Outpatient consolidation treatment with clofarabine in a phase 2 study of older adult patients with previously untreated acute myelogenous leukemia

Physiological and pathological implications of 5-hydroxymethylcytosine in diseases

Gene expression is the prerequisite of proteins. Diverse stimuli result in alteration of gene expression profile by base substitution for quite a long time. However, during the past decades, accumulating studies proved that bases modification is involved in this process. CpG islands (CGIs) are DNA fragments enriched in CpG repeats which mostly locate in promoters. They are frequently modified, methylated in most conditions, thereby suggesting a role of methylation in profiling gene expression. DNA methylation occurs in many conditions, such as cancer, embryogenesis, nervous system diseases etc. Recently, 5-hydroxymethylcytosine (5hmC), the product of 5-methylcytosine (5mC) demethylation, is emerging as a novel demethylation marker in many disorders. Consistently, conversion of 5mC to 5hmC has been proved in many studies. Here, we reviewed recent studies concerning demethylation via 5hmC conversion in several conditions and progress of therapeutics-associated with it in clinic. We aimed to unveil its physiological and pathological significance in diseases and to provide insight into its clinical application potential.

Control of relapsed or refractory acute myeloid leukemia by clofarabine in preparation for allogeneic stem cell transplant

Allogeneic stem cell transplant is indicated for patients with refractory or relapsed acute myeloid leukemia (AML). Since elimination of the leukemic load is thought to be a prerequisite for treatment success, we here investigate toxicity and anti-leukemic activity of a clofarabine-AraC salvage protocol preceding transplant. In this retrospective analysis, we observed induction of objective remissions in 86% of patients receiving clofarabine-AraC as compared to 83% with sequential high dose AraC/mitoxantrone (S-HAM) and 50% after mitoxantrone/topotecane/AraC (MTC) salvage strategies. In addition, clofarabine conferred anti-leukemic activity to some patients who failed initial MTC or S-HAM therapy. For overall and leukemia-free survival, we identified cytogenetically defined adverse risk markers but not response to therapy to be a strong predictor. In summary, the clofarabine-AraC salvage strategy combines pronounced anti-leukemic activity with an acceptable toxicity profile and allows the majority of patients with relapsed or refractory AML to proceed to allo-SCT, even in cytogenetically defined high risk situations.

New drug toxicities in the onco-nephrology world

New anticancer medications are rapidly entering the clinical arena offering patients with previously resistant cancers the promise of more effective therapies capable of extending their lives. However, adverse renal consequences develop in treated patients with underlying risk factors, requiring the nephrology community to be familiar with the nephrotoxic effects. The most common clinical nephrotoxic manifestations of these drugs include acute kidney injury, varying levels of proteinuria, hypertension, electrolyte disturbances, and at times chronic kidney disease. Thus, to practice competently in the 'onco-nephrology' arena, nephrologists will garner benefit from an update on older drugs with newly recognized nephrotoxic potential as well as newer agents, which may be associated with kidney injury. With that in mind, this brief update is meant to provide clinicians with the currently available evidence on the nephrotoxicity of a group of anticancer medications.

Optimal therapy for adult patients with acute myeloid leukemia in first complete remission

Although it is absolutely clear that postremission therapy is currently necessary to obtain disease-free long-term survivorship for patients with acute myeloid leukemia (AML) in first complete remission (CR), it is not entirely clear what form that treatment should take. High-dose cytarabine is clearly effective and there definitely is a dose-response relationship for cytarabine and remission duration. High-dose cytarabine is effective for younger patients but not elderly patients. It is effective for patients with favorable cytogenetics but it is not clear whether it is effective for patients with intermediate or unfavorable cytogenetics. Furthermore, it is not clear what the most effective and least toxic dose and schedule of high-dose cytarabine is.

Low efficacy and high mortality associated with clofarabine treatment of relapsed/refractory acute myeloid leukemia and myelodysplastic syndromes

Clofarabine, a second-generation nucleoside analog, has clinical activity in relapsed or refractory acute myelogenous leukemia (AML) and higher-risk myelodysplastic syndromes (MDS). However, there are few data evaluating performance of clofarabine in populations of patients not enrolled in clinical trials. We reviewed outcomes for 84 patients treated with clofarabine for relapsed or refractory AML or MDS, either with clofarabine as monotherapy (n=19) or in combination with cytarabine (n=65). Using International Working Group (IWG) response criteria, the overall response rate (ORR) of all treated patients was 21%, with a complete response rate with either complete or incomplete hematopoietic recovery (CRR=CR+CRi) of 14%. For combination therapy, ORR was 22% with CRR of 18%, and monotherapy patients had an ORR of 21% with CRR of 11%. Although limited by small numbers, subgroup analysis did not reveal variation in response rates when comparing different risk factors. The 30-day mortality was 21% and median survival was 3 months; a subset of 12 patients who were able to go to transplant had an 18-month median survival. Clofarabine's efficacy in a "real-world" setting appears to be less than has been reported in clinical trials, and treatment is associated with a high early mortality rate.

The role of Clofarabine in the treatment of adults with acute myeloid leukemia

The therapeutic scenario available for adult patients with acute myeloid leukemia (AML) has shown only partial progresses over the last few years. This is especially true for refractory and relapsed AML whose outcome is still extremely disappointing. In this context Clofarabine has offered new promising perspectives within first and second line protocols. This review will firstly describe the initial development in monotherapy, considering then the different potential combination strategies which include both polichemotherapeutic regimens and less conventional approaches with new generation drugs. The potential use of Clofarabine as induction treatment for patients candidate to stem cell transplantation and within conditioning regimens will be finally evaluated.

Clofarabine-associated acute kidney injury in patients undergoing hematopoietic stem cell transplant

Abstract We examined clofarabine pharmacokinetics and association with renal toxicity in 62 patients participating in a phase I-II study of clofarabine-melphalan-alemtuzumab conditioning for hematopoietic stem cell transplant (HSCT). Pharmacokinetic parameters, including clofarabine area under the concentration-time curve (AUC), maximum concentration and clearance, were measured, and patients were monitored for renal injury. All patients had normal pretreatment creatinine values, but over half (55%) experienced acute kidney injury (AKI) after clofarabine administration. Age was the strongest predictor of AKI, with older patients at greater risk (p = 0.002). Clofarabine AUC was higher in patients who developed AKI, and patients with the highest dose-normalized AUCs experienced the most severe grades of AKI (p = 0.01). Lower baseline renal function, even when normal, was associated with lower clofarabine clearance (p = 0.008). These data suggest that renal-adjustment of clofarabine dosing should be considered for older and at-risk patients even when renal function is ostensibly normal.

Phase I study of oral clofarabine consolidation in adults aged 60 and older with acute myeloid leukemia

Clofarabine has shown activity and tolerability in older patients with acute myeloid leukemia (AML). We investigated the safety and tolerability of an oral formulation of clofarabine for consolidation therapy of patients aged 60 and older with AML. In this phase I study, twenty-two patients older than 60 years with AML in first complete remission were treated once daily with oral clofarabine for 14 or 21 days of a 28-day cycle, for up to five cycles. Dose escalation from 1 mg to 6 mg daily using a 3 + 3 design was used to determine dose-limiting toxicities (DLT), the maximum tolerated dose (MTD), and tolerability of oral clofarabine. No DLTs or Grade 3-4 nonhematologic toxicities were observed. The primary toxicities were hematologic, including uncomplicated grade 3-4 neutropenia (50%) and thrombocytopenia (50%). Given that myelosuppression necessitating dose delays/reductions was observed more commonly at higher doses, the recommended phase II dose is 2 mg daily for 21 of 28 days. At doses equal to or greater than 2 mg, the median relapse-free survival was 28.35 months. Oral clofarabine was well-tolerated with encouraging activity in patients older than 60 years. Further investigation of oral clofarabine as a consolidation and/or maintenance therapy in AML for older individuals is warranted. (ClinicalTrials.gov:NCT00727766).

Update on optimal management of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a malignant accumulation of immature myeloid cells in the marrow, presenting with impaired hematopoiesis and its attendant complications, including bleeding, infection, and organ infiltration. Chromosomal abnormalities remain the most powerful predictors of AML prognosis and help to identify a subgroup with favorable prognosis. However, the majority of AML patients who are not in the favorable category succumb to the disease. Therefore, better efforts to identify those patients who may benefit from more aggressive and investigational therapeutic approaches are needed. Newer molecular markers aim at better characterizing the large group of intermediate-risk patients and to identify newer targets for therapy. A group that has seen little improvement over the years is the older AML group, usually defined as age ≥ 60. Efforts to develop less intensive but equally efficacious therapy for this vulnerable population are underway.

Clofarabine in the treatment of acute myeloid leukemia in older adults

OBJECTIVE

To review the literature evaluating the efficacy and tolerability of clofarabine as a single agent and in combination therapy for older patients with acute myeloid leukemia (AML).

METHOD

A literature search of the PubMed database (1996-April 2012) using the search terms clofarabine and acute myeloid leukemia was performed. All relevant English language articles were reviewed. Clinical trials with patients aged 50 years or older diagnosed with AML were included.

RESULTS

Two studies evaluating clofarabine as monotherapy and five studies evaluating clofarabine in combination with cytarabine were reviewed. Clofarabine demonstrated activity in older adults with AML. Response rates and median overall survival (OS) for patients receiving clofarabine were similar to those for patients receiving conventional induction chemotherapy. The induction mortality rate with clofarabine was lower than that seen with intensive chemotherapy. However, clofarabine was associated with a significant risk of severe complications including myelosuppression and sepsis.

CONCLUSION

Clofarabine is an active agent for the treatment of older patients with AML as a single agent or in combination therapy. Based on published data and side-effect profiles, clofarabine may be an appropriate alternative to intensive chemotherapy for older patients with AML, offering similar response rates to traditional 7+3 chemotherapy with potentially decreased induction mortality. The use of clofarabine in combination with newer agents including DNA methyltransferase inhibitors like decitabine is a promising approach for older patients who are not eligible for intensive chemotherapy. Additional randomized controlled trials are needed to directly compare the efficacy of clofarabine as a single agent and in combination therapy compared with intensive chemotherapy regimens.