Key Points• Gilteritinib is active against a wide range of clinically relevant activating FLT3 mutations.• Resistance-conferring FLT3 kinase domain mutations are responsible for a minority of clinical resistance to gilteritinib.Gilteritinib is the first FMS-like tyrosine kinase 3 (FLT3) tyrosine kinase inhibitor (TKI) approved as monotherapy in acute myeloid leukemia with FLT3 internal tandem duplication and D835/I836 tyrosine kinase domain (TKD) mutations. Sequencing studies in patients have uncovered less common, noncanonical (NC) mutations in FLT3 and have implicated secondary TKD mutations in FLT3 TKI resistance. We report that gilteritinib is active against FLT3 NC and TKI resistance-causing mutations in vitro. A mutagenesis screen identified FLT3 F691L, Y693C/N, and G697S as mutations that confer moderate resistance to gilteritinib in vitro. Analysis of patients treated with gilteritinib revealed that 2/9 patients with preexisting NC FLT3 mutations responded and that secondary TKD mutations are acquired in a minority (5/31) of patients treated with gilteritinib. Four of 5 patients developed F691L mutations (all treated at ,200 mg). These studies suggest that gilteritinib has broad activity against FLT3 mutations and limited vulnerability to resistance-causing FLT3 TKD mutations, particularly when used at higher doses.

Long-term disease-free survival in adults with T-cell acute lymphoblastic leukemia (T-ALL) remains poor, particularly after relapse, with few available salvage options. Preclinical data suggest that inhibition of the antiapoptotic protein BCL-2 (B-cell lymphoma 2) either alone or in combination with other agents, may be a unique therapeutic approach for the treatment of T-ALL. We present a case of a young male with T-ALL, relapsed after allogeneic hematopoietic stem cell transplant, who achieved a second complete remission following salvage therapy with combined venetoclax and decitabine. Assessment of measurable residual disease by next generation sequencing showed no evidence of residual disease of a sensitivity of 1 × 10−6. While the combination of venetoclax and hypomethylating agents has shown promise in the treatment of relapsed/refractory AML, and to our knowledge, this is the first report of this combination demonstrating clinical activity in relapsed/refractory T-ALL.

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Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic disorder which shares clinical and morphological features of myelodysplastic syndrome and myeloproliferative neoplasms. Conventional therapeutic options include hydroxyurea, hypomethylating agents, and systemic chemotherapy, which are all palliative measures and are associated with potential side effects. Allogeneic hematopoietic cell transplantation is the only curative option. Natural health products such as papaya leaf extract and dandelion root extract have been shown to demonstrate anticancer activity in preclinical and clinical studies, respectively. We present a case study of a 76-year-old male with previously untreated CMML, whose hematological parameters remained stable and whose bone marrow blast counts vastly improved while taking papaya leaf extract and dandelion root extract.

Chronic graft-versus-host disease (cGvHD) is a grave complication of allogeneic hematopoietic cell transplantation (alloHCT). Despite the use of prophylactic regimens for cGvHD, a significant proportion of patients develop cGvHD following alloHCT. The standard first-line therapy for cGvHD is high-dose corticosteroids. However, roughly 50% of patients will exhibit steroid-refractory or steroid-dependent cGvHD, which increases the risk of non-relapse mortality. Ibrutinib was approved by the U.S. Food and Drug Administration (FDA) in August 2017 for the treatment of cGvHD after failure of one or more lines of systemic therapy. The approval was based on a study that demonstrated high rates of sustained responses and manageable toxicities in patients with steroid-refractory or -dependent cGvHD. In this review, we address the mechanisms of action of ibrutinib in cGvHD, as well as preclinical and clinical data supporting its use in patients with this important post-transplant complication.