Pfizer revives breast cancer treatment; 'Most exciting' breakthrough.
Pfizer Inc., Eli Lilly & Co. and Novartis AG have dug an idea out of the pharmaceutical dust bin to create new medicines that are showing blockbuster potential against hard-to-treat forms of breast cancer.
Pfizer's drug, called palbociclib, stopped tumor growth for 20.2 months in advanced forms of hormone-related breast cancer, twice the time seen with an older therapy alone. The treatment, projected to add $3.1 billion in sales by 2020, is based on a strategy largely abandoned in the 1990s after it failed to show consistent response against a broad range of cancers.
Since then, a deeper understanding of cancer's diverse genetic underpinnings has emerged, giving drugmakers new information on how the drugs, called CDK inhibitors, keep tumors from growing and spreading. The breakthrough offers the first major new therapy in a decade for patients whose breast cancer fails to respond to other treatments, doctors say.
"There haven't been a lot of new drugs in this space,'' said Judy Garber, an oncologist at the Dana-Farber Cancer Institute in Boston. "These, to me, are the most exciting drugs to come along in the treatment of estrogen-receptor-positive breast cancer in a long time.''
$6 billion a year
The Pfizer findings, coming in the second of three phases of testing normally needed for U.S. approval, were reported Sunday at the American Association for Cancer Research meeting in San Diego, along with results from an earlier-stage study on a similar treatment from Lilly. The Pfizer outcome may help the company secure faster clearance for a therapy that could one day generate peak sales of $6 billion a year, said Mark Schoenebaum, an ISI Group analyst in New York.
Other CDK blockers
Pfizer isn't alone in pursuing CDK drugs, which block a genetic pathway for cellular growth. Indianapolis-based Lilly, London-based AstraZeneca Plc and Novartis, based in Basel, Switzerland, are all testing targets among about 20 types of CDK blockers, with the breast tumor drugs the furthest along.
Lilly's drug, called bemaciclib, stopped tumor growth for an average of 9.1 months, according to results announced at the cancer meeting Sunday. About 25 percent of patients with hormone receptor-positive breast cancer saw their tumors shrink, while the tumors stayed the same size for 55 percent.
Breast cancer is the most diagnosed cancer among American women with 207,000 cases in 2010, according to the U.S. Centers for Disease Control and Prevention. Hormone-sensitive cancers are the most common type in post-menopausal women with metastatic or advanced disease and among the deadliest.
The CDK strategy almost didn't make it.
In the early 1990s, researchers suspected CDK inhibitors could be used to slow uncontrolled growth in a broad spectrum of cancers. The science at the time, though, was unable to identify subtle differences in how the inhibitors worked in different types of tissue, and the research was largely scuttled after trials shows a lack of consistency in outcomes.
Since then, scientists have learned more about how genetics affect cancer. Instead of it being one disease, researchers now believe it is dozens of diseases, each with their own unique genetic characteristics. In determining that, they have looked deeper into the genetic switches that turn malignancies on and off, giving them new insight in how the CDK inhibitors block growth in different cell types.
The drugs from Pfizer and Lilly are being tested in patients whose disease has spread from their breasts into their brain, lungs and elsewhere. Both are moving their therapies into final-stage testing. Novartis' similar drug also is in a late-stage trial with an expected filing for marketing clearance in 2016.
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|Author:||Armstrong, Drew; Connolly, Allison|
|Publication:||Telegram & Gazette (Worcester, MA)|
|Date:||Apr 8, 2014|
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