Key Points: Cytomegalovirus after bone marrow transplantation remains associated with lower survival but not prevention of leukemia relapse.

Belumosudil, an investigational oral selective inhibitor of Rho-associated coiled-coil–containing protein kinase 2 (ROCK2), reduces type 17 and follicular T helper cells via downregulation of STAT3 and enhances regulatory T cells via upregulation of STAT5. Belumosudil may effectively treat patients with chronic graft-versus-host disease (cGVHD), a major cause of morbidity and late nonrelapse mortality after an allogeneic hematopoietic cell transplant. This phase 2 randomized multicenter registration study evaluated belumosudil 200 mg daily (n = 66) and 200 mg twice daily (n = 66) in subjects with cGVHD who had received 2 to 5 prior lines of therapy. The primary end point was best overall response rate (ORR). Duration of response (DOR), changes in Lee Symptom Scale score, failure-free survival, corticosteroid dose reductions, and overall survival were also evaluated. Overall median follow-up was 14 months. The best ORR for belumosudil 200 mg daily and 200 mg twice daily was 74% (95% confidence interval [CI], 62-84) and 77% (95% CI, 65-87), respectively, with high response rates observed in all subgroups. All affected organs demonstrated complete responses. The median DOR was 54 weeks; 44% of subjects have remained on therapy for ≥1 year. Symptom reduction with belumosudil 200 mg daily and 200 mg twice daily was reported in 59% and 62% of subjects, respectively. Adverse events (AEs) were consistent with those expected in patients with cGVHD receiving corticosteroids and other immunosuppressants. Sixteen subjects (12%) discontinued belumosudil because of possible drug-related AEs. Belumosudil, a promising therapy for cGVHD, was well tolerated with clinically meaningful responses. This trial was registered at www.clinicaltrials.gov as #NCT03640481.

Relapsed/refractory primary central nervous system lymphoma (PCNSL) and secondary central nervous system lymphoma (SCNSL) are associated with short survival and represent an unmet need, requiring novel effective strategies. Anti-CD19 chimeric antigen receptor (CAR) T cells, effective in systemic large B-cell lymphoma (LBCL), have shown responses in PCNSL and SCNSL in early reports, but with limited sample size. We, therefore, performed a comprehensive systematic review and meta-analysis of all published data describing CAR T-cell use in PCNSL and SCNSL. This identified 128 patients with PCNSL (30) and SCNSL (98). Our primary objectives were to evaluate CAR T-cell specific toxicity (immune effector cell-associated neurotoxicity syndrome [ICANS] and cytokine release syndrome [CRS]) as well as response rates in these 2 populations. Seventy percent of patients with PCNSL had CRS of any grade (13% grade 3-4) and 53% had ICANS of any grade (18% grade 3-4). Comparatively, 72% of the SCNSL cohort experienced CRS of any grade (11% grade 3-4) and 48% had ICANS of any grade (26% grade 3-4). Of the patients with PCNSL, 56% achieved a complete remission (CR) with 37% remaining in remission at 6 months. Similarly, 47% of patients with SCNSL had a CR, with 37% in remission at 6 months. In a large meta-analysis of central nervous system (CNS) lymphomas, toxicity of anti-CD19–CAR T-cell therapy was similar to that of registrational studies in systemic LBCL with no increased signal of neurotoxicity observed. Encouraging efficacy was demonstrated in patients with CNS lymphoma with no discernible differences between PCNSL and SCNSL.

Non-Hodgkin’s lymphomas (NHL) are a heterogeneous group of lymphoproliferative disorders originating in B lymphocytes, T lymphocytes, or natural killer cells. Mantle cell lymphoma (MCL) accounts for approximately 6% of all newly diagnosed NHL cases. Radiation therapy with or without systemic therapy is a reasonable approach for the few patients who present with early-stage disease. Rituximab-based chemoimmunotherapy followed by high-dose therapy and autologous stem cell rescue (HDT/ASCR) is recommended for patients presenting with advanced-stage disease. Induction therapy followed by rituximab maintenance may provide extended disease control for those who are not candidates for HDT/ASCR. Ibrutinib, a Bruton tyrosine kinase inhibitor, was recently approved for the treatment of relapsed or refractory disease. This manuscript discusses the recommendations outlined in the NCCN Guidelines for NHL regarding the diagnosis and management of patients with MCL.

Hematopoietic cell transplantation from HLA-haploidentical related donors is increasingly used to treat hematologic cancers; however, characteristics of the optimal haploidentical donor have not been established. We studied the role of donor HLA mismatching in graft-versus-host disease (GVHD), disease recurrence, and survival after haploidentical donor transplantation with posttransplantation cyclophosphamide (PTCy) for 1434 acute leukemia or myelodysplastic syndrome patients reported to the Center for International Blood and Marrow Transplant Research. The impact of mismatching in the graft-versus-host vector for HLA-A, -B, -C, -DRB1, and -DQB1 alleles, the HLA-B leader, and HLA-DPB1 T-cell epitope (TCE) were studied using multivariable regression methods. Outcome was associated with HLA (mis)matches at individual loci rather than the total number of HLA mismatches. HLA-DRB1 mismatches were associated with lower risk of disease recurrence. HLA-DRB1 mismatching with HLA-DQB1 matching correlated with improved disease-free survival. HLA-B leader matching and HLA-DPB1 TCE-nonpermissive mismatching were each associated with improved overall survival. HLA-C matching lowered chronic GVHD risk, and the level of HLA-C expression correlated with transplant-related mortality. Matching status at the HLA-B leader and HLA-DRB1, -DQB1, and -DPB1 predicted disease-free survival, as did patient and donor cytomegalovirus serostatus, patient age, and comorbidity index. A web-based tool was developed to facilitate selection of the best haploidentical-related donor by calculating disease-free survival based on these characteristics. In conclusion, HLA factors influence the success of haploidentical transplantation with PTCy. HLA-DRB1 and -DPB1 mismatching and HLA-C, -B leader, and -DQB1 matching are favorable. Consideration of HLA factors may help to optimize the selection of haploidentical related donors.

Corticosteroid refractory graft-versus-host disease (GVHD) is one of the major challenges in the management of allogeneic stem cell transplant recipients. Although numerous agents have been employed to treat this patient population, no standardized second-line therapy exists. In this study, we report our experience with the administration of tocilizumab, an anti-interleukin 6 receptor antibody, in the treatment of steroid refractory GVHD. Tocilizumab was administered to 8 patients with refractory acute (n = 6) or chronic GVHD (cGVHD) (n = 2) once every 3 to 4 weeks. The majority of patients with acute GVHD (aGVHD) had grade IV organ involvement of the skin or gastrointestinal tract, whereas both patients with cGVHD had long-standing severe skin sclerosis at the time of treatment. There were no allergic or infusion-related adverse events. Treatment was discontinued in one patient over concerns that tocilizumab may have worsened preexisting hyperbilirubinemia. Several patients also had transient elevations in serum transaminase values. Infections were the primary adverse events associated with tocilizumab administration. Four patients (67%) with aGVHD had either partial or complete responses apparent within the first 56 days of therapy. One patient with cGVHD had a significant response to therapy, whereas the second had stabilization of disease that allowed for a modest reduction in immune suppressive medications. These results indicate that tocilizumab has activity in the treatment of steroid refractory GVHD and warrants further investigation as a therapeutic option for this disorder.