scholarly journals Current challenges in clinical development of “targeted therapies”: the case of acute myeloid leukemia

Blood ◽  
2015 ◽  
Vol 125 (16) ◽  
pp. 2461-2466 ◽  
Author(s):  
Elihu Estey ◽  
Ross L. Levine ◽  
Bob Löwenberg

Abstract A fundamental difficulty in testing “targeted therapies” in acute myeloid leukemia (AML) is the limitations of preclinical models in capturing inter- and intrapatient genomic heterogeneity. Clinical trials typically focus on single agents despite the routine emergence of resistant subclones and experience in blast-phase chronic myeloid leukemia and acute promyelocytic leukemia arguing against this strategy. Inclusion of only relapsed-refractory, or unfit newly diagnosed, patients risks falsely negative results. There is uncertainty as to whether eligibility should require demonstration of the putative target and regarding therapeutic end points. Although use of in vivo preclinical models employing primary leukemic cells is first choice, newer preclinical models including “organoids” and combinations of pharmacologic and genetic approaches may better align models with human AML. We advocate earlier inclusion of combinations ± chemotherapy and of newly diagnosed patients into clinical trials. When a drug plausibly targets a pathway uniquely related to a specific genetic aberration, eligibility should begin with this subset, including patients with other malignancies, with subsequent extension to other patients. In other cases, a more open-minded approach to initial eligibility would facilitate quicker identification of responsive subsets. Complete remission without minimal residual disease seems a particularly useful short-term end point. Genotypic and phenotypic studies should be prespecified and performed routinely to distinguish responders from nonresponders.

Haematologica ◽  
2020 ◽  
pp. 1-13
Author(s):  
Vikas Madan ◽  
H. Phillip Koeffler

Acute myeloid leukemia is characterized by arrested differentiation, and agents that overcome this block are therapeutically useful, as shown by the efficacy of all-trans retinoic acid in acute promyelocytic leukemia. However, the early promise of differentiation therapy did not translate into clinical benefit for other subtypes of acute myeloid leukemia, in which cytotoxic chemotherapeutic regimens remained the standard of care. Recent advances, including insights from sequencing of acute myeloid leukemia genomes, have led to the development of targeted therapies, comprising agents that induce differentiation of leukemic cells in preclinical models and clinical trials, thus rejuvenating interest in differentiation therapy. These agents act on various cellular processes including dysregulated metabolic programs, signaling pathways, epigenetic machinery and the cell cycle. In particular, inhibitors of mutant IDH1/2 and FLT3 have shown clinical benefit, leading to approval by regulatory bodies of their use. Besides the focus on recently approved differentiation therapies, this review also provides an overview of differentiation- inducing agents being tested in clinical trials or investigated in preclinical research. Combinatorial strategies are currently being tested for several agents (inhibitors of KDM1A, DOT1L, BET proteins, histone deacetylases), which were not effective in clinical studies as single agents, despite encouraging anti-leukemic activity observed in preclinical models. Overall, recently approved drugs and new investigational agents being developed highlight the merits of differentiation therapy; and ongoing studies promise further advances in the treatment of acute myeloid leukemia in the near future.


Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2465-2470 ◽  
Author(s):  
J.F. San Miguel ◽  
A. Martı́nez ◽  
A. Macedo ◽  
M.B. Vidriales ◽  
C. López-Berges ◽  
...  

Abstract A high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1073-1073
Author(s):  
Hiroto Inaba ◽  
Jeffrey E Rubnitz ◽  
Elaine Coustan-Smith ◽  
Lie Li ◽  
Brian D Furmanski ◽  
...  

Abstract Abstract 1073 Background: Aberrant receptor tyrosine kinase (RTK) signaling arising from genetic abnormalities, such as FLT3-internal tandem duplications (FLT3-ITD), is an important mechanism in the development and growth of acute myeloid leukemia (AML) and is often associated with a poor outcome. Hence, inhibition of RTK signaling is an attractive novel treatment option, particularly for disease that is resistant to conventional chemotherapy. We evaluated the clinical activity of the multikinase inhibitor sorafenib in children with de novo FLT3-ITD–positive AML or relapsed/refractory AML. Methods: Fourteen patients were treated. Six patients with newly diagnosed FLT3- ITD–positive AML (aged 9–16 years; median, 12 years) received 2 cycles of remission induction therapy and then started sorafenib (200 mg/m2 twice daily for 20 days) the day after completing induction II (low-dose cytarabine, daunorubicin, and etoposide). Nine patients (aged 6–17 years; median, 9 years) with relapsed AML (including one treated on the above regimen) received sorafenib alone (2 dose levels; 200 and 150 mg/m2) twice daily for the first week of therapy, concurrently with clofarabine and cytarabine on days 8–12, and then alone from days 13 to 28. Sorafenib pharmacokinetics were analyzed at steady-state on day 8 of sorafenib in patients with newly diagnosed AML and on day 7 in patients with relapsed AML. In patients with relapsed AML, the effect of sorafenib on signaling pathways in AML cells was assessed by flow cytometry. Results: All 6 newly diagnosed patients, including 2 whose AML was refractory to induction I, achieved a complete remission (CR) after induction II; 5 had negative minimal residual disease (MRD; <0.1% AML cells in bone marrow) after induction II. Both patients in this group who relapsed achieved second remissions, one with sorafenib alone and one on the relapse regimen described above. Of the 9 patients with relapsed AML, 6 (4 with FLT3-ITD) were treated with sorafenib 200 mg/m2. All 6 had a >50% decrease in blast percentage and/or bone marrow cellularity after 1 week of sorafenib. After concurrent sorafenib and chemotherapy, 5 of the 9 patients with relapsed AML achieved CR (2 had negative MRD) and 2 achieved a partial remission (PR; 5%-25% AML cells in bone marrow); all 4 patients with FLT3-ITD had a CR or PR. After sorafenib treatment, 6 patients underwent HSCT while 2 with FLT3-ITD who could not receive HSCT were treated with single-agent sorafenib and have maintained CR for up to 8 months. Hand-foot skin reaction (HFSR) or rash occurred in all patients and improved with cessation of sorafenib. Dose-limiting toxicity (DLT, grade 3 HFSR and/or rash) was observed in 3 of the 6 patients with relapsed AML treated with 200 mg/m2 of sorafenib; no DLT was observed at 150 mg/m2. The effect of sorafenib on downstream RTK signaling was tested in the leukemic cells of 4 patients: in most samples, phosphorylation of S6 ribosomal protein and 4E-BP1 was inhibited. The mean (± SD) steady-state concentration (Css) of sorafenib was 3.3 ± 1.2 mg/L in the newly diagnosed group and 6.5 ± 3.6 mg/L (200 mg/m2) and 7.3 ± 3.6 mg/L (150 mg/m2) in those with relapsed AML. In both groups, the mean conversion of sorafenib to sorafenib N-oxide was 27%-35% (approximately 3 times greater than previously reported), and mean sorafenib N-oxide Css was 1.0–3.2 mg/L (2.1-6.7 μM). In a 442-kinase screen, the inhibitory profiles of sorafenib N-oxide and sorafenib were similar, and FLT3-ITD phosphorylation was potently inhibited by both forms (sorafenib N-oxide Kd = 0.070 μM; sorafenib Kd = 0.094 μM). Sorafenib N-oxide inhibited the growth of an AML cell line with FLT3-ITD (IC50 = 0.026 μM) and 4 AML cell lines with wild-type FLT3 (IC50 = 3.9–13.3 μM) at approximately half the potency of sorafenib. Conclusion: In children with de novo FLT3-ITD and relapsed/refractory AML, sorafenib given alone or with chemotherapy induced dramatic responses and inhibited aberrant RTK signaling in leukemic cells. Sorafenib and its active metabolite (sorafenib N-oxide) likely contribute to both efficacy and toxicity. These results warrant the incorporation of sorafenib into future pediatric AML trials. Disclosures: Inaba: Bayer/Onyx: Research Funding. Off Label Use: Sorafenib and clofarabine: both used for treatment of pediatric acute myeloid leukemia.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2357-2357
Author(s):  
Michael Boyiadzis ◽  
Chang Sook Hong ◽  
Theresa L Whiteside

Abstract Background: Exosomes are virus-size (30–100 nm in diameter) membrane-bound microvesicles that are formed within the endocytic compartments and via fusion of multivesicles bodies are released into extracellular space. The exosomal cargo includes proteins/glycoproteins expressed on the cell membrane as well as molecules and soluble factors present in the cytosol of parental cells. While exosome secretion occurs under physiologic conditions, and all cells are capable of their release, tumor cells are avid exosome producers. Patients newly diagnosed with acute myeloid leukemia (AML) prior to any therapy have higher levels of exosomes compared to normal controls (NC). We hypothesize that the molecular content of isolated exosomes, which are thought to mimic that of leukemic blasts, could be informative about the presence in the bone marrow of leukemic blasts that might avoid detection by conventional hematopathological assays. Methods: Samples of venous blood (20-50 mL) were obtained from patients newly diagnosed with AML prior to any treatment (n=13), after completion of initial induction chemotherapy in patients who achieved complete remission (n=8), during consolidation therapy and age-matched healthy volunteers. Exosome fractions were isolated from plasma by exclusion chromatography on Sephadex G50 columns followed by ultracentrifugation. Exosome protein content was determined and expressed in µg protein/mL plasma. Isolated exosomes were characterized by western blots for expression of classical exosomal markers and for expression of novel myeloid cell surface markers associated with AML, interleukin-3 receptor a chain (CD123) and C-type lectin-like molecule-1 (CLL-1). Results: The exosome fractions isolated from AML patients’ plasma at diagnosis had a considerably greater mean protein content (81.5 ± 10.8 μg protein/mL plasma) than did exosome fractions isolated from the plasma of NC (13.1 ± 2.4 μg protein/mL plasma) with p < 0.005. The molecular profile of exosomes isolated from plasma of AML patients at diagnosis was distinct from that of exosomes isolated from plasma of NC. In addition to classical exosomal markers (MHC class I molecules, LAMP-1, CD81) exosomes isolated from AML patients at diagnosis contained CD34, CD117, CD123 and CLL-1. The exosome fractions isolated from the patients’ plasma who achieved complete remission (n=8) remained elevated, similar to the levels at the time of AML diagnosis (78.5 vs 77.5 μg protein/mL plasma). Exosomes in AML patients who achieved complete remission and in patients receiving consolidation therapy when leukemic blasts are undetectable in the bone marrow by conventional hematopathological methods contained CD123 and CLL-1. Conclusions: Exosomes in AML patients have a unique and distinctive molecular profile. The exosomal profile suggest the presence of residual disease in patients considered to have achieved complete remission by conventional hematopathologic assays. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3695-3695 ◽  
Author(s):  
Michele Malagola ◽  
Crisitina Skert ◽  
Enrico Morello ◽  
Francesca Antoniazzi ◽  
Erika Borlenghi ◽  
...  

Abstract Background: Although a complete remission (CR) can be achieved in 70-80% of newly diagnosed acute myeloid leukemia (AML) patients, relapses occur in up to the 50% of cases. Thus, minimal residual disease (MRD) monitoring is a major issue for early detection of patients at high-risk of treatment failure and relapse. Aim: to dynamically evaluate WT1 pan-leukemic molecular marker of MRD in patients with AML. Matherial and methods: 107 newly diagnosed AML patients consecutively treated between 2010 and 2013 were monitored with quantitative WT-1 from bone marrow (BM) and peripheral blood (PB) at baseline, after induction, after the first consolidation course, before allogeneic stem cell transplantation (allo-SCT), at the 3rd and the 6th month after transplantation Results: At diagnosis, 104/107 (97%) had increased PB and BM WT1 levels assessed according to the ELN assay. Eighty-eight out of 107 patients (82%) achieved a complete remission (CR) after induction, 30/88 (34%) relapsed during follow up and 24/107 (22%) were addressed to allogeneic stem cell transplantation (allo-SCT). By univariate analysis, PB-WT > 50x10^4/ABL and BM-WT1 > 250x10^4/ABL after induction (PB: p=0.02; BM: p=0.04), after consolidation (PB: p=0.003), at the end of treatment (PB and BM: p=0.001), at 3rd month of follow up (PB and BM: p=0.005) and at 6th month of follow up (PB: p=0.005) were associated with a reduced overall survival (OS). By multivariate analysis, a BM-WT1 > 250 x 10^4/ABL at the end of treatment was significantly associated with a reduced OS. In order to adapt the cut-off of WT1 in our series of patients, we considered WT1 levels as continuous variables and categorized them at approximately the 25th, 50th, and 75th percentile. A cut-off of PB-WT1 > 25x10^4/ABL and BM-WT1 > 125x10^4/ABL at the end of the treatment program was identified as correlated with reduced leukemia-free survival (LFS) and OS (p=0.001). Similarly, and restricting the analysis on the 24 patients allo-transplanted in CR, 8/11 (73%) with pre-transplant PB-WT1 ≥ 5 and 4/13 (31%) with PB-WT1 < 5 relapsed, respectively (p=0.04). The incidence of relapse was higher in AML patients with PB-WT1 ≥ 5 measured at 3rd (56% vs 38%; p=0.43) and 6th month (71% vs 20%; p=0.03) after allo-SCT. Interestingly, 5/5 (100%) patients with pre-transplant PB-WT1 ≥ 5 who never reduced this level at 3rd or 6th month after allo-SCT experienced a disease recurrence. Conclusions: our data, although retrospectively collected, show that WT1 monitoring may be useful to predict the relapse in AML patients. Acknowledgments: This work was supported in part by Banca di Credito Cooperativo di Pompiano e Franciacorta and Lions Club Bassa Bresciana Association. Disclosures Russo: Celgene: Research Funding; Gilead: Research Funding; Novartis: Consultancy.


2011 ◽  
Vol 2011 ◽  
pp. 1-23 ◽  
Author(s):  
Håkon Reikvam ◽  
Kimberley Joanne Hatfield ◽  
Astrid Olsnes Kittang ◽  
Randi Hovland ◽  
Øystein Bruserud

The t(8;21) abnormality occurs in a minority of acute myeloid leukemia (AML) patients. The translocation results in an in-frame fusion of two genes, resulting in a fusion protein of one N-terminal domain from the AML1 gene and four C-terminal domains from the ETO gene. This protein has multiple effects on the regulation of the proliferation, the differentiation, and the viability of leukemic cells. The translocation can be detected as the only genetic abnormality or as part of more complex abnormalities. If t(8;21) is detected in a patient with bone marrow pathology, the diagnosis AML can be made based on this abnormality alone. t(8;21) is usually associated with a good prognosis. Whether the detection of the fusion gene can be used for evaluation of minimal residual disease and risk of leukemia relapse remains to be clarified. To conclude, detection of t(8;21) is essential for optimal handling of these patients as it has both diagnostic, prognostic, and therapeutic implications.


2018 ◽  
Vol 49 (1) ◽  
pp. 20-27
Author(s):  
Amina H Hassab ◽  
Dalia A Nafea ◽  
Rania S Swelem ◽  
Basma M Ghazal

AbstractBackgroundAcute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by a clonal expansion of myeloid blasts. Treatment strategies of patients with AML are based on various prognostic factors, including age and performance status of the patient, as well as cytogenetic and molecular characteristics of the leukemic clone.Our aim was to study the expression of cluster of differentiation (CD)25 in adult Egyptian patients with newly diagnosed AML and to assess its prognostic relevance.MethodsThis study was conducted on 50 newly diagnosed AML patients at the Hematology Unit, Internal Medicine Department, Alexandria Main University Hospital. All patients were subjected to full history taking, thorough clinical examination, and laboratory investigations, including detection of CD25 expression on blast cells by flow cytometry. Conventional karyotyping was done on 11 patients at the time of diagnosis.ResultsIn our study group, 12 patients were positive for CD25 expression, and this positivity was associated with worse overall survival and shorter leukemia-free survival. On evaluating the response to treatment among CD25-positive AML patients with normal karyotype, they had lower complete remission rates and higher relapse and death rates.ConclusionsExpression of CD25 in AML patients at presentation can be considered a poor independent prognostic factor.


Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2465-2470 ◽  
Author(s):  
J.F. San Miguel ◽  
A. Martı́nez ◽  
A. Macedo ◽  
M.B. Vidriales ◽  
C. López-Berges ◽  
...  

A high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.


Blood ◽  
1994 ◽  
Vol 84 (4) ◽  
pp. 1237-1242 ◽  
Author(s):  
VM Santana ◽  
CA Hurwitz ◽  
RL Blakley ◽  
WR Crom ◽  
X Luo ◽  
...  

Abstract The majority of children with acute myeloid leukemia (AML) who are treated exclusively with chemotherapy die of progressive disease. Improvement in outcome will likely require new active drugs capable of eradicating resistant blast cells early in the clinical course. We therefore assessed the cytoreductive potential of 2- chlorodeoxyadenosine (2-CdA), a halogenated purine analogue, in 22 consecutive children with newly diagnosed AML. The drug was administered as a single 120-hour continuous infusion (8.9 mg/m2 of body surface area per day) before the introduction of standard remission induction therapy. Six patients (27%) had complete hematologic remissions by a median of 21 days after treatment with the nucleoside (range, 14 to 33 days). Seven others had partial responses, yielding a total response rate of 59%. The drug also eliminated leukemic cells from cerebrospinal fluid in 4 of the 6 patients tested. Concentrations of 2-CdA in cerebrospinal fluid on day 5 after the initiation of treatment ranged from 12.4% to 38.0% (mean, 22.7%) of the steady-state plasma concentrations. Severe but reversible myelosuppression and thrombocytopenia developed in all patients. Analysis of factors that may have influenced the complete remission rate suggested a better outcome in patients with myeloblastic leukemia (M0-M2 subtypes in the revised French-American-British classification system). These results demonstrate clinically significant activity by 2- CdA against previously untreated AML in children, including leukemic blast cells in the central nervous system. Its use in combination chemotherapy may improve the outlook for patients with this often fatal hematologic cancer.


Sign in / Sign up

Export Citation Format

Share Document