Study of the Effect on Non-small Cell Lung Cancer of the Investigational Drug Motexafin Gadolinium When Used in Combination With Docetaxel (Taxotere)

* ≥ 18 years old * Histologically or cytologically confirmed diagnosis of NSCLC * Inoperable Stage IIIA, unresectable Stage IIIB or metastatic NSCLC patients who have received 1 prior platinum-based chemotherapy regimen * Measurable disease per RECIST * ECOG performance status score of 0 or 1 * Willing and able to provide written informed consent

* Laboratory values of: ANC \< 1500/mm³, Platelet count \< 100,000/mm³, hemoglobin \< 10 g/dL, AST or ALT \> 2.5 x upper limit of normal (ULN), Alkaline phosphatase \> 5 x ULN, bilirubin \> 1.5 x ULN, serum creatinine \> 2.0 mg/dL (176 umol/dL), albumin \< 3.0 g/dL (30 g/L) * Symptomatic or uncontrolled (untreated or treated and progressing) brain metastases * Evidence of meningeal metastasis * \> 1 prior cytotoxic regimen (not counting adjuvant or neo-adjuvant cytotoxic chemotherapy if completed \> 12 months prior to cytotoxic regimen, or prior MGd) * Chemotherapy, radiation therapy, experimental therapy, immunotherapy, or systemic biologic anticancer therapy within 21 days before beginning study treatment * Significant weight loss ≥ 10% of body weight within preceding 6 weeks * Treatment for another cancer within 3 years before enrollment, except basal cell carcinoma of the skin or cervical cancer in situ * Myocardial infarction within 6 months of enrollment or congestive heart failure rated New York Heart Association Class III or IV * Uncontrolled hypertension (systolic blood pressure \> 160 mm Hg and diastolic blood pressure \> 110 mm Hg on maximal medical therapy) * Known history of porphyria (testing not required at screening visit) * Known history of glucose-6-phosphate dehydrogenase (G6PD) deficiency (testing not required at screening visit) * History of hypersensitivity to taxanes or polysorbate 80 * Known history of HIV infection (testing not required at screening visit) * Female who is pregnant or lactating (serum pregnancy test is required for all female patients of childbearing potential) * Sexually active male or female of childbearing potential unwilling to use adequate contraceptive protection * Physical or mental condition that makes patient unable to complete specified follow-up assessments