DA-EPOCH-R Is an Effective Regimenin High Grade B-Cell Lymphoma Defined By Cell-of-Origin, Karyotype and BCL2/MYC/BCL6 Status and Expression

Background: MYC, BCL2 and BCL6 are known to be altered in high grade B-cell lymphoma (HGBL). Double/triple-hit lymphomas (D/THLs) are characterized by chromosomal rearrangementsof MYC, BCL2 and/or BCL6. D/THLs have been included in the updated 2016 WHO classification, as a new category of "High grade B-cell lymphoma with rearrangements" (HGBL-R) or Diffuse Large B-cell lymphoma (DLBCL) entity, depending on morphology/cytogenetic features. BCL2 protein is expressed in a much higher proportion of DLBCL and HGBL, not otherwise specified (HGBL,NOS), and is often associated with a concomitant expression of MYC and BCL6. Most of HGBLs do not carry BCL2/MYC/BCL6 rearrangements and are referred to as "double/triple-expressor lymphomas" (D/TELs). D/THLs patients usually progress rapidly, are resistant to R-CHOP immunochemotherapy, and have very poor prognosis. D/TELs also have a worse outcome than other DLBCL,NOS. BCL2 overexpression is observed in both germinal centre B-cell-like (GCB) and non-GCB HGBL. We have previously described a diagnostic algorithm for subtypes of HGBL based on flow-cytometry immunphenotyping (FCM) with CD38 overexpression, which correlates with MYC rearrangement assessed in fine needle aspiration biopsy (FNAB) samples. Here, we propose that patients with HGBL/DLBCL,NOS, with BCL2 overexpression, especially those with D/THLs and D/TELs, may benefit from DA-EPOCH-R (dose-adjusted cyclophosphamide, doxorubicin, etoposide, vincristine, prednisone with rituximab) treatment.

Methods: 30 patients (male/female 18/12, median age/range 51/35-76/) diagnosed with DLBCL,NOS (13 pts), HGBL-R (11 pts), HGBL,NOS (2 pts), primary mediastinal B-cell lymphoma - PMBL (3 pts) and DLBCL,leg type (1 pt), based on 2016 WHO classification, were treated with DA-EPOCH-R as first-line therapybetween January 2015 - July 2016. Clinical stage III or IV and IPI 3 or more were found in 27 pts (90%) and 22 pts (73%), respectively. All cases were evaluated by histopathological/immunohistochemical/flow-cytometry examination (HP/IHC/FCM), with panels of antibodies, including also CD5/CD10/CD20/CD38/BCL2/BCL6/MYC. In most cases, MYC, BCL2, BCL6 and, in case of relapse, also TP53 status was evaluated by karyotyping (CC) and FISH.

Results: Considering the cell-of-origin, there were 20 pts with GCB, 3 non-GCB, 4 CD5+ and 3 PMBL. In addition, 15 pts were DEL, 12 - TEL, 3 - one-expressor lymphoma, 8 - D/THL, 12 - one-hit lymphoma and 10 - non-hit lymphoma, mostly with BCL2 overexpression. Karyotype was successfully assessed in 70%, while BCL2 overexpression was found in 83% of HGBL pts. MYC, BCL2, and BCL6 rearrangement was found in 48%, 35% and 21%, respectively. In 50%, 46% and 54% of cases there was an increase in copy number/amplification of MYC, BCL2 and BCL6, respectively. In 15 evaluable pts., overall and complete response was 80% and 53%, respectively. Median follow-up of HGBL pts treated with DA-EPOCH-R was 5 months (range 1-17), and the probability of one year overall survival was 91%, 95% C.I. (80%,100%). Progression free survival at 1 year was 62%, 95C.I. (36%,90%). 3 of 4 patients with progressive disease had TP53 deletion. The main toxicity was pancytopenia with neutropenia grade 3 or more in 24 pts (80%). Treatment-related mortality due to septic shock occurred in 2 patients (7%).

Conclusions: DA-EPOCH-R regimen shows a promising activity considering D/THL and D/TEL-associated drug resistance. DA-EPOCH-R regimen seems to overcome drug resistance associated with BCL2/MYC/BCL6 overexpression, but not with TP53 deletion. Combining HP/IHC with FNAB/FCM/CC/FISH is a reliable method for D/THL and D/TEL diagnosis but the most sensitive method for fast MYC/BCL2 rearrangement assessment in DHL is FNAB/FCM CD38 and BCL2 overexpression.