CD19 CAR T-cell therapy with axicabtagene ciloleucel (axi-cel) for relapsed or refractory (R/R) large B cell lymphoma (LBCL) may lead to durable remissions, however, prolonged cytopenias and infections may occur. In this single center retrospective study of 85 patients, we characterized immune reconstitution and infections for patients remaining in remission after axi-cel for LBCL. Prolonged cytopenias (those occurring at or after day 30 following infusion) were common with >= grade 3 neutropenia seen in 21/70 (30-0%) patients at day 30 and persisting in 3/31 (9-7%) patients at 1 year. B cells were undetectable in 30/34 (88-2%) patients at day 30, but were detected in 11/19 (57-9%) at 1 year. Median IgG levels reached a nadir at day 180. By contrast, CD4 T cells decreased from baseline and were persistently low with a median CD4 count of 155 cells/μl at 1 year after axi-cel (n=19, range 33 – 269). In total, 23/85 (27-1%) patients received IVIG after axi-cel, and 34/85 (40-0%) received G-CSF. Infections in the first 30 days occurred in 31/85 (36-5%) patients, of which 11/85 (12-9%) required intravenous antibiotics or hospitalization (“severe”) and were associated with cytokine release syndrome (CRS), neurotoxicity, tocilizumab use, corticosteroid use, and bridging therapy on univariate analyses. After day 30, 7 severe infections occurred, with no late deaths due to infection. Prolonged cytopenias are common following axi-cel therapy for LBCL and typically recover with time. Most patients experience profound and prolonged CD4 T cell immunosuppression without severe infection.

Axicabtagene ciloleucel (axi-cel) is a chimeric antigen receptor (CAR) T cell therapy for relapsed or refractory large B cell lymphoma (LBCL). Here, we evaluated whether immune dysregulation, present prior to CAR-T cell therapy, associated with treatment failure. Tumor expression of interferon (IFN) signaling, high blood levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and high blood IL-6 and ferritin each associated with a lack of durable response. Similar to other cancers, we found that in LBCL tumor IFN signaling is associated with the expression of multiple checkpoint ligands including PD-L1, and these were higher in patients who lacked durable responses to CAR-T therapy. Moreover, tumor IFN signaling and blood M-MDSCs associated with decreased axi-cel expansion. Finally, patients with high tumor burden had higher immune dysregulation with increased serum inflammatory markers and tumor IFN signaling. These data support that immune dysregulation in LBCL promotes axi-cel resistance via multiple mechanistic programs: insufficient axi-cel expansion associated with both circulating M-MDSC and tumor IFN signaling, that also gives rise to expression of immune checkpoint ligands.

Mutations in IDH1 and IDH2 occur in 15-20% of AML cases, resulting in the production of 2-hydroxyglutarate, which promotes aberrant hypermethylation of DNA in leukemic cells. Although these mutations have been shown to have prognostic implications for patients with AML, optimal treatment strategies have yet to be defined. We retrospectively identified forty-two patients with AML treated with DNA methyltransferase inhibitors (DNMTIs) decitabine (n 5 36) or azacitidine (n 5 6) and performed analysis of stored samples for the presence of IDH1 and IDH2 mutations. Of the forty-two samples analyzed, seven (16.7%) had IDH mutations. Thirteen patients (31%) achieved remission [(complete remission (CR)/complete remission with incomplete count recovery (CRi)/partial response (PR)] after treatment with a DNMTI, five of seven (71.4%) with IDH mutations and eight of thirty-five (22.9%) without IDH mutations (P 5 0.01). When adjusted for age at diagnosis, sex, bone marrow blast percentage and cytogenetic, the odds of achieving response after administration of a DNMTI among patients with an IDH mutation was 14.2 when compared to patients without an IDH mutation (95%CI: 1.3-150.4). IDH1 and IDH2 mutations may predict a favorable response to DNMTI in patients with AML.

Conflict of interest: MLD and RF received research funding from Novartis. MLD receives research funding from Precigen, Atara Biotherapeutics, and ELICIO Therapeutics. MLD has received licensing fees from Atara Biotherapeutics for CAR intellectual property. MLD has equity in Precision Biosciences and Adaptive Biotechnologies and unexercised options with Bellicum and CERtainty.

Idecabtagene vicleucel (ide-cel) was FDA approved in March 2021 for the treatment of relapsed/refractory multiple myeloma (RRMM) after 4 lines of therapy. On the KarMMa trial, grade ≥3 cytopenias and infections were common. We sought to characterize cytopenias and infections within 100 days after ide-cel in the standard of care (SOC) setting. This multi-center retrospective study included 52 patients who received SOC ide-cel; 47 reached day 90 follow-up. Data was censored at day 100. Grade ≥3 cytopenia was present among 65% of patients at day 30 and 40% of patients at day 90. Granulocyte colony stimulating factor (G-CSF) was administered to 88%, packed red blood cell (pRBC) transfusions to 63%, platelet transfusions to 42%, thrombopoietin (TPO) agonists to 21%, intravenous immunoglobulin (IVIG) to 13%, and CD34+ stem cell boosts to 8%. At day 100, 19% and 13% of patients had ongoing use of TPO agonists and G-CSF, respectively. Infections occurred in 54% of patients and were grade ≥3 in 23%. Earlier infections in the first 30 days were typically bacterial (68%) and severe (50%). Later infections between days 31 - 100 were 50% bacterial and 42% viral; only 13% were grade ≥3. On univariate analysis, high pre-CAR-T marrow myeloma burden (>/= 50%), circulating plasma cells at pre-lymphodepletion (LD), and grade ≥3 anemia at pre-LD were associated with grade ≥3 cytopenia at both days 30 and 90. Longer time from last bridging treatment to LD was the only significant risk factor for infection.