SAN DIEGO — CD19-directed chimeric antigen receptor (CAR) T-cell therapy, which has transformed the treatment landscape for B-cell malignancies, is now showing great promise in at least three distinct autoantibody-dependent autoimmune diseases.
A single infusion of autologous CD19-directed CAR T-cell therapy led to persistent, drug-free remission in 15 patients with life-threatening systemic lupus erythematosus, idiopathic inflammatory myositis, or systemic sclerosis, according to research presented at the American Society of Hematology (ASH) annual meeting.
The responses persisted at 15 months median follow-up, with all patients achieving complete remission, reported Fabian Mueller, MD, of the Bavarian Cancer Research Center and Friedrich-Alexander University of Erlangen-Nuremberg, Bavaria, Germany.
The CAR T-cell treatment appears to provide an "entire reset of B cells," possibly even a cure, for these 15 patients who had run out of treatment options and had short life expectancies, Mueller said. "It's impressive that we have treated these patients."
Some of the cases have been described previously — including in Annals of the Rheumatic Diseases earlier this year, Nature Medicine in 2022, and the New England Journal of Medicine in 2021.
Now with substantially longer follow-up, the investigators have gained a greater understanding of "the B-cell biology behind our treatment," Mueller said. However, "we need longer follow-up to establish how effective the treatment is going to be in the long run."
All 15 patients included in the analysis were heavily pretreated and had multi-organ involvement. Prior to CAR T-cell therapy, patients had a median disease duration of 3 years, ranging from 1 to as many as 20 years, and had failed a median of five previous treatments. Patients were young — a median age of 36 years — which is much younger than most oncology patients who undergo CAR T-cell therapy, Mueller said.
The 15 patients underwent typical lymphodepletion and were apheresed and treated with a single infusion of 1x106 CD19 CAR T cells per kg of body weight — an established safe dose used in a phase 1 trial of B cell malignancies.
The CAR T cells, manufactured in-house, expanded rapidly, peaking around day 9. B cells disappeared within 7 days and began to reoccur in peripheral blood in all patients between 60 and 180 days. However, no disease flares occurred, Mueller said.
After 3 months, eight patients with systemic lupus erythematosus showed no sign of disease activity and dramatic improvement in symptoms. Three patients with idiopathic inflammatory myositis experienced major improvements in symptoms and normalization of creatinine kinase levels, the most clinically relevant marker for muscle inflammation. And three of four patients with systemic sclerosis demonstrated major improvements in symptoms and no new disease activity. These responses lasted for a median of 15 months, and all patients stopped taking immunosuppressive drugs.
Patients also tolerated the CAR T-cell treatment well, especially compared with the adverse event profile in oncology patients. Only low-grade inflammatory CAR T-related side effects occurred, and few patients required support for B-cell-derived immune deficiency.
However, infectious complications occurred in 14 patients, including urinary tract and respiratory infections, over the 12-month follow-up. One patient was hospitalized for severe pneumonia a few weeks after CAR T therapy, and two patients experienced herpes zoster reactivations, including one at 6 months and one at 12 months following treatment.
During a press briefing at the ASH conference, Mueller addressed the "critical question" of patient selection for CAR T-cell therapy, especially in light of the recently announced US Food and Drug Administration (FDA) investigation exploring whether CAR T cells can cause secondary blood cancers.
Although the T-cell malignancy risk complicates matters, CAR T cells appear to behave differently in patients with autoimmune diseases than those with cancer, he said.
"We don't understand the biology" related to the malignancy risk yet, Mueller said, but the benefit for end-of-life patients with no other treatment option likely outweighs the risk. That risk-benefit assessment, however, is more uncertain for those with less severe autoimmune diseases.
For now, it's important to conduct individual assessments and inform patients about the risk, Mueller said.
Mueller disclosed relationships with BMS, AstraZeneca, Gilead, Janssen, Miltenyi Biomedicine, Novartis, Incyte, Abbvie, Sobi, and BeiGene.
Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape, MDedge, and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at sworcester@mdedge.com or on Twitter: @SW_MedReporter.
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