This is a phase 2 study of the HSP90 inhibitor, STA-9090 (ganetespib) in subjects with stage IIIB or IV non-small cell lung cancer (NSCLC).

Inclusion Criteria:

• Pathologically confirmed diagnosis of Stage IIIB (with pleural effusion) or Stage IV NSCLC with measurable disease by RECIST and evidence of progression
• Availability of tissue for analysis
• ECOG Performance Status 0 or 1
• Adequate organ function as defined in the protocol.
• Must be at least 18 years old and able and willing to sign a written informed consent document

Exclusion Criteria:

• Poor venous access requiring an indwelling catheter for study drug administration
• Women who are pregnant or lactating
• Ventricular ejection fraction < or = to 55% at baseline
• Any uncontrolled intercurrent illness