The main aims of this clinical study are to: (a) Find out if the best course of study treatment is to take either VS-6766 alone (monotherapy) or to take VS-6766 together (in combination) with defactinib; (b) Understand the safety of VS-6766 taken alone or taken together with defactinib; (c) Describe how well and how long the study treatment with VS-6766 alone or in combination with defactinib works; and (d) Measure the amount of VS-6766, defactinib and compounds related to the two study drugs in your blood at different times (this is called pharmacokinetics).