Cytopenia associated with CAR T-cell therapy

CAR T-cell therapies have shown efficacy across a range of hematologic and solid tumors, are standard of care for certain types of lymphoma. As with other therapies, patients may report CAR T-cell treatment-related adverse events (AE). Cytopenia has been reported following lymphodepletion and CAR T-cell infusion with axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tis-cel).^1-3 During the 2^nd European CAR T Meeting, Sitges, ES session dedicated to the management of the side effects, Marion Subklewe, from the Ludwig Maximilian University of Munich, DE, discussed cytopenia in patients who received CAR T- cell therapy.⁴ This article summarizes the key messages from the presentation.

Marion Subklewe started the presentation by describing the grading of cytopenia by Common Terminology Criteria for Adverse Events (CTCAE) presented in Table 1.

Table 1. Grading of cytopenia according to the CTCAE version 3.0 (values per mm³ unless otherwise stated)⁴

N/A, not available *transfusion indicated
	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5
Anemia	> 10 g/dL	> 8 g/dL	< 8 g/dL*	Life-threatening	Death
Neutropenia	> 1500	> 1000	> 500	< 500	N/A
Thrombocytopenia	> 75000	> 50000	> 25000	< 25000	N/A
Lymphocytes	> 800	> 500	> 200	< 200	N/A
CD4 lymphocytes	> 500	> 200	> 50	< 50

She then followed with an overview of the CAR-T clinical trials in lymphoma and multiple myeloma (MM) (Table 2).

Table 2. Overview of clinical trials evaluating CAR T-cell therapies in lymphoma and MM^1,4-7

ALC, absolute lymphocyte count; ANC, absolute neutrophil count; axi-cel, axicabtagene ciloleucel; benda, bendamustine; cy, cyclophosphamide; DLBCL, diffuse large B-cell lymphoma; HGBCL, high grade B-cell lymphoma (double/triple hit lymphomas); FL3B, follicular lymphoma Grade 3B; flu, fludarabine; HSCT, hematopoietic stem cell transplant; MM, multiple myeloma; liso-cel, lisocabtagene maraleucel; NR, Not reported; PMBCL, primary mediastinal B-cell lymphoma; PTL, platelet count; R/R relapsed or refractory; tCLL, transformed chronic lymphocytic leukemia, tis-cel, tisagenlecleucel; tFL, transformed follicular lymphoma; tMZL, marginal zone lymphoma *pediatric and young adult patients
	JULIET1,4 (N = 111)	ZUMA4 (N = 108)	TRANSCEND4-6 (N = 269)	EVOLVE4,7,8 (N = 44)
CAR T-cell therapy	tis-cel	axi-cel	liso-cel	JCARH125
NCT number	NCT02445248	NCT02348216	NCT02631044	NCT03430011
Disease area	R/R DLBCL	R/R DLBCL PMBCL tFL HGBCL	DLBCL PBMCL tFL tCLL tMZL MCL FL3B HGBCL	R/R MM
Median age, years HGBCL, % Refractory to last therapy, % ≥ 3 prior therapies, % Prior HSCT, %	56 (22–76) 27 55   52 49	58 (23–76) NR 74   76 NR	63 (18–86) 13 67   26 35	62 (36–79) 100 100   100 NR
Blood count threshold	ANC < 1000/ul PLT < 50000 g/L	ANC < 1000/ul PTL < 75000 g/L ALC < 1000/ul	No threshold for blood count	No threshold for blood count
Lymphodepletion	Flu 25 mg/m2 + Cy 250 mg/m2 for 3 days or benda 90 mg/m2 for 2 days	Flu 30 mg/m2 + Cy 500 mg/m2 for 3 days	Flu 30 mg/m2 + Cy 300 mg/m2 for 3 days	Flu 30 mg/m2 + Cy 300 mg/m2 for 3 days

Cytopenia (most frequently neutropenia) is the most common AE, seen in patients across different hematological tumors who underwent lymphodepletion and infusion with any CAR T-cell therapy

• Early cytopenia (> 10 days) occurred in < 80% of patients
• Late cytopenia (> 21–28 days) Grade 3/4 occurred in 30–40% of patients
• Prolonged cytopenia (> 90 days) occurred in 8–18% of patients

In the ZUMA-1 trial, cytopenia was the most frequent AE, reported in 93% of patients:

• Neutropenia was the most common form of any-grade cytopenia, experienced by 86% of patients vs thrombocytopenia 62% of patients, and anemia 68% of patients
• Neutropenia was also the most common Grade ≥ 3 cytopenia, 80% vs40% and 45%, respectively
• There were no significant differences in the incidence of cytopenia between patients older and younger than 65 years

Early and late cytopenia⁴

• In the JULIET trial, 44% of patients had any-grade cytopenia on Day 28, including 32% with Grade ≥ 3
• The incidence of late cytopenia in ZUMA-1, TRANSCEND and EVOLVE is presented in Table 3

Table 3. Incidence of late cytopenia with axi-cel, liso-cel, and JCARH125*^{, 4}

*cytopenia present on Day 30
	ZUMA-1 (N = 108)	TRANSCEND (N = 269)	EVOLVE (N = 44)
Neutropenia, n (%) All Grade Grade ≥ 3	39 (36) 28 (26)	169 (63) 161 (60)	NA 38 (86)
Anemia, n (%) All Grade Grade ≥ 3	31 (29) 11 (10)	129 (48) 101 (38)	NA 22 (50)
Thrombocytopenia, n (%) All Grade Grade ≥ 3	44 (41) 26 (24)	84 (31) 72 (27)	NA 19 (43)

Prolonged cytopenia⁴

In JULIET trial, prolonged cytopenia, defined as Grade 3/4 cytopenia not resolved to Grade ≤ 2 by Day 28, was reported in

• 8% of patients (16.7% of patients responding to treatment) had neutropenia at 6 months; all cases resolved by 9 months
• 7% of all patients (26.2% of responding patients) had thrombocytopenia at 6 months; 7.2% of cases remained unresolved at 9 months; all cases resolved by 12 months
• 1% of all patients (36.4% of responding patients) had lymphocytopenia at 6 and 9 months, with 31.6% of cases unresolved at 12 months
• There were no cases of unresolved anemia reported between 6 and 12 months

In the ZUMA trial

• On Day > 90, 34% of patients experienced cytopenia of any grade, including 17% with Grade ≥ 3

• • Neutropenia in 19% and 11% of patients, respectively
  • Thrombocytopenia in 18% and 7% of patients, respectively
  • Anemia in 18% and 3% of patients, respectively

• Incidence of cytopenia at 1- and 2-years after infusion are described in Table 4

Table 4. Prolonged cytopenia at 1 and 2 years⁴

ALC, absolute lymphocyte count; ANC, absolute neutrophil count; HGB, hemoglobulin count; PLT, platelet count
Treatment-emergent cytopenia	At 1 year	At 2 years
ANC/HGB/PLT < Grade 3, %	75	85
ALC (> 1x 109/L), %	80	100
CD4 (> 200 cells/mm3), %	63	86
CD8 (> 82 cells/mm3), %	100	100
CD56 (> 0 cells/mm3), %	100	100

Infectious complications after CAR T-cell therapy⁴

Patients on CAR T-cell therapies are at risk of infections and the presence of cytopenia can further increase susceptibility and reduce the ability to fight pathogens.

ZUMA-1

• Infections of any grade occurred in 38% of patients, including 23% Grade ≥ 3
• Viral in 16% and 4% of patients, respectively
• Bacterial in 13% and 9% of patients, respectively
• Fungal in 5% and 0%, respectively
• Unspecified pathogen 26% and 16% of patients, respectively
• Grade ≥ 3 lung infections occurred in 12/108 (11%) patients

TRANSCEND

• Infections Grade ≥ 3 occurred in 12% of patients
  • Viral in 1% of cases
  • Bacterial in 4% of cases
  • Fungal in 1% of cases
  • Unspecified pathogen in 8% of cases

Infectious complications after anti-CD19 CAR T-cell therapy at Fred Hutchinson Cancer Research Center, Seattle, US

In total 133 patients were analyzed for the incidence of infection in the first 100 days post CAR-T (n = 62 with lymphoma, n = 24 with CLL, and n = 47 with acute lymphoblastic leukemia).

• Patients received antimicrobial prophylaxis
  • Levofloxacin 750 mg/day
  • Fluconazole 400 mg/day while the ANC was < 500 G/L
  • Acyclovir 800 g/day or valacyclovir 500 mg twice a day (until > 3 months after CAR T-cell infusion)
  • Trimethoprim 160 mg or sulfamethoxazole 800 mg twice a day for 2 days a week starting after neutrophil recovery till > 3 months after infusion
  • Granulocyte-colony stimulating factor (G-CSF) after lymphodepletion if the neutrophil count was < 500 cells
• Within 28 days after CAR T-cell infusion, 43 infections were recorded in 30 patients (23%), including:
  • Bacterial infections 17%
  • Viral infections 9%
  • Fungal infections 4%
  • Fatal or life-threatening infection in 4%
• Median time of the first infection was six days after infusion

Causes of cytopenia and role of prophylaxis⁴

• Early cytopenia was an AE after lymphodepleting chemotherapy with fludarabine, cyclophosphamide and mitoxantrone (FCM) and rituximab-FCM
• Late cytopenia was associated with inflammation and was more frequent in patients with Grade ≥ 3 cytokine release syndrome (CRS) and within one year after HSCT

Infectious prophylaxis at Ludwig Maximilian University of Munich Hospital

• Recommend influenza vaccination of patients and family members
• Acyclovir 400 mg 3x daily and cotrimoxazol 160 mg/trimethoprim 800 mg twice a day, two days a week, for 6 months following CAR T-cell infusion and until CD4 cell count is > 200 cells/ul
• Antifungal agents should be considered for high-risk patients
• G-CSF should be considered in patients after CRS with > 7 days of neutropenia
• Empiric antibiotics should be considered upon the onset of fever
• Patients, family, and physicians should be educated about late cytopenia and risk of infection

Conclusion

CART-cell therapies are becoming established in clinical practice, increasing the treatment options available to patients with refractory or relapsed disease. As with many treatment regiments, CAR-Ts are associated with an increased risk of cytopenia and higher susceptibility to infections. However, clinical benefits outweigh the risks, which can be reduced with appropriate prophylaxis.