Merck KGaA eyes KRAS-gene focus to boost Erbitux sales

In 2009, the FDA allowed Merck KGaA to narrow Erbitux's indication for advanced colon cancer. Its label was changed to recommend the drug for treatment for EGFR-expressing tumors only in patients without a mutation in the KRAS gene. But though Merck may have shrunk its patient pool, the more personalized approach gives it "room to grow" as a therapy for colorectal cancer, a company exec said Friday.

In an interview with Reuters, Belén Garijo, head of the company's pharma unit Merck Serono, outlined a strategy for Erbitux centered on the KRAS mutation-free subgroup, which accounts for about 60% of all cases. In June, Erbitux beat out Roche ($RHHBY) giant Avastin in a trial for that patient population, proving more effective at prolonging the lives of those colorectal cancer patients.

Those results will help Merck's marketing teams highlight Erbitux's benefits, Garijo told the news service. The drug, unlike its megablockbuster competitor, comes with a genetic test for KRAS mutations that's performed on cancer tissue before starting treatment. Merck hopes that distinction, in combination with the study results, will draw patients to Erbitux and build on the drug's 2012 sales. Those amounted to €887 million ($1.21 billion) for Merck KGaA and another $702 million for Bristol-Myers Squibb ($BMY), which sells the drug in North America.

When the FDA first approved the label change to Erbitux and Amgen's ($AMGN) Vectibix, drugmakers celebrated. BMS and Eli Lilly ($LLY), which receives royalties, wanted to weed out patients with the mutated gene. Erbitux didn't work well in those patients, which brought effectiveness stats down when doctors prescribed the drug across the board.

But testing for the mutation has its own challenges, which is where Garijo sees room for growth. Depending on the country, testing can cause treatment delays ranging from a few days to a week and a half, she told Reuters, making it "a priority for Merck to provide support for faster testing and lab procedures."

The company could use some expanded sales from Erbitux. It hasn't had an easy time of expanding the drug's market. Erbitux failed Phase III trials last year, for adjuvant treatment after colon cancer surgery and for stomach cancer. And as Reuters points out, analysts aren't quite on board with the long-term growth Garijo predicts. On average, the news service found, they expect the drug's peak sales to register at $1.25 billion in 2014, sliding to $1.1 billion by 2018. Biosimilars could play into that, with competitors free to launch their Erbitux copies in Europe beginning in 2015.

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