Impact of Cell of Origin on Outcomes After Autologous Hematopoietic Cell Transplant in Diffuse Large B-Cell Lymphoma.

Germinal center B-cell-like diffuse large B cell lymphoma (GCB-DLBCL) at diagnosis is associated with superior long-term outcomes compared to non-GCB-DLBCL in patients treated with conventional chemo-immunotherapy. Whether cell of origin (COO) by Hans algorithm retains its prognostic significance in patients with (R/R) relapsed/refractory DLBCL undergoing autologous hematopoietic cell transplant (auto-HCT) is not well established. Three hundred and fifty-seven patients underwent auto-HCT between 2005 and 2018. The COO status was determined in 284 patients and these were included in the analysis. One hundred ninety-four patients had GCB-DLBCL while 90 had non-GCB-DLBCL. Median follow up was 1.7 (0-13) years. The GCB-DLBCL was associated with inferior 5-year overall survival at 44% (95%CI, 36-52) versus 64% (95%CI, 54-77) (P = .004) and a higher relapse incidence at 67% (95%CI, 58-74) versus 49% (95%CI, 35-60) (P = .01) in the non-GCB-DLBCL. The difference between GCB and non-GCB-DLBCL remained statistically significant in multivariate analysis. Additionally, response at the time of transplant was an independent prognostic factor. GCB-DLBCL was enriched in double-hit and triple hit phenotype based on available fluorescence in situ hybridization data. These results suggest an enrichment of high-risk genetic rearrangements in R/R GCB-DLBCL resulting in limited efficacy of auto-HCT.

Does bridging radiation therapy affect the pattern of failure after CAR T-cell therapy in non-Hodgkin lymphoma?

PURPOSE: Analyze the pattern of disease failure after anti-CD19-directed chimeric antigen receptor T-cell therapy (CART) for non-Hodgkin lymphoma, assess the local control rate of bridging radiotherapy (bRT) and characterize in-field recurrences. METHODS: We retrospectively reviewed 120 patients with NHL who received CART between 2018 and 2020. Baseline characteristics and treatment outcomes were compared between patients who received bRT and those who did not (noRT). RESULTS: Of the 118 patients included, 14 (12%) received bRT, while 104 (88%) did not. bRT group had more localized and extranodal disease. bRT was delivered with a median dose of 20 Gy (range: 15-36) in 5 fractions (range: 3-24). Pattern of failure analysis revealed that progression involving pre-existing sites was the predominant pattern of failure in both the bRT and noRT groups (86% and 88%, respectively). Median duration of response was 128 days (range: 25-547) for bRT group and 93 days (range: 22-965) for noRT group (p = 0.78). In the bRT group, only 2/15 sites irradiated had infield recurrence and where characterized by bulky disease, SUVmax >20, elevated LDH at the time of CART infusion, and extranodal involvement. The bRT 1-year LC was 86%. Median duration of local response was 257 days (range: 25-630) for radiation-bridged sites. CONCLUSION: Majority of progressions after CART infusion involve pre-existing sites. Bridging RT prior to CART provides excellent in-field local control and durable response. Patients with bulky disease, SUVmax >20, elevated LDH, and extranodal involvement are likely at higher risk of in-field recurrence after bRT and may benefit from higher curative doses of bRT.

Hypomagnesemia at the time of autologous stem cell transplantation for patients with diffuse large B-cell lymphoma is associated with an increased risk of failure.

Magnesium is an essential element that is involved in critical metabolic pathways. A diet deficient in magnesium is associated with an increased risk of developing cancer. Few studies have reported whether a serum magnesium level below the reference range (RR) is associated with prognosis in patients with diffuse large B cell lymphoma (DLBCL). Using a retrospective approach in DLBCL patients undergoing autologous stem cell transplant (AHSCT), we evaluated the association of hypomagnesemia with survival. Totally, 581 patients eligible for AHSCT with a serum magnesium level during the immediate pre-transplant period were identified and 14.1% (82/581) had hypomagnesemia. Hypomagnesemia was associated with an inferior event-free (EFS) and overall survival (OS) compared to patients with a serum magnesium level within RR; median EFS: 3.9 years (95% CI: 1.63-8.98 years) versus 6.29 years (95% CI: 4.73-8.95 years) with HR 1.63 (95% CI: 1.09-2.43, p = 0.017) for EFS, and median OS: 7.3 years (95% CI: 2.91-upper limit not estimable) versus 9.7 years (95% CI: 6.92-12.3 years) with HR 1.90 (95% CI: 1.22-2.96, p = 0.005) for OS months 0-12, respectively. These findings suggest a potentially actionable prognostic factor for patients with DLBCL undergoing AHSCT.