- Participants having undergone recent resection of recurrent or progressive tumor will be eligible for Cohort 2 as long as the following conditions apply: a) They have recovered from the effects of surgery; b) Residual disease following resection of recurrent tumor is not mandated for eligibility. To best assess the extent of residual disease postoperatively, an MRI or CT scan should ideally been performed no later than 96 hours following surgery or at least 28-days postoperatively, but scans performed outside of this window are considered acceptable if no alternative is available. In either case, the baseline/screening MRI must be performed within 14 days prior to registration. If the participant is taking corticosteroids, the dose must be stable or decreasing for at least 5 days prior to the scan. If steroids are added or the steroid dose is increased between the date of the screening MRI or CT scan and the start of treatment, a new baseline MRI or CT is required.