Inclusion Criteria:

- Patients must have histologically confirmed non-small cell lung cancer (NSCLC);
cytology alone is not acceptable

- Patients must have progressive or recurrent NSCLC, and must have failed one and only
one prior cytotoxic chemotherapy regimen for advanced disease; patients must not have
received prior gemcitabine chemotherapy

- Patients must have measurable disease, as defined by RECIST, within 4 weeks prior to
registration

- Patients must have an ECOG performance status of 0 or 1

- Bilirubin < 1.5 x upper limit of normal

- AST (SGOT) < 3 x upper limit of normal

- Serum creatinine =< 1.5 mg/dL, or calculated creatinine clearance >= 60 mL/min

- Absolute granulocyte count >= 1500/mm3 and WBC >= 3000/mm^3

- Hemoglobin >= 9 g/L

- Platelet count >= 100,000/mm^3

- Patients must have completed any radiation therapy >= 3 weeks prior to registration

- Patients must have completed prior cytotoxic chemotherapy >= 3 weeks prior to
registration and have recovered from adverse effects from the chemotherapy to =<
Grade 1, or baseline

- Patients with brain metastases which have been treated are eligible if the patient is
> 3 weeks post completion of treatment for their brain metastases, and patient is
neurologically stable; patients with previous brain metastases who have not yet
received therapy specifically intended for their brain metastases are not eligible to
enroll in this protocol

- Life expectancy greater than 3 months

- Pregnant women are excluded from this study because Triapine® is a heterocyclic
carboxaldehyde thiosemicarbazone with the potential for teratogenic or abortifacient
effects; because there is an unknown but potential risk for adverse events in nursing
infants secondary to treatment of the mother with Triapine®, breastfeeding should be
discontinued if the mother is treated with Triapine®; women must not be pregnant or
breastfeeding due to the absence of information regarding the use of these agents in
these populations; a negative serum pregnancy test is required within 14 days of
study entry; the effects of Triapine® on the developing human fetus at the
recommended therapeutic dose are unknown; for this reason and because heterocyclic
carboxaldehyde thiosemicarbazones as well as other therapeutic agents used in this
trial are known to be teratogenic, women of child-bearing potential and men must
agree to use adequate contraception (hormonal or barrier method of birth control;
abstinence) prior to study entry and for the duration of study participation; should
a woman become pregnant or suspect she is pregnant while participating in this study,
she should inform her treating physician immediately

- Because patients with immune deficiency are at increased risk of lethal infections
when treated with marrow-suppressive therapy, HIV-positive patients receiving
combination antiretroviral therapy are excluded from the study because of possible
pharmacokinetic interactions with Triapine®

- Patients must not have an active second malignancy

- Patients must not have, at the time of registration, uncontrolled intercurrent
illness including, but not limited to, ongoing or active infection, or psychiatric
illness/social situations that would limit compliance with study requirements;
furthermore, since hypoxemia may cause serious adverse events in persons with serious
cardiac and/or pulmonary disease, patients at the time of registration with a history
of myocardial infarction within the prior 6 months, or with symptomatic congestive
heart failure, unstable angina pectoris, cardiac arrhythmia requiring medical
intervention (with the exception of chronic, stable, asymptomatic atrial
fibrillation), or pulmonary disease requiring oxygen are excluded

- Patients must not have dementia or active psychosis

- Patients must not have used any investigational agent in the month before study
enrollment

- Patients must not have a history of allergic reactions attributed to compounds of
similar chemical or biologic composition to Triapine® or other agents used in this
study

- Patients must not have a clinical history of G6PD (glucose-6-phosphate dehydrogenase)
deficiency; persons at high risk for this condition (patients of African, Asian, or
Mediterranean origin/ancestry) must undergo specific clinical testing at protocol
entry for this condition; patients testing positive for G6PD deficiency are excluded
from protocol entry