, according to investigators in two separate studies.
Dr. Robert A. Brodsky
Meanwhile, responses to tisagenlecleucel appear to be even more durable with longer follow-up, according to preliminary results from two more CAR T-cell therapy studies slated for presentation at the annual meeting of the American Society of Hematology.
A fifth study will show that bone marrow transplant may effectively consolidate remission after CAR T-cell therapy, according to Robert A. Brodsky, MD, ASH secretary, who highlighted the studies during a media briefing.
The ibrutinib study (abstract 299) shows that administering this BTK inhibitor starting 2 weeks prior to leukapheresis and continuing until 3 months after JCAR014 could improve responses and may decrease the incidence of severe cytokine release syndrome in patients with relapsed or refractory chronic lymphocytic leukemia (CLL).
Of 16 patients in an ibrutinib cohort and 18 patients in a no-ibrutinib cohort, the proportion of responders was 88% and 56%, respectively, according to preliminary data reported in the abstract. Grade 3-5 cytokine release syndrome occurred in 5 of 19 patients in the no-ibrutinib cohort, and 0 of 17 patients in the ibrutinib cohort.
Those findings are “early and preliminary, but very exciting” for ibrutinib in combination with this CD-19 specific CAR T-cell therapy said Dr. Brodsky, director of the division of hematology at Johns Hopkins University in Baltimore.
Early results of the checkpoint inhibitor study (abstract 556) suggest that pembrolizumab or nivolumab may augment CD19-directed CAR T-cell therapy in patients with relapsed B-cell acute lymphoblastic leukemia (ALL).
In data to date, 14 patients with early CAR T-cell loss, partial response, or no response to CAR T-cell therapy received a PD-1 inhibitor.
“The idea was if you can give pembrolizumab, you can take the brakes off, and maybe you can reinitiate the immune attack,” Dr. Brodsky said. “Sure enough, they were able to see that in roughly half of the patients. So again, very small, preliminary data, but very exciting that it is safe to give checkpoint inhibitors with CAR T-cells and it may be efficacious at getting the immune response back.”
One of the two tisagenlecleucel updates (abstract 895) showed that in the ELIANA trial, which included pediatric and young adults patients with relapsed/refractory ALL, the probability of relapse-free survival at 18 months was 66%.
“These are some very fast-growing tumors and these are refractory resistant patients, so as we get further and further out, it’s more encouraging to see that there are durable responses,” Dr. Brodsky said.
In the other tisagenlecleucel update (abstract 1684), investigators showed sustained disease control in Juliet, the global trial including adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), with 40% of patients still in remission at 18 months, according to Dr. Brodsky.
One more report Dr. Brodsky highlighted (abstract 967) will look at long-term follow-up after administration of SCRI-CAR19v1, a CD19-specific CAR T-cell product. Preliminary data suggest a survival advantage when hematopoietic stem cell transplantation is done after CAR T-cell induced remission.
“This study is very small and it’s retrospective, but it suggests that bone marrow transplant is a good way to consolidate the remission after CAR T-cell therapy,” Dr. Brodsky said.