An en­gi­neered virus, in­ject­ed in­to the blood, can se­lec­tive­ly tar­get can­cer cells through­out the body in what re­searchers have la­belled a med­ical first. The virus at­tacked on­ly tu­mours, leav­ing the healthy tis­sue alone, in a small tri­al on 23 pa­tients, ac­cord­ing to the jour­nal Na­ture. Re­searchers said the find­ings could one day "tru­ly trans­form" ther­a­pies. Can­cer spe­cial­ists said us­ing virus­es showed "re­al promise." Us­ing virus­es to at­tack can­cers is not a new con­cept, but they have need­ed to be in­ject­ed di­rect­ly in­to tu­mours in or­der to evade the im­mune sys­tem.

Sci­en­tists mod­i­fied the vac­cinia virus, which is more fa­mous for be­ing used to de­vel­op a small­pox vac­cine. The virus, named JX-594, is de­pen­dent up­on a chem­i­cal path­way, com­mon in some can­cers, in or­der to repli­cate. It was in­ject­ed at dif­fer­ent dos­es in­to the blood of 23 pa­tients with can­cers which had spread to mul­ti­ple or­gans in the body. In the eight pa­tients re­ceiv­ing the high­est dose, sev­en had the virus repli­cat­ing in their tu­mours, but not in healthy tis­sue. Prof John Bell, lead re­searcher and from the Uni­ver­si­ty of Ot­tawa, said: "We are very ex­cit­ed be­cause this is the first time in med­ical his­to­ry that a vi­ral ther­a­py has been shown to con­sis­tent­ly and se­lec­tive­ly repli­cate in can­cer tis­sue af­ter in­tra­venous in­fu­sion in hu­mans.

"In­tra­venous de­liv­ery is cru­cial for can­cer treat­ment be­cause it al­lows us to tar­get tu­mours through­out the body as op­posed to just those that we can di­rect­ly in­ject." In­fec­tion pre­vent­ed fur­ther tu­mour growth in six pa­tients for a time. How­ev­er, the virus did not cure can­cer. Pa­tients were giv­en on­ly one dose of the virus as the tri­al was de­signed to test the safe­ty of the virus. It is thought that the virus could be used to de­liv­er treat­ments di­rect­ly to can­cer­ous cells in high con­cen­tra­tions.

Prof Bell ac­knowl­edges that the re­search is still in the very ear­ly stages, but he said: "I be­lieve that some day, virus­es and oth­er bi­o­log­i­cal ther­a­pies could tru­ly trans­form our ap­proach for treat­ing can­cer." Can­cer Re­search UK's Prof Nick Lemoine, al­so di­rec­tor of Barts Can­cer In­sti­tute, said: "Virus­es that mul­ti­ply in just tu­mour cells-avoid­ing healthy cells-are show­ing re­al promise as a new bi­o­log­i­cal ap­proach to tar­get hard-to-treat can­cers. "This new study is im­por­tant be­cause it shows that a virus pre­vi­ous­ly used safe­ly to vac­ci­nate against small­pox in mil­lions of peo­ple can now be mod­i­fied to reach can­cers through the blood­stream-even af­ter can­cer has spread wide­ly through the pa­tient's body. "It is par­tic­u­lar­ly en­cour­ag­ing that re­spons­es were seen even in tu­mours like mesothe­lioma, a can­cer which can be par­tic­u­lar­ly hard to treat."

Mi­crochip mon­i­tors tu­mour growth

Re­searchers in Ger­many have de­vel­oped a mi­crochip sen­sor that can be im­plant­ed close to a tu­mour to mon­i­tor its growth. The de­vice tracks oxy­gen lev­els in near­by tis­sue to de­tect if a tu­mour is ex­pand­ing. Re­sults are then trans­mit­ted wire­less­ly to a pa­tient's doc­tor-re­duc­ing the need for fre­quent hos­pi­tal scans. Fu­ture de­signs will in­clude a med­ica­tion pump that can de­liv­er drugs di­rect­ly to the af­fect­ed area. Re­searchers hope this will lead to less ag­gres­sive and more tar­get­ed can­cer treat­ments.

Med­ical en­gi­neers at the Tech­ni­cal Uni­ver­si­ty in Mu­nich de­vel­oped the de­vice as a way to track and treat tu­mours that are dif­fi­cult to reach, or bet­ter left alone.

"There are some tu­mours which are hard to re­move-for ex­am­ple, close to the spine. You run the risk of cut­ting the nerve if you re­move them sur­gi­cal­ly. Or the prob­lem may be that the tu­mour is grow­ing slow­ly, but the pa­tient is el­der­ly," said project man­ag­er Sven Beck­er. The sen­sor is im­plant­ed next to a tu­mour, and mea­sures the con­cen­tra­tion of dis­solved oxy­gen in near­by tis­sue flu­id. If this drops it can in­di­cate ag­gres­sive growth, and doc­tors can be alert­ed. "The mi­cro­elec­tron­ic chip has a set of elec­trodes that de­tect oxy­gen sat­u­ra­tion. It trans­mits this sen­sor da­ta to an ex­ter­nal re­ceiv­ing unit that's like a small box you car­ry around in your pock­et," ex­plained Mr Beck­er.

"From there it goes in­to the doc­tor's PC-and they can look at the da­ta and de­cide whether the tu­mour ac­tiv­i­ty is get­ting worse." Re­searchers be­lieve this will re­duce the need for fre­quent hos­pi­tal check-ups.

BBC