AbbVie: Consultancy; Pharmacyclics: Consultancy; Gilead: Consultancy, Research Funding, Speakers Bureau; Adaptive: Consultancy; Acerta Pharma BV: Research Funding; GSK: Research Funding; Roche: Consultancy, Research Funding; Janssen: Consultancy.

T Cells Engineered with a Chimeric Antigen Receptor (CAR) Targeting CD19 (CTL019) Have Long Term Persistence and Induce Durable Remissions in Children with Relapsed, Refractory ALL

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 380-380 ◽  
Author(s):  
Stephan A. Grupp ◽  
Shannon L Maude ◽  
Pamela Shaw ◽  
Richard Aplenc ◽  
David M. Barrett ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Dose Range ◽  
Single Chain

Abstract BACKGROUND CARs combine a single chain variable fragment (scFv) of an antibody with intracellular signaling domains. We have previously reported on CTL019 cells expressing an anti-CD19 CAR. Infusion of these cells results in 100 to 100,000x in vivo proliferation, durable anti-tumor activity, and prolonged persistence in pts with B cell tumors, including sustained CRs in adults and children with ALL (Grupp et al., NEJM 2013, Maude et al., NEJM 2014). We now report on outcomes and longer follow up of the first 30 pts with relapsed, refractory ALL treated on our pilot trial in pediatric ALL. METHODS T cells were lentivirally transduced with a CAR composed of anti-CD19 scFv/4-1BB/CD3ζ, activated/expanded ex-vivo with anti-CD3/anti-CD28 beads, and then infused into children with relapsed or refractory CD19+ ALL. 26/30 pts received lymphodepleting chemotherapy the week prior to CTL019 infusion. The targeted T cell dose range was 107 to 108 cells/kg with a transduction efficiency of 11-45%. T cells for manufacturing were collected from the pt regardless of prior SCT status, not allo donors. RESULTS 30 children median age 10y (5-22y) with CD19+ ALL were treated. 25/30 pts had detectable disease on the day before CTL019 cell infusion, while 5 were MRD(-). A median of 3.6x106 CTL019 cells/kg (1.1-18x106/kg) were infused over 1-3 days. There were no infusional toxicities >grade 2, although 9 pts developed fevers within 24 hrs of infusion and did not receive a planned 2nd infusion of CTL019 cells. 27 pts (90%) achieved a CR, including a patient with T cell ALL aberrantly expressing CD19+. 3 did not respond. MRD measured by clinical flow cytometry was negative in 23 responding pts and positive at 0.1% (negative at 3 mo), 0.09%, 0.22%, and 1.1% in 4 pts. With median follow up 8 mo (1-26 mo), 16 pts have ongoing CR, with only 3 patients in the cohort receiving subsequent treatment such as donor lymphocyte infusion or SCT, 6-month EFS measured from infusion is 63% (95% CI, 47-84%), and OS is 78% (95% CI, 63-95%). CTL019 cells were detected in the CSF of 17/19 pts and 2 pts with CNS2a disease experienced a CR in CSF. 10 pts with a CR at 1 mo have subsequently relapsed, half with CD19(-) blasts. 2/5 pts who relapsed with CD19(-) disease had previously been refractory to CD19-directed blinatumomab and subsequently went into CR with CTL019. Figure 1 Figure 1. All responding pts developed grade 1-4 cytokine release syndrome (CRS) at peak T cell expansion. Detailed cytokine analysis showed marked increases of IL6 and IFNγ (both up to 1000x), and IL2R. Treatment for CRS was required for hemodynamic or respiratory instability in 37% of patients and was rapidly reversed in all cases with the IL6-receptor antagonist tocilizumab, together with corticosteroids in 5 pts. Although T cells collected from the 21 pts who had relapsed after allo SCT were median 100% donor origin, no GVHD has been seen. Grade 4 CRS was strongly associated with high disease burden prior to infusion and with elevations in IL-6, ferritin (suggesting macrophage activation syndrome) and C reactive protein after infusion. Persistence of CTL019 cells detected by flow cytometry and/or QPCR, and accompanied by B cell aplasia, continued for 1-26 months after infusion in pts with ongoing responses. QPCR showed very high levels of CTL019 proliferation, with all patients achieving peak levels >5000 copies/ug gDNA and 26 patients with peak levels >15,000 copies/ug gDNA. B cell aplasia has been treated with IVIg without significant infectious complications. Probability of 6-mo CTL019 persistence by flow was68% (95% CI, 50-92%) andrelapse-free B cell aplasia was 73% (95% CI, 57-94%). CONCLUSIONS: CTL019 cells can undergo robust in-vivo expansion and can persist for 2 years or longer in pts with relapsed ALL, allowing for the possibility of long-term disease response without subsequent therapy such as SCT. This approach also has promise as a salvage therapy for patients who relapse after allo-SCT with a low risk of GVHD. CTL019 therapy is associated with a significant CRS that responds rapidly to IL-6-targeted anti-cytokine treatment. CTL019 cells can induce potent and durable responses for patients with relapsed/refractory ALL; however, recurrence with cells that have lost CD19 is an important mechanism of CLT019 resistance. CTL019 therapy has received Breakthrough Therapy designation from the FDA in both pediatric and adult ALL, and phase II multicenter trials have been initiated. Disclosures Grupp: Novartis: Consultancy, Research Funding. Barrett:Novartis: Research Funding. Chew:Novartis: Research Funding. Lacey:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Research Funding. Rheingold:Novartis: Consultancy. Shen:Novartis: Employment. Wood:Novartis Pharma: Employment. Porter:Novartis: managed according to U Penn Policy Patents & Royalties, Research Funding. June:Novartis: Research Funding, Royalty income Patents & Royalties.

scholarly journals Aged platelets have an impaired response to thrombin as quantitated by P-selectin expression

Blood ◽  
1994 ◽  
Vol 83 (1) ◽  
pp. 161-166 ◽  
Author(s):  
J Peng ◽  
P Friese ◽  
E Heilmann ◽  
JN George ◽  
SA Burstein ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Surface ◽  
Dose Response ◽  
Intravenous Infusion ◽  
Total Population ◽  
Response Curves ◽  
Dose Response Curves

Abstract After the intravenous infusion of N-hydroxysuccinimido biotin into dogs, 80.6% +/- 9.7% (n = 5) of platelets were covalently labeled with biotin. The in vivo survival of the biotinylated platelets was monitored by flow cytometry and was normal as compared with previous reports for dog platelets. The ability of the biotinylated platelets to be activated was analyzed by measuring the expression of cell-surface P- selectin after incubation with graded concentrations of thrombin. When P-selectin expression was examined 3 hours after labeling, biotinylated platelets were indistinguishable from the nonlabeled population of platelets, indicating that biotinylation did not adversely affect the cells. On consecutive days after biotinylation, the thrombin dose- response curves for biotinylated and nonbiotinylated platelets were repeated, and as the biotinylated-platelets aged, they became less responsive to thrombin. On days 3, 4, and 5, the thrombin EC50 for the aged, biotinylated platelets as compared with the total population of platelets was 136%, 150%, and 178%, respectively. Increasing age clearly impairs the reactivity of platelets towards thrombin as quantitated by the expression of cell-surface P-selectin.

Durable Remissions in Children with Relapsed/Refractory ALL Treated with T Cells Engineered with a CD19-Targeted Chimeric Antigen Receptor (CTL019)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 681-681 ◽  
Author(s):  
Stephan A. Grupp ◽  
Shannon L Maude ◽  
Pamela A Shaw ◽  
Richard Aplenc ◽  
David M. Barrett ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Young Adults ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Disease Burden ◽  
Children And Young Adults

BACKGROUND CARs combine a targeting antibody (scFv) domain with intracellular signaling domains. We have previously reported on CTL019 cells expressing an anti-CD19 CAR, which have resulted in up to 100,000x in vivo proliferation, durable anti-tumor activity, and prolonged persistence in pts with B cell tumors, including sustained CRs in adults and children with ALL (Grupp et al., NEJM 2013, Maude et al., NEJM 2014). We now report on outcomes and longer follow up of the first 53 pts with relapsed/refractory (r/r) ALL treated on our pilot trial in pediatric ALL. METHODS T cells were lentivirally transduced with a CAR composed of anti-CD19 scFv/4-1BB/CD3ζ, activated/expanded ex-vivo with anti-CD3/anti-CD28 beads, and then infused into children with r/r CD19+ ALL. 48/53 pts received lymphodepleting chemotherapy the week prior to CTL019 infusion. The targeted T cell dose range was 107 to 108 cells/kg with a transduction efficiency of 3.6-45%. T cells for manufacturing were collected from the pt regardless of prior SCT status, and not their allo donors. RESULTS We treated 53 children and young adults with CD19+ ALL, median age 11y, (4-24y). To assess disease burden after lymphodepleting chemotherapy, pts had BM aspirations performed 1D prior to 1st CTL019 infusion: 41/53 pts had detectable ALL while 12 were MRD(-). A median of 4.3x106 CTL019 cells/kg (1-17.4x106/kg) were infused over 1-2D (1 pt got cells over 3D). There were no infusional toxicities >gr2, although pts who developed fevers within 24h of infusion did not receive a planned 2nd infusion of CTL019 cells. 50 pts (94%) achieved a CR, including a patient with CD19+ T ALL, 3 did not respond. MRD measured by clinical flow cytometry was <0.01% at D28 in 45 responding pts and positive at 0.024%-1.1% in 5 pts, with 2 patients becoming negative by 3 mo with no further therapy. With median follow up 10.6 mo (1-39 mo), 29 pts have ongoing CR, with only 6 receiving subsequent treatment such as donor lymphocyte infusion or SCT, EFS is 70% at 6 mo (95% CI, 58-85%) and 45% at 12 mo (95% CI, 31-66%), RFS is 72% at 6 mo (95% CI, 59-87%) and 44% at 12 mo (95% CI, 30-65%), and OS is 78% at 12 mo (95% CI, 67-91%). CTL019 was detected by qPCR in the CSF of 46/47 pts and 4 pts with CNS2a ALL experienced a CR in CSF. 20 pts with a CR at 1 mo have subsequently relapsed, with 3 relapses occurring after subsequent therapy (i.e. SCT) and 13 with CD19(-) blasts. 4/5 pts previously refractory to CD19-directed blinatumomab went into CR with CTL019, 3 subsequently relapsed with CD19(-) disease. All but 5 (90%) of pts developed grade 1-4 cytokine release syndrome (CRS) at peak T cell expansion. Detailed cytokine analysis showed marked increases of IL6 and IFNγ (both up to 1000x), and IL2R. Treatment for CRS was required for hemodynamic or respiratory instability in 28% of patients and was reversed in all cases with the IL6-receptor antagonist tocilizumab, together with short courses of corticosteroids in 9 pts. Although T cells collected from the 35 pts who had relapsed after allo SCT were median 100% donor origin, no GVHD has been seen. Grade 4 CRS was associated with high disease burden prior to infusion and with elevations in IL-6, ferritin (suggesting macrophage activation syndrome) and C reactive protein after infusion. Persistence of CTL019 cells can be detected by flow cytometry and/or QPCR, and results in the pharmacodynamic marker of CTL019 function, B cell aplasia, which continued for 3-39 months after infusion in pts with ongoing responses. B cell aplasia has been treated with IVIg without significant infectious complications. CONCLUSIONS: CTL019 cells can undergo robust in vivo expansion and can persist for 3 years or longer in children and young adults with r/r ALL, allowing for the possibility of long-term disease control without subsequent therapy such as SCT. This approach also has promise as salvage therapy for patients who relapse after allo SCT with a low risk of GVHD. CTL019 therapy is associated with a significant CRS that responds rapidly to IL-6-targeted anti-cytokine treatment. CTL019 cells can induce potent and durable responses for patients with r/r ALL; however, recurrence with cells that have lost CD19 is an important mechanism of CTL019 resistance. Rapid loss of CTL019 cells (prior to 3 months) is associated with a high risk of CD19+ relapse. CTL019 therapy has received Breakthrough Therapy designation from the FDA in pediatric and adult ALL, and phase 2 multicenter registration trials are well underway. Disclosures Grupp: Novartis: Consultancy, Research Funding. Maude:Novartis: Consultancy, Research Funding. Shaw:Novartis: Research Funding. Aplenc:Sigma Tau: Consultancy. Lacey:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Research Funding. Rheingold:Novartis: Consultancy; Endo: Other: Husband's employer, has equity interest. Teachey:Novartis: Research Funding. Wood:Novartis Pharmaceuticals Corporation: Employment. Porter:Novartis: Other: IP interest, Research Funding; Genentech: Other: Spouse employment. June:University of Pennsylvania: Patents & Royalties: financial interests due to intellectual property and patents in the field of cell and gene therapy. Conflicts of interest are managed in accordance with University of Pennsylvania policy and oversight; Novartis: Research Funding.

scholarly journals Aged platelets have an impaired response to thrombin as quantitated by P-selectin expression

Blood ◽  
1994 ◽  
Vol 83 (1) ◽  
pp. 161-166
Author(s):  
J Peng ◽  
P Friese ◽  
E Heilmann ◽  
JN George ◽  
SA Burstein ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Surface ◽  
Dose Response ◽  
Intravenous Infusion ◽  
Total Population ◽  
Response Curves ◽  
Dose Response Curves

After the intravenous infusion of N-hydroxysuccinimido biotin into dogs, 80.6% +/- 9.7% (n = 5) of platelets were covalently labeled with biotin. The in vivo survival of the biotinylated platelets was monitored by flow cytometry and was normal as compared with previous reports for dog platelets. The ability of the biotinylated platelets to be activated was analyzed by measuring the expression of cell-surface P- selectin after incubation with graded concentrations of thrombin. When P-selectin expression was examined 3 hours after labeling, biotinylated platelets were indistinguishable from the nonlabeled population of platelets, indicating that biotinylation did not adversely affect the cells. On consecutive days after biotinylation, the thrombin dose- response curves for biotinylated and nonbiotinylated platelets were repeated, and as the biotinylated-platelets aged, they became less responsive to thrombin. On days 3, 4, and 5, the thrombin EC50 for the aged, biotinylated platelets as compared with the total population of platelets was 136%, 150%, and 178%, respectively. Increasing age clearly impairs the reactivity of platelets towards thrombin as quantitated by the expression of cell-surface P-selectin.

scholarly journals BRAFV600E Accelerates Disease Progression and Increases Immune Suppression in a Mouse Model of B-Cell Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1206-1206 ◽  
Author(s):  
Yo-Ting Tsai ◽  
Aparna Lakshmanan ◽  
Amy M. Lehman ◽  
Ellen J. Sass ◽  
Minh Tran ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Proliferation ◽  
T Cells ◽  
B Cell ◽  
Immune Suppression ◽  
Research Funding ◽  
Cell Leukemia ◽  
Wild Type ◽  
B Cell Leukemia

Abstract Background: Mitogen-activated protein kinase (MAPK) pathway components are frequently mutated in cancer, and abnormal MAPK signaling can drive malignancy by promoting tumor survival and proliferation. Furthermore, work in solid tumors shows that the presence of BRAFV600E further enhances tumor-induced immune suppression, but if and how this occurs in a disseminated disease such as leukemia is unknown. MAPK mutations occur in nearly 100% of classic hairy cell leukemia (HCL) and approximately 10% of chronic lymphocytic leukemia (CLL). Furthermore, up to 30% of B cell lymphomas exhibit activated MAPK signaling via expression of a BRAF pseudogene. However, the pathomechanisms of these abnormalities and the clinical utility of MAPK inhibitors in hematologic malignancies are unclear, and few models are available to evaluate this. To study these aspects, we developed in vitro and in vivo models of BRAF-mutated B cell malignancy. Methods: To mechanistically interrogate the role of BRAFV600E in malignant B cells, we transfected the CLL cell line OSUCLL with doxycycline-inducible constructs containing normal BRAF or BRAFV600E and incubated the cells -/+ doxycycline. These cells were also co-cultured with healthy donor T cells pre-incubated with anti-CD3/anti-CD28, and T cell proliferation was measured by flow cytometry. Cytokines and surface proteins were assessed by flow cytometry. To mimic human HCL, we developed a transgenic mouse model of BRAFV600E B cell leukemia. Mice with Cre-activatable BRAFV600E expression were crossed with mice carrying Cre under the control of the CD19 promoter. CD19-Cre x BRAFV600E or CD19-Cre only mice were then crossed with the well-characterized Eµ-TCL1 model of CLL to generate mice with spontaneous B cell leukemia expressing either wild-type BRAF (CD19-Cre x TCL1) or BRAFV600E (BRAFVE x CD19-Cre x TCL1) under the native BRAF promoter. B cell restricted expression of BRAFV600E was confirmed by immunoblots of purified B and T cells using a BRAFV600E specific antibody. Blood and spleen cells were examined by flow cytometry. For adoptive transfer experiments, leukemia cells (2x10^7) from transgenic mice were introduced intravenously into syngeneic healthy adult animals. Results: OSUCLL cells expressing BRAFV600E showed no significant changes in growth vs. wild-type BRAF expressing cells, but more strongly inhibited anti-CD3/CD28-induced proliferation of normal donor T cells. Transwell assays showed this effect was due both to soluble and contact-dependent factors. Expression of PD-L1 was not different between cells expressing normal and mutated BRAF, indicating this common checkpoint molecule is not the reason for greater immune suppression in this context. TNF levels were higher in BRAFV600E expressing cells and reduced by vemurafenib, but a TNF neutralizing antibody did not alter the inhibitory effect of BRAFV600E expressing cells on T cell proliferation. BRAFV600E x CD19-Cre x TCL1 mice developed B cell leukemia significantly earlier (median 4.9 vs. 8.1 months; P<0.001) and had significantly shorter lifespan (median 7.3 vs. 12.1 months; P<0.001) than their wild-type BRAF counterparts. In contrast to effects of BRAFV600E described in some solid tumors, BRAFV600E expression in B cells had no impact on the rate of B cell proliferation in vivo and only modestly reduced spontaneous apoptosis. To study the effects of this activating mutation on tumor-mediated immune suppression in vivo, leukemia cells from BRAFV600E x CD19-Cre x TCL1 or CD19-Cre x TCL1 mice were adoptively transferred into syngeneic mice. In 3 separate studies, tumor cells from BRAFV600E mice produced leukemia (>10% CD5+/CD19+ cells in blood) sooner than CD19-Cre x TCL1 tumor cells. In mice matched for disease load, BRAFV600E B cells produced a greater negative impact on T cells as evidenced by lower overall percentage of T cells, increased expression of T cell exhaustion markers PD-1, CD244, and CD160, and higher percentage of CD44+ memory T cells. Current studies are investigating the mechanism of these effects in vivo as well as the potential for pharmacologic reversal. Conclusions: Together, these results demonstrate the immune-suppressive impact of BRAFV600E in B-cell leukemias and introduce a novel mouse model to develop rational combination strategies to both directly target the tumor cell and overcome tumor-mediated immune evasion. Disclosures Lozanski: Genentech: Research Funding; Stemline Therapeutics Inc.: Research Funding; Beckman Coulter: Research Funding; Boehringer Ingelheim: Research Funding.

scholarly journals Diffuse Large B Cell Pdtx in Humanized Mice Are Valuable Models to Study Host-Lymphoma Interactions and Immune-Modulating Agents

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2406-2406
Author(s):  
Giorgia Zanetti ◽  
Giuseppina Astone ◽  
Luca Cappelli ◽  
William Chiu ◽  
Maria Teresa Cacciapuoti ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Ex Vivo ◽  
Human Immune System ◽  
Human T Cells ◽  
Human Immune

Abstract Introduction: Immunotherapy is a promising therapeutic intervention for cancer treatment. Activation of the immune system via checkpoint blockade has been shown to produce antitumor responses in patients with both solid and hematological tumors. However, many patients do not respond to checkpoint inhibitors, and additional therapies are needed to treat these patients. Testing immunotherapies requires a functional human immune system; thus, it is difficult to evaluate their effectiveness using conventional experimental models. For this reason, establishing in vivo models that closely reproduce not only human tumors, but also their interactions with the human immune system, has become mandatory. Methods: We developed a humanized mouse model and combined it with a patient-derived tumor xenograft (PDTX). Humanized mice (HuMice) were generated by transplantation of cord blood or mobilized peripheral blood CD34+ hematopoietic stem and progenitor cells into preconditioned immunodeficient mice. We compared human engraftment in 3 different mouse strains: NSG (NOD.Cg-Prkdc scidIl2rg tm1Wjl/SzJ), NSGS (NOD.Cg-Prkdc scidIl2rg tm1Wjl Tg(CMV-IL3,CSF2,KITLG)1Eav/MloySzJ) and NBSGW (NOD.Cg-Kit W-41J Tyr + Prkdc scid Il2rg tm1Wjl/ThomJ). Immune cell profiling and distribution was performed using flow cytometry and immunohistochemistry. The B cell receptor (BCR) repertoire was evaluated using an RNA-based NGS assay. To evaluate the maturation and functionality of T cells developing in HuMice we performed proliferation, degranulation and intracellular cytokine staining. Results: Two months after CD34+ cell transplantation, we observed high levels of human hematopoietic chimerism in all the 3 strains. NSGS mice supported high-level chimerism as early as 1 month after transplantation, with more than 25% of human CD45+ cells in the blood. In all mice the majority of human circulating leukocytes were CD19+ B cells. An early appearance of CD3+ human T cells was detected in NSGS mice as compared to the other strains. Notably, the T cell expansion correlated with a decrease in relative B cell abundance while the myeloid cell contribution to the graft remained steady. We documented the differentiation of CD4+ and CD8+ human T cells at a 2:1 ratio. The characterization of the T cell subsets revealed that the majority was represented by CD45RA-CCR7- effector memory cells in both the spleen and the blood of HuMice. Nevertheless, recipient mice did not exhibit overt signs of graft-versus-host disease. We also evaluated the cytotoxic potential of T cells isolated from the spleen of HuMice: ex vivo peptide antigen (i.e. EBV) presentation let to generation of effective and specific cytotoxic T-cells. After assessing a functional human immune system reconstitution in HuMice, we challenged them in vivo with low-passage tumor fragments from a diffuse large B cell lymphoma (DLBCL) PDTX. All tumor implants were successfully engrafted in both HuMice and non-humanized controls. Remarkably, all the 3 HuMice strains showed a significant reduction in the tumor volume and/or eradication compared to matched non-humanized controls. Flow cytometry analysis of the peripheral blood of humanized PDTX revealed that the tumor engraftment elicited a significant expansion of CD3+ T cells and cytotoxic CD8+ lymphocytes. Moreover, tumors developing in HuMice exhibited intermediate to high levels of tumor infiltrating T lymphocytes commingling with the neoplastic B cells, as determined by immunohistochemistry. Large areas of necrosis were often observed in PDTX of HuMice. Infiltrating CD3+ cells were TIGIT, PD-1 and Lag-3 positive, and did not efficiently proliferate ex vivo: all features consistent with an exhaustion phenotype. PDTX of HuMice often displayed larger areas of necrosis. Conclusions: Collectively, our data demonstrate that a robust reconstitution can be achieved in different strains of immunocompromised mice and that HuMice elicit effective anti-lymphoma responses. PDTX HuMice represent a powerful platform to study host-tumor interactions, and to test novel immune-based strategies (CAR-T, bifunctional Abs) and new pharmacological approaches to counteract T-cell exhaustion. Figure 1 Figure 1. Disclosures Scandura: Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Constellation: Research Funding; MPN-RF (Foundation): Research Funding; CR&T (Foudation): Research Funding; European Leukemia net: Honoraria, Other: travel fees . Roth: Janssen: Consultancy; Merck: Consultancy.

scholarly journals Drug Combinations Co-Targeting Myeloid Cell Leukemia-1 (Mcl-1) Protein Can Overcome Microenvironmentally-Induced Multi-Drug Tolerance in Non-Hodgkin Lymphomas

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2649-2649
Author(s):  
Kallesh D. Jayappa ◽  
Craig A. Portell ◽  
Vicki L. Gordon ◽  
Goutham Narla ◽  
Timothy P. Bender ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Research Funding ◽  
Ex Vivo ◽  
Drug Tolerance ◽  
Drug Combinations ◽  
Ex Vivo Model ◽  
Selective Toxicity ◽  
Apoptotic Proteins

Abstract Ibrutinib (IBR), an inhibitor of Bruton's Tyrosine Kinase (Btk) and venetoclax (VEN), an inhibitor of Bcl-2 have been used in Chronic Lymphocytic Leukemia (CLL), but single agent responses to these drugs are often incomplete and not durable. We previously reported synergistic cytotoxicity for the IBR+VEN combination and have initiated a trial to test that combination (NCT02419560). However, we noted extensive variability in response to IBR+VEN between patient samples ex vivo, suggesting intrinsic tolerance even to this combination. CLL cells with an "activation" phenotype (CD5+/19+/69+) that occurs from interactions with the microenvironment were less sensitive to IBR+VEN, implicating the cancer microenvironment as an inducer of drug tolerance. This was supported by our finding that CLL cells display decreased sensitivity to IBR+VEN in co-culture with agonists and cells that emulate the cancer cell microenvironment. The combination of CpG-oligodeoxynucleotides (ODN), sCD40L, and IL10 ("agonist mix") induced near complete loss of sensitivity to IBR+VEN and upregulated Mcl-1 and Bcl-xL expression in CLL cells. However, Mcl-1 or Bcl-xL inhibitors alone were weakly effective in these cells, suggesting that exploitation of these targets requires drug combinations. Here we report a combination drug screen with an Mcl-1 inhibitor in a CLL microenvironment model ex vivo and novel drug combinations that overcome multi-drug tolerance. CLL patient PBMCs were cultured in the microenvironment model consisting of HK follicular dendritic cells, HUVEC, Jurkat T cells expressing CD40L, and CpG-ODN. Markers characteristic of activation and drug tolerance in vivo were assessed in CLL (CD5+/19+) cells using flow cytometry. We found increased expression of Ki67, CD69, and anti-apoptotic proteins Mcl-1 and Bcl-xL and decreased CXCR4 expression, as expected upon microenvironmental stimuli in vivo.Also, CLL cells from 2 IBR-treated patients were still responsive to agonist-induced drug tolerance, suggesting Btk inhibition may be less effective in blocking these microenvironmental stimuli in vivo. By comparing the ratio of anti-apoptotic proteins with cognate pro-apoptotic proteins, we noted targetable dependence of CLL cells for diverse pro-survival proteins (Mcl-1 and Bcl-xL) in our model. Flow cytometry analysis demonstrated that inhibitors of Mcl-1 (S63845), Bcl-xL (A1155643), or Bcl-2 (VEN) when used as single agents failed to induce significant apoptosis in CLL cells cultured in our model, suggesting induction of multi-drug tolerance. Drug combinations inhibiting Mcl-1 with Bcl-xL, Bcl-2, or Bcl-xL and Bcl-2 have effectively overcome multi-drug tolerance. As direct and simultaneous inhibition of multiple pro-survival proteins could be fatal to healthy cells, we carried out a Mcl-1-anchored combinatorial drug screen with inhibitors of other survival pathways in 3 CLL patient PBMCs cultured in our ex vivo model to identify drug combination(s) that induce selective toxicity in multi-drug tolerant CLL cells. Cytotoxicity was determined by analyzing cleaved PARP and dead cell staining in CLL and healthy T (CD3+/5+) cells by flow cytometry. Results showed that inhibitors of apoptotic proteins (A1155643, VEN, ABT737), IRAK4 (CA-4948, compound 26, and AS2444697), intracellular TLRs (chloroquine), Hsp90 (ganetespib), CDK (ribociclib), proteasome (bortezomib), Btk (IBR), AKT (MK2206), and HDAC (SAHA and panobinostat) or activator of PP2A (DBK1532 and NZ8061) were synergistically toxic with Mcl-1 inhibitor (S63845) in CLL cells. By comparing toxicity in CLL and healthy T cells, drug combinations targeting Mcl-1 with proteasome, IRAK4, TLRs, Btk, Hsp90, and CDK showed selective toxicity in CLL cells, indicating a potential therapeutic window for these combinations. Drug combinations targeting Mcl-1 with other apoptotic proteins were highly toxic to healthy T cells. In conclusion, CLL cells in our ex vivo model display characteristics of microenvironmentally-induced multi-drug tolerance. A similar phenotype was noted using post IBR therapy samples, suggesting IBR alone may not be effective in overcoming this multi-drug tolerance in vivo. Drug combinations targeting Mcl-1 and proteasome, IRAK4, TLRs, Btk, Hsp90, or CDK selectively overcame multi-drug tolerance in CLL cells. Thus, these combinations may be effective in patients showing intrinsic tolerance to multiple drugs. Disclosures Portell: TG therapeutics: Research Funding; AbbVie: Research Funding; Infinity: Research Funding; Genentech/Roche: Consultancy, Research Funding; Acerta: Research Funding; BeiGene: Research Funding; Kite: Research Funding; Amgen: Consultancy. Narla:University of Michigan: Patents & Royalties: Small molecule PP2A activators. Williams:Takeda: Research Funding; TG Therapeutics: Consultancy; Seattle Genetics: Consultancy; Verastem: Consultancy; Juno: Consultancy; Sandoz: Consultancy; Celgene: Consultancy, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy; Abbvie: Consultancy; Pharmacyclics: Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Kite: Consultancy; Gilead: Consultancy, Research Funding.

scholarly journals A High-Throughput Biology Approach to Identify Novel Therapies Specifically Targeting AML Blasts and Leukemic Stem Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2755-2755
Author(s):  
Heikki Kuusanmäki ◽  
Aino Maija Leppä ◽  
Debashish Deb ◽  
Caroline A Heckman
Keyword(s):  
Stem Cells ◽  
High Throughput ◽  
Dose Response ◽  
Research Funding ◽  
Live Cell ◽  
Cell Populations ◽  
Novel Therapies ◽  
Leukemic Stem Cells ◽  
Response Curves ◽  
Drug Responses

Abstract Introduction While the majority of patients diagnosed with acute myeloid leukemia (AML) will respond to standard induction chemotherapy, recurrent and refractory disease rates are high. Much needed new therapies for AML are currently in development; however, many drugs indiscriminately target rapidly proliferating cells and are ineffective against indolent, more quiescent leukemic stem cells. To identify novel therapies specific for AML blasts and leukemic stem cells (LSC), we developed a high-throughput, multi-parametric flowcytometry(FC) based method that simultaneously distinguishes specific cell populations and their differential drug responses. Using this method, we could distinguish healthy cells from leukemic stem cells and assess the effects of several drugs on these cell populations as well as the immune profile of individual patients. In addition, we identified drugs that could target both blasts and LSC and could potentially be repositioned for the treatment of AML. Methods Mononuclear cells were enriched from bone marrow (BM) aspirates collected from 10 patients by density gradient centrifugation and seeded to pre-drugged 96-well plates at 100,000 cells/well. The drugs were tested in a 10,000-fold concentration range and included standard chemotherapy agents (cytarabineandidarubicin), corticoid steroid dexamethasone,rapalogtemosirolimus, PI3K/mTORinhibitoromipalisib, JAK1/2 inhibitorruxolitinib,Srckinase inhibitordasatiniband Bcl-2 inhibitorvenetoclax. The cells were incubated with the drugs for 3 days in RPMI medium supplemented with conditioned medium from the human BM stromal cell line HS-5. The cells were stained using six different antibodies to identify blasts (CD45+, CD34+/CD33+, CD123+), LSC (CD45+, CD34+, CD38-, CD96+), healthy stem cells (HSC) (CD45+, CD34+ CD38-, CD96-), normal BM cells (CD45+, CD34-) and lymphocytes (CD45+ high, CD34-/CD33-, SSH low). We usedAnnexinV and 7-AAD to detect and remove dead and apoptotic cells. The stained cells were measured within the 96-well plates using theiQueScreener PLUS instrument (Intellicyt) in 20 minutes and at least 50,000 events acquired per well. Live cell numbers for different cell populations were calculated and dose response curves generated for each population and drug. For comparison, the viability of the samples was also assessed using theCellTiterGlo(CTG) assay. Results Assay set up and plate reading were accomplished within a relatively short time (staining 1 h, plate reading 20 min) with more than 5 million cell events acquired from each plate. Dose response curves generated from the live cell counts of the FC assay and viability readouts of the CTG assay were highly similar for cytotoxic drugs.(Fig. 1A).However, for targeted therapies, CTG overestimated the effect of JAK andmTORinhibitors by approximately 20% compared to the FC readouts (Fig. 1B). High variation in drug responses was observed between patient samples indicating patient and sample heterogeneity. In addition, cell populations within the same patient samples showed very different responses to the tested drugs. For example lymphocytes were sensitive tovenetoclax, but unresponsive to the other tested drugs. In contrast, blast cells were sensitive to most drugs and especially tovenetoclaxandruxolitinibwhen compared to other cell populations, suggesting that these drugs are particularly effective against this rapidly proliferating cell population.(Fig. 1C).Interestingly,ruxolitinibwas also effective at targeting LSCs, although HSCs were equally sensitive to this drug. Conclusion By applying a high-throughput FC based method, we could easily assess the effects of several drugs on AML patient samples and distinguish the functional impact on different cell populations. The method differentiated leukemic and healthy stem cells and identified drugs that could target LSC, which are believed to be a main cause of relapses in AML. Interestingly, JAK1/2 inhibitorruxolitinib, approved for the treatment ofmyelofibrosisand polycythemiavera, was effective at targeting AML blasts and LSC. In addition, this method accounts for inter- and intra-patient variability, and may be useful for a precision medicine based approach to identify optimal, patient-specific treatment strategies. Figure 1 Figure 1. Disclosures Heckman: Celgene: Research Funding; Pfizer: Research Funding.

Immunophenotypic Analysis of Myeloma Precursors: Antigens for Therapeutic Targeting

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. SCI-5-SCI-5
Author(s):  
Martin Perez-Andres ◽  
Bruno Paiva ◽  
Leandro Thiago ◽  
Nico A Bos ◽  
Dirk Hose ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Tumor Cells ◽  
Research Funding ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Ex Vivo ◽  
Multidrug Resistant

Abstract Abstract SCI-5 Multiple myeloma (MM) is a malignant disorder characterized by the (mono)clonal expansion of terminally-differentiated plasma cells (M-PC) in the bone marrow (BM) that produce and secrete a monoclonal immunoglobulin (Ig), detectable in the serum and/or urine. Infiltration by the expanded M-PC is easily identified in the involved tissues, through conventional morphology and immunophenotyping. However, the possibility exists that rather than M-PC, a less differentiated B-cell that represents a minor fraction of all tumor cells and retains self-renewal properties, is responsible for the outgrowth of the more differentiated M-PC compartment. In B-cell disorders, the idiotypic Ig produced by tumor cells and defined by its CDR3 sequence, acts as a genetic fingerprint for clonally-related B-cells. In MM, the specificity of the idiotype is further enhanced through modification of V genes by somatic hypermutation (SHM) at the germinal center (GC), since M-PC display extensively mutated VH genes which are stable throughout the disease. This suggests that in MM, malignant transformation could occur in a post-GC B-cell. Based on the CDR3 sequences of the Ig genes of M-PC, preliminary studies have identified tumor-associated circulating peripheral blood (PB) CD19+ B-cells, whose malignant/clonogenic potential remained to be demonstrated. More recently, the Matsui group has reported that while in MM cell lines both CD138− and CD138+ cells retain clonogenic capacity after in vitro serial plating clonogenic assays, in primary MM samples, such (ex vivo and in vivo) ability would be restricted to the CD34−/CD138− compartment. Of note, the clonogenic growth of these later cells significantly decreased after depletion by CD19, CD22, CD20 and CD45 antibodies, and it was associated with an in vitro multidrug-resistant functional phenotype (restricted to CD19+/CD27+, CD138− cells but not CD138+ cells) and the Hedgehog (Hh) stem cell-associated signaling pathway. These results point out the potential existence of a CD19+, CD20+, CD138− pre-PC compartment responsible for the expansion of M-PC in MM. In turn, evidence also exists in both the SCID-Hu model and in Rituximab treated MM patients, which suggests that plasmablasts/PC -but not pre-plasmablasts-, could act as MM “stem” cells, the precise characteristics of such cells remaining to be precisely defined. Alternatively, it could also be possible that both cell cellular components coexist and are relevant to MM progression through appropriate interaction with the BM stroma. Independently of all the above, trafficking of such cells through PB to BM niches could also play a key role in the spread of the tumor and its malignant behavior. In this regard, we recently confirmed that a relatively high percentage of MM patients (and a substantial fraction of all MGUS cases) show circulating PB PC with i) tumor-related clonal VH gene rearrangements and ii) an aberrant immunophenotypic profile which largely overlaps with that of BM M-PC from the same subjects; the only minor differences consisted of a significantly lower expression of CD38 and CD138, smaller size and internal complexity, features that indicate a slightly more immature plasmablastic/PC profile. Noteworthy, this was the only PB B-cell compartment for which clonally-related B-cells were detected with a sensitivity of <1 cell/50μ L in all cases investigated. In summary, accumulating evidence suggest the existence of a clonal hierarchy in MM but uncertainties remain as regards the precise immunophenotypic features of those cells responsible for tumor growth in primary patient samples, that could be of help in developing new targeted therapies. Disclosures: Sonneveld: Millennium: Consultancy; Celgene: Consultancy. Orfao:Becton/Dickinson Biosciences Europe: Patents & Royalties, Research Funding; Cytognos SL: Patents & Royalties; Alexion: Membership on an entity's Board of Directors or advisory committees; Vivia Biotech: Research Funding; Mundipharma: Research Funding.

Phospho-Specific Flow Cytometry of Fixed Whole Blood During AML Clinical Trials to Monitor In Vivo FLT3 Inhibition in Leukemic Blasts,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3508-3508
Author(s):  
Alexander E Perl ◽  
Grace R Jeschke ◽  
Takashi Sato ◽  
Shiro Akinaga ◽  
Niranjan S. Rao ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Flow Cytometry ◽  
Whole Blood ◽  
Peripheral Blood ◽  
Initial Dose ◽  
Research Funding ◽  
Ex Vivo ◽  
Blood Samples ◽  
Flt3 Inhibitors

Abstract Abstract 3508 Although first-generation FLT3 inhibitors may have had limited anti-leukemic effects due to suboptimal target inhibition, newer drugs such as AC220 and KW-2449 have substantially greater in vitro potency and bioavailability. Ex vivo assays such as the plasma inhibition assay (PIA) are useful to estimate free drug bioavailability, but direct confirmation of biochemical FLT3 inhibition in leukemic blasts in vivo has proven more challenging to employ systematically for drug development. Here we report the development of a fixed whole blood intracellular flow cytometry platform to measure real-time signal inhibition during a clinical trial of the second-generation FLT3 inhibitor KW-2449. Methods: Anticoagulated blood samples were aliquoted into FACS tubes within four hours of collection; a subset was exposed to signaling inhibitors (KW-2449, rapamycin × 30 min.) or activators (phorbol ester/PMA or FLT3 ligand/FL × 10 min.) to establish dynamic controls. Following incubation, samples were formaldehyde-fixed, red cells were lysed with the permeabilizing agent triton X-100, and specimens were stored at −20C in glycerol medium. Subjects' samples from all time points were simultaneously thawed, denatured with ice-cold methanol, and stained with a single cocktail of antibodies. Blasts were identified by CD45 and side scatter (SSC) and confirmed by multiple surface markers (CD33, CD34, CD117, HLA-DR, etc.). Positive gates for phospho-proteins were created by comparing blasts in stimulated and unstimulated conditions and/or autofluorescence (FMO) controls. Results: Despite adequate controls, flow demonstrated limited changes in FLT3-ITD+ blasts' pSTAT5 signal following either FL stimulation or ex vivo KW-2449 treatment of these peripheral blood primary samples. This contrasted with the FLT3-ITD+ cell line Molm14, in which FLT3 inhibition reduced pSTAT5. However, the PI3K/AKT/mTOR downstream target ribosomal protein S6 (S6) was consistently observed to be constitutively phosphorylated in both Molm14 cells and peripheral blood FLT3-ITD+ AML blasts. pS6 in all FLT3-ITD+ samples markedly augmented with ex vivo FL, and decreased following ex vivo KW-2449 treatment. We therefore serially monitored S6 phosphorylation during therapy on a phase 1/2 trial of KW-2449. In this clinical trial, subjects were treated with KW-2449 every 6–8 hours, due to the drug's relatively short half life. 10 subjects (9 FLT3-ITD+, 1 FLT3-WT) provided serial blood samples for analysis. All FLT3-ITD+ subjects had blasts identifiable by morphology and immunophenotype. Samples with as few as 500 blasts/uL were informative for pS6. In all cases, blasts showed dynamic changes in pS6 in response to ex vivo FL. As previously described using intracellular flow cytometry, pS6 in primary AML samples was heterogeneous, and, at basal state, frequently only demonstrable in a subset of blasts. We observed constitutive S6 phosphorylation in 8/9 subjects' leukemic cells. The mean percentage of blasts with constitutive pS6 was 21% (median 7%, range 5–70%). To directly quantify FLT3 kinase inhibition in vivo, we serially monitored pS6 in blasts by flow prior to and following their initial oral KW-2449 dose. In 8/8 patients with baseline constitutive S6 phosphorylation, blood obtained two hours following the initial dose showed marked reduction in the percentage of pS6+ blasts to a mean of 3.8% (median 1.3% range 0.1 to 20%). This reflected an 83% mean reduction in the percentage of pS6+ blasts. PIA was performed in 8/9 of FLT3-ITD+ subjects and confirmed that potent FLT3-inhibitory concentrations were present 2 hours after a single dose of KW-2449 (mean reduction from baseline of 79% for pFLT3 and 88% for pSTAT5). Two subjects' samples were followed serially by flow cytometry throughout the dosing interval. One showed sustained inhibition (consistent with concurrent PIA), while in the other, pS6 returned to baseline within 4–6 hours of the initial dose (concurrent PIA not done). Summary: We confirm that PI3K/AKT/mTOR is a major downstream pathway of FLT3 signaling in primary AML samples. We further demonstrate the feasibility of intracellular flow cytometry for S6 phosphorylation to monitor the biochemical efficacy of FLT3 inhibitors in patients. Studies are underway to correlate biochemical FLT3 inhibition by flow cytometry with clinical response/resistance to KW-2449 and other FLT3 inhibitors. Disclosures: Sato: Kyowa Hakko Kirin Co., LTD: Employment. Akinaga:Kyowa Hakko Kirin Co., LTD: Employment. Rao:Kyowa Hakko Kirin Co., LTD: Employment. Levis:Kyowa Hakko Kirin Co., LTD: Research Funding; Ambit Biosciences: Consultancy. Carroll:Kyowa Hakko Kirin Co., LTD: Research Funding.

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