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Optimizing therapy with methylation inhibitors in myelodysplastic syndromes: dose, duration, and patient selection.

Azacitidine (Vidaza, Pharmion Corp., Boulder, CO, USA) and decitabine (Dacogentrade mark, SuperGen, Inc., Dublin, CA, USA, and MGI Pharma, Inc., Bloomington, MN, USA) are DNA methyltransferase (DNMT) inhibitors that have clinical activity in patients with myelodysplastic syndromes. Mechanism-based laboratory studies suggest that clinical optimization of therapy with DNMT inhibitors needs to include optimizing intracellular drug uptake and maximizing drug exposure over time while still using lower doses to avoid cytotoxicity. Clinical studies suggest that increased dose intensity and multiple cycles of administration substantially increase response rates. Other strategies for optimizing the efficacy of DNMT inhibitor therapy also include identification of patients that are best qualified for treatment, and defining in vivo mechanisms of patient responses. In the future, combination strategies to increase gene reactivation and to take advantage of increased expression of target genes may be critical for achieving optimal results.

Antimetabolites, Antineoplastic↗

Innovative approaches to the clinical development of DNA methylation inhibitors as epigenetic remodeling drugs.

The most extensively studied inhibitors of DNA methylation are the cytidine analogs 5-azacytidine (5-aza-CR; azacitidine) and 5-aza-2'- deoxycytidine (5-aza-CdR; decitabine). Despite decades of nonclinical and clinical research, there remains considerable interest in finding innovative and better ways to use these DNA methyltransferase (DNMT) inhibitors. A mounting body of data supports the role of methylation in silencing genes involved in tumor growth and resistance. This information has fueled further nonclinical and clinical research on ways to use inhibitors of methylation to restore normal gene expression and function. As such, recent clinical strategies have shifted from simply evaluating cytotoxic effects to exploring and optimizing the ability of these agents to restore or reactivate gene expression and putative targets. This article considers innovative approaches to develop and evaluate inhibitors of DNA methylation as epigenetic remodeling agents for the treatment of cancer. These include optimization of dose and schedule, restoration or enhancement of sensitivity to other treatment modalities, and combinations with other agents including histone deacetylase inhibitors.

Antineoplastic Agents↗

Combined DNA methyltransferase and histone deacetylase inhibition in the treatment of myeloid neoplasms.

Optimal reexpression of most genes silenced through promoter methylation requires the sequential application of DNA methyltransferase inhibitors followed by histone deacetylase inhibitors in tumor cell cultures. Patients with myelodysplastic syndrome or acute myeloid leukemia (AML) were treated with the methyltransferase inhibitor 5-azacitidine (aza-CR) followed by the histone deacetylase inhibitor sodium phenylbutyrate. Major responses associated with cytogenetic complete response developed in patients receiving prolonged dosing schedules of aza-CR. Bisulfite sequencing of the p15 promoter in marrow DNA during the first cycle of treatment showed heterogeneous allelic demethylation in three responding patients, suggesting ongoing demethylation within the tumor clone, but no demethylation in two nonresponders. Six of six responding patients with pretreatment methylation of p15 or CDH-1 promoters reversed methylation during the first cycle of therapy (methylation-specific PCR), whereas none of six nonresponders showed any demethylation. Gene demethylation correlated with the area under the aza-CR plasma concentration-time curve. Administration of both drugs was associated with induction of acetylation of histones H3 and H4. This study provides the first demonstration that molecular mechanisms responsible for responses to DNA methyltransferase/histone deacetylase inhibitor combinations may include reversal of aberrant epigenetic gene silencing. The promising percentage of major hematologic responses justifies the testing of such combinations in prospective randomized trials.

Acetylation↗

Postremission chemotherapy for adults with acute myelogenous leukemia: improved survival with high-dose cytarabine and daunorubicin consolidation treatment.

Results of postremission chemotherapy for adults with acute myelogenous leukemia (AML) were assessed in two sequential prospective studies involving similar induction therapy and two courses of intensive consolidation treatment. Fifty-six patients achieving remission on the acute leukemia protocol (ALP3) study received high-dose cytarabine and daunorubicin as course one and standard-dose cytarabine and daunorubicin as course two. Results are compared with forty-six patients achieving remission on the ALP2 study who received azacitidine and doxorubicin as consolidation course one and standard-dose cytarabine, daunorubicin, and thioguanine as course two. The ALP3 regimen resulted in a significantly improved 5-year disease-free survival of 32% +/- 19% versus 20% +/- 11% for the ALP2 study (P = .03). Survival from remission was also improved, 40% +/- 14% versus 24% +/- 12% (P less than .01). Favorable prognostic factors for disease-free survival included receiving the ALP3 treatment regimen, absence of a prior preleukemic syndrome, and female sex. These factors and younger patient age were significant for survival following first chemotherapy and survival after achieving remission. Six of 34 patients who relapsed after receiving the ALP3 regimen successfully achieved prolonged second remissions with high-dose cytarabine-based chemotherapy and/or allogeneic bone marrow transplantation (BMT). Overall survival for adults less than or equal to 45 years of age was 58% +/- 19% with the ALP3 postremission chemotherapy regimen, comparable to most studies of BMT for AML in first remission. Actuarial 5-year survival for ALP3 patients greater than 60 years of age was 18% +/- 20% with no improvement compared with ALP2.

Adult↗

Genome agnostic, multi-level non-oncogene addiction-based systems pharmacology for rescuing metastatic relapsed/refractory neoplasias.

Rescue therapies for relapsed/refractory (r/r) metastatic neoplasias present significant unmet needs. Tumor tissue editing regimen for 13 r/r tumor types, carcinomas, sarcomas and hematologic neoplasias, included in 15 phase I/II trials, nuclear/cytokine receptor agonists, pioglitazone, plus/minus dexamethasone or all-trans retinoic acid or interferon-α to counterbalance tumor tissue homeostasis and reprogramming of cancer hallmarks, stress response inhibitors, COX-2 inhibitor, everolimus, lenalidomide, or clarithromycin, and a stress response inducer, low-dose metronomic chemotherapy with treosulfan, trofosfamide, capecitabine, or azacitidine. CR in three, cCR in another five r/r neoplasias, as the best response occurred after transcriptional reprogramming of cancer hallmarks, inflammation control or differentiation induction. Receptor agonist combinations for cCR induction can be identical among quite different tumor types and diversified within the same tumor histology. Data reveal ubiquitous, differential transcriptional access to non-oncogene addiction (NOA) networks that cope with cancer hallmarks/stress responses and three levels of therapeutic NOA targeting. (1) Agonists of nuclear/cytokine receptor NOAs critically target tumor identity and viability, while (2) transcriptional reprogramming of NOA networks that contribute to tumor tissue addiction, thereby genome-agnostically counteracting oncogene addictions. (3) Targeting edited NOAs may improve long-term outcome with CR/cCR (everolimus, IMiD). Transcriptionally accessible NOA targets offer high specificity, modest toxicity profile, low cost of therapy and outpatient treatment, independent of comorbidities. Adaptive targeting of the transcriptomic landscapes of tumor cell compartments breaks tumor tissue addiction and overcomes M-CRAC, post-therapy metastasis, cancer cell recolonization, acquired resistance and genetic heterogeneity. Thus, editing approaches provide a template for controlling metastatic r/r tumors. In the future, diagnostics of NOA networks and transcription factors involved in tumor tissue addiction may be as valuable for therapy selection as histological/molecular genetic tumor typing for the establishment of personalized hematology/oncology.

Hodgkin’s lymphoma↗

Azacitine (vidaza) for myelodysplastic syndrome.

Azacitidine is a new drug with a novel mechanism of action; it can correct abberant gene expression in patients with myelodysplastic syndrome. The drug improves symptoms, decreases the need for transfusions, reduced the rate of transformation to leukemia and probably improves survival.

Antimetabolites, Antineoplastic↗

Intensive short-term chemotherapy for patients with acute myelogenous leukemia: long-term follow-up.

Our pilot study addresses the problem of early relapse from complete remission in young adults with acute myelogenous leukemia (AML). Twelve patients with AML, 16-58 years of age, were entered in a study of four intense courses of cytotoxic chemotherapy using the following drugs: cytarabine, daunorubicin, 5-azacitidine, and 6-thioguanine. They received no maintenance therapy. Nine of 12 patients achieved complete response. With a minimum follow-up of 35 months, the observed disease-free survival at 2 years was 67% (14 +/- SE) and the actuarial disease-free survival at 4 years was 38% (17 +/- SE). It appears that brief intensive chemotherapy early in the management of AML can produce prolonged remission without the need for maintenance therapy.

Actuarial Analysis↗

Activity of 9-nitro-camptothecin, an oral topoisomerase I inhibitor, in myelodysplastic syndrome and chronic myelomonocytic leukemia.

BACKGROUND: Topoisomerase I inhibitors, like topotecan, have activity in myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). 9-Nitro-camptothecin (9-NC) is a new oral topoisomerase inhibitor with a good safety profile. The aims of the current study were to evaluate the activity and safety of 9-NC in MDS and CMML. METHODS: Adults with a diagnosis of MDS (n = 12) and CMML (n = 32) received 9-NC 2 mg/m(2) orally daily 5 days a week, every 4 to 6 weeks. RESULTS: Overall, 5 (11%) patients achieved complete response (CR), 7 (16%) had a partial response (PR), and 6 (14%) had hematologic improvement (HI), for an overall response rate of 41%. The response rate was similar in MDS and CMML. Severe (Grade 3-4) side effects included nausea and vomiting (7%), diarrhea (18%), other gastrointestinal toxicities (5%), and genitourinary toxicities (12%). CONCLUSIONS: 9-NC is active in MDS and CMML. The paucity of available therapies in CMML makes 9-NC a good candidate for further studies as a single agent, or in combination with decitabine, 5-azacitidine or cytarabine.

Administration, Oral↗

Frequent downregulation of the runt domain transcription factors RUNX1, RUNX3 and their cofactor CBFB in gastric cancer.

Our previous studies suggest that lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer, but potential roles of other members of the RUNX family genes have not yet been reported. We examined the expression of 3 Runt-related (RUNX) genes, RUNX1, RUNX2 and CBFB, in gastric cancer cell lines and primary gastric cancer specimens and compared them to those of RUNX3 reported earlier in conjunction with clinicopathologic factors. Expression of RUNX family genes in 9 gastric cancer cell lines, 56 primary gastric cancer specimens and surrounding normal gastric mucosa were estimated by Northern blot analysis, quantitative RT-PCR and in situ hybridization. Northern blot analysis in gastric cancer cell lines showed downregulation of RUNX1 and RUNX3 in 67% and 78% of the cell lines tested, respectively. The ratio of the average RUNX mRNA/beta-actin mRNA ratio (x10(3)) for RUNX1 was 48.0 +/- 21.1 vs. 21.4 +/- 8.1; RUNX2, 1.1 +/- 0.3 vs. 1.0 +/- 0.2; RUNX3, 9.2 +/- 6.3 vs. 3.1 +/- 1.3 and CBFB, 42.0 +/- 19.4 vs. 21.0 +/- 8.4 (normal vs. tumor, respectively, average +/-SD). The basal RUNX2 expression was very weak, and there was no significant change in gastric cancers. Both RUNX1 and RUNX3 showed remarkable downregulation in 62% and 69%, respectively, of surgically resected specimens compared to surrounding mucosa analyzed by quantitative RT-PCR (p < 0.01). Furthermore, CBFB, the gene encoding the cofactor of RUNX1, -2, -3, was also downregulated in significant fraction (32%, p < 0.05). The percentage of downregulation of RUNX1, RUNX3 and CBFB increased as the cancer stage progressed. Tricostatin A and 5'-azacitidin reactivate RUNX3 expression, but they could not reactivate expression of RUNX1 and CBFBeta in gastric cancer cells, suggesting that the downregulation was due to mechanisms other than methylation of the promoter region. These findings suggest that RUNX1 and CBFBeta in addition to RUNX3 play some roles in gastric cancers and that roles of RUNX gene family in gastric cancer are more widespread and complex than previously realized.

Aged↗

Diagnostic and Monitoring Strategies for VEXAS Syndrome: Evaluating Sanger Sequencing, NGS, and the SWIM-Score.

VEXAS syndrome is an adult-onset autoinflammatory disorder caused by somatic UBA1 variants, but there are no standardized criteria for genetic testing or diagnostics. This study compared Sanger sequencing and next-generation sequencing (NGS) for detecting UBA1 variants in patients with suspected VEXAS, assessed the ability of Sanger sequencing to estimate variant allele fractions (VAFs), and evaluated the Maeda et al. scoring system for selecting patients for genetic testing in a primary cohort and a validation cohort. In the primary cohort of 104 patients, Sanger sequencing identified VEXAS variants in 12%, with no additional cases detected by NGS. Sanger sequencing accurately quantified VAFs ranging from 0.1 to 0.9. In a small longitudinal subset (n&#x2009;=&#x2009;3), VAFs in blood correlated with CRP levels, increased over time despite various treatments, but decreased in two patients after initiation of Azacitidine treatment. The novel parameters, VAF in myeloid cells and VEXAS cell concentration, showed promise as exploratory markers for patient monitoring. The Maeda-score, requiring a threshold score of 2 for 100% sensitivity, exhibited low specificity-29% in the primary cohort and 41% in the validation cohort (n&#x2009;=&#x2009;62, with 2 carrying VEXAS variants). In contrast, the simplified SWIM-score-based on Skin involvement, Weight loss, Inflammation, and Macrocytic anemia-achieved 100% sensitivity in both cohorts, with higher specificities of 47% and 65%, respectively. In conclusion, Sanger sequencing reliably detected UBA1 variants and quantified VAFs. Monitoring VAF and VEXAS cell concentration may track disease progression, and the SWIM-score demonstrated potential for accurately selecting patients for UBA1 testing.

Humans↗

Myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders with a variable clinical course and prognosis. Treatment should be individualized based on the patient's age, subtype, percent blasts in the marrow, and cytogenetics. The use of the International Prognostic Scoring Index is helpful in assigning prognosis. The standard of care for low-risk patients is supportive care. Low-risk patients with symptomatic anemia should be considered for a trial of erythropoietin. The serum erythropoietin (EPO) level may help predict response to treatment. The treatment of the symptomatic and high-risk patient is unclear. Low-dose cytarabine, amifostine, and 5-azacitidine can induce responses in selected patients, but the duration of responses is short, and treatment does not appear to prolong survival. Intensive chemotherapy should be reserved for high-risk, younger patients. Topotecan and intermediate cytarabine appear to have an active regimen, but remissions are short. Younger patients who present with high-risk MDS without an antecedent history of MDS should receive intensive acute myeloid leukemia (AML) induction chemotherapy. Younger patients with high-risk MDS and an HLA-compatible donor should be offered an allogeneic stem cell transplant.

Age Factors↗

Late acquisition of BCR::ABL1 during clonal evolution of SAMD9-associated MDS with phenotypic shift from AML to B-ALL.

We describe a unique case of SAMD9-associated myelodysplastic syndrome (MDS) with monosomy 7 that evolved over 16&#xa0;years into BCR::ABL1-positive acute myeloid leukemia (AML) and subsequently manifested as B-cell acute lymphoblastic leukemia (B-ALL). Genomic analysis at AML diagnosis revealed a germline SAMD9 mutation together with somatic RUNX1 and PPM1D mutations, supporting stepwise clonal evolution, with BCR::ABL1 emerging as a late leukemogenic event. The dominant leukemic population at AML onset showed myeloid morphology and immunophenotype, whereas a minor CD19+CD10+ population was already detectable. Following venetoclax and azacitidine therapy, the dominant leukemic phenotype shifted to B-ALL while retaining BCR::ABL1 positivity. Detection of the Philadelphia chromosome in mature neutrophils at both AML onset and ALL relapse supported multilineage involvement of a multipotent BCR::ABL1-positive clone. Ponatinib achieved disease control. This case highlights late acquisition of BCR::ABL1 during SAMD9-associated clonal evolution and therapy-driven phenotypic shift within a shared Ph-positive leukemic stem-cell hierarchy.

Humans↗

Targeting DNA Methylation: New Paradigms and the Advent of Gene-Selective Tools.

DNA methylation can function as a toxic alkylation reaction exploited by chemotherapeutic agents to induce cancer cell death. However, finely tuned DNA methylation plays a fundamental role in cellular physiology, particularly in the epigenetic regulation of gene expression. Once thought to act solely as a repressor of gene transcription, its functional role has since been elucidated as genomic locus-specific and deeply connected with other epigenetic factors. Following the clinical approval of DNA methyltransferase inhibitors, such as Azacitidine and Decitabine, for the treatment of hematological malignancies, considerable efforts have been devoted to developing pharmacological tools that modulate epigenetic DNA methylation. However, the lack of gene selectivity in these agents limits their therapeutic efficacy and increases off-target toxicity. Moreover, the non-gene-selective nature of current DNA methylation-targeting molecules fails to meet the standards required to discern the nuanced roles of DNA methylation across diverse pathophysiological contexts and genomic loci, particularly in an era where next-generation sequencing and omics technologies enable high-resolution epigenetic analyses. In this review, we examine the mechanisms and roles of DNA methylation in epigenetic regulation, evaluate the current landscape of DNA methylation modulators, from traditional DNMT inhibitors to cutting-edge CRISPR-dCas9 fusion systems and protein-protein interaction disruptors, and discuss their clinical relevance. Finally, we emphasize the need for precise, locus-specific tools to advance both cancer research and therapeutic strategies.

Humans↗

Combination therapy with DNA methyltransferase inhibitors in hematologic malignancies.

A variety of epigenetic changes contribute to transcriptional dysregulation in myelodysplastic syndromes (MDSs) and acute myeloid leukemia (AML). DNA methyltransferase (DNMT) inhibitors--azacitidine and decitabine--have significant activity in the treatment of MDS. Despite marked activity in myeloid malignancy, monotherapy with DNMT inhibitors is limited by low complete and partial response rates (7-20%) and median response durations of 15 months. As with classical cytotoxic therapy, the targeting of biologic pathways and mechanisms may best be accomplished using a combination of agents offering complementary mechanisms and synergistic pharmacodynamic interactions. The goal of this approach is to improve response rates, quality, and duration, and to minimize adverse events. There are a number of new therapies under development for the management of MDS and AML. This review article touches on some of the more promising combination regimens in various phases of investigation. The treatment of MDS and AML is undergoing rapid evolution. Cytogenetic complete remission and prolonged survival represent important goals. Incremental improvements in disease state and quality-of-life issues are also important for patients. Given the overall failure of cytotoxic chemotherapy in the achievement of cures in MDS and MDS-related AML, the application of less toxic, biologically directed agents may represent a more promising approach to treatment. Combination therapies with DNMT inhibitors using optimal dosing regimens to focus on methylation reversal with lower doses over longer periods of time, rather than direct cytotoxic effects, are beginning to suggest promising results in MDS and AML.

Antineoplastic Combined Chemotherapy Protocols↗

Treatment of childhood acute myelogenous leukemia with an intensive regimen (AML-87) that individualizes etoposide and cytarabine dosages: short- and long-term effects.

The purpose of this study was to assess the feasibility and efficacy of a treatment regimen for pediatric acute myelogenous leukemia (AML) that uses four rotating drug pairs and adjusts dosages of etoposide and cytarabine to target specific plasma concentrations. Thirty-one girls and 27 boys (median age, 9.7 years) with de novo AML were treated on the protocol. Six cycles of chemotherapy were planned. Cycles 1 to 4 comprised the drug combinations cytarabine plus etoposide, cytarabine plus daunomycin, etoposide plus amsacrine, and etoposide plus azacitidine, respectively. For cycles 5 and 6, the first two combinations were repeated. Dosages were adjusted to achieve plasma concentrations of 1.0 microM +/- 0.1 microM cytarabine and 30 microM +/- 0.3 microM etoposide. Forty-four patients (76%) entered complete remission. Of those, 24 have had relapses; 23 remain alive in first or subsequent remission. The 5-year event-free survival (EFS) estimate was 31.0% +/- 5.9%; the 5-year survival estimate was 41.4% +/- 6.3%. Six patients (10%) died of the toxic effects of therapy. Severe neutropenia occurred in all cycles. Long-term complications of therapy included hepatitis C, cardiac insufficiency, and hearing loss. Adjustment of cytarabine and etoposide dosage was feasible for achieving targeted plasma drug concentrations; however, the potential clinical efficacy of this approach was offset by substantial acute and long-term toxicity.

Adolescent↗

Increasing donor age adversely impacts beneficial effects of bone marrow but not smooth muscle myocardial cell therapy.

We evaluated the impact of donor age on the efficacy of myocardial cellular therapy for ischemic cardiomyopathy. Characteristics of smooth muscle cells (SMC), bone marrow stromal cells (MSCs), and skeletal muscle cells (SKMCs) from young, adult, and old rats were compared in vitro. Three weeks after coronary ligation, 3.5 million SMCs (n = 11) or MSCs (n = 9) from old syngenic rats or culture medium (n = 6) were injected into the ischemic region. Five weeks after implantation, cardiac function was assessed by echocardiography and the Langendorff apparatus. In the in vitro study, the numbers and proliferation of MSCs from fresh bone marrow and SKMCs from fresh tissue but not SMCs were markedly diminished in old animals (P < 0.05 both groups). SKMCs from old animals did not reach confluence. After treatment with 5-azacytidine (azacitidine), the myogenic potential of old MSCs was decreased compared with young MSCs. In the in vivo study, both SMC and MSC transplantation induced significant angiogenesis compared with media injections (P < 0.05 both groups). Transplantation of SMCs but not MSCs prevented scar thinning (P = 0.03) and improved ejection fraction and fractional shortening (P < 0.05). Load-independent indices of cardiac function in a Langendorff preparation confirmed improved function in the aged SMC group (P = 0.01) but not in the MSC group compared with the control group. In conclusion, donor age adversely impacts the efficacy of cellular therapy for myocardial regeneration and is cell-type dependent. SMCs from old donors retain their ability to improve cardiac function after implantation into ischemic myocardium.

Aging↗

Anticancer drug-induced kidney disorders.

Nephrotoxicity is an inherent adverse effect of certain anticancer drugs. Renal dysfunction can be categorised as prerenal uraemia, intrinsic damage or postrenal uraemia according to the underlying pathophysiological process. Renal hypoperfusion promulgates prerenal uraemia. Intrinsic renal damage results from prolonged hypoperfusion, exposure to exogenous or endogenous nephrotoxins, renotubular precipitation of xenobiotics or endogenous compounds, renovascular obstruction, glomerular disease, renal microvascular damage or disease, and tubulointerstitial damage or disease. Postrenal uraemia is a consequence of clinically significant urinary tract obstruction. Clinical signs of nephrotoxicity and methods used to assess renal function are discussed. Mechanisms of chemotherapy-induced renal dysfunction generally include damage to vasculature or structures of the kidneys, haemolytic uraemic syndrome and prerenal perfusion deficits. Patients with cancer are frequently at risk of renal impairment secondary to disease-related and iatrogenic causes. This article reviews the incidence, presentation, prevention and management of anticancer drug-induced renal dysfunction. Dose-related nephrotoxicity subsequent to administration of certain chloroethylnitrosourea compounds (carmustine, semustine and streptozocin) is commonly heralded by increased serum creatinine levels, uraemia and proteinuria. Additional signs of streptozocin-induced nephrotoxicity include hypophosphataemia, hypokalaemia, hypouricaemia, renal tubular acidosis, glucosuria, aceturia and aminoaciduria. Cisplatin and carboplatin cause dose-related renal dysfunction. In addition to increased serum creatinine levels and uraemia, electrolyte abnormalities, such as hypomagnesaemia and hypokalaemia, are commonly reported adverse effects. Rarely, cisplatin has been implicated as the underlying cause of haemolytic uraemic syndrome. Pharmaceutical antidotes to cisplatin-induced nephrotoxicity include amifostine, sodium thiosulfate and diethyldithiocarbamate. Dose- and age-related proximal tubular damage is an adverse effect of ifosfamide. In addition to renal wasting of electrolytes, glucose and amino acids, Fanconi syndrome, rickets and osteomalacia have occurred with ifosfamide treatment. High dose azacitidine causes renal dysfunction manifested by tubular acidosis, polyuria and increased urinary excretion of electrolytes, glucose and amino acids. Haemolytic uraemia is a rare adverse effect of gemcitabine. Methotrexate can cause increased serum creatinine levels, uraemia and haematuria. Acute renal failure is reported following administration of high dose methotrexate. Urinary alkalisation and hydration confer protection against methotrexate-induced renal dysfunction. Dose-related nephrotoxicity, including acute renal failure, are reported subsequent to treatment with pentostatin and diaziquone. Acute renal failure is a rare adverse effect of treatment with interferon-alpha. Haemolytic uraemic syndrome occurs with mitomycin administration. A mortality rate of 50 to 100% is reported in patients developing mitomycin-induced haemolytic uraemic syndrome. Capillary leak syndrome occurring with aldesleukin therapy can cause renal dysfunction. Infusion-related hypotension during infusion of high dose carmustine can precipitate renal dysfunction.

Antimetabolites, Antineoplastic↗

Six (or more) drugs in search of a mechanism: DNA methyltransferase and histone deacetylase inhibitors in the treatment of myelodysplastic syndromes.

The clinical activity of the DNA methyltransferase inhibitors 5-azacitidine and 2'-deoxy-5-azacytidine in myelodysplastic syndromes (MDS) suggests that epigenetic modulation of gene transcription may play an important pathogenetic role in the development and expression of these diseases. Approximately 50% of patients treated with these compounds experience hematologic improvement, making these the most active single agents for unselected patients with MDS. Responses include complete and partial hematologic responses. Two randomized trials have shown that the use of these drugs significantly alters the natural history of MDS compared with supportive care. Histone deacetylase inhibitors, which may also impact the expression of genes through epigenetic mechanisms, seem to have measurable activity in MDS in preliminary studies. Histone deacetylase inhibitors are most likely used in combination with other agents, including DNA methyltransferase inhibitors. Despite the clinical activity of these classes of drugs, there is no conclusive evidence that their clinical activity is attributable to their impact on the epigenome. Such information will be critical in the development of more effective congeners and drug combinations in ongoing attempts to improve the outcome of patients with MDS.

Antimetabolites, Antineoplastic↗