Is it time to consider chimeric antigen receptor (CAR) T-cell therapy for all relapsed/refractory diffuse large B-cell lymphoma patients? Maybe not, according to Andrew Zelenetz, MD, PhD.
CAR T-cell therapy has demonstrated activity in relapsed/refractory non-Hodgkin lymphoma (NHL), including diffuse large B-cell lymphoma (DLBCL), transformed indolent NHL, and mantle cell lymphoma, and can provide durable complete responses in a portion of patients with chemorefractory disease, Dr. Zelenetz, chair of the National Comprehensive Cancer Network Lymphoma Guidelines Panel and a specialist in lymphoma at Memorial Sloan Kettering Cancer Center in New York, said at the NCCN Hematologic Malignancies Annual Congress.
In chemosensitive patients, however, its role requires further examination, especially given findings from a recent analysis of patients from the Center for International Blood & Marrow Transplant Research (CIBMTR) registry showing comparable outcomes with high-dose chemotherapy and autologous stem cell rescue for patients with a positron emission testing–positive partial response (PR) after second-line chemotherapy, he said.
Of 249 patients who underwent a first autologous transplant for DLBCL between 2003 and 2018, received front-line rituximab chemotherapy, and had PET– or computed tomography–positive disease prior to transplant, 182 had early chemotherapy failure (within 12 months) and 67 had late chemotherapy failure (at 12 months or later) after therapy, according to findings from the study as reported at ASCO 2020.
The adjusted nonrelapse mortality rates in the early- and late-failure patients, respectively, were not significantly different at 7% and 3% at 1 year, and at 10% and 8% at 5 years. The corresponding progression/relapse rates were 41% and 35% at 1 year and 48% and 57% at 5 years; these were also not significantly different.
The adjusted progression-free survival (PFS) and overall survival (OS) in the groups at 5 years also did not differ significantly (PFS of 41% in both the early- and late-failure groups, and OS of 51% and 63%, respectively).
These outcomes are comparable to those seen with CAR T-cell therapy in refractory DLBCL patients in trials of CAR T-cell products, including the ZUMA-1 study of axicabtagene cyloleucel (Yescarta), which, in a 2019 update, showed survival plateaus of about 40% vs. the 5%-10% expected rate based on pre-CAR-T outcomes data; the JULIET trial of tisagenlecleucel (Kymriah), which showed survival plateaus in the range of 30%-35%; and the recently published TRANSCEND study of the investigational modified CAR-T product, lisocabtagene maraleucel, which also showed survival plateaus “in the range of 40%.”
“So all three agents are showing that CAR T cells represent a new treatment for diffuse large B-cell lymphoma in the relapsed/refractory setting,” Dr. Zelenetz said. “And as a result, [CAR T-cell therapy has] been included in the NCCN guidelines for transformed follicular lymphoma, for transformed marginal zone lymphoma, and for diffuse large B-cell lymphoma, as well as for refractory large B-cell lymphoma.
“But are CAR T cells absolutely required? Generally what we consider these days is that if you’re not in a PET-negative CR prior to high-dose therapy stem cell rescue, you should go on to CAR T cells,” Dr. Zelenetz said.
The analysis based on the CIBMTR registry data, however, suggests there may be other alternatives.
“The bottom line is that nonrelapse mortality was very low. Progression occurred in about half of the patients, but if we look at the overall and progression-free survival curves, there’s a plateau at around 45%,” Dr. Zelenetz said, explaining that the results are “very similar to the results that we’re getting in third-line treatment with CAR T cells, and this is a very similar population [of] PET-positive patients after second-line chemotherapy.”
CAR T-cell therapy can provide a durable CR in a portion of chemorefractory patients, and although there is room for improvement, “this represents a major step forward for these patients,” he said.
However, it’s not clear that CAR T cells are clearly superior to high-dose therapy and stem cell rescue for chemosensitive patients, he added, noting that “additional randomized trials are needed to answer this question, and they are ongoing as we speak.”
Dr. Zelenetz reported clinical research support or data safety monitoring board activity for BeiGene, Genentech, Juno Therapeutics, and MEI Pharma, and scientific advisory board, consulting, or expert witness activity for Celgene Corporation, Curries, Genentech, Gilead Sciences, Janssen Pharmaceutical Products, and several other pharmaceutical and biotechnology companies.