A Study of SDX-7320 in Combination With Eribulin for People With Breast Cancer

Inclusion Criteria:

• Male or female with histologically and/or cytologically confirmed diagnosis oftriple-negative metastatic breast cancer defined as estrogen and progesteronereceptor staining ≤10%; and HER2-negative defined as IHC 0 to 1+ at enrollinginstitution (note: if IHC is equivocal, non-amplified status by FISH is acceptable)

• Advanced (local regionally recurrent, not amenable to curative therapy or surgery)or metastatic stage with up to 2 prior lines of therapy in the advanced ormetastatic setting

• Received prior anthracycline and taxane chemotherapy in the neoadjuvant, adjuvant,or metastatic settings and considered appropriate for treatment with single agenteribulin OR was otherwise ineligible to receive anthracycline and/or taxane pertreating physician OR patients with de novo metastatic disease.

• Evidence of metabolic dysfunction defined as HbA1c > 5.5 and/or BMI ≥ 30 kg/m^2

• Measurable disease per the Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1), OR at least one evaluable, predominantly lytic bone lesion

• Eastern Cooperative Oncology Group Performance Status (ECOG-PS) ≤1.

• Adult ≥18 at the time of informed consent and has provided written informed consentbefore the performance of any study-related activities and according to localguidelines.

• Adequate bone marrow and organ function as defined by the following laboratoryvalues (as assessed by local laboratory for eligibility):

• Absolute neutrophil count (ANC) ≥ 1,000 µL

• Platelet count ≥ 140,000 µL

• Hemoglobin ≥9.0 g/dL:

• Calcium (corrected for serum albumin) and magnesium ≤ Grade 1 according toNational Cancer Institute (NCI) Common Terminology

• Calculate Corrected Calcium if the albumin and/or serum calcium are not withinnormal limits: Corrected Calcium= Serum Calcium + 0.8 x [(Normal Albumin) -Patient Albumin] Normal Albumin value = 4.4g/dL Criteria for Adverse Events (CTCAE), version 5.0, and not considered by the Investigator to be clinicallysignificant

• Potassium within normal limits, with or without correction with supplements.

• In absence of liver metastases, alanine aminotransferase (ALT) and aspartateaminotransferase (AST) ≤2.5×the upper limit of normal (ULN). If the patient hasliver metastases, ALT and AST ≤5×ULN.

• Total bilirubin ≤1.5×ULN except for patient with Gilbert's syndrome who mayonly be included if the total bilirubin is ≤3.0×ULN or direct bilirubin ≤1.5×ULN

• Creatinine ≤1.5 mg/dL.

• Patient is, in the treating Investigator's opinion, willing and able to comply withthe study requirements, including the ability to fast prior to treatment days.

• If sexually active female of childbearing potential, willing to use a contraceptionmethod listed below:

• Oral, intravaginal, or transdermal combined (estrogen and progesteronecontaining) hormonal contraception

• Oral, injectable, or implantable progesterone-only hormonal contraception

• Intrauterine device (IUD)

• Intrauterine hormone-releasing system (IUS)

• Bilateral tubal occlusion

• Vasectomized partner with documentation of successful vasectomy.

• Complete abstinence from heterosexual intercourse

• If a sexually active male, willing to use barrier contraception (condoms)

Exclusion Criteria:

• Three or greater prior lines of therapy for metastatic TNBC

• Known primary brain malignancy, brain metastases or active CNS pathology, any ofwhich as determined by the treating Investigator

• Currently participating in a study of an investigational agent

• Body mass index < 18.5 kg/m2

• Known hypersensitivity to SDX-7320 or eribulin

• Established diagnosis of diabetes mellitus type I or uncontrolled orinsulin-dependent type II. Uncontrolled is defined as fasting blood glucose >140mg/dL and/or HbA1c ≥8%

• Use of combination antihyperglycemic therapy (single agent metformin on stable dosefor at least 3 months prior to enrollment is allowable)

• Concurrent malignancy or malignancy within 3 years of randomization, with theexception of adequately treated, basal or squamous cell carcinoma, nonmelanomatousskin cancer or curatively resected cervical cancer.

• Uncontrolled human immunodeficiency virus (HIV) infection. (Testing is notmandatory.)

• Evidence of uncontrolled active Hepatitis B or C infection

• History of Stevens-Johnson Syndrome (SJS), erythema multiforme (EM), toxic epidermalnecrolysis (TEN), or other severe medication-related cutaneous reactions.

• Any other concurrent severe and/or uncontrolled medical condition that would, in theInvestigator's judgment, contraindicate patient participation in the clinical study (e.g., chronic active hepatitis, severe hepatic impairment).

• Clinically significant, uncontrolled heart disease and/or recent cardiac eventsincluding any of the following:

• History of angina pectoris, coronary artery bypass graft (CABG) symptomaticpericarditis, or myocardial infarction within 6 months prior to study entry.

• History of documented congestive heart failure (New York Heart Associationfunctional classification III-IV).

• Documented cardiomyopathy.

• Left ventricular ejection fraction (LVEF) <45%, as determined by Multiple Gatedacquisition (MUGA) scan or echocardiogram (ECHO).

• History of any cardiac arrhythmias, (e.g., ventricular tachycardia), completeleft bundle block, high grade atrioventricular (AV) block (e.g., bifascicularblock, Mobitz type II and third-degree AV block) supraventricular, nodalarrhythmias, or conduction abnormality in the previous 12 months.

• Uncontrolled hypertension, defined by a systolic blood pressure (SBP) ≥160 mmHgand/or diastolic blood pressure (DBP) ≥100 mmHg, with or withoutantihypertensive medication. Initiation or adjustment of antihypertensivemedication(s) is allowed prior to screening

• Long QT syndrome, family history of idiopathic sudden death or congenital longQT syndrome or any of the following: risk factors for torsades de pointeincluding uncorrected hypokalemia or hypomagnesemia, history of cardiac failureor history of clinically significant/symptomatic bradycardia; concomitantmedications with a known risk to prolong the QT interval and known to causetorsades de pointe that cannot be discontinued or replaced by safe alternativemedications.

• Bradycardia (heart rate less than 50 at rest), by electrocardiogram (ECG) orpulse.

• Inability to determine the QT interval on the ECG (i.e., unreadable or notinterpretable) or corrected QT (QTcF) >450 msec for males and >470 msec forfemales (using Fridericia's correction) during Screening, based on the mean oftriplicate ECGs

• Currently receiving any of the following medications and cannot be discontinued 7days prior to the start of the treatment: Medications with a known risk to prolongthe QT interval or induce Torsade de Pointes (TdP). CredibleMeds list of drugs knownto cause TdP may be used as a reference for this study to determine which drugs areprohibited using the following link: https://crediblemeds.org/new-drug-list or acrediblemeds mobile application.

°Herbal preparations/medications, with the exception of cannabinoids, CBD compounds,etc.

• Participation in a prior investigational study within 14 days prior to the start ofthe study treatment or within 5 half-lives of study drug, whichever is longer.

• History of acute pancreatitis within 1 year of Screening or past medical history ofchronic pancreatitis

• Pregnant patients