New HER2+ Breast Cancer Rx Approved

Patients with HER2-positive breast cancer have a new medication to treat the disease in its late stages, after it has started to spread.

The US Food and Drug Administration has approved Kadcyla (ado-trastuzumab emtansine) for patients with HER2-positive metastatic (has spread) breast cancer.

Kadcyla is intended for patients who have previously been treated with trastuzumab and taxanes, a class of chemotherapy agents commonly used to treat breast cancer.

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“Kadcyla delivers the drug to the cancer site to shrink the tumor, slow disease progression and prolong survival. It is the fourth approved drug that targets the HER2 protein.” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.

There are now four HER2-positive medications on the market. Kadcyla joins Herceptin (trastuzumab, Tykerb (lapatinib) and Perjecta (pertuzumab).

Kadcyla’s approval is based on study involving 991 patients who were randomly assigned to receive Kadcyla or lapatinib plus capecitabine, another chemotherapy drug. The study was looking at progression-free survival, the time during which the cancer doesn’t worsen, and overall survival.

The median overall survival was 30.9 months in the Kadcyla group and 25.1 months in the lapatinib plus capecitabine group.

Patients in the Kadcyla group had three more months of stable disease - 9.6 month compared to 6.4 months for patients who received lapatinib plus capecitabine.

The most common side effects reported in patients treated with Kadcyla were nausea, fatigue, muscle and joint pain, low levels of platelets in the blood (thrombocytopenia), increased levels of liver enzymes and constipation.

Kadcyla is being approved with a Boxed Warning alerting patients and healthcare professionals that the drug can cause liver toxicity, heart toxicity and death. The drug can also cause severe life-threatening birth defects, so women who are pregnant or planning to become pregnant should not take the medication. Pregnancy status should be verified prior to starting Kadcyla treatment.

The FDA reviewed T-DM1, the name of Kadcyla during clinical trials, under the agency’s expedited 6-month review program. The priority review system applies to drugs that prove to be more effective than other medicines currently on the market or are safe and effective therapies for conditions that have no satisfactory alternative medications.

Kadcyla, trastuzumab and pertuzumab are marketed by Genentech, a member of the Roche Group. Lapatinib is marketed by GlaxoSmithKline.

Genentech reports that the new medication should be available to patients in about 2 weeks.