Inclusion Criteria:

- Patients must be ≥18 years of age

- Voluntarily signed an informed consent

- Confirmed NSCLC and Stage IIIB or IV disease.

- At least a ≥15 pack year smoking history and must have been an active smoker within
20 years of diagnosis.

- Must have archival NSCLC tissue available to provide for analysis or have a lesion
that is accessible for biopsy

- Must have experienced disease progression during or after receiving at least 1 prior
platinum-containing chemotherapy regimen.

- Must have received no more than 2 prior chemotherapy regimens

- Measurable disease by RECIST 1.1 criteria.

- ECOG performance status of 0 or 1 (Refer to scale in Appendix 1).

- Women of child-bearing potential (WCBP), all sexually active male patients, and
partners of patients must agree to use adequate methods of birth control.

Exclusion Criteria:

- Prior docetaxel, IPI-504 or other Hsp90 inhibitor treatment

- Known hypersensitivity to drugs formulated with polysorbate-80.

- Not recovered from any toxicities related to prior treatment

- Use of a medication or food that is a clinically relevant CYP3A inhibitor or inducer

- Inadequate hematologic function

- Inadequate hepatic function

- Inadequate renal function

- Symptomatic keratitis or keratoconjunctivitis.

- Uncontrolled systemic fungal, bacterial, viral or other infection

- Patients with clinically active brain metastases

- Patients with clinically stable brain metastases (previously treated or untreated)
are eligible.

- Sinus bradycardia (resting heart rate <50 bpm).

- Significant cardiac disease

- Previous or current malignancies at other sites within the last 2 years

- Prior hepatic resections or hepatic-directed therapy

- Known HIV-positive patients receiving combination antiretroviral therapy.

- Women who are pregnant or lactating.