1. Are referred to the Cachexia Clinic with involuntary weight loss of >5% of their premorbid weight within the previous 6 months. 
2. Are 18 years of age or older 
3. Have a Karnofsky performance score of 60 or higher. 
4. Can maintain oral food intake during the study 
5. Can understand the study procedures and can sign an informed consent form. 
6. Are not currently taking melatonin. 
7. Are taking megestrol acetate and continue to lose weight despite at least 2 weeks of therapy. 
8. Have a calculated creatinine clearance of >/= 60 cc/min. 

NCT00625742_inc_T1
Visit
Cachexia Clinic
NCT00625742_inc_T2
Condition
involuntary weight loss
NCT00625742_inc_T3
Value
>5% of their premorbid weight
NCT00625742_inc_T4
Temporal
within the previous 6 months
NCT00625742_inc_T5
Person
of age
NCT00625742_inc_T6
Value
18 years or older
NCT00625742_inc_T7
Measurement
Karnofsky performance score
NCT00625742_inc_T8
Value
60 or higher
NCT00625742_inc_T12
Drug
melatonin
NCT00625742_inc_T13
Temporal
currently
NCT00625742_inc_T14
Negation
not
NCT00625742_inc_T15
Drug
megestrol acetate
NCT00625742_inc_T16
Observation
lose weight
NCT00625742_inc_T17
Temporal
continue
NCT00625742_inc_T18
Temporal
at least 2 weeks
NCT00625742_inc_T19
Procedure
therapy
NCT00625742_inc_T20
Temporal
Are taking
NCT00625742_inc_T21
Measurement
calculated creatinine clearance
NCT00625742_inc_T22
Value
>/= 60 cc/min