Paris â€“ A genetically-engineered virus tested in 30 terminally-ill cancer patients significantly prolonged their lives, killing tumors and inhibiting the growth of new ones, scientists reported on Sunday.
Sixteen patients given a high dose of the therapy survived for 14.1 months on average, compared to 6.7 months for the 14 who got the low dose.
â€œFor the first time in medical history we have shown that a genetically-engineered virus can improve survival of cancer patients,â€ study co-author David Kirn told AFP.
The four week trial with the vaccine Pexa-Vec or JX-594, reported in the journal Nature Medicine, may hold promise for the treatment of advanced solid tumors.
â€œDespite advaces in cancer treatment, over the past 30 years with chemotherapy and biologics, the majority of solid tumors remain incurable once they are metastatic (have spread over the organs),â€ the authors wrote.
There was a need for the development of â€œmore potent active immunotherapies,â€ they noted.
Pexa-Vec â€œis designed to multiply in and subsequently destroy cancer cells, while at the same time making the patientâ€™s own immune system attack cancer cells also,â€ said Kirn from California-based biotherapy company Jennerex.
â€œThe results demonstrated that Pexa-Vec treatment at both doses resulted in a reduction of tumor size and decreased blood flow to tumors,â€ said a Jennerex statement.
â€œThe data further demonstrates that Pexa-Vec treatment induced an immune response against the tumor.â€
Pexa-Vec has been engineered from the vaccinia virus, which has been used as a vaccine for decades including in the eradication of smallpox.
The trial showed Pexa-Vec to be well tolerated both at high and low doses, with flu-like symptoms lasting a day or two in all patients and severe nausea and vomiting in one.
The authors said a lager trial has to confirm the results. A follow-up phase with about 120 patients is already underway.
Pexa-Vec is also being tested in other types of cancer tumors. â€“Sapa-AFP
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