Whole brain radiotherapy (WBRT) is the treatment of choice for the majority of patients with brain metastases. Although WBRT yields high radiologic response rate (27~56%) and is effective in palliation of neurologic symptoms, the response duration is limited and neurologic progression remains the main cause of death in a significant number of patients.~Vorinostat is reasonably well tolerated and there is also compelling evidence that vorinostat may serve as a radiosensitizer. Preclinical studies of HDAC inhibition have also shown efficacy in neuron protection. These data suggest that the addition of vorinostat to the standard therapy of WBRT may potentially increase their therapeutic efficacy without increasing neurotoxicity, and support the rationale of this phase II trial of vorinostat with WBRT in patients with brain metastases.
Vorinostat is a potent and well tolerated HDAC inhibitor. It has been reported to enhance radiosensitivity of cancer cells. We hypothesize that the addition of vorinostat to WBRT may increase therapeutic efficacy for patients with brain metastases.