Dual inhibition of the MEK/ERK and PI3K/AKT pathways prevents pulmonary GVHD suppressing perivenulitis and bronchiolitis.

Patients with pulmonary graft-versus-host disease (pGVHD) have a poor prognosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Furthermore, pGVHD pathogenesis is not fully elucidated in humans, and currently available immunosuppressants are inadequately effective. We performed pathologic evaluation of lung specimens from 45 allo-HSCT recipients with pGVHD who underwent lung transplantation. Patient pathology was characterized by bronchiolitis and subpleural perivascular inflammation, with B-cell, monocyte, and T-cell accumulation around bronchioles. Bronchiolitis, perivascular inflammation, and peribronchial macrophage aggregation were also identified in a murine pGVHD model after transplant of bone marrow cells and splenocytes from C57BL/6 to B10.BR mice. Among mitogen-activated protein kinase kinase (MEK) inhibitors, cobimetinib, but not trametinib, improved survival rates. Cobimetinib attenuated bronchiolitis, improved airway resistance and lung compliance in the mice, and suppressed activation of B cells and tumor necrosis factor α production by monocytes in vitro; these features were not suppressed by trametinib or tacrolimus. Furthermore, cobimetinib suppressed activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling, resulting in B-cell and monocyte suppression. Dual inhibition of the MEK/extracellular signal-regulated kinase (ERK) and PI3K/AKT pathways using a combination of trametinib and the PI3K inhibitor taselisib strongly suppressed B-cell activation in vitro and improved mouse survival rates compared with vehicle or monotherapy with trametinib or taselisib. Imaging mass cytometry of human pGVHD revealed that T cells around bronchioles were positive for phosphorylated ERK, whereas B cells were positive for phosphorylated AKT. Thus, perivascular inflammation and bronchiolitis mediated by activation of the MEK/ERK and PI3K/AKT pathways are essential for pGVHD and represent a potential novel therapeutic target in humans.

Bortezomib-cyclophosphamide-dexamethasone induction/consolidation and bortezomib maintenance for transplant-eligible newly diagnosed multiple myeloma: phase 2 multicenter trial.

OBJECTIVES: We conducted a phase II trial to prospectively evaluate the efficacy and safety of bortezomib-cyclophosphamide-dexamethasone (VCD) induction, autologous stem cell transplantation (ASCT), VCD consolidation, and bortezomib maintenance in transplant-eligible newly diagnosed multiple myeloma (NDMM) patients in Japan (UMIN000010542). METHODS: From 2013 to 2016, 42 patients with a median age of 58 (range 42-65) years with NDMM were enrolled in 15 centers. The primary endpoint was the complete response (CR) /stringent CR (sCR) rate after transplantation, and overall/progression-free survival rates were also evaluated. RESULTS: Following induction therapy, the overall response rate was obtained in 71% of patients, including a CR/sCR of 10% and a very good partial response (VGPR) of 26%. Twenty-six of the 42 patients completed ASCT following the protocol and CR/sCR and VGPR rate 100 days after ASCT was 26% and 17%, respectively. During consolidation therapy, 3 of the 24 patients achieved deeper responses. Eight of the 18 patients completed 2-year bortezomib maintenance without disease progression and grade 3/4 toxicities. Five patients were VGPR or partial response after ASCT but maintained response with 2-year bortezomib maintenance. Two-year overall and progression-free survival rates were 92.5% (95% confidence interval [CI]: 78.5%-97.5%) and 62.6% (95% CI: 45.8%-75.5%), respectively. Grade 3/4 toxicities (≥ 10%) included neutropenia (19%) and anemia (17%) in induction, and thrombocytopenia (29%) in consolidation. CONCLUSION: VCD induction/consolidation and bortezomib maintenance with ASCT for NDMM resulted in a high CR/sCR rate and provided good overall/progression-free survival in Japan.

Pharmacological MEK inhibition promotes polyclonal T-cell reconstitution and suppresses xenogeneic GVHD.

Rapid immune reconstitution without developing graft-versus-host disease (GVHD) is required for the success of allogeneic hematopoietic stem cell transplantation. Here, we analyzed the effects of pharmacological MEK inhibition on human polyclonal T-cell reconstitution in a humanized mouse GVHD model utilizing deep sequencing-based T-cell receptor (TCR) repertoire analysis. GVHD mice exhibited a skewed TCR repertoire with a common clone within target organs. The MEK inhibitor trametinib ameliorated GVHD and enabled engraftment of diverse T-cell clones. Furthermore, trametinib also ameliorated GVHD sparing diverse T cell repertoire, even when it was given from day 15 through 28. Although tacrolimus also reduced development of GVHD, it disturbed diverse T cell reconstitution and resulted in skewed TCR repertoire. Thus, trametinib not only suppresses GVHD-inducing T cells but also promotes human T cell reconstitution in vivo, providing a novel rationale for translational studies targeting human GVHD.

Effect of Cytomegalovirus Reactivation With or Without Acute Graft-Versus-Host Disease on the Risk of Nonrelapse Mortality.

BACKGROUND: Despite a strong association between acute graft-versus-host disease (GVHD) and cytomegalovirus reactivation (CMVR), the joint effect of acute GVHD and CMVR on nonrelapse mortality (NRM) has not been well studied. METHODS: We evaluated the impact of CMVR on NRM stratified according to the development of acute GVHD using a landmark method. This study included 6078 patients who received their first allogeneic hematopoietic cell transplantation (HCT) with a preemptive strategy for CMVR between 2008 and 2017. RESULTS: The cumulative incidences of grade 2-4 acute GVHD (G24GVHD), CMVR by day 100, and CMV disease by day 365 were 37.3%, 52.1%, and 2.9%, respectively. Patients with G24GVHD were associated with the subsequent development of CMVR, and the presence of CMVR also increased the risk of G24GVHD. In a landmark analysis at day 65, the cumulative incidence of NRM at 1 year was 5.4%, 10.0%, 13.9%, and 19.7% in patients with G24GVHD-/CMVR-, G24GVHD-/CMVR+, G24GVHD+/CMVR-, and G24GVHD+/CMVR+, respectively. In a multivariate analysis, CMVR was respectively associated with an increased risk of NRM by day 365 in patients without G24GVHD (hazard ratio [HR], 1.59; 95% confidence interval [CI], 1.24-2.05; P < .001) and with G24GVHD (HR, 1.34; 95% CI, 1.06-1.70; P = .014), but the interaction between G24GVHD and CMVR was not significant (P = .326). Subgroup analyses suggested that the joint effect of acute GVHD and CMVR might vary according to the baseline characteristics. CONCLUSIONS: These data regarding the close relationship between acute GVHD and CMVR should provide important implications for the treatment strategy after HCT.

GVHD-free, relapse-free survival provides novel clues for optimizing allogeneic-HSCT for adult T-cell leukemia/lymphoma.

The outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult T-cell leukemia/lymphoma (ATL) is still unsatisfactory. To illustrate the advantages and disadvantages of each donor source, we performed a nationwide retrospective study of graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) of patients with allo-HSCT-treated ATL. One-year GRFS did not significantly differ between patients who received related bone marrow transplantation (R-BMT; 26%, n = 117), related peripheral blood stem cell transplantation (R-PBSCT; 22%, n = 225), unrelated bone marrow transplantation (UR-BMT; 26%, n = 619), and cord blood transplantation (CBT; 21%, n = 359; p = 0.09). This was attributable to a low incidence of systemically-treated chronic GVHD after CBT (9% at 1 year) and reduced non-GVHD/relapse mortality after R-PBSCT (9% at 1 year). Among patients transplanted in complete remission (CR), 1-year overall survival after CBT (52%, n = 132) was not inferior to that after R-BMT (55%, n = 51), R-PBSCT (57%, n = 79), and UR-BMT (58%, n = 280; p = 0.15), and relapse rates were equivalent among the four sources (p = 0.19). Our results suggest that all donor sources are feasible for CR patients and that GRFS provides important clues toward optimizing allo-HSCT for ATL.

Drug monitoring for mycophenolic acid in graft-vs-host disease prophylaxis in cord blood transplantation.

AIMS: We performed the retrospective analysis to clarify the significance of drug monitoring for mycophenolic acid (MPA), the active form of mycophenolate mofetil (MMF), in prophylaxis for graft-vs-host disease (GVHD) in cord blood transplantation. METHODS: We retrospectively analysed the data of 46 patients who underwent first cord blood transplantation and received GVHD prophylaxis with tacrolimus plus MMF. MPA levels were measured on days 7 and 21, and 24-hour areas under the curve (AUC0-24 ) were estimated. RESULTS: The engraftment and 3-year overall survival rates of all patients were 94% and 78%, respectively. The cumulative incidence of sepsis before engraftment was higher in patients with AUC0-24 on day 7 of >60 µg h/mL than in other patients (33 vs 6%, P = .02). The cumulative incidence of grade II-IV acute GVHD was higher in patients with AUC0-24 on day 21 of ≤30 µg h/mL than in other patients (80 vs 50%, P = .04). The cumulative incidence of human herpesvirus 6 reactivation was higher in patients with AUC0-24 on day 21 of ≤48 µg h/mL (median) than in other patients (50 vs 19%, P = .03). CONCLUSION: Blood level of MPA was associated with risk of acute GVHD and infection. A prospective trial evaluating the benefit of personalized MMF dosing using MPA levels is needed.

Hairy Cell Leukemia with Systemic Lymphadenopathy: Detection of BRAF Mutations in Both Lymph Node and Peripheral Blood Specimens.

A 47-year-old woman with pancytopenia, excessive systemic lymphadenopathy and splenomegaly was referred to our hospital. The peripheral blood (PB) smear findings indicated neutropenia with lymphoid cells exhibiting hairy projections, while the histological findings of the cervical lymph node (LN) suggested hairy cell leukemia (HCL). In addition, the BRAF V600E mutation was detected, and the immunoglobulin gene rearrangement patterns were identical in both the cervical LN and PB specimens. Based on these findings, we diagnosed the patient with systemic lymphadenopathy due to HCL. This is the first report of a BRAF mutation detected in both the PB and LN at the onset of HCL.