* Roche says Tecentriq cocktail beat Pfizer's Sutent
* Detailed results due in 2018
* Swiss drugmaker aims to expand drug's indications (Adds analyst comment, shares)
By John Miller
ZURICH, Dec 11 (Reuters) - Combining Roche's Tecentriq immunotherapy with its older drug Avastin for the initial treatment of advanced kidney cancer reduced the risk of the disease worsening or of death in certain patients, the Swiss drugmaker said on Monday.
The trial tested the combination against the current standard of care, Pfizer's Sutent, in patients with inoperable, locally advanced or metastatic renal cell carcinoma. The result follows data last week that showed a Tecentriq cocktail also slowed disease progression in first-line lung cancer treatment.
Tecentriq, whose sales pale compared to established immunotherapies from Bristol-Myers Squibb and Merck & Co Inc, is key to Roche's plan to replace revenue from its $20 billion-per-year trio of Avastin, Herceptin and Rituxan, whose expiring patents have exposed them to cheaper competition.
As a consequence it is seeking to expand indications and patients eligible for treatment with the Tecentriq cocktail, which analysts polled by Reuters see topping $4.6 billion in annual sales by 2023.
"We are encouraged by these results as they add to the emerging body of evidence that supports our rationale for this combination," said Sandra Horning, Roche's chief medical officer.
"We believe that the regimen of Tecentriq and Avastin may enhance the potential of the immune system in the initial treatment of advanced kidney cancer."
Roche shares were up 0.3 percent at 1030 GMT, roughly in line with the Stoxx European Health Care Index.
Even so, some analysts have expressed doubt that Tecentriq's study results so far have adequately differentiated it from Merck's Keytruda or Bristol-Myers Squibb's Opdivo for it to dominate the market for drugs that help the immune system better fight cancer.
Roche plans to present actual data from the trial only in 2018, so it will be difficult until then to make a comparison with Bristol-Myers Squibb's combination of Opdivo and Yervoy against kidney cancer.
In September, U.S.-based Bristol-Myers Squibb reported that its combination of Opdivo and Yervoy cut the risk of death by 37 percent in a key group of kidney cancer patients.
The "competition sets the bar", said Jefferies analyst Jeffrey Holford, in a note to investors.
"While we will have to await full presentation at an upcoming conference to assess the exact magnitude of the benefit provided by the (Roche) combination, the confirmation that it is a clinically meaningful benefit should be reassuring," he said.
Holford has a "buy" rating on Roche shares. (Editing by Michael Shields and Gareth Jones)