FDA Approves T-DM1 for Treating HER2 Positive Metastatic Breast Cancer
Women with HER2 positive metastatic breast cancer whose cancer grows despite other standard therapies have a new treatment option available next month, now that the Food and Drug Administration approved the EMILIA study’s much-anticipated medicine, ado-trastuzumab emtansine (Kadcyla), previously referred to as T-DM1.
The FDA’s decision was announced in a Feb. 22 news release by the medicine’s developer, Genentech, a member of the Roche Group. Genentech also developed trastuzumab (Herceptin), another treatment used for HER2 positive metastatic breast cancer, now also used in early-stage disease.
Background and Name
Ado-trastuzumab emtansine is an antibody drug conjugate, which pairs chemotherapy with a targeted medicine to deliver chemotherapy’s powerful effects directly to the tumor while sparing healthy cells from its toxic effects. It was the focus of the EMILIA study, and generated strong interest during the June 2012 American Society of Clinical Oncology (ASCO) meeting, when the study’s results were first presented.
The EMILIA study included women whose cancers grew despite previous treatment with trastuzumab and taxane chemotherapy. Compared to the standard therapy (the combination of lapatinib (Tykerb) plus capecitabine (Xeloda), called XL), ado-trastuzumab emtansine showed an increase in progression-free survival, the time during and after treatment the cancer remains stable. Those who received ado-trastuzumab had a progression free survival of 9.6 months compared to 6.4 months for those receiving XL.
Updated results announced in October revealed that the medicine also was associated with a significantly longer rate of overall survival, the time a person lives from the beginning of the study until death from any cause. Overall survival increased nearly six months, from a median of 25.1 months to 30.9 months.
After the FDA approval, Genentech changed the medicine’s name from trastuzumab emtansine to ado-trastuzumab emtansine to avoid potential confusion, since both Kadcyla and Herceptin’s generic names begin with trastuzumab, a company spokesperson said.
Side Effects of Ado-Trastuzumab Emtansine
In the EMILIA study, investigators reported that participants who received ado-trastuzumab emtansine had fewer side effects than those who received XL. For 41 percent of ado-trastuzumab emtansine participants, side effects included effects on liver function and low platelet counts. In the XL group, 51 percent of participants had redness and blistering on the hands and feet (hand-foot syndrome), diarrhea, nausea and vomiting.
The most common side effects reported were tiredness, nausea, pain that affects the bones, muscles, ligaments and tendons, low platelet count, headache, liver problems and constipation. The most common severe side effects were low platelet count, liver problems, low levels of red blood cells, nerve problems (neuropathy), low levels of potassium in the blood and tiredness.Other possible side effects of ado-trastuzumab emtansine include heart problems, such as reduced heart function and congestive heart failure. This medicine should not be taken during pregnancy.
The FDA will collect reports of side effects at (800) 332-1088, as will Genentech at (888) 835-2555.
What This Means for You
Ado-trastuzumab emtansine’s approval means you may access another line of treatment if you have HER2 positive metastatic breast cancer that no longer responds to treatment with trastuzumab and a taxane chemotherapy.
The medicine is the first antibody-drug conjugate to target HER2 positive metastatic breast cancer. Researchers are looking into the medicine’s effect on early-stage HER2 positive breast cancer through planned clinical trials.
Genentech says ado-trastuzumab emtansine will be available in the United States within two weeks. The cost of is estimated to be $9,800 per month, which if taken for the median progression-free survival of 9.6 months, equals about $94,000 for the whole course of therapy.
To help offset the costs, you may be able to access a patient assistance program through Genentech Access Solutions. The program, which Genentech is now developing, provides co-pay assistance to help with out-of-pocket costs for people who qualify . If you do not have health insurance, or you reached the lifetime limit set by your insurance company, you might qualify to receive the medicine free of charge. Learn more about these assistance programs at Genentech’s Kadcyla Access Solutions website.
Living Beyond Breast Cancer will continue to cover developments with ado-trastuzumab emtansine and other treatments for HER2 positive metastatic breast cancer.