Safety and Pharmacology of SNX-5422 Plus Everolimus in Subjects With Neuroendocrine Tumors

Heat shock protein 90 (Hsp90) plays a central role in the maturation and maintenance of numerous proteins, for example HER2 and mutated EGFR, that are critical for tumor cell viability and growth; SNX-5422 is a pro-drug of SNX-2112, a potent, highly selective, small-molecule inhibitor of the molecular chaperone heat shock protein 90 (Hsp90). Hsp90 has been found to be expressed in 95% of subjects with pancreatic neuroendocrine tumors.

This study will determine the MTD of SNX-5422 when given in combination with everolimus in patients with neuroendocrine tumors.The clinical starting dose of 50 mg/m2 qod for SNX-5422 in combination with daily everolimus is 50% of the SNX-5422 qod mono-therapy MTD. The choice to continue once every other day SNX-5422 dosing is based on the safety and efficacy profiles from prior studies, so that drug holidays are interspersed into weekly dosing. The planned subsequent dose levels are 75% and 100% of the SNX-5422 qod mono-therapy MTD.

Inclusion criteria

• Males or non-pregnant, non-breastfeeding females 18 years-of-age or older.
• Archived neuroendocrine tumor sample or biopsy sample (will also be used for genetic testing).
• Pathologic evidence of chemo-resistant Small Cell Lung cancer (relapse <90 days after 1st line), chemo-sensitive Small Cell Lung Cancer (relapse >90 days after first line), locally advanced metastatic neuroendocrine tumor of gastro-entero, pancreatic, pulmonary (other than Small Cell Lung) or thymic origin, or advanced renal cell carcinoma for which everolimus is indicated.
• Measurable (RECIST) indicator lesion not previously irradiated.
• Life expectancy of at least 3 months.
• No more than 4 prior lines of systemic anti-cancer therapy.
• Karnofsky performance score ≥70.
• Adequate baseline laboratory assessments, including

• Absolute neutrophil count (ANC) ≥1.5 x 109/L.
• WBC >3000/microliter
• Platelet count of ≥100 x 109/L.
• Total bilirubin level ≤1.5 times institutional upper limit of normal (ULN), alanine aminotransferase or aspartate aminotransferase ≤2 x ULN
• Hemoglobin ≥9 mg/dL.
• Creatinine <1.5 X upper limit of normal or estimated plasma creatinine clearance of ≥40 mL/min
• Signed informed consent form
• Recovered from toxicities of previous anticancer therapy
• Subjects with reproductive capability must agree to practice adequate contraception methods.

Exclusion criteria

• Subjects in whom everolimus is contraindicated.
• Subjects with clinically significant interstitial lung disease, or obstructive disease without sufficient reserve
• Carcinoid with hormone related symptoms
• Neuroendocrine cancer of the thyroid or thymus.
• Rare pancreatic neuroendocrine cancers such as, insulinomas, glucagonomas, gastrinomas.
• Prior treatment with any Hsp90 inhibitor.
• Prior failed treatment with mTOR inhibitors
• CNS metastases that are symptomatic and /or requiring escalating doses of steroids.
• Major surgery or significant traumatic injury within 4 weeks of starting study treatment.
• Conventional chemotherapy or radiation within 4 weeks.
• Palliative radiation within 2 weeks.
• The need for treatment with medications with clinically-relevant metabolism by the cytochrome P450 (CYP) 3A4 isoenzyme within 3 hours before or after administration of SNX-5422
• Screening ECG QTc interval ≥470 msec for females, ≥450 msec for males.
• At increased risk for developing prolonged QT interval, including hypokalemia or hypomagnesemia, unless corrected to within normal limits prior to first dose of SNX-5422; congenital long QT syndrome or a history of torsade de pointes; currently receiving anti-arrhythmics or other medications that may be associated with QT prolongation.
• Patients with chronic diarrhea or with Grade 2 or greater diarrhea despite appropriate medical management.
• Gastrointestinal diseases or conditions that could affect drug absorption, including gastric bypass.
• Gastrointestinal diseases that could alter the assessment of safety, including irritable bowel syndrome, ulcerative colitis, Crohn's disease, or hemorrhagic coloproctitis.
• History of documented adrenal dysfunction not due to malignancy.
• Known seropositive for human immunodeficiency virus (HIV) or hepatitis C virus (HCV).
• History of chronic liver disease.
• Active hepatitis A or B.
• Current alcohol dependence or drug abuse.
• Use of an investigational treatment from 30 days prior to the first dose of SNX-5422 and during the study.
• Glaucoma, retinitis pigmentosa, macular degeneration, or any retinal changes detected by ophthalmological examination.
• Other serious concurrent illness or medical condition.
• Psychological, social, familial, or geographical reasons that would hinder or prevent compliance with the requirements of the protocol or compromise the informed consent process.