Activity of Seviteronel in Patients With Androgen Receptor (AR)-Positive Glioblastoma

Inclusion Criteria: 1. To be eligible for treatment in the study, patients must continue to meet all of the inclusion criteria and none of the exclusion criteria at the time of registration. Male or female patients, aged 18 years and older, with pathologically confirmed advanced GBM; 2. Sufficient and accessible tissue for molecular screening; 3. Patients receiving their last line of standard treatment or who have received and failed all standard anticancer therapy (where standard therapy exists) or have documented unsuitability for any further standard anticancer therapy Poor prognosis cancers or cancers with low expected response rate to standard treatment (in the opinion of the investigator and based on available evidence) may be screened on an earlier line of treatment. 1. Failure is defined as either progression of disease (clinical or radiological) or intolerance to standard therapy resulting in the discontinuation of the therapy. 2. Documented unsuitability for further standard therapy includes known hypersensitivity, organ dysfunction or other patient factors that would make therapy unsuitable in the judgement of the responsible investigator; 4. ECOG performance status 0, 1 or 2; 5. Willing and potentially able to comply with study requirements, including treatment, timing and/or nature of required assessments; It is the intention to screen patients who are in principle wishing to take part in the START study if they are found to have an appropriate tumour biomarker and are still eligible for enrolment at the time of the treatment phase; 6. Signed, written informed consent to participation in the molecular screening and treatment study. 7. Received and failed all standard anticancer therapy or have documented unsuitability for any further standard therapy, if standard therapy exists; 8. Clinical or radiological progression on or following last anticancer therapy; 9. Adequate organ system function as assessed by the following minimal laboratory requirements (within 7 days prior to first administration of study drug): 1. bone marrow function; platelets ≥ 100 x 109/L, ANC ≥ 1.5 x 109/L, and haemoglobin ≥9g/dL (5.6mmol/L); white blood cell count ≥3,000 cells/μL 2. liver function; ALT/AST ≤ 3 x ULN (in the absence of liver metastases, ≤ 5 x ULN for patients with liver involvement) and total bilirubin ≤1.5xULN; 3. renal function; serum creatinine ≤1.5xULN; 10. Meet any additional inclusion criteria specified in the relevant study addendum; 11. Signed, written informed consent to participation in the specific treatment study. 12. AR-positive GBM confirmed by immunohistochemistry 13. Able to comply with study requirements Exclusion Criteria: Exclusion criteria will include those relevant for screening but also include: 1. Suitable for standard therapy or accepted standard care, if the patient has not been previously treated; 2. Specific comorbidities or conditions (e.g. psychiatric) or concomitant medications which may contraindicate participation and/or interact with seviteronel, dexamethasone or the GnRH analogue; 3. Other co-morbidities or conditions that may compromise assessment of key outcomes or in the opinion of the clinician, limit the ability of the patient to comply with the protocol; 4. For non central nervous system (CNS) cancers, patients with symptomatic CNS involvement of his/her cancer. Subjects with stable neurological function, on stable doses of steroids/anti-epileptics over 4 weeks, and with no evidence of CNS progression within 12 weeks prior to study entry are eligible; 5. History of another malignancy within 2 years prior to registration unless adequately treated and determined free of progressive and metastatic disease for at least 6 months. Patients with a past history of adequately treated carcinoma-in-situ, basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or superficial transitional cell carcinoma of the bladder are eligible; 6. Pregnancy, lactation, or inadequate contraception. Women must be post-menopausal, infertile, or use a reliable means of contraception. Women of childbearing potential must have a negative pregnancy test done within 7 days prior to registration. Men must have been surgically sterilised or use a barrier method of contraception (double barrier, if required). 7. Known history of hypersensitivity to active or inactive components of seviteronel, dexamethasone, and/or GnRH analoge; 8. Previous treatment with seviteronel or same class of agent; 9. Treatment with any of the following anti-cancer therapies prior to the first dose of study treatment: * Radiation therapy, surgery or tumour embolization within 14 days prior to the first dose of study treatment. Palliative radiotherapy (for analgesia) is acceptable only if the irradiated field does not include target lesions; * Immunotherapy within 28 days prior to the first dose of study treatment; * Chemotherapy, biologic therapy, or hormonal therapy within 14 days or 5 half-lives of a drug prior to the first dose of study treatment or until recovery from previous therapy (whichever is longer); 10. Administration of any investigational treatment within 30 days or 5 half-lives (whichever is longer) prior to receiving the first dose of study treatment; 11. Active prostate cancer requiring treatment. 12. Active breast cancer requiring treatment. 13. Symptomatic central nervous system cancer. Subjects with stable neurological function, on stable doses of steroids/anti-epileptics over 4 weeks prior to screening are eligible. 14. Corrected QT interval by the Fridericia correction formula (QTcF) on the screening electrocardiogram (ECG) \>470 msec. If the screening ECG QTcF interval is \>470 msec, it may be repeated once, and if the repeat ECG is \<470 msec, the patient may be enrolled. 15. Clinically significant cardiac arrhythmias (eg, ventricular tachycardia, ventricular fibrillation, torsades de pointes, second degree or third degree atrioventricular heart block without a permanent pacemaker in place). 16. Any medical condition that could preclude patient participation in the study, pose an undue medical hazard, or which could interfere with study results. 17. Class III or IV Congestive Heart Failure as defined by the New York Heart Association functional classification system within the previous 6 months. 18. Known active Human Immunodeficiency Virus, Hepatitis B, or Hepatitis C infections.