* Tecentriq fails colorectal cancer trial
* Dents Roche's immunotherapy expansion aims
* Field of immunotherapies growing more crowded
By John Miller
ZURICH, May 10 (Reuters) - Roche's hopes of its Tecentriq immunotherapy catching up rival medicines from Merck and Bristol-Myers Squibb were dealt a blow on Thursday after it failed a key combination trial.
Roche was evaluating the use of Tecentriq and its targeted drug Cotellic against colorectal cancer, a big market with some 1.4 million new cases diagnosed globally in 2012 and 694,000 deaths, according to an International Journal of Cancer study.
The Swiss company said its Phase III IMblaze370 study did not boost overall survival compared to Bayer's Stivarga in advanced or metastatic colorectal cancer (CRC) in which patients had failed previous treatments.
Roche Chief Medical Officer Sandra Hornung acknowledged the results "are not what we hoped for," but vowed to press ahead with other medicines being developed for colorectal cancer.
Tecentriq is already approved for some lung cancer patients and bladder cancer, but Roche, the world's biggest oncology drugs maker, is running multiple trials of the immunotherapy as it seeks to expand it range of uses. Trials against some lung cancers and kidney cancer have produced recent, important wins, but difficult-to-treat CRC proved elusive.
Barclays Capital analysts, who rate Roche shares "overweight", called the failure a disappointment but said CRC was always seen as a higher-risk opportunity, with only modest expectations of the indication adding significantly to sales.
Roche, which is weathering patent losses on its best selling medicines Herceptin, Rituxan and Avastin that open the market to copies, is looking for Tecentriq to make up ground to Merck's Keytruda and Opdivo from Bristol-Myers Squibb.
Each has more than ten times the quarterly sales of Tecentriq which were 139 million Swiss francs ($138 million) in the first three months of 2018.
Tecentriq is also facing an increasingly crowded market for checkpoint inhibitors, amid a fast expanding field of cancer drugs as more and more companies focus on what is one of medicine's most-lucrative markets.
Beyond Opdivo and Keytruda, there are two other so-called PD-1/PD-L1 checkpoint inhibitors on the market: AstraZeneca's Imfinzi, Pfizer and Merck KGaA's Bavencio. These could soon to be joined by a sixth, with Regeneron's and Sanofi's cemiplimab under review in the United States and Europe.
There are also molecules under development in China by companies like Beigene Ltd.
Moreover, Novartis has similar checkpoint inhibitors in the works as part of plans to have its own medicines to be used in combination therapies seen likely to dominate the next phase of cancer treatment. ($1 = 1.0042 Swiss francs) (Reporting by John Miller Editing by Alexander Smith)