The FDA today approved ado-trastuzumab emtansine for treatment of patients with HER-2–positive, late-stage breast cancer.
The FDA approved ado-trastuzumab emtansine (Kadcyla, Genentech) — also known as T-DM1 — under its priority review program, which expedites evaluation of drugs that could offer major advances in treatment or provide a safe and effective therapy when no satisfactory alternative exists.
The drug is intended for patients who underwent prior treatment with the anti-HER–2 therapy trastuzumab (Herceptin, Genentech) and taxane-based chemotherapy.
Increased amounts of HER-2 protein are found in certain types of cancer cells, including nearly 20% of breast cancers, according to the FDA. The increased amounts of protein contribute to cell survival and growth.
Ado-trastuzumab emtansine is an antibody drug conjugate that incorporates antitumor activities of trastuzumab with the potent cytotoxic agent emtansine.
“Kadcyla delivers the drug to the cancer site to shrink the tumor, slow disease progression and prolong survival,” Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said in a press release.
Ado-trastuzumab emtansine is the fourth FDA-approved drug that targets the HER-2 protein. The others are trastuzumab, lapatinib (Tykerb, GlaxoSmithKline) and pertuzumab (Perjeta, Genentech).
The FDA based its approval in part on results of a study in which 991 patients were randomly assigned to receive ado-trastuzumab emtansine or lapatinib plus capecitabine. Treatment continued until disease progression or side effects became intolerable.
Patients assigned to ado-trastuzumab emtansine experienced longer median PFS (9.6 months vs. 6.4 months) and longer median OS (30.9 months vs. 25.1 months) than those assigned to lapatinib plus capecitabine.
The most common side effects reported among patients assigned to ado-trastuzumab emtansine included nausea, fatigue, muscle or joint pain, thrombocytopenia, increased levels of liver enzymes, headache and constipation.
Ado-trastuzumab emtansine includes a Boxed Warning that alerts patients and clinicians that the drug can cause heart toxicity, liver toxicity and death. The drug also can cause life-threatening birth defects, so patients’ pregnancy status should be verified prior to treatment, according to the FDA.