The Bath-based agency won the business after a shootout against incumbent HLB and Dudley Jenkins.
The agency already handles third-party insert planning for the charity and its role has now been expanded to include the planning of all cold direct mail activity for Cancer Research UK's donor acquisition.
Christina Bates from Cancer Research UK said: "We were very impressed with Response One's innovative approach to list planning and buying. They demonstrated a strong understanding of our list buying requirements."
Cancer Research UK's advertising and direct marketing business is handled by Ogilvy & Mather and OgilvyOne respectively, following a review earlier this year. It was previously handled by WWAV Rapp Collins.
Cancer Research UK is the largest volunteer-supported cancer research organisation in the world. The charity focuses on ways of curing cancer faster, researching new ways of preventing cancer and developing better treatments and finding effective cures.
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