Combination Of ATRA Research Articles

Phase II single-arm, single-center clinical trial of all-trans-retinoic acid, bevacizumab, and atezolizumab in refractory microsatellite stable colorectal cancer.

TPS324 Background: A critical clinical challenge in microsatellite stable (MSS) metastatic colorectal (mCRC) patients is to identify strategies to overcome lack of response to immune checkpoint inhibitors. An immunosuppressive tumor microenvironment comprising myeloid-derived suppressor cells (MDSC), endothelial cells, regulatory T cells, tumor associated macrophages, and cancer associated fibroblasts promotes immune evasion and resistance to these agents. MDSCs are bone marrow derived myeloid cells that suppress T-cell function and promote tumor growth. Among all cancers, mCRC patients have one of the highest frequency of MDSC (CD11b+, CD33+, CD14+ HLA-DRneg) in blood (1). It was demonstrated that altering the MDSC% in the tumor microenvironment by ATRA and anti-VEGF therapy (bevacizumab) can enhance the effects of immune checkpoint inhibitors (2-4). The hypothesis of the current clinical trial is that the combination of ATRA, bevacizumab and atezolizumab will lead to a decrease in MDSC population in tumor microenvironment leading to a clinically meaningful improvement in response rates among refractory MSS mCRC patients. Methods: This is a single-arm, open-label, phase 2 clinical trial combining ATRA, bevacizumab, and atezolizumab in refractory MSS mCRC patients. It will enroll a total of 21 patients over 24 months at UT Southwestern Medical Center that are MSS by PCR or NGS testing or are proficient in immunohistochemical expression of all four mismatch repair enzymes (MLH1, MSH2, MSH6, PMS2). ATRA will be administered orally at 45 mg/m2/day in 2 divided doses on days 1-7 and repeated every 14 days; atezolizumab will be given intravenously on day 1 at 840 mg dose every 14 days, and bevacizumab will be administered intravenously on day 1 at 10 mg/kg dose every 14 days. The first six patients enrolled on this study will contribute to the safety lead-in phase of this study. The primary outcome is to assess the overall response rate by RECIST v1.1. Secondary outcomes include assessment of disease control rate and frequency of adverse events using CTCAE v5.0. Exploratory outcomes include assessment of PFS and OS and collecting blood and tissue samples at defined timelines to study the changes in the MDSC population among responders and non-responders (NCT05999812). 1. Kobayashi, M. et. al., Clin Cancer Res, 2019. 2. Mirza, N., et al., Cancer Res, 2006. 3. Tobin, R.P., et al., Int Immunopharmacol, 2018. 4. Tobin, R.P., et. al., Clin Can Res, 2023. Clinical trial information: NCT05999812 .

All-trans retinoic acid-mediated ADAR1 degradation synergizes with PD-1 blockade to suppress pancreatic cancer.

As a double-stranded RNA-editing enzyme and an interferon-stimulated gene, double-stranded RNA-specific adenosine deaminase (ADAR1) suppresses interferon signaling and contributes to immunotherapy resistance. Suppression of ADAR1 overcomes immunotherapy resistance in preclinical models, but has not yet been translated to clinical settings. By conducting a screening of a subset of the FDA-approved drugs, we found that all-trans retinoic acid (ATRA, also known as tretinoin) caused ADAR1 protein degradation through ubiquitin-proteasome pathways and concomitantly increased PD-L1 expression in pancreatic and breast cancers. In addition, the combination of ATRA and PD-1 blockade reprogrammed the tumor microenvironment and unleashed antitumor immunity and thereby impeded tumor growth in pancreatic cancer mouse models. In a pilot clinical trial, a higher dose of ATRA plus the anti-PD-1 antibody nivolumab prolonged median overall survival in patients with chemotherapy-resistant pancreatic cancer compared to a lower dose of the same regimen. In this study, ATRA was the first drug to be found to cause ADAR1 degradation. We propose translation of a promising 2-pronged antitumor strategy using ATRA and nivolumab to convert immunologically "cold" into "hot" tumors susceptible to immune checkpoint blockade.

A rare incidence of severe dermatological toxicities triggered by concomitant administration of all-trans retinoic acid and triazole antifungal in patients with acute promyelocytic leukemia: a case series and review of the literature

BackgroundAll-trans retinoic acid (ATRA) is an indispensable part of the treatment of acute promyelocytic leukemia (APL). Although, mild cutaneous toxicities like mucocutaneous xerosis, rash, and pruritus are well reported, ATRA associated severe dermatological toxicities are extremely rare. ATRA is primary metabolized by cytochrome P450 (CYP450) enzyme system, and triazole antifungals are notorious for their strong inhibitory effect on CYP450.Case presentationThree Asian APL patients experienced rare ATRA-induced severe dermatological toxicities: exfoliative dermatitis (ED) in cases 1 and 2, and necrotic scrotal ulceration in case 3. Both case 1 (33-year-old female), and case 2 (28-year-old male) landed in emergency department with dehydration, generalized skin erythema and xerosis during their induction chemotherapy. Both of these patients also developed invasive aspergillosis and required concomitant triazole antifungals during their chemotherapy. For ED, intravenous fluids and broad-spectrum antibiotics were started along with application of local emollients to prevent transdermal water loss. Although their general condition improved but skin exfoliation continued with complete desquamation of palms and soles. Dermatology was consulted, and clinical diagnosis of ED was established. Discontinuation of ATRA resulted in complete resolution of ED. Case 3 (15-year-old boy) reported two blackish mildly tender scrotal lesions during induction chemotherapy. He also had mucocutaneous candidiasis at presentation and was kept on triazole antifungal. Local bacterial & fungal cultures, and serological testing for herpes simplex virus were reported negative. Despite adequate local care and optimal antibiotic support, his lesions persisted, and improved only after temporary discontinuation of ATRA. After a thorough literature review and considering the temporal association of cutaneous toxicities with triazole antifungals, we speculate that the concomitant use of triazole antifungals inhibited the hepatic metabolism of ATRA, resulting in higher serum ATRA concentration, and markedly accentuated cutaneous toxicities in our patients.ConclusionBy highlighting this crucial pharmacokinetic interaction, we want to caution the fellow oncologists to be mindful of the inhibitory effect of triazole antifungals on CYP450. We propose using a non-myelosuppressive combination of ATRA and arsenic trioxide for management of APL hence, obliterating the need of prophylactic antifungals. However, in the event of invasive fungal infection (IFI), we suggest using alternative class of antifungals.

The CDK4/6 Inhibitor Palbociclib Synergizes with ATRA to Induce Differentiation in AML.

Differentiation therapy based on ATRA almost cured acute promyelocytic leukemia (APL). However, it is disappointing that ATRA is not effective against other acute myeloid leukemia (AML) subtypes. Developing new and effective anti-AML therapies that promote leukemia differentiation is necessary. The CDK4/6-cyclin D pathway is a key initiator of the G1-S phase transition, which determines cell fate. Herein, we investigated whether the CDK4/6 inhibitor palbociclib would synergize with ATRA to promote leukemia differentiation in vitro and in vivo. Our findings revealed that CDK4/6-cyclin D pathway genes were aberrantly expressed in AML, and we observed that palbociclib sensitized AML cells to ATRA-induced morphologic, biochemical, and functional changes indicative of myeloid differentiation. The combination of palbociclib and ATRA attenuated AML cell expansion in vivo. These enhanced differentiation effects may be associated with the regulation of transcription factors, including RARα, E2F1, and STAT1. Overall, our findings demonstrate that CDK4/6 inhibition sensitizes AML cells to ATRA and could guide the development of novel therapeutic strategies for patients with AML.

Long-term decitabine/retinoic acid maintenance treatment in an elderly sAML patient with high-risk genetics

Elderly patients with AML ineligible for induction have a dismal prognosis; hence disease stabilization is a primary treatment goal. This case of a 75-year-old patient with secondary AML receiving the combination of decitabine and ATRA (within the DECIDER trial, NCT00867672) demonstrates an above-average survival. The therapy administered over 52 cycles led to complete molecular and hematological remission and resulted in 5.3 years overall survival. Clonal evolution of the leukemic clone could be demonstrated using DNA sequencing methods. According to the literature, this case constitutes the longest continued HMA exposure in an elderly AML patient ineligible for standard chemotherapy.

Comparison of maintenance regimens in Acute Promyelocytic Leukemia patients

Maintenance therapy in APL is still a standard especially in high-risk patients treated with chemotherapy+ATRA combination whereas the role of the maintenance therapy in low-risk patients is controversial. This study aims to compare the efficacy and toxicity of ATRA monotherapy and ATRA+MTX+ 6-MP combination as the maintenance treatment for 2 years in APL patients who achieved molecular complete response after induction and consolidation with ATRA+chemotherapy. A total of 71 patients from 4 different centers were included in this study. After a median follow-up of 54 months (5–180 months), the 5-year RFS was 89 % in the ATRA monotherapy arm, the 5-year RFS was 78.5 % in the combined treatment arm (p = 0.643, HR:1.3, 95 % CI: 0.35–5.3). Hematological toxicity in all grades and Grade III/IV hematological toxicity was observed significantly more in the combined treatment arm than in the ATRA monotherapy arm (All grades: 76.9 % vs 18.9 %, p < 0.001; Grade III/IV: 20.5 % vs. 3.1 %, p = 0.035). Hepatotoxicity at all levels was significantly higher in the combined treatment arm than in the ATRA monotherapy arm (61.5 % vs 25 %, p = 0.002). Our study concluded that two years of ATRA monotherapy and combined maintenance therapy, both of which were found to be similar in terms of disease control and long term survival, ATRA Monotherapy could be a safer maintenance treatment option since both hematological and non-hematological toxicities were observed less often in the ATRA monotherapy arm.

Shifting gears to differentiation agents in acute promyelocytic leukemia with resource constraints—a cohort study

Background Treatment of acute promyelocytic leukaemia has emerged as a major success in hemato-oncology. While literature from the developed world boasts of outstanding outcomes, there is a paucity of data from the developing world. This study aimed to assess complications and outcomes of acute promyelocytic leukaemia in a resource-constrained setting. Methods We retrospectively collected data from patients diagnosed with APL from January 2016 to December 2020. Results Sixty-four patients were treated-32 in both the Sanz high and low-risk groups. In the Sanz low-risk group, 12.5% of patients received ATRA with daunorubicin and 81.25% received ATRA with ATO. In the Sanz high-risk group, 18.8% of patients received ATRA with daunorubicin, 34.3% received ATRA with daunorubicin and ATO while 40.6% received ATRA with ATO. 56.25% of patients developed differentiation syndrome. The incidence was higher in Sanz high-risk group as compared to Sanz low-risk group. 57.4% of patients had an infection at the time of presentation. 62.5% of patients developed neutropenic fever during treatment. 17.2% of patients developed pseudotumor cerebri. The 4-year EFS and OS were 71.25 and 73.13%, respectively. Sanz low-risk group had a better 4-year EFS and OS as compared to the Sanz high-risk group. Haemoglobin at presentation and Sanz high-risk group were associated with poorer outcomes with a hazard ratio of 0.8 and 3.1, respectively. Outcomes in high-risk patients were better with the use of ATRA + ATO + daunorubicin. Conclusion In the Indian population, APL patients have a high incidence of differentiation syndrome, pseudotumor cerebri, and infections during induction. CR, EFS, and OS compared to the developed world can be achieved with optimal therapy. Low haemoglobin at presentation and Sanz high-risk group were associated with poorer outcomes. ATRA, ATO, and daunorubicin combination is the preferred protocol for treating high-risk patients.

H2O2-activatable hybrid prodrug nanoassemblies as a pure nanodrug for hepatic ischemia/reperfusion injury

Self-assembling prodrugs are able to form stable nanoparticles without additional excipients and therefore have gained increasing interest in the field of drug delivery. As a natural derivative of vitamin A, all-trans retinoic acid (atRA) exerts antioxidant, anti-inflammatory, and immunostimulatory effects. However, the clinical translation of atRA has been hampered by its insufficient therapeutic efficacy. In this work, to fully maximize the therapeutic potential of atRA, we developed delicately designed self-assembling RABA (atRA-based hybrid prodrug) as a hybrid prodrug of atRA and hydroxybenzyl alcohol (HBA). RABA could form nanoassemblies and decompose to release atRA and HBA simultaneously in response to hydrogen peroxide (H2O2). In a mouse model of hepatic ischemia/reperfusion (IR) injury, RABA nanoassemblies accumulated in liver preferentially and exerted highly potent antioxidant, anti-inflammatory, and antiapoptotic effects, leading to effective protection of liver from IR injury. RABA nanoassemblies exhibited significantly higher therapeutic efficacy than the combination of equivalent atRA and HBA. Given its H2O2-responsiveness, self-assembling and self-immolating behaviors, and cooperative therapeutic actions, RABA nanoassemblies have great potential as a pure nanodrug for hepatic IR injury. This study also provides a new valuable addition in the development of prodrug self-assemblies that will emerge as next generation of drugs.

Evaluation of a DNA demethylating agent in combination with all-trans retinoic acid for IDH1-mutant gliomas.

Isocitrate Dehydrogenase 1/2 (IDH1/2) mutations are diagnostic for Astrocytoma or Oligodendroglioma, IDH-mutant. In these IDH-mutant gliomas, retinoic acid-related gene expression is commonly silenced by DNA hypermethylation. DNA demethylating agents can epigenetically reprogram IDH-mutant cells and reduce proliferation, likely by re-expression of silenced tumor suppressor pathways. We hypothesized that DNA demethylation might restore the retinoic acid pathway and slow tumor growth. This was the rationale for a preclinical evaluation combining the DNA demethylating agent, 5-Azacytidine (5-Aza), and retinoic acid pathway activation with all-trans retinoic acid (atRA) in IDH-mutant glioma. In this study, we evaluated the effect of 5-Aza and atRA combination on cell proliferation, apoptosis, and gene expression in human glioma cells. In addition, the efficacy of this combination was tested in patient-derived xenograft (PDX) bearing the IDH1R132H mutation, utilizing subcutaneous and orthotopic models. 5-Aza reduced the DNA methylation profile and increased the gene expression of retinoic acid-related genes. Combination of 5-Aza and atRA reduced cell growth, increased differentiation marker expression, and apoptosis in IDH1R132H glioma cells. Mechanistically, 5-Aza sensitized IDHIR132H glioma cells to atRA via upregulation of the retinoic acid pathway. Importantly, the drug combination reduced significantly the growth rate of subcutaneous tumors, but in an orthotopic mouse model, the combination did not improve survival and 5-Aza alone provided the best survival benefit. Use of DNA demethylating agent in combination with retinoids shows promise, but further optimization and preclinical studies are required for treatment of intracranial IDH-mutant gliomas.

Clinical Efficacy Analysis of the Low-Dose Decitabine in Combination with Cytarabine, All-Trans Retinoic Acid and Granulocyte Colony-Stimulating Factor for Patients with MDS-EB

▪AbstractPurpose:Treatment of patients with myelodysplastic syndromes with excess blasts (MDS-EB) remains a great challenge. In this study, we evaluated the tolerance and efficacy of the combination of low-dose decitabine, cytarabine, all-trans retinoic acid and granulocyte colony-stimulating factor (DLAAG) for MDS-EB patients.Methods:A total of 18 patients with MDS-EB were enrolled in this study and 1 patient who did not follow-up the bone marrow evaluation was excluded from analysis. This study is registered at ClinicalTrials.gov, NCT03356080.The DLAAG regimen consisted of subcutaneous injection of decitabine (0.1-0.2mg/kg, d1-3/w, lasted for 1-3 weeks), cytarabine (6-15mg/m 2,q12h,d1-10), oral all-trans retinoic acid (45mg/m 2/d, d4-6; 15mg/m 2/d, d7-20) and G-CSF (300ug, from d0 until neutrophil count recovery to 20×10 9 cells/L).Results:Patient characteristicsA total of 18 patients (11 males, 7 females) with a median age of 61 years (range 45 to 88 years) were enrolled in our study. The clinical characteristics of the patients were shown in Table 1.Response and survivalThe clinical outcome and overall survival (OS) of patients were summarized in Table2 including 1 could not evaluable after the first protocol. As shown in Table3, after one course of DLAAG, the CR and OR rate was 55.56% and 77.78% respectively. In addition, 3 patients suffered the disease progression (PD) (n=3,16.67%). We found that those who achieved the bone marrow remission after DLAAG had significantly pro-longed OS than others (p=0.0001, Fig.1). The Kaplan-Meier analysis revealed the median overall survival for all patients enrolled was 15 months (Fig.2A), and the relapse-free survival (RFS) for patients achieving CR or CRm was 11 months (Fig.2B).Genetic mutations and response to DLAAGPaired samples (pre- and post-treatment) of the objects were tested for gene mutations which were recurrently mutated in myeloid malignancies, except 1 patient who was failure to perform bone marrow review. 2 patients (11.1%) had no genetic or cytogenetic abnormalities either at baseline or during therapy (they were tested at baseline and d28). Most patients (15 out of 18) had at least one somatic mutation. In this latter group, only 1 patient acquired specific mutation of IDH2 during the therapy (it was tested on d28, data was not shown), while all the other genes were mutated in patients at baseline. Collectively, the most frequently mutated genes at diagnosis were RUNX1 (n=5, 29.4%), ASXL1 (n=4, 23.5%), as well as the overexpression of WT1 (n=4, 23.5%), and the others with an incidence of more than 10% were TET2(n=3,17.6%),TP53 (n=2, 11.8%), EZH2 (n=2, 11.8%), STAG2 (n=2, 11.8%), SF3B1 (n=2, 11.8%) and U2AF1 (n=2, 11.8%).Genes less frequently mutated such as CEBPA,CUX1 et al. were not shown. Remarkably, the proportion of patients with the above gene mutations showing no significant increasing during therapy as compared to baseline, the clones of WT1/TET2/TP53/EZH2/STAG2 can decrease or even disappear(Fig.3A).Moreover, we noted the complete response in patients with ASXL1, TP53 mutations or WT1 overexpression despite the concomitant presence of complex cytogenetic at diagnosis, whereas patients with the EZH2 mutation were less likely to respond (Fig.3B).Subgroup analysisA subgroup analysis based on the 2016 WHO classification revealed an association of EB-I patients with longer OS(P=0.002) (Fig. 4A). On the other hand, based on the IPSS score our study revealed that the lower-risk group patients have better OS (p= 0.0054) (Fig. 4B).In addition to this, we also compared the OS in different groups of age and karyotype, but there were no statistical difference (Fig. 4C-D).Safety and TolerabilityAll patients who received the therapy were eligible for toxicity evaluation. Given the patient-population enrolled and treatment regimen, myelosuppression occurred in all patients (Table 4). The grade 3 to 4 hematological toxicities including neutropenia and thrombocytopenia were common after treatment. Febrile neutropenia occurred in 77.8% of the patients.Conclusion: This study suggested the novel combination of LD-DAC, Ara-C, ATRA and G-CSF might be an optimal introduction therapy for patients with MDS-EB, and this combination warrants further investigation in larger trials. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Transcriptomic analysis reveals that combinations of vitamins A, D2, and D3 have synergistic effects in HCT-116 colon cancer cells by altering the expression of genes involved in multiple canonical pathways including apoptosis, regulation of the...

Integrated systems biology approaches suggest that combinations of nutrients may be more effective against cancer due to the large number of signaling pathways associated with cancer initiation and promotion. In a previous work, we have reported that combinations of vitamins A (as all trans-retinoic acid, ATRA), D2, and D3 act synergistically to induce apoptosis in colon and gastric cancer cells. In this work, we use whole-genome transcriptomic profiling to detect gene expression changes using RNA-seq to more comprehensively investigate the biological pathways affected by the combination of vitamin D2, D3 and ATRA. HCT-116 colon cancer cells were harvested, RNA was isolated and RNA-seq libraries were prepared using a Universal Plus mRNASeq kit. Sequencing was carried out on NovaSeq 6000. General quality-control metrics were obtained using FastQC and raw reads were aligned to human reference genome hg38 using STAR and BWA MEM. ENSEMBL genes were quantified using FeatureCounts, and differential expression statistics were computed using EdgeR. Specific gene expression was validated using qPCR. Transcriptomic analysis showed that of 26,313 genes analyzed, the expression of 8,402 genes was significantly altered (4030 up-regulated and 4373 down-regulated, FDR&lt;0.05) in the treated cells, of which, 3,621 genes were differentially expressed (fold change &lt;-1 or &gt;+1 and an FDR &lt;0.05). IngenuityÒ Pathway analysis revealed the involvement of 97 canonical pathways, with the top pathways including: mechanisms of cancer, apoptosis, myc-mediated apoptosis, regulation of the epithelial mesenchymal transition, and immunity. Keywords: apoptosis, cholcalciferol, colon cancer, caspase, CRMP1, ergocalciferol, IL-12, NOTCH1, RNA-seq, SMAD7, synergism, transcriptome

A rare case of acute promyelocytic leukemia with ider(17)(q10)t(15;17)(q22;q21) and favorable outcome

BackgroundChromosomal rearrangements in addition to t(15;17) have been reported in 25-40% of APL patients, with a large predominance of trisomy 8. Other abnormalities are far less frequent, particularly as ider(17), and the prognostic significance is still unclear.Case presentationWe present the case of a patient with t(15;17)(q22;q21), der(15)t(15;17) and ider(17)(q10)t(15;17)(q22;q21). In particular, the RT-PCR result for PML-RARA of this patient was a false negative and mutational analysis of AML-related genes showed SNP rs2454206 in the TET2 gene and yielded negative findings in other genes including AML1, ASXL1, CEBPA, DNMT3A, FLT3, KIT, NPM1, TP53, and U2AF1. After the early usage of arsenic trioxide combinated with ATRA and vigorous supportive treatment to maintain PLT ≥30×109/L and FIB >1500 mg/L, this patient was under MMR and HCR without any clinical symptoms or signs until now.ConclusionFalse negative reslults of RT-PCR analysis for PML-RARA are rare in APL and ider(17) is even more infrequent. To our knowledge, this is the first reported case of APL with ider(17) and false negative RT-PCR analysis results. The role of ider(17) in APL is still an ongoing investigation and limited by the small number of published cases. The patient reported here benefited from vigorous supportive treatment during the combination of ATRA and arsenic trioxide in induction chemotherapy and the clinical outcome was favorable.

The Combination of ATRA and High-dose Dexamethasone as First-line Treatment in Adult Immune Thrombocytopenia

The Combination of ATRA and High-dose Dexamethasone as First-line Treatment in Adult Immune Thrombocytopenia

RNF8 is responsible for ATRA resistance in variant acute promyelocytic leukemia with GTF2I/RARA fusion, and inhibition of the ubiquitin\u2013proteasome pathway contributes to the reversion of ATRA resistance

BackgroundGTF2I-RARA is a newly identified RARA fusion gene in variant acute promyelocytic leukemia (APL) patients with t(7;17)(q11;q21). Clinical manifestation in the patient showed that it is a sort of ATRA-insensitive oncogene and is different from the classic PML-RARA in terms of therapeutic reaction.MethodsTo reveal the functional characteristics and regulating mechanism of the GTF2I-RARA fusion gene, we established a GTF2I-RARA-transfected HL60 cell model and examined its sensitivity to ATRA by western blot, MTT assay, flow cytometry, and Wright-Giemsa staining. Coimmunoprecipitation and confocal microscopy were used to examine the binding of GTF2I-RARA and transcriptional corepressors. We also performed ChIP-seq to search for potential target genes. Immunoprecipitation, ubiquitination assay, western blot, luciferase assay, and real-time PCR were used to analyze the effects of RNF8 on RARA. Flow cytometry and Wright-Giemsa staining were used to study the effect of MG132 and ATRA on the GTF2I-RARA-transfected HL60 cell model.ResultWe confirmed resistance of GTF2I-RARA to ATRA. Compared with PML-RARA, GTF2I-RARA has a higher affinity to HDAC3 under ATRA treatment. Using the ChIP-sequencing approach, we identified 221 GTF2I-RARA binding sites in model cells and found that the RING finger protein 8 (RNF8) is a target gene of GTF2I-RARA. RNF8 participates in disease progression and therapy resistance in APL with the GTF2I-RARA transcript. Elevated RNF8 expression promotes the interaction between RARA and RNF8 and induces RARA Lys-48 linkage ubiquitylation and degradation, resulting in attenuated transcriptional activation of RARA.ConclusionOur results suggest that RNF8 is a key GTF2I-RARA downstream event. Using the combination of MG132 and ATRA to treat GTF2I-RARA-HL60 cells, a synergistic effect leading to GTF2I-RARA-HL60 cell differentiation was confirmed. Taken together, the targeting of RNF8 may be an alternative choice for treatment in variant APL with GTF2I-RARA fusion.

The combination of UCN-01 and ATRA triggers differentiation in ATRA resistant acute promyelocytic leukemia cell lines via RAF-1 independent activation of MEK/ERK

With the introduction of arsenic trioxide and all-trans retinoic acid, the prognosis of acute promyelocytic leukemia has greatly improved. However, all-trans retinoic acid resistance is still unresolved in acute promyelocytic leukemia relapsed patients. In this study, the clinical achievable concentration of 7-hydroxystaurosporine synergized with all-trans retinoic acid to induce terminal differentiation in all-trans retinoic acid resistant acute promyelocytic leukemia cell lines. Though 7-hydroxystaurosporine is a PKC inhibitor, PKC might not be involved in the combination-induced differentiation since other PKC selective inhibitors, Gö 6976 and rottlerin failed to cooperate with all-trans retinoic acid to trigger differentiation. The combination significantly enhanced the protein level of CCAAT/enhancer binding protein β and/or PU.1 as well as activated MEK/ERK. U0126 (MEK specific inhibitor) not only suppressed the combination-induced differentiation but also restored the protein level of CCAAT/enhancer binding protein β and/or PU.1. However, RAF-1 inhibitor had no inhibitory effect on MEK activation and the combination-induced differentiation. Therefore, the combination overcame differentiation block via RAF-1 independent MEK/ERK modulation of the protein level of CCAAT/enhancer binding protein β and/or PU.1. These findings may provide a preclinical rationale for the potential role of this combination in the treatment of all-trans retinoic acid resistant acute promyelocytic leukemia patients.

Recurrent Fusion Genes in Leukemia: An Attractive Target for Diagnosis and Treatment.

Introduction: Since the first fusion gene was discovered decades ago, a considerable number of fusion genes have been detected in leukemia. The majority of them are generated through chromosomal rearrangement or abnormal transcription. With the development of techniques, high-throughput sequencing method makes it possible to detect fusion genes systematically in multiple human cancers. Owing to their biological significance and tumor-specific expression, some of the fusion genes are attractive diagnostic tools and therapeutic targets. Tyrosine kinase inhibitors (TKI) targeting BCR-ABL1 fusions have been widely used to treat CML. The combination of ATRA and ATO targeting PML-RARA fusions has proven to be effective in acute promyelocytic leukemia (APL). Moreover, therapy with high dose cytarabine (HDAC) has significantly improved the prognosis of core binding factor (CBF) acute myeloid leukemia (AML) patients. Therefore, studies on fusion genes may benefit patients with leukemia by providing more diagnostic markers and therapies in the future.Conclusion: The presented review focuses on the history of fusion genes, mechanisms of formation, and treatments against specific fusion genes in leukemia.

Efficacy of combination of ATRA, ATO and anthracyclines induction therapy in patients with acute promyelocytic leukemia

目的比较全反式维甲酸（ATRA）、三氧化二砷（ATO）联合蒽环类药物三药诱导方案与ATRA联合ATO双药诱导方案治疗急性早幼粒细胞白血病（APL）的疗效。方法2009年1月至2016年3月确诊并治疗的APL患者184例，随机分为三药诱导组（58例）和双药诱导组（126例）。三药诱导方案为ATRA 20 mg·m−2·d−1，第1~28天；ATO 0.16 mg·kg−1·d−1，第1~28天；蒽环类药物去甲氧柔红霉素8 mg·m−2·d−1或柔红霉素40 mg·m−2·d−1，第3~5天。双药诱导方案为ATRA联合ATO，剂量用法同上。184例患者中WBC>10×109/L者69例，WBC≤10×109/L者115例。结果①近期疗效：三药诱导组1个疗程的血液学缓解率、遗传学缓解率、分子学缓解率及诱导分化综合征发生率分别为98.3%、87.9%、72.4%和0，双药诱导组分别为87.3%、65.9%、51.6%和12.7%，差异均有统计学意义（P值分别为0.017、0.002、0.008、0.005）；在WBC>10×109/L的患者中，三药诱导组诱导分化综合征的发生率及早期病死率低于双药诱导组（0对15.6%，P=0.042；4.2%对15.6%，P=0.246）；在WBC≤10×109/L的患者中，三药诱导组诱导分化综合征的发生率也低于双药诱导组（0对12.3%，P=0.032），但缓解率及早期病死率两组差异无统计学意义（P值均>0.05）。②远期疗效：三药诱导组的复发率、总生存率及无病生存率分别为0、98.5%、96.6%，双药诱导组分别为8.6%、86.5%、84.1%，差异均有统计学意义（P值分别为0.013、0.018、0.019）；尤其是WBC>10×109/L的患者，三药诱导组优势更加明显。③不良反应：三药诱导组的胃肠道反应、肝功能损害、心肌损伤及头痛的发生率未见明显增加。结论在APL的诱导治疗中，三药诱导方案的疗效优于双药诱导方案。

ATRA, Arsenic Trioxide (ATO), and Gemtuzumab Ozogamicin (GO) Is Safe and Highly Effective in Patients with Previously Untreated High-Risk Acute Promyelocytic Leukemia (APL): Final Results of the SWOG/Alliance/ECOG S0535 Trial

▪Introduction: APL, while highly curable in the modern era, remains a therapeutic challenge in the high-risk subset, with high rates of early mortality and relapse compared to non-high-risk APL. Recent evidence has confirmed excellent outcomes in non- high-risk APL with the combination of ATO and ATRA, and a previous pilot study had indicated the efficacy of a combination of ATO + ATRA + GO in high-risk APL. The North American Leukemia Intergroup designed a larger phase 2 study to confirm the efficacy and safety of this combination in high-risk APL.Primary Objectives: 1) assessment of 3-year event-free survival (EFS); 2) assessment of early (6 week) death rate.Methods: Adult patients with newly diagnosed high-risk APL (WBC ≥10k/uL) were eligible. Induction therapy consisted of: ATRA (45 mg/m2/day), beginning on day 1; ATO 0.15 mg/kg/day, beginning on day 10; GO 9 mg/m2on day 1. ATRA and ATO were continued until remission achieved. Patients in remission went on to receive consolidation with ATO x 2 cycles, followed by ATRA + daunorubicin x 2 cycles, followed by GO x 2 cycles. Subsequent maintenance therapy consisted of ATRA + 6-mercaptupurine + methotrexate for up to 1 year.Results: Between 2008 and 2013, 73 registered patients began protocol treatment. Median age was 46.5 years, with 52% females and 48% males. Sixty-two (85%) patients completed induction therapy as planned, and 50 patients (68%) completed all planned consolidation.Sixty-two patients (85%) achieved a documented complete response (CR). Non-responses were attributable to lack of response assessment (n=10), most commonly related to death. One patient had resistant disease. With a median follow-up of 3.3 years, the Kaplan Meier 3-year EFS estimate was 79% (95% CI 68% - 87%), which was significantly improved compared to the protocol-defined historical rate of 50% (p<0.001). The 3-year overall survival estimate was 88% (95% CI 78% to 93%). The 3-year relapse-free survival estimate was 93% (95% CI 82% to 97%). At data cut-off, there was 1 documented death during remission and no reported cases of relapse.Eight of 73 patients (11%) died within 6 weeks of treatment initiation (95% confidence interval 5-20%), at a median time of 11 days (range 3-31), which was significantly lower than the protocol defined null rate of 30% (p<0.001). The most common treatment-emergent grade 3-4 adverse events during induction included: febrile neutropenia (34%), AST/ALT elevation (12%), hypoxia/differentiation syndrome (11%), hyperglycemia (11%), headache (11%), prolonged QTc (11%).Summary: the combination of ATO + ATRA + GO was safe and effective in patients with high-risk APL, producing highly durable responses, low rates of early mortality, and comparing favorably with chemotherapy-based induction regimens in this setting. Although GO is not currently commercially available in the US, this regimen should be considered as a therapeutic option for patients with high-risk APL in the future.Support: NIH/NCI grants CA180888, CA180819, CA180820, CA180821, and in part by Wyeth Pharmaceuticals (Pfizer, Inc.) [Display omitted] DisclosuresKomrokji:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy. Coutre:Gilead Sciences: Consultancy, Research Funding. DeAngelo:Amgen: Consultancy; Ariad: Consultancy; Baxter: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Incyte: Consultancy; Celgene: Consultancy. Othus:Glycomimetics: Consultancy; Celgene: Consultancy.

Acute myeloid Leukemia

Acute myeloid leukemia (AML) has been genetically characterized extensively and can now be subdivided into 9 to 11 pathogenetically different subtypes according to their profile of driver mutations. In clinical practice karyotyping and molecular analysis of NPM1, cEBPa and FLT3-ITD are required for treatment stratification and potentially genotype specific treatment. Some markers such as NPM1 not only offer prognostic information but can also serve as markers of minimal residual disease and thus have the potential to guide therapy in the future.The basis of curative treatment is intensive combination chemotherapy comprizing cytarabine and an anthracycline ("7 + 3" regimen). The prolonged duration of aplasia can be reduced significantly by accelerated therapy ("S-HAM" regimen). Following achievement of a complete remission patients with a low risk of relapse - based on genetic and clinical features - receive chemotherapy based consolidation therapy whereas high risk patients - and potentially also those with an intermediate risk - receive an allogeneic stem cell transplantation. Whereas adding the rather unspecific tyrosinekinase inhibitor sorafenib to standard treatment in unselected AML patients has not improved overall survival (OS), the addition of midostaurin to standard therapy in the selected group FLT3 mutated patients has resulted in a moderate but significant OS benefit.Real world data show that in patients below 50 years a cure rate of ca. 50 % can be achieved. However less than 10 % of patients above the age of 70 will be alive after five years even after intensive treatment. Therefore when curative and intensive treatment is deemed impossible the therapeutic standard in elderly and unfit patients used to be low-dose cytarabine with an average OS of 4 months. This has now been replaced by a new standard of care of hypomethylating agents - azacytidine and decitabine - which both achieve higher remission rates and show strong trends towards a prolonged OS of between 8 and 10 months.The paradigm for genotype-specific therapy is acute promyelocytic leukemia (APL - or AML M3 in the former FAB classification). This entity used to be a problematic AML subgroup because of its frequent coagulation disturbances and potentially fatal bleeding problems. Today patients with APL can be treated with a chemotherapy free combination of ATRA - a differentiating agent - and Arsenic Trioxide - an apoptosis inducing agent. In patients with a leukocyte count < 10 000 / µl a cure rate of > 90 % can now be achieved.

Characteristics and Therapeutic Outcomes of Acute Promyelocytic Leukemia in Children and Adolescents

P=0.045), but their 5-year OS and EFS were not significantly different. Better survival was observed in ATRA plus chemotherapy group both for 5-year OS (100% vs. 60.0±21.9%, P=0.018), and for 5-year EFS (60.0±21.9% vs. 91.7±8.0%, P=0.080) than ATRA only group. Stem cell transplantations were given to 3 patients and they are alive without disease for 8.3-16.5 years of follow-up. One death after relapse, another death in remission and development of secondary leukemia were encountered during the study period. Conclusion: This study analyzed clinical characteristics of pediatric APL and demonstrated very good outcome with the combination of ATRA and chemotherapy.