Cancer battle: Scientists engineer new tumor-killing virus
11 Feb, 2013 10:05
A new genetically-engineered virus has been developed to kill cancer tumors and prevent the growth of new ones, according to a study. It was tested in 30 terminally-ill liver cancer patients and proved to significantly prolong their lives.
The study, which was recently published in the journal Nature Medicine, describes a four-week trial of the vaccine Pexa-Vec or JX-594 marking a step forward towards a successful treatment of solid tumors, AFP reports. Sixteen out of 30 patients who were given a high dosage of therapy lived for 14.1 months on average, while the other 14 patients were given a low dosage and survived for 6.7 months. "For the first time in medical history we have shown that a genetically-engineered virus can improve survival of cancer patients," study co-author David Kirn from California-based biotherapy company Jennerex told AFP.The results of the study indicate that "Pexa-Vec treatment at both doses resulted in a reduction of tumor size and decreased blood flow to tumors," Jennerex said in a statement. “This is the first randomized clinical trial of an oncolytic immunotherapy demonstrating significantly prolonged overall survival.” Pexa-Vec is a leading product of Jennerex, which is a private biotherapeutics company based out of San Francisco, USA, that is focused on development and commercialization of therapies that would combat solid tumors. The new treatment uses oncolytic immunotherapy, which is a genetically modified type of virus that attacks tumors to induce a systemic immune response to cancer. It selectively replicates in tumor cells to achieve an antitumor effect. The new virus "is designed to multiply in and subsequently destroy cancer cells, while at the same time making the patients' own immune defense system attack cancer cells also," added Kirn. Authors of the study argue that despite certain progress in development of various cancer treatments majority of solid tumors remain “incurable once they are metastatic [have spread to other organs]," according to the study. And this trial shows concrete progress and proves that “Pexa-Vec treatment induces an immune response against the tumor."Pexa-Vec has been engineered from the vaccinia virus, which has been used in the past to treat smallpox. Some of the side effects included flu-like symptoms lasting a day or two in all patients and severe nausea and vomiting was reported in another patient. The study argues that a larger trial is needed to confirm the results of the trial and a follow-up phase with about 120 patients is already in progress. Jennerex also stated that it is “currently enrolling patients in multiple mid and late-stage trials with Pexa-Vec with the goal of bringing this groundbreaking therapy to market.”On top of that other trials are underway to see how Pexa-Vec can help patients with other types of cancer tumors.