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Researchers modify herpes virus to fight cancer

July 7, 2007
Special to World Science  

A vi­rus de­signed to kill can­cer cells while spar­ing healthy ones is show­ing prom­ise in a pre­lim­i­nar­y stu­dy, sci­en­tists say. The vi­rus, called NV1020, is a type of her­pes sim­plex vi­rus mod­i­fied so that it se­lec­tively repli­cates in vi­rus cells, then kills them.

Re­search­ers pre­sented the find­ings July 7 at the Eu­ro­pe­an So­ci­e­ty for Med­i­cal On­col­o­gy Con­fer­ence in Lugano, Switz­er­land. 

“It does­n’t rep­li­cate in nor­mal, healthy cells, so our hope is that it will help fight can­cers with­out caus­ing side ef­fects,” said Ax­el Mescheder of the Munich-based biotech com­pa­ny Medi­Gene, de­vel­op­er of the vi­rus. The study is be­ing con­ducted in sev­en U.S. can­cer cen­ters, with Tony Reid of the Un­ivers­ity of Cal­i­for­nia in San Die­go as prin­ci­pal in­ves­ti­ga­tor.

A virus is a minute pack­age of gen­e­tic mat­erial that in­vades liv­ing cells and uses their mach­inery to rep­lic­ate its­elf.

Mescheder pre­sented pre­lim­i­nar­y safe­ty and ef­fi­ca­cy re­sults and a case re­port from the on­go­ing clin­i­cal tri­al. “The sci­en­tists are test­ing the treat­ment in pa­tients with ad­vanced col­orec­tal can­cer that have not re­sponded to chem­o­ther­a­py and where the can­cer has spread to the liv­er,” Mes­che­der said.

Re­searchers are look­ing for the treat­ment to ex­tend sur­vi­val, he said, not ne­ces­sarily cure the dis­ease.

He de­scribed a pa­tient whose can­cer had spread to 10 places around the liv­er and four in the lungs. The pa­tient re­ceived the vi­rus in four weekly in­fu­sions in­to the blood stream, fol­lowed by two cy­cles of chem­o­ther­apy. 

Six months af­ter treat­ment, the liv­er tu­mors had nearly dis­ap­peared, Mes­che­der said. “The re­duc­tion in the tu­mor mass­es was really im­pres­sive in this pa­tient,” who lived for a year af­ter treat­ment, he added. Al­most 40 per­cent of pa­tients with col­orec­tal can­cer ul­ti­mately die af­ter the dis­ease spreads to oth­er parts of the body, re­search­ers said; most of the spread­ing oc­curs to the liv­er.

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A virus designed to kill cancer cells while sparing healthy ones is showing promise in a preliminary study, scientists said today. The virus, called NV1020, is a type of herpes simplex virus modified so that it selectively replicates in virus cells, then kills them. Researchers presented the findings today at the European Society for Medical Oncology Conference in Lugano, Switzerland. “It doesn’t replicate in normal, healthy cells, so our hope is that it will help fight cancers without causing side effects,” said Axel Mescheder of the Munich-based biotech company MediGene, developer of the virus. The study is being conducted in seven U.S. cancer centers, with Tony Reid of the University of California in San Diego as principal investigator. Mescheder presented preliminary safety and efficacy results and a case report from the ongoing clinical trial in patients with colorectal cancer. “The scientists are testing the treatment in patients with colorectal cancer that have not responded to chemotherapy and where the cancer has spread to the liver,” Mescheder said. Mescheder described a patient whose cancer had spread to 14 places around the liver and in the lungs. He received the virus in four weekly infusions into the blood stream, followed by two cycles of chemotherapy. Six months after treatment, the liver tumors had nearly disappeared, he said. “The reduction in the tumor masses was really impressive in this patient,” The patient lived for 12 months after treatment. Almost 40% of patients with colorectal cancer ultimately die after the disease spreads to other parts of the body, researchers said. Most of the spreading occurs to the liver; 15% of patients have liver tumors at the time of diagnosis.