Using chimeric antigen receptor T-cell (CAR-T) therapy in patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) frequently leads to neutropenia,1 which in turn increases the risk of serious and life-threatening infections.1,2 Physicians may attempt to protect patients from such infections by administering granulocyte colony-stimulating factor (G-CSF) therapy to those with very low neutrophil counts following CAR-T infusion.

A recent study examined whether administering G-CSF in this context worsens toxicities, and authors of the study concluded that is does not.3 The treatment also appeared to reduce hospital stay, though there were no significant differences in neutropenia duration or infection rates between patients who were treated with G-CSF and those who were not.

Despite the fact that no statistically significant differences in neutropenia and infections were observed between patients in these groups, the patients who received G-CSF were older and began treatment with deeper neutropenia, lead study author Eugenio Galli, MD, of the Catholic University of the Sacred Heart in Rome, Italy, wrote in an email to Cancer Therapy Advisor. Because of the deeper neutropenia among patients in the G-CSF group around the onset of treatment, these patients might have had a higher risk of infections compared with patients in the no–G-CSF group. But considering that the infection rates following G-CSF administration were similar across the 2 groups, it is possible that the treatment helped to lower that increased risk in the G-CSF group, Dr Galli said.

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Dr Galli noted that the main goal of the study was to determine whether administering G-CSF would lead to a potential worsening of toxicities, which did not occur.

The authors of the study noticed that patients at their institution who were treated with CAR-T tended to experience long and severe neutropenia, so they chose to treat patients with prophylactic G-CSF from day 5 after CAR-T infusion if grade 4 neutropenia occurred.

In their study, the researchers looked at 70 patients with R/R DLBCL who had been treated with commercialized anti-CD19 CAR-T tisagenlecleucel (tisa-cel) or axicabtagene ciloleucel (axi-cel). The patients were treated at a single center and were not part of a clinical trial.

Of all patients, 42 (60%) received prophylactic G-CSF and 28 (40%) did not receive G-CSF. The patients in the G-CSF group were older than those in the other group (63 vs 50 years, P =.002), and had lower neutrophil count at day 0 (830 vs 1565/mm3, P =.002) and at day 5 (205 vs 590/mm3, P =.001).

The researchers examined how long the patients were hospitalized, how long their severe neutropenia lasted, and whether they experienced infections in the first 30 days following CAR-T reinfusion. The investigators also examined the presence and severity of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and measured overall survival and progression-free survival.

In the G-CSF group, median duration of hospitalization was shorter (17.5 days) compared with the other cohort (20 days).

For grade 3 to grade 4 neutropenia, median duration was 8 days (interquartile range [IQR], 5–10), and median duration of grade 4 neutropenia was 6 days (IQR, 3–8), and there was no difference between the G-CSF and no–G-CSF group. The researchers also found no difference between the groups in terms of risk of late-onset neutropenia.