Pfizer eyes PhIII with impressive data for breast-cancer fighter

Pfizer ($PFE) turned in more upbeat data from a midstage trial of its dual-kinase blocker in women with breast cancer, giving analysts more results to factor into their blockbuster projections for the experimental drug. And the U.S. drug giant's interim data bolster its decision to keep the program amid a spate of deals to license out other clinical-stage oncology assets in recent years of R&D cost cutting.

Today the company reported additional results from a randomized Phase II trial of PD-0332991, showing that postmenopausal patients with estrogen-receptor-positive breast tumors on the kinase inhibitor lived for a median of 26.1 months without their cancer getting worse compared with 7.5 months of progression-free survival in women in the placebo group. All patients received letrozole, which Novartis ($NVS) markets as Femara. The response rate for PD-991-treated patients was 45% compared with 31% in the letrozole-only patients.

"This magnitude of benefit is probably one of the largest with any new agent in breast cancer, or perhaps any solid tumor," UCLA's Dr. Richard S. Finn, a study investigator, told Bloomberg. "It's dramatic to see this level of benefit with a new agent."

Pfizer, which revealed the data at the 35th Annual San Antonio Breast Cancer Symposium, aims to advance the drug into a Phase III trial next year. And as Bloomberg reported, Citigroup analyst Andrew Baum last month noted that Pfizer's 991 has "mega-blockbuster potential" and could have a two-year lead in development on Eli Lilly's ($LLY) and Novartis' rival compounds. The drug could provide a new option for patients with estrogen-receptor-driven tumors that are HER2 negative, which describes about 60% of all diagnoses for breast cancer, Pfizer said in a press release. 

Under CEO Ian Read, Pfizer has been shrinking its focus in R&D to novel meds with potential to address major medical needs in cancer and other areas such as rheumatology. The company crossed the finish line last month with FDA approval of Xeljanz, the first drug of its kind against rheumatoid arthritis. Yet Read and his crew will need an abundance of new potential blockbusters to make up for the decline of its Lipitor franchise.

PD-991 could eventually help Pfizer in its quest for new multibillion-dollar sellers, especially if the program keeps churning out impressive data in breast cancer and other tumors for which it's being tested.

- here's the release
- check out Bloomberg's article

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