Inclusion Criteria:

1. Ability to sign an approved informed consent form (ICF).

2. Must be ≥ 18 years of age.

3. Histology confirmed diagnosis of non-small cell lung cancer (adenocarcinoma,
squamous, adenosquamous, or adenocarcinoma with other NSCLC variants of the lung)
(Stage IIIB or IV).

4. All (RECIST v1.1-defined) target lesions positive for the folate receptor [FR(++)] by
SPECT scan.

5. Only one prior systemic therapy for advanced disease (e.g.,a platinum doublet or a
maintenance regimen that includes a platinum doublet; in addition, the participant
may have received an epidermal growth factor receptor [EGFR] inhibitor).

6. Radiological evaluation conducted no more than 28 days prior to beginning study
therapy. If history of CNS metastasis baseline radiological imaging must include
brain MRI or CT.

7. Radiologic evidence of disease progression following the most recent prior treatment.

8. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.

9. Must have recovered (to baseline/stabilization) from prior
cytotoxic-therapy-associated acute toxicities.

10. Prior radiation therapy is allowed if the following criteria is met:

- Radiation to < 25% of the bone marrow; whole pelvis radiation is excluded.

- Prior radiotherapy must be completed at least 2 weeks before randomization.

- Must have recovered from the acute toxic effects of the treatment before
randomized.

- Prior thoracic radiation must be completed 30 days before study enrollment.

- Irradiated pulmonary lesions cannot be used as target or non-target lesions (and
must be excluded) unless there is previous documented progression of these
lesions.

- Palliative extrathoracic radiotherapy can continue, but these lesions must be
excluded as target and non-target lesions.

11. Adequate organ function:

- Bone marrow reserve: Absolute neutrophil count (ANC) ≥ 1.5 x 109/L. Platelets ≥
100 x 109/L. Hemoglobin ≥ 9 g/dL.

- Hepatic: Total bilirubin ≤ 1.5 x the upper limit of normal (ULN). Alanine
aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl
transferase (GGT), and lactate dehydrogenase (LDH) and alkaline phosphatase ≤
2.5 x ULN.

- Renal: Serum creatinine ≤ 1.5 x ULN, or for participants with serum creatinine >
1.5 ULN, creatinine clearance ≥ 50 mL/min/1.73 m2 (50mL/min/1.73m2 is equivalent
to 0.83 mL/s/m2).

12. Participants of childbearing potential:

- Women who are capable of becoming pregnant must have a negative serum pregnancy
test within 1 week prior to exposure to EC20 and within 1 week prior to exposure
to treatment with EC145 and/or docetaxel.

- Women who are capable of becoming pregnant and male participants who are
sexually active must practice an effective method of birth control for the
duration of their participation in the trial through 3 months following the last
dose of EC145 and through 6 months following the last dose of docetaxel.

Exclusion Criteria:

1. Prior therapy with docetaxel, vinorelbine, or vinca-containing compounds.

2. Known hypersensitivity to docetaxel or polysorbate 80.

3. Symptomatic central nervous system (CNS) metastases or metastases that result in
midline shift, significant edema.

4. Malignancies other than NSCLC that are expected to alter life expectancy or may
interfere with disease assessment. Patients with adequately treated non-melanoma skin
cancer, carcinoma in situ of the cervix, or low-grade (Gleason score ≤ 6) localized
prostate cancer and patients with prior history of malignancy who have been disease
free for more than 3 years are eligible.

5. Serious cardiac illness or medical conditions such as unstable angina, pulmonary
embolism, or uncontrolled hypertension.

6. Anti-folate therapy such as methotrexate for rheumatoid arthritis.

7. Baseline peripheral neuropathy CTCAE ≥ Grade 2.

8. Pregnant or lactating women.

9. Other concurrent chemotherapy, immunotherapy, radiotherapy, or investigational
therapy.

10. Active infections (e.g., hepatitis or HIV carriers)