(Corrects first name of Roche Chief Medical Officer in third paragraph)
* Data shows Tecentriq helped breast cancer patients
* Survival data is immature, but Roche optimistic
* Trailing rivals, Roche seeking immunotherapy niches
By John Miller and Ludwig Burger
ZURICH/MUNICH, Oct 20 (Reuters) - An immunotherapy cocktail from Roche helped slow a type of breast cancer where new treatments have proven elusive, data released on Saturday showed, offering positive news for the Swiss drugmaker as it chases medicines produced by its rivals.
Women with advanced triple-negative breast cancer lived a median 7.2 months without their disease worsening (PFS) with Roche's Tecentriq plus chemotherapy as an initial treatment, compared with 5.5 months for those getting chemotherapy alone.
Overall survival (OS) data from the IMpassion 130 study is not yet mature, but Roche Chief Medical Officer Sandra Horning told Reuters she had reason for optimism.
Patients getting the Tecentriq cocktail lived a median 21.3 months, so far, compared to 17.6 months for those on chemotherapy, she said.
Horning said these results offered new hope for people struggling with a difficult disease where patients and doctors desperately need new treatment options.
"It's really extraordinary to see a survival benefit of any kind in triple-negative breast cancer," she said. "We're quite excited about the degree of effect."
Tecentriq's benefit was greater among the roughly 40 percent of triple-negative breast cancer patients in its study whose tumours had high levels of a protein known as PD-L1, that helps tumours avoid immune system detection, Horning added.
Interim OS data for that group showed patients lived a median of 25 months, compared to just 15.5 months on chemotherapy.
Roche has filed with regulators for approval.
Triple-negative tumours, which affect 15 percent of breast cancer patients, have no hormone receptors or HER2 receptors, so patients do not benefit from hormone therapy or HER2-targeting drugs like Roche's $7 billion-per-year blockbuster Herceptin or GlaxoSmithKline's Tykerb.
Standard treatments include surgery, radiation and chemotherapy.
Roche in July announced the 902-patient study had showed Tecentriq to chemotherapy boosted outcomes, but the specific data was released at the European Society for Medical Oncology's annual conference in Munich on Saturday.
NICHE ASPIRATIONS
With Roche's Tecentriq trailing immunotherapies from Merck and Bristol-Myers Squibb in the main form of lung cancer, Chief Executive Severin Schwan is pursuing smaller but still lucrative treatment areas where he can gain an approval head start.