Inclusion Criteria:

- Age ≥ 3 years. (No dosing or adverse event data are currently available on the use
of valganciclovir in patients < 16 years of age.)

- Life expectancy of > 3 months.

- ECOG Performance Status 0-2 or Karnofsky Performance Scale ≥ 60%.

- Baseline (untransfused) HbF level > 2%

- Normal organ and marrow function defined as: (i) absolute neutrophil count of ≥
1,000/µL. (ii) platelets ≥ 50,000/ µL. (iii) total bilirubin of ≤ 2.0 x upper limit
of normal. (iv) AST (SGOT)/ALT(SGPT) of ≤ 2.0 x institutional upper limit of normal.
(v) creatinine within normal range for institution.

- Women of child-bearing potential and men must agree to use adequate contraception
prior to study entry and for the duration of study participation.

- Able and willing to give informed consent.

Exclusion Criteria:

- Patients that have received chemotherapy or radiotherapy within 4 weeks (6 weeks for
nitrosoureas or mitomycin C) prior to entry, or those who have not recovered form
adverse events due to agents administered 4 weeks earlier.

- Patients may not be receiving any other investigational agents.

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to Arginine Butyrate, ganciclovir or valganciclovir.

- Patients who have an acute myocardial infarction or onset of atrial fibrillation
within the past 6 months.

- Uncontrolled intercurrent illness including, but not limited to , ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements.

- Tumor impinging on an organ or anatomical structure deemed critical by the
investigator.

- Pregnant women.