Chang, Tiffany

Abstract Use of brentuximab vedotin (BV) and PD-1 monoclonal antibodies (mAbs) before autologous stem cell transplantation (ASCT) could impact the benefit of post-ASCT BV maintenance in relapsed/refractory (R/R) classic Hodgkin lymphoma (cHL). We identified 1091 patients with R/R cHL who underwent ASCT between 2010-2022. In total, 244 (22%) received a PD-1 mAb and 443 (41%) received BV before ASCT, while 305 (28%) received BV maintenance. We performed 1:1 propensity score matching to assess the efficacy of BV maintenance in different patient subgroups. Among 608 matched patients, the 3-year progression-free survival (PFS) and overall survival were 73% (95% confidence interval [CI], 70-78) and 95% (95%CI, 93-97), respectively. BV maintenance was associated with improved PFS for patients with no exposure to novel agents, especially those with 2+ modified AETHERA risk factors (0-1 factors: hazard ratio (HR), 0.51; 95%CI, 0.24-1.09; P =.083; 2+ factors: HR, 0.40; 95%CI, 0.25-0.65; P< .001). In contrast, BV maintenance was not associated with a significant PFS benefit for any patient subgroup who received novel agents before ASCT (BV-treated, 0-1: HR, 1.43; 95%CI, 0.53-3.81; P =.48; 2+: HR, 0.79; 95%CI, 0.34-1.82; P =.58; PD-1-treated, 0-1 [P>.99], 2+: HR, 0.25; 95%CI, 0.03-2.14; P =.21). In particular, we observed excellent outcomes for patients undergoing ASCT in a complete response after one line of PD-1-based salvage treatment with no significant benefit for BV maintenance observed (2-year PFS 100% vs 95%; P>.99). The benefit of BV maintenance appears to be attenuated for patients receiving novel agents with salvage therapy. Omission of BV maintenance should be considered for patients anticipated to have excellent outcomes.

Abstract Combination therapy incorporating programmed cell death protein 1 (PD-1) blockade results in unprecedented response rates in both frontline and relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL). Previous retrospective studies have suggested benefit for PD-1 blockade before autologous stem cell transplant (ASCT) but included few patients receiving PD-1 blockade with cytotoxic chemotherapy. To explore the impact of anti–PD-1 based salvage on outcomes for patients with R/R cHL, we retrospectively reviewed 1280 patients with R/R cHL who underwent ASCT from 2010 to 2022 at 6 transplant centers, none of whom received PD-1 blockade as part of frontline therapy. Overall, 25% received a PD-1 inhibitor at any point before ASCT (10% in conjunction with chemotherapy), 28% received salvage brentuximab vedotin (BV) without PD-1 blockade, and the rest received salvage chemotherapy alone. Patients who received PD-1 inhibitors at any point before ASCT had a significantly higher 2-year progression-free survival than those who received BV without PD-1 inhibitors or patients receiving chemotherapy alone (88.2%, 70.2%, and 67.4%, respectively; P< .0001). When restricted to patients in complete response before ASCT, the benefit of PD-1 blockade remained significant. PD-1 blockade before ASCT is independently associated with superior post-ASCT outcomes and patients proceeding to ASCT should be treated with PD-1–based salvage.

Gene fusions involving tumor protein p63 gene (TP63) occur in multiple T and B cell lymphomas and portend a dismal prognosis for patients. The function and mechanisms of TP63 fusions remain unclear, and there is no target therapy for patients with lymphoma harboring TP63 fusions. Here, we show that TP63 fusions act as bona fide oncogenes and are essential for fusion-positive lymphomas. Transgenic mice expressing TBL1XR1::TP63, the most common TP63 fusion, develop diverse lymphomas that recapitulate multiple human T and B cell lymphomas. Here, we identify that TP63 fusions coordinate the recruitment of two epigenetic modifying complexes, the nuclear receptor corepressor (NCoR)—histone deacetylase 3 (HDAC3) by the N-terminal TP63 fusion partner and the lysine methyltransferase 2D (KMT2D) by the C-terminal TP63 component, which are both required for fusion-dependent survival. TBL1XR1::TP63 localization at enhancers drives a unique cell state that involves up-regulation of MYC and the polycomb repressor complex 2 (PRC2) components EED and EZH2. Inhibiting EZH2 with the therapeutic agent valemetostat is highly effective at treating transgenic lymphoma murine models, xenografts, and patient-derived xenografts harboring TP63 fusions. One patient with TP63 -rearranged lymphoma showed a rapid response to valemetostat treatment. In summary, TP63 fusions link partner components that, together, coordinate multiple epigenetic complexes, resulting in therapeutic vulnerability to EZH2 inhibition.