Inclusion Criteria:

- Estrogen or progesterone receptor positive stage IIIb/IV non-small cell lung cancer

- Eligible patients will have stable disease on erlotinib monotherapy at FDA- approved
doses after a minimum duration of erlotinib therapy of 2 months

- 18 years or older

- ECOG Performance Status ≤2

- Adequate Organ Function Requirements

- Adequate coagulation function

- Postmenopausal status in female patients is required and is defined as no menstrual
periods for 12 month or surgical menopause

- All patients must sign a written informed consent.

Exclusion Criteria:

- Pregnant or breast-feeding women will not be entered on this study

- Patients who are currently receiving another investigational drugs

- Patients who are currently receiving other anti-cancer agents.

- Hormone replacement therapy will not be allowed and have to be stopped 1 month prior
to entry into the study

- Patients who have an uncontrolled infection.

- Patients receiving less than 100mg/day of erlotinib

- Patients with evidence of progression after 2 months of erlotinib monotherapy.

- Patients with a history of bleeding diathesis (i.e., disseminated intravascular
coagulation [DIC], clotting factor deficiency) or long-term anticoagulant therapy
(other than antiplatelet therapy).

- Patients with a history of hypersensitivity to active or inactive excipients of
fulvestrant (i.e. castor oil or Mannitol).

- Patients who in the opinion of the investigator may not be able to comply with the
safety monitoring requirements of the study.