LOS ANGELES, CA (Catholic Online) - The U.S. Food and Drug Administration approved Kadcyla this week, noting it was for patients whose cancer cells contain increased amounts of a protein known as HER2.

Kadcyla has the potential to cause liver and heart damage or even death, as well as cause life-threatening birth defects. A warning label will be affixed on all packaging.

Patients who took the drug in clinical trials survived an average of 30.9 months, compared with 25.1 months in a control group.

It's estimated that Kadcyla could generate annual peak sales of $1.9 billion as usage in different settings increases. The drug will be priced at $9,800 a month.

"We don't expect to see significant payer push back on pricing at launch, given the drug's efficacy and safety," Simos Simeonidis, an analyst at Cowen and Company wrote in a research note.

Kadcyla works by attaching trastuzumab, sold under the brand name Herceptin, to a drug called DM1, developed by ImmunoGen Inc, which interferes with cancer cell growth.

"Kadcyla delivers the drug to the cancer site to shrink the tumor, slow disease progression and prolong survival," Dr. Richard Pazdur, director of the FDA's office of hematology and oncology products says. "It is the fourth approved drug that targets the HER2 protein."

Other drugs approved for the disease include Herceptin in 1998, lapatinib, made by GlaxoSmithKline Plc and sold under the brand name Tykerb in 2007, and pertuzumab, marketed as Perjeta and also made by Roche in 2012.

Kadcyla is the first drug in its class, known as antibody-drug conjugates, or "armed antibodies" to be approved to treat a solid tumor. These drugs combine an antibody, Herceptin in the case of Kadcyla, with a killer toxin, in this case ImmunoGen's DM1, and links them together to deliver a highly potent bomb to the diseased cells.

The drugs seek out specific cells that express proteins associated with the cancer, while leaving other cells unharmed.

Breast cancer is the second-leading cause of cancer-related death among women.

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