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By Ben Hirschler
Oct 25 (Reuters) - A type of HIV medicine that stops theAIDS virus from entering immune system cells could in future beput to work against cancer in new combination therapies beingdeveloped by drug companies.
Interest in using so-called CCR5 inhibitors to fight tumourswas fuelled last year when U.S. researchers, testing the drugson mice, reported a marked reduction in aggressive breast cancercells spreading to the animals' lungs.
Researchers from the Thomas Jefferson University KimmelCancer Center described the results as "dramatic" after theywere published in the Journal of Cancer Research.
Now industry analysts at Citi believe Merck & Co Inc is set to take things to the next stage by testing its CCR5 drugvicriviroc in cancer patients. The product was abandoned as atreatment for HIV in 2010 following an unsuccessful study.
Pfizer Inc and Bristol-Myers Squibb - whichalso have similar drugs in their portfolios - could follow suit,Citi said in a note on Friday.
Asked to comment on the suggestion that it would starttesting vicriviroc in patients in 2014 as part of a combinationtherapy for cancer, a spokesman for Merck said: "We have notdisclosed any such plans."
Citi said it expected vicriviroc to re-enter clinicaltesting in combination with cancer immunotherapy as Merckexplores its potential across multiple tumour types, includingmelanoma, colorectal, breast, prostate and liver cancer.
Immunotherapy, which harnesses the body's immune system tofight cancer, is a hot new area for cancer research, with someexperts predicting the approach will in future form the backboneof many cancer treatments.
However, drug combinations are expected to be critical toits success as oncologists will need to block cancer cells onseveral fronts at once.
One option is to combine two immunotherapies, while anotherapproach, also being pursued by other companies like RocheHolding AG and AstraZeneca Plc, is to combineimmunotherapy medicines with different drug types.
CCR5 inhibitors are one such option, given the encouragingsignals from pre-clinical research. As these drugs have alreadybeen studied in HIV, their development could be relativelyrapid.
Pfizer could also start clinical trials in cancer with itsapproved CCR5 drug Selzentry, which is currently marketed forHIV via the ViiV Healthcare alliance with GlaxoSmithKline Plc and Shionogi & Co Ltd.
Bristol, meanwhile, has a dual CCR2/5 inhibitor in mid-stagePhase II development, which is being tested for diabetes andkidney disease.
