Roche’s hopes of its Tecentriq immunotherapy catching rival medicines from Merck and Bristol-Myers Squibb were dealt a blow on Thursday after it failed a key combination trial.

Roche was evaluating 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.

Shares in Exelixis, which is the Swiss company’s partner on Cotellic and discovered the drug, plunged in pre-market trading following news of the trial results.

Roche 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.

Its 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.

Exelixis shares revenue from Cotellic, while providing a portion of the U.S. sales force. The San Francisco-based firm also gets royalties from Cotellic sales elsewhere.

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.

Expectations for Tecentriq and Cotellic in CRC were also muted in April, when investigators halted enrollment in a separate Roche-sponsored study after four deaths, including one in a treatment-related event where the patient’s heart stopped pumping blood sufficiently.

At the time, Roche said it was encouraged by the early results of that trial, called MODUL, but wanted to assess data.

“There is a scientific rationale for the combination,” Roche said. “However as patient safety is our number one priority we are taking this proactive step to ensure we appropriately evaluate the combination.”

PATENT LOSSES

Roche’s need for Tecentric to perform better is heightened by patent losses on its best selling medicines Herceptin, Rituxan and Avastin that are opening the market to copies and eroding their combined $21 billion annual sales.

But it has a long way to go: Merck’s Keytruda and Opdivo from Bristol-Myers Squibb have more than ten times the quarterly sales of Tecentriq which were a disappointing 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 in 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 for combination therapies seen likely to dominate the next phase of cancer treatment.

(Source: https://www.reuters.com/article/us-roche-immunotherapy/setback-to-roche-hopes-for-tecentriq-as-fails-key-cancer-trial-idUSKBN1IB16N)