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Local trials cast doubt on Erbitux, Avastin drugs

* Erbitux disappoints in Nordic study with unusual chemo

* Small Greek study finds no benefit with Roche’s Avastin

* Merck KGaA, Roche say wealth of other data supports drugs

* Both products blockbuster drugs for bowel cancer

By Ben Hirschler

MILAN, Oct 10 (Reuters) - Two small European studies cast doubt on the benefits of two key bowel cancer drugs on Sunday, puzzling experts at Europe’s biggest cancer meeting in Milan.

An independent Nordic study found 566 patients given Erbitux plus a three-drug chemotherapy regimen called FLOX in first-line treatment did not live longer or have any significant benefit than those on chemotherapy alone.

At the same time a Greek study of 222 patients found those on Avastin plus chemotherapy did marginally worse when compared with patients on chemotherapy alone, although the difference was not statistically significant.

Erbitux had worldwide sales of $1.7 billion in 2009, primarily in bowel cancer, while Avastin, which is used in a number of different cancers, sold some $6 billion.

Merck KGaA MRCG.DE, which sells Erbitux in Europe, and Avastin's maker Roche ROG.VX both said results were at odds with a wealth of other clinical data from much larger studies.

Still, oncologists at the European Society for Medical Oncology (ESMO) congress said the findings showed the complexity of understanding how new cancer drugs -- often costing tens of thousands of dollars a year -- will perform in local settings.

In both cases there could be confounding factors, since the Nordic study used an unusual chemotherapy regimen called FLOX that is uncommon outside Scandinavia, while the Greek study was very small.

The benefits of first-line use of Erbitux -- also a big product for Eli Lilly LLY.N and Bristol-Myers Squibb BMY.N -- have been questioned before, with a British study called COIN also failing to show a positive effect in 2009.

EARLY RESPONDERS

Kjell Magne Tveit from Oslo University Hospital, who led the Nordic study, said the combined data from COIN and his group’s analysis of patients from Sweden, Denmark, Norway, Finland and Iceland fuelled real doubts about first-line use.

Wolfgang Wein, head of oncology at German drugmaker Merck, said he was perplexed by the new findings, which could be a function of the unusual chemotherapy regimen used.

“It contradicts all the previous evidence,” he told Reuters. “It suggests that Erbitux should ideally not be combined with FLOX.”

The Nordic data was particularly baffling because it found patients with a mutated version of a gene called KRAS actually seemed to do better on Erbitux, when all the previous evidence suggested the drug only works in people with a normal version.

Separately, further findings were also presented from a company-sponsored trial of Erbitux called CRYSTAL, showing that patients with normal, or wild-type, KRAS did particularly well if they experienced tumour shrinkage within eight weeks.

The median overall survival for such early responders was 28.3 months.

Erbitux currently dominates the market for so-called EGFR drugs, which block a protein called epidermal growth factor involved in cancer cell growth. It competes with Amgen's AMGN.O Vectibix, which had 2009 sales of $233 million. (Editing by Greg Mahlich)

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