©ASCO/Rodney White 2018
McCormick Place during ASCO 2018
CHICAGO—Prior exposure to blinatumomab does not appear to affect the successful manufacture of KTE-C19 or its efficacy in patients with relapsed/refractory acute lymphoblastic leukemia (ALL), an investigator reported at the 2018 ASCO Annual Meeting.
The clinical benefit of KTE-C19, an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, was preserved regardless of whether patients were exposed to blinatumomab, said Bijal D. Shah, MD, of Moffitt Cancer Center in Tampa, Florida.
High rates of complete response and undetectable minimal residual disease (MRD) were independent of exposure to blinatumomab, a CD19/CD3 bispecific T-cell engager.
“We feel the results of these data support KTE-C19 as an effective option for adults with refractory leukemia, regardless of prior exposure to CD19-directed therapy,” Dr Shah reported at the meeting (abstract 7006*).
The current standard of care for adults with relapsed/refractory ALL includes blinatumomab, raising the question of whether prior exposure to this CD19-directed treatment could influence the manufacture or efficacy of KTE-C19.
Sara Cooley, MD, of Masonic Medical Center, University of Minnesota in Minneapolis, said results of this analysis suggest prior blinatumomab should not be a contraindication or concern in the context of KTE-C19.
“This remains to be shown with other CAR T-cell therapies,” she said in a presentation at ASCO on cellular therapy in leukemia.
The analysis by Dr Shah and co-investigators was based on ZUMA-3 (NCT02614066), a phase 1 study including adults with relapsed/refractory ALL who received KTE-C19 at doses of 0.5, 1, or 2 x 106 cells/kg.
They excluded patients in the highest dose cohort, who were required to be blinatumomab naïve, per protocol. That left 23 patients who received 0.5 or 1 x 106 cells/kg, of whom 11 had prior blinatumomab exposure and 12 did not.
Best overall response appeared to be independent of prior blinatumomab treatment, with a CR rate of 72% overall, and 63% and 80% for blinatumomab-exposed and blinatumomab-naïve patients, respectively.
The rate of undetectable MRD was likewise high at 88% in the prior blinatumomab group and 100% in the no-blinatumomab group.
Product characteristics did not vary according to blinatumomab exposure, though there was a trend toward a more differentiated phenotype in those patients who had received prior CD19-directed treatment, he said.
There were no significant differences between groups in the rate of grade 3 or greater cytokine release syndrome. Neurologic events were higher in the blinatumomab-naïve patients, though a higher percentage of those patients received the 1 x 106 cells/kg dose, Dr Shah reported.
Investigators also looked at CAR T levels by treatment.
“We cannot appreciate any significant differences between the blinatumomab-naïve and the blinatumomab-exposed groups,” Dr Shah told ASCO attendees.
The ZUMA-3 trial was sponsored by Kite, a Gilead Company.
*Data in the abstract differ from the presentation.