CHICAGO – A bispecific anti-CD19, anti-CD20 chimeric antigen receptor (CAR) T cell approach is safe and produced complete responses in the majority of patients with relapsed or refractory non-Hodgkin lymphoma in a phase 1 study, an investigator reported.
Eleven of 17 assessable patients had a response to treatment with the bispecific lentiviral CAR T cell (LV20.19CAR) at day 28, and of those 11 patients, 9 had complete responses, all of which are ongoing, said Nirav Niranjan Shah, MD, of the Medical College of Wisconsin in Milwaukee.
“To date, there’s no dose-limiting toxicity, no ICU-level care, no deaths attributed to treatment, no grade 3 to 4 cytokine release syndrome, and only two patients had reversible grade 3 neurotoxicity,” Dr. Shah said at the annual meeting of the American Society of Clinical Oncology.
Patients who did relapse or progress on treatment maintained CD19 or CD20 positivity, with no observed downregulation of target receptors, he reported in an oral abstract session.
Of note, the CAR T cells were produced locally at the point of care, with a 100% success rate and a set 14-day manufacturing time, he added.
Bispecific targeting of CD19 and CD20 is a new approach being investigated at a time when there are already two CD19-specific CAR T cell therapies approved for aggressive B-cell non-Hodgkin lymphomas, Dr. Shah told attendees.
“Despite the great promise of CD19 CAR T cell therapies, very quickly after the development of these therapies, we discovered mechanisms of resistance—specifically, the development of a CD19 negative relapse,” he said.
The hypothesis that targeting more than one B-cell antigen could potentially mitigate that effect stemmed from preclinical studies showing that targeting both CD19 and CD20 decreased downregulation of CD19 but not other B-cell antigens, he added.
In the present phase 1 study of the first-in-human, bispecific tandem CAR T cell against CD19 and CD20, patients have been treated at several dose levels, some with a split infusion over 2 days to evaluate safety, and some with a single infusion, Dr. Shah said.
A total of 17 patients have been treated with a lymphodepletion regimen followed by LV20.19CAR: 8 patients with diffuse large B-cell lymphoma, 6 with mantle cell lymphoma, 2 with chronic lymphocytic leukemia, and 1 with follicular lymphoma, according to the investigator. The median age of patients is 59 years, and patients had received at least 3 and up to 11 prior lines of therapy.
There have been no dose-limiting toxicities to date with dosing up to the target of 2.5 x 106 cells/kg, Dr. Shah reported, adding that there has been no grade 3-4 cytokine release syndrome and no grade 4 neurotoxicity. Grade 1-2 cytokine release syndrome has been seen in 11 patients, while grade 3 neurotoxicity occurred in 2 patients.
Fourteen of 17 patients had a response, including 11 complete responses and 3 partial responses. Eleven patients were treated at the target dose of 2.5 x 106 cells/kg, and of those, 9 had a complete response and 1 had a partial response (overall response rate, Dr. Shah said.
To date, all patients in complete response have remained in a complete response, with durations of response of 1 to 18 months.
Next, investigators plan to conduct phase 2 studies in more specific cohorts, including patients with mantle cell lymphoma, and patients who have relapsed after CD19 CAR T cell therapy, Dr. Shah said.
Dr. Shah reported disclosures related to Cidara Therapeutics, Exelixis, Geron, Oncosec, Incyte, Jazz Pharmaceuticals, Juno Therapeutics, Kite Pharma, and Miltenyi Biotec.
SOURCE: Shah NN et al. ASCO 2019. .
This article was updated on 7/8/2019