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
Another important alteration is methylation of MGMT, a "suicide" DNA repair enzyme. Methylation is described to impair DNA transcription and therefore, expression of the MGMT enzyme. Since an MGMT enzyme can repair only one DNA alkylation due to its suicide repair mechanism, reverse capacity is low and methylation of the MGMT gene promoter greatly affects DNA-repair capacity. Indeed, MGMT methylation is associated with an improved response to treatment with DNA-damaging chemotherapeutics, such as temozolomide.