* Analysts see big potential sales of drug, if approved
* Pfizer shares rise 1.8 percent
By Ransdell Pierson
Dec 5 An experimental drug showed impressive
effectiveness and safety in a mid-stage trial against a common
form of advanced breast cancer, lifting Pfizer Inc
shares nearly 2 percent.
The favorable results prompted the drugmaker to plan large
late-stage trials of the drug next year. If approved, the
medicine could fetch multi-billion dollar sales, industry
The drug, called PD-0332991, delayed by more than 18 months
the worsening of symptoms for postmenopausal women with the most
common form of breast cancer. Data from the study of the drug
was presented on Wednesday at the annual San Antonio Breast
The medicine, which blocks enzymes known as CDK4 and 6
kinases, was taken in combination with a standard drug called
letrozole among women who were estrogen receptor positive -
meaning tumors grow in response to estrogen - and HER2-negative,
meaning that the HER2 protein is not causing the cancer. Such
patients make up about 60 percent of breast cancer cases.
Patients had either locally advanced tumors or cancer that
had spread to other parts of the body.
Those taking both drugs went an average of 26.1 months
before tumors worsened. That compared with 7.5 months for those
taking letrozole, but not PD-0332991. The 18.6 month difference
was considered statistically significant.
"In a disease where a several-month improvement in
progression-free survival is considered impressive, we view an
18.6-month improvement in PFS as remarkable," said analyst Jon
LeCroy of MKM Partners. He predicted Pfizer will introduce the
medicine in 2017.
Letrozole is the chemical name of Femara, a Novartis
drug that belongs to a class of treatments called
aromatase inhibitors that block production of estrogen.
Side effects seen in patients taking the drug combination
included anemia, fatigue and neutropenia - a decline in white
blood cells called neutrophils that can put patients at higher
risk of infection.
"If approved in a front-line breast cancer setting, this
drug has the potential to generate $2 billion to $6 billion" in
worldwide sales for these types of breast cancer patients, said
Mark Schoenebaum, an analyst with ISI Group, of PD-0332991.
Schoenebaum, who had not previously predicted any revenue
for the drug, said the medicine could provide considerable
"upside" to Pfizer revenue if it is cleared by regulators.
He noted that researchers have not yet disclosed to what
degree the Pfizer drug might have prolonged patient survival.
Pfizer had released some data from the trial in May, but
released updated findings on Wednesday.
Shares of Pfizer closed up 46 cents, or 1.8 percent, at
$25.64 on the New York Stock Exchange on Wednesday.