Inclusion Criteria:

- Patients with any malignancy that is deemed appropriate for treatment with a
chemotherapy regimen incorporating a < 3 hour infusion of doxorubicin ≥ 40 mg/m2/dose
not more frequently than weekly. Single agent doxorubicin and combination
chemotherapy are allowed. The duration of treatment and the cumulative dose of
doxorubicin are determined by the chemotherapy regimen chosen for treatment of each
individual's disease and up to the discretion of the treating provider. Prior
doxorubicin-based regimen(s) allowed.

- At least 30 days since last doxorubicin before initiation of current
doxorubicin-based regimen

- Patients > 18 years of age

- ECOG performance status
- Able to understand and the willingness to sign a written informed consent. A signed
informed consent must be obtained prior to any study-specific procedures

Exclusion Criteria:

- Known congestive heart failure (active disease or history of)

- Left ventricular ejection fraction less than 50%

- Planned concurrent administration of other investigational agents

- Swallowing or absorption problems that might interfere with oral bioavailability of
sildenafil

- Known hypersensitivity to doxorubicin, sildenafil or any component of either agent

- Planned chronic nitrate or alpha blocker therapy

- Anticipated prolonged treatment with any strong CYP3A4 inhibitor: indinavir,
nelfinavir, ritonavir, saquinavir, clarithromycin, itraconazole, ketoconazole,
nefazodone, telithromycin

- Other relative contraindications to sildenafil as defined in the prescribing
information:

- Myocardial infarction, stroke, or life-threatening arrhythmia within the last 6
months

- Coronary artery disease causing unstable angina

- Resting hypotension (BP <90/50) or hypertension (BP >170/110) despite
appropriate treatment

- Known retinitis pigmentosa

- Persisting or anticipated toxicity from prior therapy that might confound attribution
of on study adverse events

- Pregnant or nursing

- Known hearing loss

- History of priapism when exposed to PDE5 inhibitors (sildenafil, vardenafil,
tadalafil)

- Other condition(s) that in the opinion of the investigator might compromise the
objectives of the study