Phase 2a Desipramine in Small Cell Lung Cancer and Other High-Grade Neuroendocrine Tumors

Inclusion Criteria: * Metastatic small-cell lung cancer * Metastatic high-grade neuroendocrine carcinoma of any organ system (high-grade defined by Ki-67 ≥ 20% and/or ≥ 20 mitoses/10 (HPF). * Received at least one line of prior chemotherapy treatment for metastatic disease. * Daily chemotherapy must be completed ≥ 2 weeks prior to registration * Weekly chemotherapy must be completed ≥ 2 weeks prior to registration * Chemotherapy every 2 weeks must be completed ≥ 3 weeks prior to registration * Chemotherapy every 3 weeks must be completed ≥ 4 weeks prior to registration * ECOG Performance Status 0 to 2 * Measurable disease by RECIST 1.1 criteria * Age at least 18 years * Estimated life expectancy at least 3 months * Absolute neutrophil count ≥ 1,500/ mm³ * Platelets ≥ 100,000/mm³ * Hemoglobin ≥ 9 g/dL * Total bilirubin ≤ 1.5 mg/dL, OR ≤ 2 X ULN if tumor involves the liver * AST(SGOT) * ALT(SGPT) ≤ 3 X ULN * Creatinine ≤ 1.5 X ULN * Creatinine clearance ≥ 45 mL/min/1.73m²) for patients with creatinine levels above institutional normal * QT interval corrected using Fridericia's method (QTcF) \< 450 msec (males) or \< 470 msec (females) * PR \< 240 msec * QRS \< 100 msec * Brain metastases must be asymptomatic and have been adequately treated with radiation finishing at least 1 week prior to initiation of study treatment. * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Clinically-significant ventricular arrhythmia including cardiac arrest * Myocardial infarction from coronary artery disease within 3 months of study enrollment * Implantable pacemaker or implantable cardioverter defibrillator * NYHA Class III or greater congestive heart failure * Other clinically-significant cardiac disorders * Family history of long QT syndrome. * Concomitant or expected treatment with strong inhibitors of cytochrome p450 CYP2D6, specifically including Bupropion; Fluoxetine; or Paroxetine (must be discontinued at least 2 weeks or 5-half lives prior to the initiation of desipramine, whichever is shortest, except fluoxetine which requires at least a 5-week washout period). * Use of medications known to increase risk of torsades de pointes, including Amiodarone; Arsenic trioxide; Astemizole; Azithromycin; Bepridil; Chloroquine; Chlorpromazine; Cisapride; Citalopram; Clarithromycin; Disopyramide; Dofetilide; Domperidone; Droperidol; Erythromycin; Flecainide; Halofantrine; Haloperidol; Ibutilide; Levomethadyl; Mesoridazine; Methadone; Moxifloxacin; Pentamidine; Pimozide; Probucol; Procainamide; Quinidine; Sotalol; Sparfloxacin; Terfenadine; Thioridazine; Vandetanib * Other anti-depressant or anti-psychotic medications including selective serotonin re-uptake inhibitors (SSRIs); other tricyclic, monoamine oxidase inhibitors (MAOIs); serotonin-norepinephrine reuptake inhibitors (SNRIs, typical or atypical anti-psychotic) * Metoclopramide (Reglan) because of increased risk of extrapyrimidal symptoms and neuroleptic malignant syndrome * Symptomatic orthostatic hypotension despite adequate volume resuscitation. * Medical history of narrow angle glaucoma * Bipolar disorder, ongoing or active within the last 5 years * Suicidal ideation, ongoing or active within the last 5 years * Suicide attempt, ongoing or active within the last 5 years * Pregnancy * Breastfeeding * Receiving any other investigational agents * Any other serious or unstable concomitant systemic disorder that in the opinion of the investigator is incompatible with the clinical study