This study will compare the anti-tumor efficacy of apricoxib and erlotinib with placebo and erlotinib as measured by time to disease progression to test the hypothesis that down regulation of COX-2 and EGFR pathways in patients with up-regulated COX-2 expression in tumor will have a clinical benefit compared with erlotinib alone.

Inclusion Criteria:

• Pathologically determined Stage IV NSCLC including Stage IIIb (pleural effusion)
• Failed at least one prior platinum-based chemotherapy for Stage IIIb or Stage IV NSCLC. Patients receiving platinum-based chemotherapy only given in an adjuvant setting are not eligible.
• Measurable disease by RECIST
• Greater than or equal to 18 years of age
• ECOG PS of 0 or 1

Exclusion Criteria:

• Radiation therapy within 2 weeks; chemotherapy within 3 weeks; non-cytotoxic investigational agents within 4 weeks of initiating study treatment
• Evidence of NYHA class III or greater cardiac disease
• History of MI, stroke, ventricular arrhythmia, or symptomatic conduction abnormality within 12 months
• Known HIV infection or AIDS
• Symptomatic CNS metastases
• Pregnant or nursing women
• Hypersensitivity or intolerance to erlotinib, sulfonamides, aspirin, or other NSAIDs.
• History of upper GI bleeding, ulceration, or perforation
• Prior history of COX-2 inhibitor therapy for the treatment of metastatic NSCLC
• Previous anti-EGFR kinase therapy