ProstAtak

Drug Overview

ProstAtak (AdV-tk + valacyclovir) is a viral cancer vaccine being developed by Advantagene for the treatment of prostate cancer. It works by gene-mediated cytotoxic immunotherapy, an approach that generates a tumor-specific vaccine. The treatment consists of an intratumoral injection of an adenoviral vector containing the herpes simplex virus thymidine kinase gene (AdV-tk) followed by valacyclovir, an anti-herpetic prodrug. Initial local cytotoxicity is mediated by the nucleoside analog generated through phosphorylation of the prodrug. Cell death via necrosis and apoptosis, viral factors that stimulate the innate immune system, and the acute inflammation from surgical debulking attract and activate antigen-presenting cells that incorporate and present tumor-associated antigens to T cells. This stimulates T-cell proliferation and interleukin 2 production, which generates a systemic anti-tumor immune response.

Analyst Outlook

Advantagene is assessing whether adding ProstAtak (AdV-tk + valacyclovir) to radiotherapy and androgen deprivation therapy (ADT) can improve the recurrence rate in patients treated for intermediate- or high-risk localized prostate cancer. In this setting, ProstAtak’s main competitors will be pharmacological ADTs – gonadotropin-releasing hormone (GnRH)/luteinizing hormone-releasing hormone (LHRH) analogs. ProstAtak will only be approved for use in the US market, meaning it will miss out on uptake and sales in the lucrative five major EU markets (France, Germany, Italy, Spain, and the UK) and Japan.