TP53 copy number and protein expression inform mutation status across risk categories in acute myeloid leukemia.

Mutant TP53 is an adverse risk factor in acute myeloid leukemia (AML), but large-scale integrated genomic-proteomic analyses of TP53 alterations in patients with AML remain limited. We analyzed TP53 mutational status, copy number (CN), and protein expression data in AML (N = 528) and provide a compilation of mutation sites and types across disease subgroups among treated and untreated patients. Our analysis shows differential hotspots in subsets of AML and uncovers novel pathogenic variants involving TP53 splice sites. In addition, we identified TP53 CN loss in 70.2% of TP53-mutated AML cases, which have more deleterious TP53 mutations, as well as copy neutral loss of heterozygosity in 5/32 (15.6%) AML patients who had intact TP53 CN. Importantly, we demonstrate that mutant p53 protein expression patterns by immunohistochemistry evaluated using digital image-assisted analysis provide a robust readout that integrates TP53 mutation and allelic states in patients with AML. Expression of p53 by immunohistochemistry informed mutation status irrespective of TP53 CN status. Genomic analysis of comutations in TP53-mutant AML shows a muted landscape encompassing primarily mutations in genes involved in epigenetic regulation (DNMT3A and TET2), RAS/MAPK signaling (NF1, KRAS/NRAS, PTPN11), and RNA splicing (SRSF2). In summary, our data provide a rationale to refine risk stratification of patients with AML on the basis of integrated molecular and protein-level TP53 analyses.

Ten-day decitabine with venetoclax versus intensive chemotherapy in relapsed or refractory acute myeloid leukemia: A propensity score-matched analysis.

BACKGROUND: Relapsed/refractory (R/R) acute myeloid leukemia (AML) has poor outcomes. Although lower-intensity venetoclax-containing regimens are standard for older/unfit patients with newly diagnosed AML, it is unknown how such regimens compare with intensive chemotherapy (IC) for R/R AML. METHODS: Outcomes of R/R AML treated with 10-day decitabine and venetoclax (DEC10-VEN) were compared with IC-based regimens including idarubicin with cytarabine, with or without cladribine, clofarabine, or fludarabine, with or without additional agents. Propensity scores derived from patient baseline characteristics were used to match DEC10-VEN and IC patients to minimize bias. RESULTS: Sixty-five patients in the DEC10-VEN cohort were matched to 130 IC recipients. The median ages for the DEC10-VEN and IC groups were 64 and 58 years, respectively, and baseline characteristics were balanced between the 2 cohorts. DEC10-VEN conferred significantly higher responses compared with IC including higher overall response rate (60% vs 36%; odds ratio [OR], 3.28; P < .001), complete remission with incomplete hematologic recovery (CRi, 19% vs 6%; OR, 3.56; P = .012), minimal residual disease negativity by flow cytometry (28% vs 13%; OR, 2.48; P = .017), and lower rates of refractory disease. DEC10-VEN led to significantly longer median event-free survival compared with IC (5.7 vs 1.5 months; hazard ratio [HR], 0.46; 95% CI, 0.30-0.70; P < .001), as well as median overall survival (OS; 6.8 vs 4.7 months; HR, 0.56; 95% CI, 0.37-0.86; P = .008). DEC10-VEN was independently associated with improved OS compared with IC in multivariate analysis. Exploratory analysis for OS in 27 subgroups showed that DEC10-VEN was comparable with IC as salvage therapy for R/R AML. CONCLUSION: DEC10-VEN represents an appropriate salvage therapy and may offer better responses and survival compared with IC in adults with R/R AML.

Isavuconazole as Primary Antifungal Prophylaxis in Patients With Acute Myeloid Leukemia or Myelodysplastic Syndrome: An Open-label, Prospective, Phase 2 Study.

BACKGROUND: Mold-active primary antifungal prophylaxis (PAP) is routinely recommended in neutropenic patients with newly diagnosed acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) undergoing remission-induction chemotherapy (RIC). Isavuconazole (ISAV) is an extended spectrum mold-active triazole and has superior tolerability and fewer significant drug-drug interactions compared with other triazoles. METHODS: In our investigator-initiated, phase 2 trial, treatment-naive adult patients with AML or MDS starting RIC received ISAV per the dosing recommendations in the US label until neutrophil recovery (absolute neutrophil count [ANC] ≥ 0.5 × 109/L) and attainment of complete remission, occurrence of invasive fungal infection (IFI), or for a maximum of 12 weeks. The primary endpoint was the incidence of proven/probable IFI during ISAV PAP and up to 30 days after the last dose. RESULTS: Sixty-five of 75 enrolled patients received ISAV PAP (median age, 67 years, median ANC at enrollment, 0.72 × 109/L). Thirty-two patients (49%) received oral targeted leukemia treatments (venetoclax, FTL3 inhibitors). Including the 30-day follow-up period, probable/proven and possible IFIs were encountered in 4 (6%) and 8 patients (12%), respectively. ISAV trough serum concentrations were consistently > 1 µg/mL, showed low intraindividual variation, and were not significantly influenced by chemotherapy regimen. Tolerability of ISAV was excellent, with only 3 cases (5%) of mild to moderate elevations of liver function tests and no QTc prolongations. CONCLUSIONS: ISAV is a safe and effective alternative for PAP in patients with newly diagnosed AML/MDS undergoing RIC in the era of recently approved or emerging small-molecule antileukemia therapies. CLINICAL TRIALS REGISTRATION: NCT03019939.

Factors associated with risk of central nervous system relapse in patients with non-core binding factor acute myeloid leukemia.

Central nervous system (CNS) relapse is uncommon in patients with acute myeloid leukemia (AML) with the use of high-dose cytarabine containing chemotherapy regimens. The clinical and molecular features associated with a higher risk of CNS relapse are not well defined. We assessed the incidence and outcome of CNS relapses among 1245 patients with relapsed/refractory AML referred to our institution between 2000 and 2014. CNS leukemia relapse was observed in 51 patients (4.1%). Using a multivariate regression model and after adjusting for age, FLT3-ITD mutation (OR = 2.33; P = .02) and elevated LDH (>1000 IU/L, OR = 1.99; P = .04) were independent predictive factors for CNS relapse. Patients under 64 years of age with 0, 1, or 2 baseline adverse features had a probability of 3.8%, 7.0%-8.0%, and 13.9% for developing CNS disease, respectively. Our study identifies patients with AML at higher risk for CNS relapse in whom prophylactic CNS therapy may be warranted.

Phase 2 study of the JAK kinase inhibitor ruxolitinib in patients with refractory leukemias, including postmyeloproliferative neoplasm acute myeloid leukemia.

We conducted a phase 2 study of ruxolitinib in patients with relapsed/refractory leukemias. Patients with acceptable performance status (0-2), adequate organ function, and no active infection, received ruxolitinib 25 mg orally twice a day for 4 weeks (1 cycle). Response was assessed after every 2 cycles of treatment, and patients who completed 2 cycles were allowed to continue treatment until disease progression. Dose escalation to 50 mg twice daily was permitted in patients demonstrating a benefit. Thirty-eight patients, with a median age of 69 years (range, 45-88), were treated. The median number of prior therapies was 2 (range, 1-6). Twelve patients had JAK2V617F mutation. Patients received a median of 2 cycles of therapy (range, 1-22). Three of 18 patients with postmyeloproliferative neoplasm (MPN) acute myeloid leukemia (AML) showed a significant response; 2 achieved complete remission (CR) and one achieved a CR with insufficient recovery of blood counts (CRi). The responding patients with palpable spleens also had significant reductions in spleen size. Overall, ruxolitinib was very well tolerated with only 4 patients having grade 3 or higher toxicity. Ruxolitinib has modest antileukemic activity as a single agent, particularly in patients with post-MPN AML. The study was registered at www.clinicaltrials.gov as NCT00674479.

A phase I and pharmacokinetic study of XK469R (NSC 698215), a quinoxaline phenoxypropionic acid derivative, in patients with refractory acute leukemia.

A phase I study was performed to determine the safety and pharmacokinetics of XK469R in patients with refractory acute leukemia. The study aimed to determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of XK469R given intravenously over 30 to 60 min on days 1, 3, and 5 of a 21 day cycle. Patients were treated in successive cohorts of six until DLT was observed. Once the MTD was determined, an additional cohort of six patients was enrolled at the previous dose level and that dose was considered the recommended phase 2 dose (RPTD). Forty-six patients were treated at dose levels of 1,400, 1,750, 2,200, and 2,750 mg. The DLTs were: mucositis, colitis and hyperbilirubinemia. Reversible myelosuppression was noted at all dose levels. One (2%) of 42 patients achieved a complete remission and five patients (11%) had hematologic improvement. The half-life of the drug was long with a mean value of 48 h. The mean clearance was 206 mL/h with a coefficient of variation of 32%. No correlation was observed between the development of DLT and pharmacokinetics. The RTPD is 1,750 mg. XK469R induced hematological responses in patients with refractory leukemia at tolerable doses.

Troxacitabine activity in extramedullary myeloid leukemia.

Troxacitabine is a novel L-enantiomer nucleoside analog with unique properties in terms of its structure, pharmacokinetics, intracellular transport, and susceptibility to mechanisms of resistance. Troxacitabine has significant activity in patients with refractory myeloid leukemias, both as a single agent and when combined with standard anti-leukemia agents. In a cohort of 170 patients with refractory myeloid leukemia treated with troxacitabine-based regimens on Phase 1 or 2 studies, 10 (6%) had biopsy-proven extramedullary disease, either with or without bone marrow involvement. Six of these patients who received single-agent troxacitabine, 4 received a combination of troxacitabine and cytarabine. Complete response and disappearance of all extramedullary lesions were observed in 6 (60%) of these 10 patients. Two of the 6 responding patients relapsed within 3 months, 2 patients had remissions of 8 and 9 months duration, respectively, 1 patient is in on-going remission at 3, and 1 patient is lost to follow-up. Troxacitabine-based therapy had significant antileukemic activity in extramedullary myeloid leukemias and warrants further investigation in this clinical situation.

Phase II study of troxacitabine, a novel dioxolane nucleoside analog, in patients with refractory leukemia.

PURPOSE: To investigate the activity of a novel dioxolane L-nucleoside analog, troxacitabine (L-(-)-OddC, BCH-4556), in patients with refractory leukemia. PATIENTS AND METHODS: Study participants were patients with refractory or relapsed acute myeloid (AML) or lymphocytic (ALL) leukemia, myelodysplastic syndromes (MDS), or chronic myelogenous leukemia in blastic phase (CML-BP). Troxacitabine was provided as an intravenous infusion for more than 30 minutes daily for 5 days at a dose of 8.0 mg/m(2)/d (40 mg/m(2) per course). Courses were given every 3 to 4 weeks according to antileukemic efficacy. RESULTS: Forty-two patients (AML, 18 patients; MDS, one patient; ALL, six patients; CML-BP, 17 patients) were treated. Median age was 51 years (range, 23 to 80 years); 22 patients were male. Stomatitis was the most significant adverse event, with three patients (7%) and two patients (5%), respectively, experiencing grade 3 or 4 toxicity. Ten patients (24%) had grade 3 hand-foot syndrome, and two patients (5%) had grade 3 skin rash. One patient (2%) had grade 3 fatigue and anorexia. Marrow hypoplasia occurred between days 14 and 28 in 12 (75%) of 16 assessable patients with AML. Two complete remissions and one partial remission (18%) were observed in 16 assessable patients with AML. None of six patients with ALL responded. Six (37%) of 16 assessable patients with CML-BP experienced a return to chronic-phase disease. CONCLUSION: Troxacitabine has significant antileukemic activity in patients with AML and CML-BP.