Prostvac disappoints in phase 3 trial
The tailored prostate cancer vaccine, Prostvac, has failed to show any benefit in overall survival (OS) compared to placebo in patients with metastatic castration-resistant prostate cancer (mCRPC). Secondary end points of radiographic progression, pain progression or chemotherapy initiation also showed no benefit. Combining the treatment with granulocyte-macrophage colony-stimulating factor failed to improve the outcomes.
The results of the 1300-patient study published in Journal of Clinical Oncology are disappointing given that Prostvac prolonged median OS by 8.5 months versus placebo in mCRPC in a phase 2 study.
The treatment was well tolerated with adverse events similar for the treatment and placebo groups, with the most common being injection site reactions (62% versus 72%) and fatigue (21% versus 24%). Arrhythmias were the most common cardiac-related events (1.4% versus 3.5%). There were no reports of either myocarditis or pericarditis. Serious treatment-related events occurred in less than 1% of all patients.
Prostvac is currently being trialled in combination with other treatment modalities.