Inclusion Criteria:

1. Diagnosis of AML (de novo, secondary, or hematological disorder), according to WHO
criteria.

2. Older than or equal to 60 years

3. ECOG performance status 0-2

4. At least one of the following factors:

- Older than or equal to 70 years

- Prior hematological disorder (AHD)

- ECOG performance status 2

- Unfavorable karyotype (ie, adverse) defined as any cytogenetic profile except
the presence of any of the following:

t(8;21)(q22;q22) inv(16)(p13q22) or t(16;16)(p13;q22) t(15;17)(q22;q12) and
variants

5. Provide written informed consent form.

6. Being able to comply with study procedures and follow-up evaluations.

7. Not to be fertile or willing to use a method of birth control during the study until
the end of the last visit of the treatment.

8. Adequate renal and hepatic function as follows:

- Total bilirubin <= 1,5 x upper of institutional normal limit (ULN) and

- AST y ALT <=2,5 x ULN and

- Serum creatinine <=1,0 mg/dL of serum creatinine <01,0 mg/dL, then, glomerular
filtration rate (GFR) estimated must be >60 mL/min/1,73 m2 calculated from the
equation of the Modification of Diet in Renal Disease (MDRD).

9. Adequate cardiac function determined by at least one of the following:

- Left ventricular ejection fraction (LVEF) >=40% measured by echocardiography in
Multiple Gated Acquisition (MUGA) scan or isotope angiography or

- Left ventricular fractional shortening >=22% measured by echocardiography.

Exclusion Criteria:

1. Diagnosis of acute promyelocytic leukaemia (APL) in French-American-British
classification M3º or attending to the WHO classification t(15;17)(q22;q12), (PML/RAR
and variants).

2. Pre-treatment with clofarabine.

3. Previous treatment for AML or a hematological disorder AHD (excluding palliative
care, hydroxyurea, hematopoietic cytokines or lenalidomide [the latter only for a
specific AHD]). Hematopoietic cytokines and lenalidomide should not have been
administered within the 14 days preceding the first dose of study drug. If it is
received any previous treatment for AML or AHD within the time limits allowed,
drug-related toxicity, must have recovered to Grade 1 or less before the first dose
of study drug.

4. Previous hematopoietic stem cell transplantation (HSCT).

5. External beam pelvic radiotherapy.

6. Have received an investigational product within 30 days before the first dose of
study drug. If the patient has received any investigational product before this time,
the drug-related toxicity, must have recovered to Grade 1 or less before the first
dose of study drug.

7. Inadequate renal and hepatic function as follows:

- Total bilirubin >1,5 x institutional upper limit normal (ULN) provided it is not
attributable to the very LMA or

- AST y ALT >2,5 x ULN provided it is not attributable to the very LMA or

- Serum creatinine >1,0 mg/dL provided that the glomerular filtration rate (GFR)
estimated to be ≤60 mL/min/1,73 m2 calculated by the equation of the
Modification of Diet in Renal Disease (MDRD).

8. Inadequate cardiac function determined by at least one of the following:

- Left ventricular ejection fraction <40% measured by echocardiography in Multiple
Gated Acquisition (MUGA) or isotope angiography; or

- Left ventricular fractional shortening <22% measured by echocardiography.

9. Poor general condition ECOG 3-4.

10. Refusal to sign informed consent form.

11. Inability to comply with study visits and inspections.

12. Psychiatric disorders that could interfere with the consent, participation or
monitoring of the study.

13. Fungal Systemic disease, bacterial, viral or other uncontrolled infection (defined as
manifestation of signs / symptoms related to ongoing infection and without
improvement, although receiving adequate antibiotic therapy or other treatment).

14. Any other concomitant serious disease or a history of severe organ dysfunction or
heart, kidney, liver or other organ system which may involve the patient in excessive
risk when exposed to clofarabine.

15. Diagnosis of another malignancy neoplasia, unless the patient has been disease-free
for at least five years after completing an attempt curative therapy with the
following exceptions:

- Patients with non-melanoma skin cancer, carcinoma in situ or cervical
intraepithelial neoplasia, irrespective of the duration of disease-free period,
are eligible for the study if it has finalized a definitive treatment for the
disease.

- Patients with prostate cancer confined to the organ without evidence of
recurrent or progressive disease based on figures for the prostate specific
antigen (PSA) are also candidates for the study if hormonal therapy has been
initiated or has made a radical prostatectomy.

16. Clinical evidence which may indicate central nervous system (CNS) leukemia unless
lumbar puncture to confirm the absence of leukemic blasts in the cerebrospinal fluid
(CSF).

17. Previous positive test for human immunodeficiency virus (HIV).