Key

Inclusion Criteria:

- Diagnosis of LGS carcinoma of the ovary, fallopian tube or primary peritoneum
(invasive micropapillary serous carcinoma or invasive grade 1 serous carcinoma),
confirmed histologically and verified by central pathology review.

- Recurrent or persistent measurable disease that has progressed (defined as
radiological and/or clinical progression; an increase in cancer antigen [CA]-125
alone is not sufficient) on or after last therapy (i.e., chemotherapy, hormonal
therapy, surgery) and is not amenable to potentially curative intent surgery, as
determined by the patient's treating physician.

- Must have received at least 1 prior platinum-based chemotherapy regimen but have
received no more than 3 lines of prior chemotherapy regimens, with no limit to the
number of lines of prior hormonal therapy.

- Available archival tumor sample (excisional or core biopsy) for confirmation of LGS
carcinoma diagnosis. If adequate archival tumor sample is not available, willingness
to consent to tissue biopsy.

- Suitable for treatment with at least one of the physician's choice chemotherapy
options (liposomal doxorubicin, paclitaxel or topotecan) as determined by the
Investigator.

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

- Additional criteria exist.

Key Exclusion Criteria:

- History or current evidence of central serous retinopathy (CSR) or retinal vein
occlusion (RVO), or predisposing factors to CSR or RVO.

- History of retinal degenerative disease.

- Prior therapy with a MEK or BRAF inhibitor.

- History of Gilbert's syndrome.

- Impaired cardiovascular function or clinically significant cardiovascular diseases.

- Uncontrolled or symptomatic brain metastases that are not stable, require steroids or
enzyme inducing anti-epileptic drugs, are potentially life-threatening or have
required radiation within 28 days prior to first dose of study treatment.

- Concomitant malignancies or previous malignancies with less than a 5-year
disease-free interval at the time of first dose of study treatment; patients with
adequately resected basal or squamous cell carcinoma of the skin, carcinoma in situ
of the cervix or ductal carcinoma in situ may be enrolled irrespective of the time of
diagnosis.

- Known positive serology for the human immunodeficiency virus (HIV), active hepatitis
B and/or active hepatitis C.

- Additional criteria exist.