CHICAGOCHICAGO (Reuters) - In a disappointment for Roche Holding AG (ROG.S), two of its oncology drugs provided only modest protection from disease progression in lung cancer and breast cancer, according to data from separate clinical trials presented on Saturday.

Adding Roche's high-profile immunotherapy Tecentriq to other standard cancer drugs extended by only about three weeks the median time patients with advanced squamous cell lung cancer lived before their disease progressed in one late stage study.

Meanwhile, Roche said it was scrapping development plans for its experimental drug taselisib after data showed adding it to hormone therapy extended by just two months the length of time women with advanced breast cancer lived before their disease worsened. Patients on the drug also experienced serious side effects.


The taselisib benefit to patients "was more modest than we had hoped for, and there is a risk of considerable side effects," said Dr. José Baselga, the study's lead investigator from Memorial Sloan Kettering Cancer Center in New York.

Roche in a statement also said the results were disappointing, adding "we will not be pursuing an FDA submission for taselisib based on the data presented at ASCO."

The company also said it had no plans to further test taselisib in other types of cancer.

Both studies were being presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago. For more coverage of the meeting, see: here

Sales of Roche's Tecentriq trail two rival lucrative therapies that also spur the body's immune system to attack tumors: Keytruda from Merck & Co (MRK.N) and Opdivo from Bristol-Myers Squibb (BMY.N). Roche is under pressure to show success for the drug, which is central to replacing falling revenue from older, off-patent medicines.

Tecentriq is already approved for previously treated patients with advanced non-small cell lung cancer (NSCLC) and certain patients with advanced bladder cancer. Analysts are forecasting annual Tecentriq sales reaching about $6 billion by 2024, according to Thomson Reuters data.


Roche said it will continue to evaluate results from the study presented on Saturday.

"The study is one of eight Phase III trials from our extensive research program evaluating Tecentriq alone or in combination with other medicines in different types of lung cancer," Roche said in a statement. 

Merck's Keytruda, in combination with chemotherapy, is approved as an initial treatment for non-squamous NSCLC, the most common form of lung cancer. Keytruda is also approved as a stand-alone treatment for lung cancer patients whose tumors have high levels of a protein known as PDL1.

The new Tecentriq trial studied 1,021 patients with late-stage squamous NSCLC, which accounts for about 30 percent of lung cancer and is considered particularly difficult to treat.

One group of patients received the Roche drug plus the chemotherapy carboplatin and Celgene Corp's CELG.O Abraxane, while a second group were only treated with carboplatin and Abraxane.

After 12 months, 25 percent of patients given the Tecentriq combination had not experienced disease progression compared with 12 percent in the chemotherapy group, Roche said.


But median progression-free survival was 6.3 months for Tecentriq patients versus 5.6 months for the standard chemotherapy combination.

The modest benefit was observed regardless of tumor PDL1 levels, researchers said. The analysis did not find an overall survival advantage with Tecentriq, although Roche said those data are not yet mature.

Merck last month said a study of Keytruda in combination with chemotherapy for squamous NSCLC showed a benefit in both overall survival and progression-free survival. [nL3N1SU48D]

In the study of taselisib, patients who received the Roche drug plus the hormone therapy fulvestrant saw their breast cancer worsen after a median of 7.4 months compared with 5.4 months for people who received fulvestrant alone.

The trial involved 516 postmenopausal women with advanced estrogen receptor-positive breast cancer, whose disease had progressed or returned after prior treatment.

Serious side effects in the taselisib group included diarrhea, high blood sugar and colon inflammation, leading 17 percent of treated patients to drop out of the trial.


(Reporting by Deena Beasley; Editing by Bill Berkrot)