1. Males and females age ≥18 years in second relapse or refractory. 
2. Males and females age ≥60 years in first relapse or refractory. 
3. Must have baseline bone marrow sample taken. 
4. Morphologically documented primary AML or AML secondary to myelodysplastic syndrome (MDS with ≥20% bone marrow or peripheral blasts), as defined by the World Health Organization (WHO) criteria, confirmed by pathology review at treating institution. 
5. Able to swallow the liquid study drug. 
6. ECOG performance status of 0 to 2 
7. In the absence of rapidly progressing disease, the interval from prior treatment to time of AC220 administration will be at least 2 weeks for cytotoxic agents or at least 5 half-lives for noncytotoxic agents. The use of chemotherapeutic or antileukemic agents other than hydroxyurea is not permitted during the study with the possible exception of intrathecal (IT) therapy at the discretion of the Investigator and with the agreement of the Sponsor. 
8. Persistent chronic clinically significant non-hematological toxicities from prior treatment must be ≤Grade 1. 
9. Prior therapy with FLT3 inhibitors is permitted, except previous treatment with AC220. 
10. Serum creatinine ≤1.5 × ULN and glomerular filtration rate (GFR) > 30 mL/min 
11. Serum potassium, magnesium, and calcium levels should be at least within institutional normal limits. 
12. Total serum bilirubin ≤1.5 × ULN 
13. Serum aspartate transaminase (AST) and/or alanine transaminase (ALT) ≤2.5 × ULN 
14. Females of childbearing potential must have a negative pregnancy test (urine β-hCG). 
15. Females of childbearing potential and sexually mature males must agree to use a medically accepted method of contraception throughout the study. 
16. Written informed consent must be provided. 

NCT00989261_inc_T1
Person
Males
NCT00989261_inc_T2
Person
females
NCT00989261_inc_T3
Person
age
NCT00989261_inc_T4
Value
≥18 years
NCT00989261_inc_T5
Condition
relapse
NCT00989261_inc_T6
Condition
refractory
NCT00989261_inc_T7
Scope
relapse or refractory
NCT00989261_inc_T8
Multiplier
second
NCT00989261_inc_T9
Person
Males
NCT00989261_inc_T10
Person
females
NCT00989261_inc_T11
Person
age
NCT00989261_inc_T12
Value
≥60 years
NCT00989261_inc_T13
Multiplier
first
NCT00989261_inc_T14
Condition
relapse
NCT00989261_inc_T15
Condition
refractory
NCT00989261_inc_T16
Scope
relapse or refractory
NCT00989261_inc_T17
Procedure
bone marrow sample
NCT00989261_inc_T18
Temporal
baseline
NCT00989261_inc_T19
Qualifier
Morphologically documented
NCT00989261_inc_T20
Qualifier
primary
NCT00989261_inc_T21
Condition
AML
NCT00989261_inc_T22
Condition
AML
NCT00989261_inc_T23
Condition
myelodysplastic syndrome
NCT00989261_inc_T24
Condition
MDS
NCT00989261_inc_T25
Value
≥20%
NCT00989261_inc_T26
Measurement
bone marrow
NCT00989261_inc_T27
Measurement
peripheral blasts
NCT00989261_inc_T28
Scope
bone marrow or peripheral blasts
NCT00989261_inc_T29
Procedure
World Health Organization (WHO) criteria
NCT00989261_inc_T30
Procedure
pathology review
NCT00989261_inc_T33
Measurement
ECOG performance status
NCT00989261_inc_T34
Value
0 to 2
NCT00989261_inc_T36
Condition
toxicities
NCT00989261_inc_T37
Qualifier
non-hematological
NCT00989261_inc_T38
Qualifier
clinically significant
NCT00989261_inc_T39
Temporal
prior
NCT00989261_inc_T40
Qualifier
≤Grade 1
NCT00989261_inc_T41
Value
≤Grade 1
NCT00989261_inc_T42
Qualifier
from prior treatment
NCT00989261_inc_T43
Procedure
treatment
NCT00989261_inc_T44
Drug
FLT3 inhibitors
NCT00989261_inc_T45
Mood
permitted
NCT00989261_inc_T46
Procedure
therapy
NCT00989261_inc_T47
Procedure
treatment
NCT00989261_inc_T48
Drug
AC220
NCT00989261_inc_T49
Negation
except
NCT00989261_inc_T50
Measurement
Serum creatinine
NCT00989261_inc_T51
Value
≤1.5 × ULN
NCT00989261_inc_T52
Measurement
glomerular filtration rate (GFR)
NCT00989261_inc_T53
Value
> 30 mL/min
NCT00989261_inc_T54
Measurement
Serum potassium
NCT00989261_inc_T55
Measurement
Serum magnesium
NCT00989261_inc_T56
Measurement
Serum calcium
NCT00989261_inc_T57
Value
at least within institutional normal limits
NCT00989261_inc_T58
Scope
Serum potassium, magnesium, and calcium
NCT00989261_inc_T59
Measurement
Total serum bilirubin
NCT00989261_inc_T60
Value
≤1.5 × ULN
NCT00989261_inc_T61
Measurement
Serum aspartate transaminase (AST)
NCT00989261_inc_T62
Measurement
alanine transaminase (ALT)
NCT00989261_inc_T63
Value
≤2.5 × ULN
NCT00989261_inc_T64
Measurement
pregnancy test
NCT00989261_inc_T65
Value
negative
NCT00989261_inc_T66
Procedure
urine β-hCG
NCT00989261_inc_T67
Person
Females
NCT00989261_inc_T68
Condition
childbearing potential
NCT00989261_inc_T69
Scope
Females of childbearing potential