The analysis also showed the value of next-generation sequencing (NGS). “As we think about utilizing CAR T therapy as a bridge to transplant, we wanted to study the depth of CAR T–induced remission by next-gen sequencing,” Dr. Shalabi said.
Eight patients on the CD22 CAR trial had MRD analyses based on both flow cytometry and NGS. According to flow cytometry, all eight were MRD negative by 1 month; however, according to NGS, two did have detectable disease, which decreased with time. “Next-gen sequencing can identify earlier time points for relapse or ongoing remission” than flow cytometry can, she said.
An additional finding was that two-thirds of the patients who received the CD19/CD28z CAR T cells had no detectable CAR T cells when the pre-HCT conditioning regimen was initiated, said Dr. Shalabi. “CAR persistence – or lack thereof – didn’t impact post-HCT outcomes,” she said, adding that shorter-acting CAR T cells may actually be preferable when HCT is readily available as an option.
“The impact of CAR persistence peritransplant requires further analysis,” Dr. Shalabi said. It’s possible, though, that “consolidative HCT following CAR may synergistically improve event-free and overall survival for this high-risk population.”