A Phase 1b Study to Assess the Safety of PLX3397 and Paclitaxel in Patients With Advanced Solid Tumors

Inclusion Criteria:

- Advanced, incurable solid tumor.

- Patients with stable brain metastases are eligible. However, patients must not have
required steroid treatment for their brain metastases within 30 days of Screening.

- Bone-directed therapy (e.g., bisphosphonates or denosumab) is permitted. However,
patients should not have started bone-directed therapy within 2 weeks of C1D1, and
new bone-directed therapy should not be initiated during the first 4 weeks of study
(i.e., cycle 1).

- Washout from any prior investigational therapy of at least 28 days prior to Cycle 1,
Day 1 (i.e.,C1D1).

- Washout from prior chemotherapy of at least 2 weeks or 1 elimination half-life,
whichever is longer, prior to C1D1.

- Washout from prior hormonal therapy of at least 2 weeks prior to C1D1.

- Washout of at least 2 weeks from the most recent radiation treatment prior to C1D1.

- Resolution of all prior treatment-related toxicities to Grade 1 or less, except for
Grade 2 fatigue or alopecia prior to C1D1.

- Age 18 years or older.

- ECOG performance status 0-2, inclusive.

- Anticipated life expectancy of at least 12 weeks.

- Adequate bone marrow reserve: ANC ≥ 1000/mm3, platelets ≥ 100,000/mm3.

- Adequate renal function: serum creatinine < 1.5X ULN or calculated CrCl > 60 mL/min
using Cockcroft-Gault formula. GFR = [(140-age)*(weight in kg)*(0.85 if
female)]/(72*Cr)

- Adequate hepatic function: AST and ALT < 2.5X ULN, Total and Direct Bilirubin < 1.5X
ULN. However, in the presence of liver metastases, AST and ALT must be < 5X ULN and
Total and Direct Bilirubin < 3X ULN.

- Cardiac ejection fraction ≥ 50%, and QTcF < 450 ms on ECG at Baseline. Fridericia's
Formula: QTcF = (QT)/RR0.33

- Able to swallow capsules and maintain adequate hydration.

- Ability to give written informed consent and willing to comply with the requirements
of the protocol.

- Women of child-bearing potential must agree to use an effective method of birth
control during treatment and for three months after receiving their last dose of
study drug. Fertile men must also agree to use an acceptable method of birth control
while on study drug and for at least 3 months after last dose.

Exclusion Criteria:

- Presence of an active secondary malignancy.

- Patients with a non-melanomatous, in situ malignancy or disease that is
completely resectable with surgery may be considered after discussion with the
Medical Monitor.

- Patients with a completely treated prior malignancy with no evidence of disease
for ≥ 3 years are eligible.

- Refractory nausea and vomiting, malabsorption, external biliary shunt or significant
small bowel resection that would preclude adequate absorption of PLX3397.

- Ongoing treatment with any other investigational therapy.

- Prior anaphylactic or severe hypersensitivity reaction to paclitaxel or
Cremophor-containing agent.

- Persistent grade 2 fatigue at Baseline.

- Severe, concurrent illness including congestive heart failure, significant cardiac
disease and uncontrolled hypertension, that would likely prevent the patient from
being able to comply with the study protocol.

- Active untreated infection.

- Known chronic Hepatitis B or C, or HIV infection.

- The presence of a medical or psychiatric condition that, in the opinion of the
Principal Investigator, makes the patient inappropriate for inclusion in this study.