Team reports latest results of CTL019 in CLL

Five patients with CRS required anti-cytokine-directed therapy—tocilizumab (n=4) and/or steroids (n=3). Four patients required intensive care for complications related to CRS, such as hypotension and hypoxia. They remained in the intensive care unit for a median of 6 days (range, 1-9).

Concurrent with CRS were 6 neurologic events in 5 patients—grade 1/2 hallucinations, confusion, or delirium typically associated with high fevers, intensive care, or medication use. There was 1 case of grade 4 confusion that lasted 2 days and was attributed, at least partly, to CTL019.

There were 2 cases of tumor lysis syndrome. And 1 patient died in remission 21 months after CTL019 infusion, having developed overwhelming ecthyma gangrenosum from a pseudomonas wound infection from a skin biopsy site.

CTL019 durability

“Importantly, our tests of patients who experienced complete remissions showed that the modified cells remain in patients’ bodies for years after their infusions, with no sign of cancerous or normal B cells,” said study author Carl H. June, MD, of the University of Pennsylvania Perelman School of Medicine.

“This suggests that at least some of the CTL019 cells retain their ability to hunt for cancerous cells for long periods of time.”

A lab experiment using CAR T cells isolated from one of the first patients to receive CTL019 confirmed the potential for long-term function of these cells. At nearly 3 years after infusion, the patient’s CTL019 cells demonstrated immediate and specific reactivity against cells expressing CD19.

CTL019 development

The investigators did not identify demographic or disease-related factors, such as age or types of prior therapies, that could be used to predict response to CTL019. And there was no association between T-cell dose and patient response.

An ongoing dose-optimization study is exploring this relationship in greater detail. Further future areas of study may include strategies to combine CTL019 with immune checkpoint inhibitors or other therapies to stimulate T-cell recognition of tumor cells.

In addition to CLL, CTL019 is under investigation in patients with acute lymphoblastic leukemia, non-Hodgkin lymphoma, and myeloma. The product has breakthrough designation from the US Food and Drug Administration for acute lymphoblastic leukemia.