A Study of PRT1419 in Patients With Advanced Solid Tumors

Inclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2 * Adequate organ function (bone marrow, hepatic, renal, cardiovascular) * Left ventricular ejection fraction of ≥ 50% * Female patients of childbearing potential must have a negative pregnancy test within 7 days of the start of treatment and must agree to use a highly effective method of contraception during the trial * Patients must have recovered from the effects of any prior cancer related therapy, radiotherapy or surgery (toxicity ≤ Grade 1) * All patients on prior investigational agents must wait at least 5 half-lives of the agent in question, or 28 days, whichever is longer before study entry * Most recent lab values meet the following criteria: * Absolute neutrophil count \> 1.0 x 10\^3/μL; * Platelet count \> 75,000/μL; * Hemoglobin \> 9.0 g/dL * Histologically confirmed advanced or metastatic solid tumor indicated below that is relapsed, refractory, or intolerant to available therapies with known benefit: * Sarcoma not amendable to curative treatment with surgery or radiotherapy; * Melanoma (non-resectable or metastatic); * Small cell lung cancer (extensive-stage); * Non-small cell lung cancer; * Triple negative breast cancer (histopathologically or cytologically confirmed). * Esophageal cancer * Cervical cancer * Head and neck cancer Exclusion Criteria: * Known hypersensitivity to any of the components of PRT1419 * Primary malignancies of the CNS, or uncontrolled CNS metastases, including impending spinal cord compression * Female patients who are pregnant or lactating * Inflammatory disorders of the gastrointestinal tract, or subjects with GI malabsorption * Mean QTcF interval of \>480 msec * History of heart failure, additional risk factors for arrhythmias or requiring concomitant medications that prolong the QT/QTc interval * HIV positive; known active hepatitis B or C * Uncontrolled intercurrent illnesses * Treatment with strong inhibitors of CYP2C8 * Prior exposure to an MCL1 inhibitor * History of another malignancy except: * Malignancy treated with curative intent with no known active disease for \>2 years at study entry; * Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease; * Adequately treated carcinoma in situ without evidence of disease; * Other concurrent low-grade malignancies (i.e chronic lymphocytic leukemia (Rai 0)) may be considered after consultation with Sponsor.