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Aims: Subclassification of large B cell lymphoma (LBCL) is challenging due to the overlap in histopathological, immunophenotypical and genetic data. In particular, the criteria to separate diffuse large B cell lymphoma (DLBCL) and high‐grade B cell lymphoma (HGBL) are difficult to apply in practice. The Lunenburg Lymphoma Biomarker Consortium previously reported a cohort of over 5000 LBCL that included fluorescence in‐situ hybridisation (FISH) data. This cohort contained 209 cases with MYC rearrangement that were available for a validation study by a panel of eight expert haematopathologists of how various histopathological features are used. Methods and results: Digital whole slide images of haematoxylin and eosin‐stained sections allowed the pathologists to visually score cases independently as well as participate in virtual joint review conferences. Standardised consensus guidelines were formulated for scoring histopathological features and included overall architecture/growth pattern, presence or absence of a starry‐sky pattern, cell size, nuclear pleomorphism, nucleolar prominence and a range of cytological characteristics. Despite the use of consensus guidelines, the results show a high degree of discordance among the eight expert pathologists. Approximately 50% of the cases lacked a majority score, and this discordance spanned all six histopathological features. Moreover, none of the histological variables aided in prediction of MYC single versus double/triple‐hit or immunoglobulin‐partner FISH‐based designations or clinical outcome measures. Conclusions: Our findings indicate that there are no specific conventional morphological parameters that help to subclassify MYC‐rearranged LBCL or select cases for FISH analysis, and that incorporation of FISH data is essential for accurate classification and prognostication. [ABSTRACT FROM AUTHOR]

Discusses the proceedings of the Second International Lunenburg Workshop on prognostic factors in follicular lymphoma and diffuse large-cell lymphoma at the Lunenburg Estate in Langbroek, the Netherlands on May 19 and 20, 2003. Problems related to the International Prognostic Index; Prognostic factors in follicular non-Hodgkin's lymphoma; Prognostic factors in diffuse large-B-cell lymphoma.

A letter to the editor is presented regarding a rationale for combination therapy of ibrutinib and idelalisib in B-cell receptor (BCR)-controlled adhesion in mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) .

Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for the treatment (Tx) of patients (pts) with R/R LBCL with ≥ 2 prior systemic therapies. In Cohorts 1+2 (C1+2) of the ZUMA-1 study, Grade ≥ 3 cytokine release syndrome (CRS) and neurologic events (NEs) occurred in 11% and 32% of pts, respectively (Locke FL et al, Lancet Oncol 2019). A nonrandomized safety expansion cohort (Cohort 4 [C4]) evaluated the impact of earlier steroid use on CRS and NE rates. Here we present the primary analysis of ZUMA-1 C4 with a greater number of pts and longer follow-up (F/U). Eligible pts were leukapheresed, could receive optional bridging chemotherapy (not allowed in C1+2), and received conditioning chemotherapy before axi-cel infusion at a targeted 2 × 106 anti-CD19 CAR T cells/kg. C4 pts received early steroid intervention at Grade 1 NE and at Grade 1 CRS after 3 days of supportive care. Primary endpoints were incidence and severity of CRS and NEs. ORR and CAR T cell levels were compared across quartiles of tumor burden (TB). As of May 6, 2019, 41 pts had received axi-cel, with a median F/U of 8.7 mo. Pts who received bridging therapy prior to axi-cel (68%) all had evidence of disease after bridging, documented by a new baseline PET/CT scan. The median age was 61 y (range, 19 – 77 y; 32% ≥ 65 y). The majority of pts (63%) had DLBCL; 49% had an ECOG 1; 70% had disease stage III/IV; 68% were refractory to ≥ 2nd-line therapy; 63% had ≥ 3 prior lines of therapy; and 20% had relapsed after ASCT. C4 pts had a lower median TB by sum of product diameters (SPD; C4: 2100 mm2; C1+2: 3723 mm2) and lower pre-Tx serum LDH level than C1+2 pts. A greater proportion of C4 pts received steroids and tocilizumab vs C1+2 (73% and 76% vs 27% and 43%). Fewer C4 pts experienced Grade ≥ 3 CRS (2%) and NE (17%) than C1+2 pts. The ORR in C4 was 73% with a CR rate of 51%. Response was ongoing in C4 54% of pts with ≥ 6 mo F/U vs the 44% ongoing response rate at the primary analysis of C1+2 (also ≥ 6 mo F/U). Although most pts in C4 had lower SPDs than those in C1+2, responses were comparable when evaluated by TB. Median DOR was 8.9 mo, consistent with that observed for C1+2 (8.1 mo; Locke, AACR 2017; Figure). Median PFS was 11.7 mo; median OS was not reached. Peak CAR T cell levels were 42 cells/µL blood in C1+2 vs 59 cells/µL in C4. C1+2 had a median CAR AUC of 462 cells/µL × days vs 512 cells/µL in C4. CAR T cell expansion was comparable between cohorts when adjusted by TB. Levels of key NE-associated biomarkers including ferritin (pre- and post-Tx) and IL-2 (post-Tx) appeared lower in C4 than in C1+2. Earlier steroid use may reduce the rates of CAR T cell Tx-related CRS and NEs without affecting efficacy. Conclusions are limited by the nonrandomized study design and differences in population sizes and baseline characteristics between cohorts. Optimizing AE management is important to improve the benefit–risk profile of CAR T cell therapy. [ABSTRACT FROM AUTHOR]