No abstract

From a liquid biopsy, cell-free DNA (cfDNA) can provide information regarding basal tumoral genetic patterns and changes upon treatment. In a prospective cohort of 30 diffuse large B-cell lymphomas (DLBCL), we determined the clinical relevance of cfDNA using targeted next-generation sequencing and its correlation with PET scan imaging at the time of diagnosis and during treatment. Using a dedicated DLBCL panel, mutations were identified at baseline for 19 cfDNAs and profiles were consistent with expected DLBCL patterns. Tumor burden-related clinical and PET scan features (LDH, IPI, and metabolic tumor volume) were significantly correlated with the quantity of tumoral cfDNA. Among the four patients presenting additional mutations in their cfDNAs, three had high metabolic tumor volumes, suggesting that cfDNA more accurately reflects tumor heterogeneity than tissues biopsy itself. Mid-treatment, four patients still had basal mutations in their cfDNAs, including three in partial response according to their Deauville scores. Our study highlights the major interests in liquid biopsy, in particular in the context of bulky tumors where cfDNA allows capturing the entire tumoral mutation profile. Therefore, cfDNA analysis in DLBCL represents a complementary approach to PET scan imaging.

Primary mediastinal B-cell lymphoma (PMBL) is an entity of B-cell lymphoma distinct from the other molecular subtypes of diffuse large B-cell lymphoma (DLBCL). We investigated the prevalence, specificity, and clinical relevance of mutations of XPO1, which encodes a member of the karyopherin-b nuclear transporters, in a large cohort of PMBL. PMBL cases defined histologically or by gene expression profiling (GEP) were sequenced and the XPO1 mutational status was correlated to genetic and clinical characteristics. The XPO1 mutational status was also assessed in DLBCL, Hodgkin lymphoma (HL) and mediastinal gray-zone lymphoma (MGZL).The biological impact of the mutation on Selective Inhibitor of Nuclear Export (SINE) compounds (KPT-185/330) sensitivity was investigated in vitro. XPO1 mutations were present in 28/117 (24%) PMBL cases and in 5/19 (26%) HL cases but absent/rare in MGZL (0/20) or DLBCL (3/197). A higher prevalence (50%) of the recurrent codon 571 variant (p.E571K) was observed in GEP-defined PMBL and was associated with shorter PFS. Age, International Prognostic Index and bulky mass were similar in XPO1 mutant and wild-type cases. KPT-185 induced a dose-dependent decrease in cell proliferation and increased celldeath in PMBL cell lines harboring wild type or XPO1 E571K mutant alleles. Experiments in transfected U2OS cells further confirmed that the XPO1 E571K mutation does not have a drastic impact on KPT-330 binding. To conclude the XPO1 E571K mutation represents a genetic hallmark of the PMBL subtype and serves as a new relevant PMBL biomarker. SINE compounds appear active for both mutated and wild-type protein.

PURPOSE Romidepsin, a histone deacetylase inhibitor, has demonstrated activity in relapsed or refractory peripheral T-cell lymphoma (PTCL) as a single agent. Cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy is widely used as first-line treatment of PTCL; however, it has limited efficacy. Results from a phase Ib and II study showed the feasibility of combining romidepsin with CHOP (Ro-CHOP). METHODS This study is a randomized phase III study of Ro-CHOP versus CHOP in adult patients with previously untreated PTCL. All patients received CHOP in 3-week cycles for six cycles. Romidepsin, 12 mg/m2, was administered intravenously over a 4-hour period on days 1 and 8 of each 3-week cycle for six cycles. The primary end point was progression-free survival (PFS) according to International Working Group 1999 criteria. RESULTS Between January 2013 and December 2017, 421 patients were enrolled (Ro-CHOP, n = 211; CHOP, n = 210). The median PFS for Ro-CHOP versus CHOP was 12.0 months (95% CI, 9.0 to 25.8) versus 10.2 months (95% CI, 7.4 to 13.2) with a hazard ratio of 0.81 ( P = .096). In the Ro-CHOP versus CHOP arms, the median overall survival was 51.8 versus 42.9 months and the objective response rate was 63% versus 60% with complete response plus unconfirmed complete response rates of 41% versus 37% ( P > .1 in all comparisons), respectively. Grade 3 or 4 treatment-emergent adverse events occurring in ≥ 30% of patients in the Ro-CHOP arm included thrombocytopenia (50% v 10% in the Ro-CHOP v CHOP arms, respectively), neutropenia (49% v 33%), anemia (47% v 17%), and leukopenia (32% v 20%). CONCLUSION The addition of romidepsin to CHOP did not improve PFS, response rates, nor overall survival and increased the frequency for grade ≥ 3 treatment-emergent adverse events. Ro-CHOP does not represent a significant advance in the standard of care for patients with previously untreated PTCL.