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Chronic lymphocytic leukemia (CLL) is a chronic form of leukemia that originates from an abnormal expansion of CD5+B‐1 cells. Deregulation in the BCR signaling is associated with B‐cell transformation. Contrariwise to B‐2 cells, BCR engagement in B‐1 cells results in low proliferation rate and increased apoptosis population, whereas overactivation may be associated with lymphoproliferative disorders. It has been demonstrated that several transcription factors that are involved in the B cell development play a role in the regulation of BCR function. Among them, Ikaros is considered an essential regulator of lymphoid differentiation and activation. Several reports suggest that Ikaros expression is deregulated in different forms of leukemia. Herein, we demonstrated that CLL cells show decreased Ikaros expression and abnormal cytoplasmic cell localization. These alterations were also observed in radioresistant B‐1 cells, which present high proliferative activity, suggesting that abnormal localization of Ikaros could determine its loss of function. Furthermore, Ikaros knockdown increased the expression of BCR pathway components in murine B‐1 cells, such as Lyn, Blnk, and CD19. Additionally, in the absence of Ikaros, B‐1 cells become responsive to BCR stimulus, increasing cell proliferation even in the absence of antigen stimulation. These results suggested that Ikaros is an important controller of B‐1 cell proliferation by interfering with the BCR activity. Therefore, altered Ikaros expression in CLL or radioresistant B‐1 cells could determine a responsive status of BCR to self‐antigens, which would culminate in the clonal expansion of B‐1 cells.

Reduced-intensity-conditioned allogeneic stem cell transplantation (SCT) remains a potentially curative approach for patients with relapsed/refractory Hodgkin lymphoma (HL) after an autologous stem cell transplantation. In the absence of an HLA-identical donor, haploidentical SCT (haplo-SCT) with post-transplantation cyclophosphamide (PT-Cy) has been evaluated with favorable preliminary results. We evaluated 24 patients who underwent haplo-SCT for relapsed/refractory HL. The conditioning regimen consisted of cyclophosphamide, fludarabine, and total body irradiation. Graft-versus-host disease (GVHD) prophylaxis consisted of a calcineurin inhibitor, mycophenolate mofetil, and PT-Cy (50 mg/kg/day for 2 days) for all patients. After a median follow-up of 2 years, the cumulative incidence (CI) of nonrelapse mortality was 26% and the CI of grades II to IV acute GVHD and chronic GVHD were 17% and 24%, respectively. Estimation of progression-free and overall survival at 2 years were 54% and 66%%, respectively. Haplo-SCT is a valuable option for relapsed/refractory HL patients after a failed autologous SCT, with favorable survival and relatively low risk of GVHD.

Introduction: Combination of doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) is the standard of care in frontline therapy for classic Hodgkin lymphoma (cHL). Since 2018, bleomycin shortages have been reported in Brazil, with severe consequences for cHL patients. In the private setting, many institutions chose to use A+AVD, in which bleomycin is replaced by brentuximab-vedotin, or to import bleomycin from vendors not registered at the national drug agency. For public institutions, however, these costly strategies are largely unattainable. Methods: We conducted a single-arm open-label study to evaluate the substitution of bleomycin with etoposide 100 mg/m2 on days 1 and 15 of every 28-day cycle (AEVD) in previously untreated cHL, at Hospital Municipal São José, in Joinville, Brazil. Here we present preliminary data on the safety and efficacy of this combination in a scenario of lack of approved treatment options for this patient population. Results: Twenty-five patients aged 18 or more with cHL diagnosed between June 2018 and November 2020 were included. Fourteen patients (56%) were male, with median age of 27 years (range: 18-66). Most patients were stage II (60%, n=15), presented with B symptoms (56%, n=14) and high lactate dehydrogenase (LDH, n=13, 52%). For stage III-IV (n=5), high-risk IPS was present in 3 patients (score >2; 60%). For localized disease (n=20), unfavorable features according to the GHSG were seen in 16 patients (n=80%). All patients received between 3 and 6 chemotherapy cycles, with no recorded adverse event requiring hospitalization, treatment interruption or discontinuation. PET-CT was performed solely outside of our institution. Eight patients had access to interim PET-CT, all with Deauville scores (DS) 1-3. Overall response rate was 96%, with one disease progression after 5 cycles. Seven patients had CT scan-alone end-of-treatment (EOT) assessment, with 5 complete responses (CR) and 2 partial responses (PR), with both PR patients sustaining remissions after 10 and 12 months. EOT assessment with PET-CT (n=18) resulted in DS 1-3 in 72% (n=13), 4 in 22% (n=4) and 5 in one (6%). All 5 patients with DS 4-5 underwent biopsy after EOT assessment, with confirmation of relapsed or refractory (RR) cHL in 4 cases (22 year-old, stage IV high-risk female with progressive disease; 65 year-old, stage III low-risk male with relapse 11 months after EOT; 26 year-old, stage II high-risk male with relapse 6 months after EOT; 25 year-old, stage II high-risk female with relapse 4 months after EOT). Two RR cHL patients (50%) had treatment delays exceeding 30 days due to psychosocial or financial impacts emerging from the COVID-19 pandemic. All RR cHL patients had access to salvage treatments. At a median follow-up of 16 months (range: 8-36), no death was recorded and 12-month progression-free survival probability was 86% (95%CI: 72%-100%). Conclusions: Drug shortages impacting chemotherapy treatments have been a recurring problem worldwide, most noticeably among cytotoxic agents without in-class validated substitutions, as is the case with bleomycin. AEVD, as a novel approach to newly diagnosed cHL, appears to be safe, feasible and highly active in a population composed mostly of high-risk patients. Figure 1 Figure 1. Disclosures Boettcher: Novartis: Speakers Bureau.