Vorinostat
A recent study suggested that vorinostat also possesses some activity against recurrent glioblastoma multiforme, resulting in a median overall survival of 5.7 months (compared to 4–4.4 months in earlier studies). Further brain tumor trials are planned in which vorinostat will be combined with other drugs.
Glioblastoma
A good initial Karnofsky Performance Score (KPS) and MGMT methylation are associated with longer survival. A DNA test can be conducted on glioblastomas to determine whether or not the promoter of the "MGMT" gene is methylated. Patients with a methylated MGMT promoter have longer survival than those with an unmethylated MGMT promoter, due in part to increased sensitivity to temozolomide. This DNA characteristic is intrinsic to the patient and currently cannot be altered externally. Another positive prognostic marker for glioblastoma patients is mutation of the "IDH1" gene, which can be tested by DNA-based methods or by immunohistochemistry using an antibody against the most common mutation, namely IDH1-R132H.