Inclusion Criteria:

- The patient has histologic or cytologic confirmation (upon local review) of small
cell lung cancer (SCLC).

- The patient has extensive-stage small cell lung cancer (ES-SCLC), as defined by
National Comprehensive Cancer Network (NCCN) guidelines.

- The patient has measurable disease as assessed by Response Evaluation Criteria
Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1).

- The patient has not received any prior chemotherapy, biological agent, or
investigational drug for SCLC.

- The patient has an Eastern Cooperative Oncology Group (ECOG) performance status of 0
or 1.

- The patient is 18 years of age or older at the time informed consent is obtained.

- The patient must be accessible for study treatment and follow-up. Patients enrolled
in this study must be treated at participating study centers for all 3 days of study
drug administration in either treatment group.

- The patient has normal organ function.

- Women of childbearing potential must have a negative serum pregnancy test 72 hours
prior to study enrollment. Women of childbearing potential and men with partners of
childbearing potential must use a highly effective method of contraception throughout
the entire study and up to 8 weeks after the last dose of any study drug (including
obatoclax maintenance). Effective contraception or birth control is defined as those
with a low failure rate (less than 1% per year) when used consistently and correctly.

- Women must not be breastfeeding.

- Written informed consent is obtained.

- Patients with asymptomatic brain metastases may be enrolled and if clinically
indicated, may be treated with steroids to be tapered as tolerated by the patient.
Patients with symptomatic brain metastases will be eligible for the study after they
have received therapeutic whole brain irradiation (WBI), which must be completed at
least 7 days before the day of first treatment with study drugs. Since these patients
will also be treated with steroids it is recommended that steroids be tapered as
clinically indicated and tolerated by the patient. The use of chronic, low-dose
steroids is not contraindicated for these patients (or any other patients).
Stereotactic radiation will be allowed for 1 to 3 brain metastatic lesions that meet
appropriate criteria for that procedure; however, this must be discussed with the
study monitor prior to consideration for enrollment into this study.

- The patient must be willing and able to comply with study restrictions and to remain
at the study center for the required duration during the study period and willing to
return to the study center for the follow-up evaluation as specified in this
protocol.

Exclusion Criteria:

- The patient has had any prior systemic therapy for ES-SCLC other than radiation
therapy or surgery.

- The patient has a history of prior malignancy with the exception of cervical
intraepithelial neoplasia, basal cell or squamous cell carcinoma of the skin, or
other localized malignancy that has undergone potentially curative therapy and is
deemed by his or her treating physician to be at low risk for recurrence for 5 years.

- The patient has a history of hypersensitivity or allergic reactions attributed to
components of the obatoclax mesylate formulation (ie, polysorbate 20 and polyethylene
glycol [PEG] 300) or to carboplatin or etoposide.

- The patient currently has leptomeningeal disease or paraneoplastic syndromes.

- The patient has uncontrolled intercurrent illness including, but not limited to,
symptomatic neurologic illness; active, uncontrolled systemic infection considered
opportunistic, life-threatening, or clinically significant at the time of treatment;
symptomatic congestive heart failure; unstable angina pectoris; clinically
significant cardiac arrhythmia; significant pulmonary disease or hypoxia; or
psychiatric illness that would limit compliance with study requirements.

- The patient is a pregnant or lactating woman. (Any women becoming pregnant during
the study will be withdrawn from the study but will be monitored for safety.)

- The patient has a positive test result for hepatitis B surface antigen (HBsAg) or
antibodies to hepatitis C virus (HCV Ab) or a known positive history of antibodies to
human immunodeficiency virus (HIV) and is receiving combination antiretroviral
therapy.