User login
HOUSTON – Cytokine release syndrome and neurotoxicity frequently occur with CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapies, but targetable factors for mitigating the risk and effects of these complications are emerging, according to Cameron Turtle, MBBS, PhD.
These factors include infused CAR T-cell dose, bone marrow disease burden, immune response, and the lymphodepletion regimen used, Dr. Turtle, of Fred Hutchinson Cancer Research Center, Seattle, said at the Transplantation & Cellular Therapies Meetings. This list is based on an analysis of several studies that included a total of 195 patients with B-cell malignancies who were treated with defined-composition CD19 CAR T cells.
In a 2016 study included in the analysis, for instance, Dr. Turtle and his colleagues found that CD19 CAR T cells administered to adults with B-cell acute lymphoblastic leukemia (B-ALL) after lymphodepletion chemotherapy were “remarkably potent.” Remission was achieved in 27 of 29 patients (J Clin Invest. 2016 Jun 1;126[6]:2123-38).
However, the study also established that high CAR T-cell doses and tumor burden increased the risk of severe cytokine release syndrome (CRS) and neurotoxicity, Dr. Turtle said at the meeting, held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At its meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy (ASTCT).
“Importantly, we identified serum biomarkers that allow testing of early intervention strategies in the patients who have the highest risk of toxicity,” he said.
Dr. Turtle explained that significantly higher peak interleuken-6 (IL-6) and interferon (IFN)-gamma levels were seen after CAR T-cell infusion in patients with high bone marrow tumor burden and in patients requiring treatment in an intensive care unit (ICU).
ICU care correlated with a higher percentage of bone marrow blasts before lymphodepletion chemotherapy, he added.
Elevations of serum C-reactive protein (CRP) and ferritin also correlated with bone marrow disease burden and with the occurrence of severe CRS requiring ICU care, he said, noting that ferritin and CRP levels declined after tocilizumab or corticosteroid therapy.
In addition, all patients in the study who developed neurotoxicity had evidence of CRS. Peak levels of IL-6, IFN-gamma, ferritin, and CRP were significantly higher in those who developed grade 3 or higher neurotoxicity. Further, serum IL-6 and IFN-gamma concentrations on day 1 after infusion were significantly higher in those who required ICU care and in those who subsequently developed grade 4 neurotoxicity than in patients who developed grade 3 neurotoxicity.
Multivariate analysis indicated that serum IL-6 concentration of more than 30 pg/mL on day 1 and the total number of CD19+ cells in bone marrow before therapy were independent predictors of subsequent development of grade 3 or higher neurotoxicity.
Notably, serum IL-6 of more than 30 pg/mL on day 1 identified all patients in the study who subsequently developed grade 4 or higher neurotoxicity, Dr. Turtle and his colleagues noted.
“The findings suggested that evaluation of serum IL-6 concentration early after CAR T-cell infusion might be useful for identifying patients at high risk of severe neurotoxicity and to evaluate early intervention approaches,” he said.
Neurotoxicity
In a 2017 study from Juliane Gust, MD, PhD, and her colleagues, bone marrow disease burden, lymphodepletion regimen, and CAR T-cell dose were found to be significantly associated with neurotoxicity during multivariate analysis (Cancer Discov. 2017 Dec;7[12]:1404-19).
Patients with severe neurotoxicity in that study demonstrated evidence of endothelial activation, including disseminated intravascular coagulation, capillary leak, and increased blood-brain barrier permeability – with the latter leading to a failure to protect the cerebrospinal fluid from high concentrations of systemic cytokines, including IFN-gamma. These high levels of cytokines may cause vascular pericyte activation and stress, Dr. Turtle explained.
Patients who subsequently developed grade 4 or higher neurotoxicity had higher pretreatment levels of endothelial activation biomarkers.
“Endothelial cells and pericytes contribute to the integrity of the blood-brain barrier; this suggests a potential role for IL-6 and vascular endothelial growth factor from pericytes to augment endothelial permeability,” Dr. Turtle said.
CRS
In another 2017 study, from Kevin A. Hay, MD, and his colleagues, similar factors were found to be associated with CRS (Blood. 2017 Nov 23;130[21]:2295-306).
Multivariable analysis identified high marrow tumor burden, lymphodepletion using cyclophosphamide and fludarabine, higher CAR T-cell dose, thrombocytopenia before lymphodepletion, and manufacturing of CAR T cells without selection of CD8+ central memory T cells as independent predictors of CRS.
Severe CRS was characterized by hemodynamic instability, capillary leak, and consumptive coagulopathy. As in the study by Dr. Gust and her colleagues, biomarkers of endothelial activation, including angiopoietin-2 and von Willebrand factor, were increased during severe CRS and before lymphodepletion in patients who subsequently developed CRS.
Potential modifications
The findings to date suggest that risk stratification, prophylaxis, early intervention and therapeutic intervention are among potential strategies for mitigating the risk of CD19-directed CAR T toxicity, Dr. Turtle said. Steroids, tocilizumab, siltuximab, anakinra, anti-GM-CSF, small molecules, plasma exchange, angiopoietin-1, and hypertransfusion are among candidates under consideration for such interventions, he noted.
Other approaches that have been tested in small studies, and which may reduce toxicity and improve the therapeutic index of CD19 CAR T-cell therapy for B-ALL, include split dosing and risk-adapted dosing.
“These approaches do appear to mitigate toxicity, but larger studies are needed to confirm that treatment efficacy is maintained,” Dr. Turtle said.
Toxicity prediction and early intervention to maintain the CAR T-cell dose while avoiding grade 4 or greater toxicities would be helpful and is within reach, he said, noting that the findings by Dr. Hay and his colleagues led to the development of “day-1 cytokine combination algorithms that predict grade 4-5 CRS and could direct preemptive intervention.”
One algorithm based on three cytokines had high sensitivity and specificity, but would require screening of all patients.
Early intervention in patients in whom toxicity is predicted has not been extensively evaluated in clinical studies, he said.
Dr. Hay and his colleagues did, however, develop a “classification tree model of early intervention strategies” using their findings.
A complicating factor in predicting risk and intervening is that each CAR T-cell product is associated with differing levels of toxicity risk. The varying rates of toxicity suggest that promising approaches for addressing CAR T toxicity require validation for each product with respect to cutpoints, efficacy, and maintenance of response, Dr. Turtle said.
“The findings to date are encouraging and show that potentially targetable factors for mitigating the toxicity of CAR T-cell therapy can be identified,” he said. “But clinical studies have yet to convincingly establish the best approach.”
Dr. Turtle has served on advisory boards for Juno/Celgene, Kite/Gilead, Novartis, Precision Biosciences, Eureka Therapeutics, Caribou Biosciences, Nektar Therapeutics, Humanigen, and Aptevo; has intellectual property rights licensed to Juno; has stock options with Precision Biosciences, Eureka Therapeutics, and Caribou Biosciences; and has received research funding from Juno and Nektar Therapeutics.
HOUSTON – Cytokine release syndrome and neurotoxicity frequently occur with CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapies, but targetable factors for mitigating the risk and effects of these complications are emerging, according to Cameron Turtle, MBBS, PhD.
These factors include infused CAR T-cell dose, bone marrow disease burden, immune response, and the lymphodepletion regimen used, Dr. Turtle, of Fred Hutchinson Cancer Research Center, Seattle, said at the Transplantation & Cellular Therapies Meetings. This list is based on an analysis of several studies that included a total of 195 patients with B-cell malignancies who were treated with defined-composition CD19 CAR T cells.
In a 2016 study included in the analysis, for instance, Dr. Turtle and his colleagues found that CD19 CAR T cells administered to adults with B-cell acute lymphoblastic leukemia (B-ALL) after lymphodepletion chemotherapy were “remarkably potent.” Remission was achieved in 27 of 29 patients (J Clin Invest. 2016 Jun 1;126[6]:2123-38).
However, the study also established that high CAR T-cell doses and tumor burden increased the risk of severe cytokine release syndrome (CRS) and neurotoxicity, Dr. Turtle said at the meeting, held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At its meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy (ASTCT).
“Importantly, we identified serum biomarkers that allow testing of early intervention strategies in the patients who have the highest risk of toxicity,” he said.
Dr. Turtle explained that significantly higher peak interleuken-6 (IL-6) and interferon (IFN)-gamma levels were seen after CAR T-cell infusion in patients with high bone marrow tumor burden and in patients requiring treatment in an intensive care unit (ICU).
ICU care correlated with a higher percentage of bone marrow blasts before lymphodepletion chemotherapy, he added.
Elevations of serum C-reactive protein (CRP) and ferritin also correlated with bone marrow disease burden and with the occurrence of severe CRS requiring ICU care, he said, noting that ferritin and CRP levels declined after tocilizumab or corticosteroid therapy.
In addition, all patients in the study who developed neurotoxicity had evidence of CRS. Peak levels of IL-6, IFN-gamma, ferritin, and CRP were significantly higher in those who developed grade 3 or higher neurotoxicity. Further, serum IL-6 and IFN-gamma concentrations on day 1 after infusion were significantly higher in those who required ICU care and in those who subsequently developed grade 4 neurotoxicity than in patients who developed grade 3 neurotoxicity.
Multivariate analysis indicated that serum IL-6 concentration of more than 30 pg/mL on day 1 and the total number of CD19+ cells in bone marrow before therapy were independent predictors of subsequent development of grade 3 or higher neurotoxicity.
Notably, serum IL-6 of more than 30 pg/mL on day 1 identified all patients in the study who subsequently developed grade 4 or higher neurotoxicity, Dr. Turtle and his colleagues noted.
“The findings suggested that evaluation of serum IL-6 concentration early after CAR T-cell infusion might be useful for identifying patients at high risk of severe neurotoxicity and to evaluate early intervention approaches,” he said.
Neurotoxicity
In a 2017 study from Juliane Gust, MD, PhD, and her colleagues, bone marrow disease burden, lymphodepletion regimen, and CAR T-cell dose were found to be significantly associated with neurotoxicity during multivariate analysis (Cancer Discov. 2017 Dec;7[12]:1404-19).
Patients with severe neurotoxicity in that study demonstrated evidence of endothelial activation, including disseminated intravascular coagulation, capillary leak, and increased blood-brain barrier permeability – with the latter leading to a failure to protect the cerebrospinal fluid from high concentrations of systemic cytokines, including IFN-gamma. These high levels of cytokines may cause vascular pericyte activation and stress, Dr. Turtle explained.
Patients who subsequently developed grade 4 or higher neurotoxicity had higher pretreatment levels of endothelial activation biomarkers.
“Endothelial cells and pericytes contribute to the integrity of the blood-brain barrier; this suggests a potential role for IL-6 and vascular endothelial growth factor from pericytes to augment endothelial permeability,” Dr. Turtle said.
CRS
In another 2017 study, from Kevin A. Hay, MD, and his colleagues, similar factors were found to be associated with CRS (Blood. 2017 Nov 23;130[21]:2295-306).
Multivariable analysis identified high marrow tumor burden, lymphodepletion using cyclophosphamide and fludarabine, higher CAR T-cell dose, thrombocytopenia before lymphodepletion, and manufacturing of CAR T cells without selection of CD8+ central memory T cells as independent predictors of CRS.
Severe CRS was characterized by hemodynamic instability, capillary leak, and consumptive coagulopathy. As in the study by Dr. Gust and her colleagues, biomarkers of endothelial activation, including angiopoietin-2 and von Willebrand factor, were increased during severe CRS and before lymphodepletion in patients who subsequently developed CRS.
Potential modifications
The findings to date suggest that risk stratification, prophylaxis, early intervention and therapeutic intervention are among potential strategies for mitigating the risk of CD19-directed CAR T toxicity, Dr. Turtle said. Steroids, tocilizumab, siltuximab, anakinra, anti-GM-CSF, small molecules, plasma exchange, angiopoietin-1, and hypertransfusion are among candidates under consideration for such interventions, he noted.
Other approaches that have been tested in small studies, and which may reduce toxicity and improve the therapeutic index of CD19 CAR T-cell therapy for B-ALL, include split dosing and risk-adapted dosing.
“These approaches do appear to mitigate toxicity, but larger studies are needed to confirm that treatment efficacy is maintained,” Dr. Turtle said.
Toxicity prediction and early intervention to maintain the CAR T-cell dose while avoiding grade 4 or greater toxicities would be helpful and is within reach, he said, noting that the findings by Dr. Hay and his colleagues led to the development of “day-1 cytokine combination algorithms that predict grade 4-5 CRS and could direct preemptive intervention.”
One algorithm based on three cytokines had high sensitivity and specificity, but would require screening of all patients.
Early intervention in patients in whom toxicity is predicted has not been extensively evaluated in clinical studies, he said.
Dr. Hay and his colleagues did, however, develop a “classification tree model of early intervention strategies” using their findings.
A complicating factor in predicting risk and intervening is that each CAR T-cell product is associated with differing levels of toxicity risk. The varying rates of toxicity suggest that promising approaches for addressing CAR T toxicity require validation for each product with respect to cutpoints, efficacy, and maintenance of response, Dr. Turtle said.
“The findings to date are encouraging and show that potentially targetable factors for mitigating the toxicity of CAR T-cell therapy can be identified,” he said. “But clinical studies have yet to convincingly establish the best approach.”
Dr. Turtle has served on advisory boards for Juno/Celgene, Kite/Gilead, Novartis, Precision Biosciences, Eureka Therapeutics, Caribou Biosciences, Nektar Therapeutics, Humanigen, and Aptevo; has intellectual property rights licensed to Juno; has stock options with Precision Biosciences, Eureka Therapeutics, and Caribou Biosciences; and has received research funding from Juno and Nektar Therapeutics.
HOUSTON – Cytokine release syndrome and neurotoxicity frequently occur with CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapies, but targetable factors for mitigating the risk and effects of these complications are emerging, according to Cameron Turtle, MBBS, PhD.
These factors include infused CAR T-cell dose, bone marrow disease burden, immune response, and the lymphodepletion regimen used, Dr. Turtle, of Fred Hutchinson Cancer Research Center, Seattle, said at the Transplantation & Cellular Therapies Meetings. This list is based on an analysis of several studies that included a total of 195 patients with B-cell malignancies who were treated with defined-composition CD19 CAR T cells.
In a 2016 study included in the analysis, for instance, Dr. Turtle and his colleagues found that CD19 CAR T cells administered to adults with B-cell acute lymphoblastic leukemia (B-ALL) after lymphodepletion chemotherapy were “remarkably potent.” Remission was achieved in 27 of 29 patients (J Clin Invest. 2016 Jun 1;126[6]:2123-38).
However, the study also established that high CAR T-cell doses and tumor burden increased the risk of severe cytokine release syndrome (CRS) and neurotoxicity, Dr. Turtle said at the meeting, held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At its meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy (ASTCT).
“Importantly, we identified serum biomarkers that allow testing of early intervention strategies in the patients who have the highest risk of toxicity,” he said.
Dr. Turtle explained that significantly higher peak interleuken-6 (IL-6) and interferon (IFN)-gamma levels were seen after CAR T-cell infusion in patients with high bone marrow tumor burden and in patients requiring treatment in an intensive care unit (ICU).
ICU care correlated with a higher percentage of bone marrow blasts before lymphodepletion chemotherapy, he added.
Elevations of serum C-reactive protein (CRP) and ferritin also correlated with bone marrow disease burden and with the occurrence of severe CRS requiring ICU care, he said, noting that ferritin and CRP levels declined after tocilizumab or corticosteroid therapy.
In addition, all patients in the study who developed neurotoxicity had evidence of CRS. Peak levels of IL-6, IFN-gamma, ferritin, and CRP were significantly higher in those who developed grade 3 or higher neurotoxicity. Further, serum IL-6 and IFN-gamma concentrations on day 1 after infusion were significantly higher in those who required ICU care and in those who subsequently developed grade 4 neurotoxicity than in patients who developed grade 3 neurotoxicity.
Multivariate analysis indicated that serum IL-6 concentration of more than 30 pg/mL on day 1 and the total number of CD19+ cells in bone marrow before therapy were independent predictors of subsequent development of grade 3 or higher neurotoxicity.
Notably, serum IL-6 of more than 30 pg/mL on day 1 identified all patients in the study who subsequently developed grade 4 or higher neurotoxicity, Dr. Turtle and his colleagues noted.
“The findings suggested that evaluation of serum IL-6 concentration early after CAR T-cell infusion might be useful for identifying patients at high risk of severe neurotoxicity and to evaluate early intervention approaches,” he said.
Neurotoxicity
In a 2017 study from Juliane Gust, MD, PhD, and her colleagues, bone marrow disease burden, lymphodepletion regimen, and CAR T-cell dose were found to be significantly associated with neurotoxicity during multivariate analysis (Cancer Discov. 2017 Dec;7[12]:1404-19).
Patients with severe neurotoxicity in that study demonstrated evidence of endothelial activation, including disseminated intravascular coagulation, capillary leak, and increased blood-brain barrier permeability – with the latter leading to a failure to protect the cerebrospinal fluid from high concentrations of systemic cytokines, including IFN-gamma. These high levels of cytokines may cause vascular pericyte activation and stress, Dr. Turtle explained.
Patients who subsequently developed grade 4 or higher neurotoxicity had higher pretreatment levels of endothelial activation biomarkers.
“Endothelial cells and pericytes contribute to the integrity of the blood-brain barrier; this suggests a potential role for IL-6 and vascular endothelial growth factor from pericytes to augment endothelial permeability,” Dr. Turtle said.
CRS
In another 2017 study, from Kevin A. Hay, MD, and his colleagues, similar factors were found to be associated with CRS (Blood. 2017 Nov 23;130[21]:2295-306).
Multivariable analysis identified high marrow tumor burden, lymphodepletion using cyclophosphamide and fludarabine, higher CAR T-cell dose, thrombocytopenia before lymphodepletion, and manufacturing of CAR T cells without selection of CD8+ central memory T cells as independent predictors of CRS.
Severe CRS was characterized by hemodynamic instability, capillary leak, and consumptive coagulopathy. As in the study by Dr. Gust and her colleagues, biomarkers of endothelial activation, including angiopoietin-2 and von Willebrand factor, were increased during severe CRS and before lymphodepletion in patients who subsequently developed CRS.
Potential modifications
The findings to date suggest that risk stratification, prophylaxis, early intervention and therapeutic intervention are among potential strategies for mitigating the risk of CD19-directed CAR T toxicity, Dr. Turtle said. Steroids, tocilizumab, siltuximab, anakinra, anti-GM-CSF, small molecules, plasma exchange, angiopoietin-1, and hypertransfusion are among candidates under consideration for such interventions, he noted.
Other approaches that have been tested in small studies, and which may reduce toxicity and improve the therapeutic index of CD19 CAR T-cell therapy for B-ALL, include split dosing and risk-adapted dosing.
“These approaches do appear to mitigate toxicity, but larger studies are needed to confirm that treatment efficacy is maintained,” Dr. Turtle said.
Toxicity prediction and early intervention to maintain the CAR T-cell dose while avoiding grade 4 or greater toxicities would be helpful and is within reach, he said, noting that the findings by Dr. Hay and his colleagues led to the development of “day-1 cytokine combination algorithms that predict grade 4-5 CRS and could direct preemptive intervention.”
One algorithm based on three cytokines had high sensitivity and specificity, but would require screening of all patients.
Early intervention in patients in whom toxicity is predicted has not been extensively evaluated in clinical studies, he said.
Dr. Hay and his colleagues did, however, develop a “classification tree model of early intervention strategies” using their findings.
A complicating factor in predicting risk and intervening is that each CAR T-cell product is associated with differing levels of toxicity risk. The varying rates of toxicity suggest that promising approaches for addressing CAR T toxicity require validation for each product with respect to cutpoints, efficacy, and maintenance of response, Dr. Turtle said.
“The findings to date are encouraging and show that potentially targetable factors for mitigating the toxicity of CAR T-cell therapy can be identified,” he said. “But clinical studies have yet to convincingly establish the best approach.”
Dr. Turtle has served on advisory boards for Juno/Celgene, Kite/Gilead, Novartis, Precision Biosciences, Eureka Therapeutics, Caribou Biosciences, Nektar Therapeutics, Humanigen, and Aptevo; has intellectual property rights licensed to Juno; has stock options with Precision Biosciences, Eureka Therapeutics, and Caribou Biosciences; and has received research funding from Juno and Nektar Therapeutics.
REPORTING FROM TCT 2019
