Patients must have corrected QT (QTc) interval < /msec (by Bazetts formula) on baseline ECG Corrected QT interval (QTc) < msec Patients with a baseline QTc of > msec are excluded; Bazetts formula is to be used for measurement of the corrected QT interval: the QT interval (msec) divided by the square root of the RR interval (msec) Corrected QT interval, QTc < msec\r\n* Note: Repeat echocardiogram is not required if echocardiogram was obtained within days of study enrollment Corrected QT interval (QTc) on electrocardiogram (EKG) > msec Resting electrocardiography (EKG) with corrected QT (QTc) > msec or family history of long QT syndrome; if EKG demonstrates QTc > msec, patient will be eligible only if repeat EKG demonstrates QTc ? msec Baseline corrected QT interval (QTc) =< msec\r\n* Note: QT interval calculation by the Fridericia formula is permitted Corrected QT interval (QTc) < msec Unstable cardiac dysrhythmias or persistent prolongation of the corrected QT interval (QTc) (Fridericia) to > msec for males or > msec for females. Corrected QT interval (QTc) interval greater than msec (males) or greater than msec (females). Patients must have a corrected QT (QTc) interval of less than msec Patients must not have a corrected QT interval (QTc) of > msec using Bazetts formula Corrected QT (QTc) interval > msec Participants must have a corrected QT (QTc) of =< msec for females and =< for males on the screening electrocardiogram (EKG) ENROLLMENT TO THE DOSE ESCALATION, EXPANSION AND PART II: Corrected QT (QTc) =< msec Corrected QT (QTc) interval < msec Participants must have a corrected QT (QTc) of =< msec on the screening electrocardiography (EKG) Corrected QT (QTc) interval > msec, unless a bundle branch block is also present Corrected QT interval (QTc) =< msec Consistent corrected QT (QTc) > msec for men and > msec for women by Fridericia formula, on separate electrocardiograms (ECGs) Documented within days of registration: Cardiac corrected QT (QTc) interval < msec on electrocardiogram (EKG) Subject has corrected QT (QTc) interval < msec on baseline electrocardiogram Patients with corrected QT (QTc) interval of > msec or those on medications known to prolong QTc interval Patients who have corrected QT (QTc) interval of > msec on a screening electrocardiogram Baseline electrocardiogram (EKG) with corrected QT interval (QTc) > msec (including subjects on medication); subjects with ventricular pacemaker for whom QT interval is not measurable will be eligible on a case-by-case basis Participants with any history of corrected QT (QTc) prolongation (i.e. QTc interval of > msec) Mean QT interval ? msec Corrected QT (QTc) < msec by Fridericia Corrected QT interval (QTc) prolongation > msec Baseline electrocardiogram (EKG) with corrected QT (QTc) > msec (including subjects on medication); subjects with ventricular pacemaker for whom QT interval is not measurable will be eligible on a case-by-case basis at medical doctor (MD) discretion Patients with a corrected QT (QTc) interval of > milliseconds (msec) on screening electrocardiogram (ECG) for men or > msec for women Baseline corrected QT Interval (QTc) > milliseconds (msec) in women and > msec in men; concomitant treatment with medications that prolong the QT interval and have a known risk of Torsades De Pointes is not contraindicated, but should be avoided if possible and will require more frequent electrocardiogram (EKG) monitoring Mean resting corrected QT interval (QTc) > msec Marked baseline prolongation of QT/corrected QT (QTc) interval (QTc interval >= msec) using the Fridericia method (QTc = QT/RR.) for QTc analysis Electrocardiogram (EKG) corrected QT interval (QTc) < msec (females) PART GROUP INCLUSION CRITERIA: Corrected QTc =< msec PART GROUP A INCLUSION CRITERIA: Corrected QTc =< msec PART GROUP INCLUSION CRITERIA: Corrected QTc =< msec Corrected QT (QTc) =< msec. for men or QTc =< msec. for women -lead electrocardiogram (EKG) showing no active ischemia and corrected QT (QTc) interval less than msec Subject has corrected QT (QTc) interval < msec on baseline electrocardiogram Corrected QT interval (QTc) =< msec Screening electrocardiography (ECG) with corrected QT (QTc) interval > milliseconds (corrected by Fridericia); in the event that a single QTc is > msec, the subject may enroll if the average QTc for ECGs is < msec Patients with prolonged corrected QT interval, defined as corrected QT (QTc) > msec Corrected QT (QTc) interval >= msec (>= msec for subjects with bundle branch block) Baseline electrocardiogram (EKG) with corrected QT interval (QTc) > msec (including subjects on medication); subjects with ventricular pacemaker for whom QT interval is not measurable will be eligible on a case-by-case basis Syndrome of congenital corrected QT interval (QTc) prolongation or QTc > msec QT interval corrected for heart rate (QTc) (corrected by Fridericia's method) > msec at Screening QT intervals of QTc ? msec Corrected QT (QTc) interval =< msec Patients with prolonged corrected QT(QTc) interval defined as male > msec and female > msec Corrected QT (QTc) interval > msec (females) or > msec (males) Obtained =< days prior to registration: Corrected QT (QTc) interval =< msec on the baseline electrocardiogram Corrected QT (QTc) interval > msec on baseline electrocardiogram (EKG) Corrected QT interval (QTc) =< msec (based on average of screening triplicates) Subjects must have normal corrected QT interval (QTc) =< msec (based on average of screening triplicates) Baseline corrected QT (QTc) interval > msec Corrected QT interval (QTc) =< msec per Fridericias formula AND PR interval =< msec (using -lead electrocardiography [EKG]) Corrected QT (QTc) interval on electrocardiogram must be =< msec (Fridericia correction) Corrected QT interval (QTc) =< msec Patients must have corrected QT (QTc) interval < msec on baseline electrocardiogram (EKG) Corrected QT interval (QTc) =< msec Heart-rate corrected QT interval (QTc) prolongation > msec at screening Has QT interval corrected for heart rate (QTc) ? msec. Mean resting corrected QT interval (QTc) ? msec for males and ? msec for females. Patients must have corrected QT (QTc) =< msec Corrected QT interval (QTc) < msec Corrected QTc interval > msec; baseline electrocardiogram (EKG) obtained pre-transplant does not need to be repeated unless clinically indicated QT interval corrected (QTc) < millisecond (msec) or QTc < msec for patients with bundle branch block. Mean resting correct QT interval (QTc) > msec obtained from triplicate electrocardiagrams Grade corrected QT interval (QTc) prolongation (QTc > msec on two separate electrocardiograms (ECGs) Subjects with a corrected QT interval (QTc) > msec (QTc > msec for subjects with bundle branch block) at baseline Normal corrected QT (QTc) interval defined on electrocardiogram (EKG) as QTc =< msec\r\n* Note: patients who are assigned to arm B must have QTc =< msec on day (D) and D of cycle of eribulin treatments for continued eligibility\r\nPostmenopausal women defined as women with:\r\n* Prior bilateral surgical oophorectomy, or\r\n* Medically confirmed post-menopausal status defined as spontaneous cessation of regular menses for at least consecutive months with no alternative pathological or physiological cause On electrocardiogram, corrected QT (QTc) interval > msec Corrected QT interval (QTc) of > msec using Bazetts formula Corrected QT (QTc) interval > msec, unless a bundle branch block is also present Patient with corrected QT (QTc) interval must be less than msec Patients must have corrected QT (QTc) < msec Corrected QTc > msec; the corrected QTc may be corrected using either Bazetts or Fridericias formula; in general Fridericia corrected QT interval (QTcf) is the preferred correction method Corrected QT (QTc) interval > msec Corrected QT interval (QTc) (based on Bazett) > msec on baseline ECG; if QTc > msec and electrolytes are not within normal ranges, electrolytes should be corrected and then the patient re-screened for QTc At eltrombopag dose levels mg and above cohorts, subjects with a corrected QT (QTc) > msec at screening, if other drugs known to cause prolonged QT are stopped an electrocardiogram (EKG) documenting QTc below msec is required Corrected QT (QTc) interval >/= msec at the time of transition to this study Corrected QT interval (QTc) must be < msec Currently receiving medications known to cause QT prolongation AND corrected QTc of msec for females, msec for males. Corrected QT (QTc) (Frederica) prolongation > msec Corrected QT (QTc) interval =< msec Screening electrocardiogram (EKG) with a corrected QT (QTc) > msec Corrected QT interval (QTc) > msec Patients with a baseline QT/corrected QT (QTc) interval >= msec QTc (corrected QT) interval < msec. Corrected QT (QTc) interval > msec (males) or > msec (females) Corrected QT interval (QTc) of greater than msec Have chronic atrial fibrillation or QTc interval corrected for heart rate of greater than msec. Patient must have a QT/QTc interval ? msec. Corrected QT interval (QTc) < msec (with Bazetts correction) in screening electrocardiogram Electrocardiogram (EKG) with mean corrected QT (QTc) interval < msec Corrected QT (QTc) interval > msec on baseline electrocardiogram (EKG) Corrected QT (QTc) interval > msec Corrected QT interval (QTc) ? msec at least days prior to registration for protocol therapy. Patients with marked baseline prolongation of QT/corrected QT (QTc) interval (QTc interval > msec for males or > msec for females) using the Fridericia method for QTc analysis Corrected QT interval (QTc) =< msec Patients with a known or screening-period-determined corrected QT (QTc) interval > msec and patients who require a therapy with a drug known to prolong the QT/QTc interval, are ineligible Corrected QT (QTc) interval within normal range for age Corrected QT interval (QTc) =< msec Corrected QT interval (QTc) > msec (male) or > msec (female) on -lead electrocardiogram Cardiovascular risk, including:\r\n* Poorly controlled hypertension, defined as either systolic > or diastolic > \r\n* Congestive heart failure\r\n* Myocardial infarction within the past year\r\n* QT prolongation, defined as pretreatment corrected QT interval (QTc) > msec in males or > msec in females