Inclusion Criteria:

- Histologically confirmed, malignant solid tumor (measurable or non-measurable
disease) and cannot be a candidate for known regimens or protocol treatments of
higher efficacy or priority.

- Recovered to Grade 1 from all acute toxicities of prior therapies, except for
residual toxicities, such as alopecia, which do not pose an ongoing medical risk.

- ECOG performance status of 0, 1, or 2.

- At least 18 years of age.

- Patients must have normal organ and marrow function as defined by:

- Absolute neutrophil count 1,500/µL

- Platelets 100,000/µL

- Total bilirubin within normal institutional limits

- AST(SGOT)/ALT(SGPT) 2.5 x institutional upper limit of normal (ULN) or 5.0 x ULN
in patients with liver metastases

- Serum creatinine 1.5 x ULN or measured creatinine clearance of 60 mL/min/1.73 m2

- Negative serum pregnancy test at the time of enrollment for women of child-bearing
potential. For men and women of child-producing potential, use of effective
contraceptive methods is required during the study.

- Ability to understand the requirements of the study. Must provide written informed
consent and authorization of use and disclosure of protected health information. Must
agree to abide by the study restrictions and to return for the required assessments.

Exclusion Criteria:

- Received previous anticancer chemotherapy, immunotherapy, radiotherapy or any other
investigational therapy in the 4 weeks (6 weeks for nitrosoureas or mitomycin C)
prior to study entry.

- Receiving any other investigational agents.

- Known brain metastases with the exception of patients with a history of treated brain
metastases who are stable for at least 3 months off glucocorticoids and seizure
medications.

- Prolongation of QT/QTc interval > 450 milliseconds (ms).

- Known HIV, HBV, or HCV infection.

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to PNT2258.

- History of allergic reaction to egg or chicken antigens.

- Pregnant or nursing women.

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