A nonrandomized phase I and biomarker trial of regorafenib in advanced myeloid malignancies.

We conducted a single-center, open-label, dose escalation, and expansion phase I trial of the antiangiogenic multikinase inhibitor regorafenib in patients with advanced myeloid neoplasms. We enrolled 16 patients with relapsed/refractory acute myeloid leukemia (AML), myeloproliferative neoplasms (MPN), chronic myelomonocytic leukemia (CMML), or myelodysplastic syndrome (MDS). A 3 + 3 dose escalation design was used with two planned dose levels (120 or 160 mg daily) and one de-escalation level (80 mg daily). An additional 10 patients were treated on an expansion cohort. The recommended phase two dose of regorafenib was 160 mg daily, with no dose-limiting toxicities. The best overall disease response by International Working Group criteria included one partial and stable disease in 11 patients. Tissue studies indicated no change in Ras/mitogen-activated protein kinase (MAPK) pathway activation in responders. Pharmacodynamic changes in plasma VEGF, PlGF, and sVEGFR2 were detected during treatment. Baseline proinflammatory and angiogenic cytokine levels were not associated with clinical response. Single-agent regorafenib demonstrated an acceptable safety profile in relapsed/refractory myeloid malignancy patients. Most patients achieved stable disease, with modest improvements in cell counts in some MDS patients. Biomarker studies were consistent with on-target effects of regorafenib on angiogenesis. Future studies should investigate the role of regorafenib in combination therapy approaches.

Ixazomib in addition to chemotherapy for the treatment of acute lymphoblastic leukemia in older adults.

We sought to assess the safety of adding ixazomib, an oral proteasome inhibitor, to a multi-agent treatment regimen for older adults with acute lymphoblastic leukemia (ALL). Patients 51 to 75 years of age with newly diagnosed ALL were screened. Induction consisted of prednisone (P), vincristine (V), and doxorubicin (D). For BCR-ABL1+ patients, dasatinib was added. On Days 1, 8, 15 of induction, ixazomib was given orally. After induction patients received 1 cycle of consolidation in which ixazomib was given on Days 1, 8, 15. After consolidation, patients in remission (CR) were offered stem cell transplantation. Among the 19 patients treated, 15 (79%) [90% CI, 58-92%] achieved CR or CRi. At 2 years, the overall survival was 47% [95%CI, 29-72%]. In this study the dose of 2.3 mg of ixazomib in combination was the MTD for older patients with ALL and is the recommended dose for future phase 2 studies.

PD-1 inhibition in advanced myeloproliferative neoplasms.

Myelofibrosis (MF) is a clonal stem cell neoplasm characterized by abnormal JAK-STAT signaling, chronic inflammation, cytopenias, and risk of transformation to acute leukemia. Despite improvements in the therapeutic options for patients with MF, allogeneic hematopoietic stem cell transplantation remains the only curative treatment. We previously demonstrated multiple immunosuppressive mechanisms in patients with MF, including increased expression of programmed cell death protein 1 (PD-1) on T cells compared with healthy controls. Therefore, we conducted a multicenter, open-label, phase 2, single-arm study of pembrolizumab in patients with Dynamic International Prognostic Scoring System category of intermediate-2 or greater primary, post-essential thrombocythemia or post-polycythemia vera myelofibrosis that were ineligible for or were previously treated with ruxolitinib. The study followed a Simon 2-stage design and enrolled a total of 10 patients, 5 of whom had JAK2V617mutation, 2 had CALR mutation, and 6 had additional mutations. Most patients were previously treated with ruxolitinib. Pembrolizumab treatment was well tolerated, but there were no objective clinical responses, so the study closed after the first stage was completed. However, immune profiling by flow cytometry, T-cell receptor sequencing, and plasma proteomics demonstrated changes in the immune milieu of patients, which suggested improved T-cell responses that can potentially favor antitumor immunity. The fact that these changes were not reflected in a clinical response strongly suggests that combination immunotherapeutic approaches rather than monotherapy may be necessary to reverse the multifactorial mechanisms of immune suppression in myeloproliferative neoplasms. This trial was registered at www.clinicaltrials.gov as #NCT03065400.

A phase 1 study of the antibody-drug conjugate brentuximab vedotin with re-induction chemotherapy in patients with CD30-expressing relapsed/refractory acute myeloid leukemia.

BACKGROUND: Outcomes for patients with relapsed/refractory acute myeloid leukemia (R/R AML) remain poor. Novel therapies specifically targeting AML are of high interest. Brentuximab vedotin (BV) is an antibody-drug conjugate that is specific for human CD30. In this phase 1 dose escalation study, the authors evaluated the safety of BV combined with mitoxantrone, etoposide, and cytarabine (MEC) re-induction chemotherapy for patients with CD30-expressing R/R AML. METHODS: Using a standard dose escalation design, the authors evaluated 3 dose levels of BV (0.9 mg/kg, 1.2 mg/kg, and 1.8 mg/kg) administered once on day 1 followed by MEC on days 3 through 7. RESULTS: There were no dose-limiting toxicities noted and the maximum tolerated dose was not reached. The recommended phase 2 dose of BV was determined to be 1.8 mg/kg when combined with MEC. The side effect profile was similar to that expected from MEC chemotherapy alone, with the most common grade ≥3 toxicities being febrile neutropenia, thrombocytopenia, and anemia (toxicities were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). Among the 22 patients enrolled on the trial, the composite response rate was 36%, with a composite response rate of 42% noted among those who received the highest dose of BV. The median overall survival was 9.5 months, with a median disease-free survival of 6.8 months observed among responders. Approximately 55% of patients were able to proceed with either allogeneic hematopoietic stem cell transplantation or donor lymphocyte infusion. CONCLUSIONS: The combination of BV with MEC was found to be safe in patients with CD30-expressing R/R AML and warrants further study comparing this combination with the use of MEC alone in this population (ClinicalTrials.gov identifier NCT01830777). LAY SUMMARY: The outcomes for patients with relapsed/refractory acute myeloid leukemia (R/R AML) are exceptionally poor. New and emerging treatment combinations are actively being studied in an effort to improve outcomes. The authors examined the combination of brentuximab vedotin, an antibody product that recognizes a marker called CD30, with mitoxantrone, etoposide, and cytarabine (MEC), a common chemotherapy regimen, in patients with R/R AML that expressed the CD30 marker. The authors found that the combination was safe and well tolerated. Future studies comparing this new combination with the use of MEC alone can help to inform its effectiveness for this patient population.

Alisertib plus induction chemotherapy in previously untreated patients with high-risk, acute myeloid leukaemia: a single-arm, phase 2 trial.

BACKGROUND: Increased aurora A kinase (AAK) expression occurs in acute myeloid leukaemia; AAK inhibition is a promising therapeutic target in this disease. We therefore aimed to assess the activity of alisertib combined with 7 + 3 induction chemotherapy in previously untreated patients with high-risk acute myeloid leukaemia. METHODS: We did a single-arm, phase 2 trial of patients recruited from the Dana-Farber/Harvard Cancer Center in the USA. Eligible patients had previously untreated acute myeloid leukaemia, an Eastern Cooperative Oncology Group performance status of 0-2, and were at high risk of disease as defined by the presence of an adverse-risk karyotype, the presence of secondary acute myeloid leukaemia arising from previous myelodysplastic syndrome or myeloproliferative neoplasm, the presence of therapy-related acute myeloid leukaemia, or being 65 years or older. Enrolled patients received 7 + 3 induction chemotherapy of continuous infusion of cytarabine (100 mg/m2 per day on days 1-7) and intravenous bolus of idarubicin (12 mg/m2 per day on days 1-3). Oral alisertib (30 mg) was given twice per day on days 8-15. Patients could receive up to four consolidation cycles with cytarabine and alisertib, and alisertib maintenance for 12 months. The primary endpoint was a composite including the proportion of patients achieving complete remission and those with a complete remission with incomplete neutrophil or platelet count recovery. Analyses were per-protocol. This study is registered with Clinicaltrials.gov, number NCT02560025, and has completed enrolment. FINDINGS: Between Dec 31, 2015, and Aug 1, 2017, we enrolled a total of 39 eligible patients. 19 (49%) of 39 patients had secondary acute myeloid leukaemia and three (8%) had therapy-related acute myeloid leukaemia. At mid-induction, 33 (85%) of 39 patients showed marrow aplasia, six (15%) received re-induction. The median follow-up was 13·7 months (IQR 12·7-14·4). Composite remission was 64% (two-stage 95% CI 48-79), with 20 (51%) of 39 patients achieving complete remission and five (13%) achieving complete remission with incomplete neutrophil or platelet count recovery. The most common grade 3 or 4 adverse events included febrile neutropenia (16 [41%] of 39), neutropenia (12 [31%]), thrombocytopenia (13 [33%]), anaemia (11 [28%]), anorexia (nine [23%]), and oral mucositis (four [10%]). No treatment-related deaths were observed. INTERPRETATION: These results suggest that alisertib combined with induction chemotherapy is active and safe in previously untreated patients with high-risk acute myeloid leukaemia. This study met criteria to move forward to a future randomised trial. FUNDING: Millennium Pharmaceuticals.

Cabozantinib is well tolerated in acute myeloid leukemia and effectively inhibits the resistance-conferring FLT3/tyrosine kinase domain/F691 mutation.

BACKGROUND: Cabozantinib, a tyrosine kinase inhibitor of FMS-like tyrosine kinase 3 (FLT3), MET, AXL, vascular endothelial growth factor receptor, and KIT, is approved for use in multiple malignancies. We assessed the safety and tolerability of cabozantinib in AML, given up-regulation of multiple relevant pathways. METHODS: Adults were eligible if they were 18 years old or older with relapsed/refractory AML or if they were 70 years old or older with newly diagnosed AML but were ineligible for conventional therapy. Cabozantinib was administered in 28-day cycles, and dose escalation occurred via cohorts. A pharmacodynamic evaluation of serial plasma samples via a plasma inhibitory assay (PIA) was used to assess FLT3-inhibitory activity in FLT3-mutant cell lines. RESULTS: Among 18 patients enrolled, 5 were found to harbor FLT3/ITD mutations. Sixteen patients (89%) had relapsed/refractory AML, and most were treated with 2 or more lines of prior treatment. No dose-limiting toxicities (DLTs) were detected at the first dose level (40 mg daily), but 2 patients experienced DLTs at the next level (60 mg daily). The remaining patients were then dosed at 40 mg daily, the maximum tolerated dose (MTD). Additional grade 2 or higher toxicities, possibly/probably related to cabozantinib, included fatigue, nausea, transaminitis, and electrolyte imbalance. No patients had a marrow response according to formal criteria, but 4 had peripheral blast reductions; 2 of these 4 patients transiently cleared circulating blasts. One patient experienced a reduction in marrow blasts, and 1 had stable disease. The FLT3-inhibitory activity of plasma samples, as assessed with the PIA, revealed potent and sustained inhibition in FLT3/ITD and, notably, F691 tyrosine kinase domain (TKD)-mutant cells. CONCLUSIONS: Cabozantinib is well tolerated in AML patients at an MTD of 40 mg daily and is a potent inhibitor of FLT3/ITD- and F691 TKD-altered tyrosine kinases. Cancer 2018;124:306-14. © 2017 American Cancer Society.

Phase I study of the aurora A kinase inhibitor alisertib with induction chemotherapy in patients with acute myeloid leukemia.

Aberrant expression of aurora kinase A is implicated in the genesis of various neoplasms, including acute myeloid leukemia. Alisertib, an aurora A kinase inhibitor, has demonstrated efficacy as monotherapy in trials of myeloid malignancy, and this efficacy appears enhanced in combination with conventional chemotherapies. In this phase I, dose-escalation study, newly diagnosed patients received conventional induction with cytarabine and idarubicin, after which alisertib was administered for 7 days. Dose escalation occurred via cohorts. Patients could then receive up to four cycles of consolidation, incorporating alisertib, and thereafter alisertib maintenance for up to 12 months. Twenty-two patients were enrolled. One dose limiting toxicity occurred at dose level 2 (prolonged thrombocytopenia), and the recommended phase 2 dose was established at 30mg twice daily. Common therapy-related toxicities included cytopenias and mucositis. Only three (14%) patients had persistent disease at mid-cycle, requiring "5+2" reinduction. The composite remission rate (complete remission and complete remission with incomplete neutrophil recovery) was 86% (nineteen of twenty-two patients; 90% CI 68-96%). Among those over age 65 and those with high-risk disease (secondary acute leukemia or cytogenetically high-risk disease), the composite remission rate was 88% and 100%, respectively. The median follow up was 13.5 months. Of those treated at the recommended phase 2 dose, the 12-month overall survival and progression-free survival were 62% (90% CI 33-81%) and 42% (90% CI 17-65%), respectively. Alisertib is well tolerated when combined with induction chemotherapy in acute myeloid leukemia, with a promising suggestion of efficacy. (clinicaltrials.gov Identifier:01779843).