This is an adaptive, randomized controlled, Phase 3 clinical trial in adult patients with histologically confirmed diagnosis of a recurrent glioblastoma multiforme (GBM) or gliosarcoma (GS), who have been previously treated with surgery (if appropriate), standard of care chemo-radiation with temozolomide, +/- adjuvant temozolomide, and bevacizumab and now have progressive disease during or after bevacizumab. Patients with prior low-grade glioma or anaplastic glioma are eligible, if histologic assessment demonstrates transformation to GBM or GS.
Treatment Groups: Eligible patients will be randomized to receive either the investigational drug (VAL-083) or "Investigator's choice of salvage therapy" as a contemporaneous control, in a 2:1 fashion. A total of up to 180 patients with recurrent/progressive GBM or GS will be enrolled; patients will be randomized to one of two treatment arms as follows:
Group 1: Up to 120 eligible patients will be randomized to receive VAL-083 at 40 mg/m2 IV on days 1, 2, and 3 of a 21-day treatment-cycle, for up to 12, 21-day treatment cycles or until they fulfill one of the criteria for study discontinuation (death, intolerable toxicities, investigator's judgment, or withdrawal of consent). In patients who demonstrate response, stable disease or who continue therapy at the discretion of the investigator following initial progression and tolerate therapy, permission to continue treatment beyond 12 cycles will be considered but will require consent of the Sponsor. VAL-083 will be administered as an IV infusion over 30-60 minutes.
Group 2: Up to 60 patients will be randomized to receive "Investigator's choice of salvage therapy" until they fulfill one of the criteria for study discontinuation (death, intolerable toxicities, investigator's judgment, or withdrawal of consent). "Investigator's choice of salvage therapy" will be limited to the following: temozolomide, lomustine, or carboplatin. The dose level for Investigator's choice salvage therapy (temozolomide, lomustine, or carboplatin), will be in accordance with the product label or institutional guidelines.
In both arms, disease status will be evaluated with clinical and imaging evaluation. Baseline total tumor burden must be assessed by MRI within 2 weeks prior to randomization. For patients randomized to VAL-083, post-baseline tumor assessments are to be performed prior to every other 21-day cycle for VAL-083, i.e., prior to Cycles 3, 5, etc., while the patient is receiving VAL-083 treatment, and then approximately every 42 ± 7 days while remaining on study. For patients randomized to the Physician's choice salvage therapy arm, post-baseline tumor assessments are to be performed approximately every 42 ± 7 days while remaining on study, as long as the patient continues to demonstrate response or stable disease or comes off the study.
In both study arms, assessments will include interval medical histories, Karnofsky Performance Status, physical and neurological examinations, vital signs, weight, adverse events, hematology and serum biochemistry, pregnancy test (females), urinalysis, chest x-ray and EKG approximately every 21-days while receiving treatment, as well as MDASI-BT self-reporting assessment when MRI tumor measurements are performed.
In a subgroup of 60 study subjects receiving VAL-083, blood samples will be obtained to determine population pharmacokinetics at pre-dose Cycle 1 Day 1, then at post-infusion on Cycle 1 Day 1, Cycle 1 Day 3, Cycle 2 Day 1 and Cycle 3 (or Cycle 4) Day 1 (or Day 3) in accordance with the study subject's assigned sampling block. EKGs will be taken pre-dose and approximately 10 minutes post-infusion Cycle 1 Day 1, prior to the 15 min (15 ± 5 min) blood draw for PK assessment, as well as pre-dose and approximately 10 minutes post-infusion Cycle 1 Day 3, prior to the 15 min (15 ± 5 min) blood draw for PK.
In a separate sub-group of 15 study subjects receiving VAL-083, blood will be drawn from Cycle 1 Day 1 and Cycle 1 Day 3 of dosing for determination of plasma levels of VAL-083 over the first 6 hours after the end of infusion (i.e., 0.25, 0.5, 1, 2, 4 and 6 hr). Trough levels 24 hr after infusion will also be obtained in these subjects. EKGs will be taken pre-dose and approximately 10 minutes post-infusion Cycle 1 Day 1, prior to the 15 min (15 ± 5 min) blood draw for PK assessment, as well as pre-dose and approximately 10 minutes post-infusion Cycle 1 Day 3, prior to the 15 min (15 ± 5 min) blood draw for PK.
Patients will be followed until death to ensure adequate power (90%) for the primary analysis.
Toxicity will be evaluated and documented using the NCI CTCAE version 4.
Quality of life will be evaluated using the MD Anderson Symptom Inventory-Brain Tumor (MDASI-BT). This questionnaire will be completed by patients at baseline and at the time of each imaging evaluation, until progression.
The study is estimated to take approximately 20 months, including 18 months to enroll 180 patients and another 2 months to reach 125 events (deaths).