Ann: Kazia's paxalisib awarded Orphan Drug Designation, page-18

Once it's approved by the FDA, physicians can prescribe it "off-label" for anything they want to, even though it may not be approved by the FDA via the clinical trial process for that particular indication. By the time it gets approved by the FDA for GBM or DIPG, there will likely be evidence that it is effective vs. secondary brain cancer, and I would expect it to be prescribed for that immediately after the first FDA approval.