Phase 1/2 Study of TP-0903 (an Inhibitor of AXL Kinase) in Patients With Previously Treated CLL

This is a combined Phase 1/2 study of oral TP-0903 in patients with previously treated CLL/SLL. In both Phase 1 and Phase 2, study participants will be assigned to one of two defined patient groups: * Group 1 (TP-0903 monotherapy): Patients with CLL/SLL who are intolerant to, or have progressed on, B-cell receptor antagonists and/or BCL-2 antagonists * Group 2 (TP-0903 and ibrutinib combination therapy): Patients with CLL/SLL who have progressed on ibrutinib yet the treating provider considers continuation of ibrutinib therapy to be in the best interest of the patient. Both groups of patients will be treated identically with TP 0903 and will undergo the same study assessments. Phase 1 Patients will be enrolled in Group 1 and Group 2 in cohorts of 3 to 6 patients simultaneously. Group 2 will start at one dose level below the Group 1 starting dose. In each group, escalation of the TP-0903 dose will follow a standard 3+3 design with sequential cohorts of three patients treated with incrementally higher doses of TP 0903 until a dose-limiting toxicity (DLT) is observed and the maximum tolerated dose (MTD) is established. In the absence of DLTs, the dose will be increased using a modified Fibonacci dose escalation scheme. Once the MTD or preliminary RP2D is identified, an expansion cohort of up to 6 patients will be enrolled in each patient group to confirm safety/suitability of the preliminary RP2D, to collect additional biomarker data, and to further explore efficacy. It is expected that up to 27 patients will be enrolled in each patient group for a total of up to 54 patients (TP-0903 monotherapy and combination therapy with ibrutinib). Additional dose levels, schedules, or disease indications of TP 0903 may be explored, as appropriate, based on the modulation of key biomarkers and the safety profile and clinical signals of activity. Phase 2 In Phase 2, patients will be enrolled in Group 1 (TP 0903 monotherapy) and Group 2 (TP-0903 combination therapy with ibrutinib) based on the Simon 2 stage design. In Stage 1, up to 13 patients will be enrolled into each patient group (total of 26 patients). If there are no responses among these 13 patients in each group, the study will be stopped. Otherwise, Stage 2 will open to enroll 14 additional patients in each group for a total of 27 patients per group. If 4 or more responses are observed among 27 patients, the conclusion will be that the study treatment is worthy of further investigation. If both patient groups enroll through Stage 2, it is anticipated that the total enrollment for Phase 2 will be 54 patients.