STAR CNS: This phase I/II study is seeking to determine the safety and best dose level of a new drug (GB5121) in people with relapsed or refractory central nervous system lymphomaA Phase 1b/2, Open-label Dose Escalation With Expansion Study of GB5121 in Adult Patients With Relapsed/Refractory Primary or Secondary Central Nervous System Lymphoma or Primary Vitreoretinal Lymphoma, With a Phase 2 Open-label Single Dose Level Study of GB5121 in Adult Patients With Relapsed/Refractory Primary Central Nervous System Lymphoma

Exclusion

1. Patients are concurrently using other approved or investigational antineoplastic agents.
2. Patients have an active concurrent malignancy requiring active therapy.
3. Patients are allergic to components of the study drug.
4. Patients have a known bleeding diathesis (eg, von Willebrand's disease) or hemophilia.
5. Patients who require therapeutic anticoagulation, including dual antiplatelet agents. Patients who have received therapeutic anticoagulation, including dual antiplatelet agents, within 5 half-lives of the anticoagulant or 14 days, whichever is longer, prior to starting the study drug. Patients who require the use of antiplatelet agents should be discussed with the Sponsor's Medical Monitor.
6. Patients have significant abnormalities on screening electrocardiogram (ECG) and active and significant cardiovascular disease such as uncontrolled or symptomatic arrhythmias, congestive heart failure, uncontrolled hypertension, valvular disease, pericarditis, or myocardial infarction within 6 months of screening.

7. Patients with any of the following will be excluded:

   1. A marked baseline prolongation of QT/QTc interval (eg, repeated demonstration of a QTc interval > 480 ms [CTCAE grade 2]) using Frederica's QT correction formula.
   2. A history of additional risk factors for Torsades de Pointes (eg, heart failure, hypokalemia, family history of long QT syndrome).
   3. The use of concomitant medications that prolong the QT/QTc interval.
8. Patients are known to have a history of active or chronic infection with hepatitis C virus (HCV), hepatitis B virus (HBV), as determined by serologic tests.
9. Known history of infection with human immunodeficiency virus (HIV).
10. Patients are known to have an uncontrolled active infection.
11. Patients have a history of stroke or intracranial hemorrhage within 6 months prior to enrollment.
12. Patients have a life-threatening illness, medical condition, or organ system dysfunction that, in the opinion of the Investigator, could compromise the subject's safety or put the study outcomes at undue risk.
13. Women who are pregnant or nursing (lactating).