A small study suggests that a new formulation of the chemotherapy medicine doxorubicin may be safer for the heart than traditional formulations. The results were presented at the 2011 San Antonio Breast Cancer Symposium.
Anthracyclines are a type of chemotherapy often used to treat both early-stage and advanced-stage breast cancer. The following medicines are anthracyclines:
- Adriamycin (chemical name: doxorubicin)
- Doxil (chemical name: doxorubicin)
- daunorubicin (brand names: Cerubidine, DaunoXome)
- Ellence (chemical name: epirubicin)
- mitoxantrone (brand name: Novantrone)
Over time, anthracyclines can cause heart damage, sometimes cutting its use short. The risk of heart problems can be higher when other treatments that may cause heart damage -- Herceptin (chemical name: trastuzumab), for example -- are used at the same time as an anthracycline.
One doxorubicin formulation, Doxil, wraps the active ingredient in a capsule of fats (called a liposomal capsule) that may help lower the risk of heart problems. Doxil is sometimes called liposomal doxorubicin.
Another possibly serious side effect of the anthracyclines is "hand foot syndrome." This syndrome is a skin reaction that happens when a small amount of medicine leaks out of capillaries (small blood vessels), usually into the palms of the hands and soles of the feet. The leaked medicine can damage the surrounding tissue. This can cause pain that's sometimes severe and make it hard to use your hands or walk.
Doxorubicin is pegylated, which means each molecule of the medicine has a compound attached to it to make the medicine more stable and work better in the body. Many medicines are pegylated. Unfortunately, pegylation is thought to increase the risk developing hand-foot syndrome with doxorubicin.
To address these side effect issues, researchers developed a new way to prepare doxorubicin that is not pegylated and wrapped in a different type of liposomal capsule than Doxil. The new doxorubicin formulation is called Myocet.
In this study, 25 of 56 women diagnosed with advanced-stage breast cancer had been treated in the past with an anthracycline; the other women hadn't received an anthracycline before. All the women were treated with a combination of Taxotere (chemical name: docetaxel) and Myocet. The researchers monitored the women's heart function during treatment and for 6 months afterward.
Most of the women had only a very small decline in heart function during and after treatment -- even women who previously had been treated with an anthracycline and might have been considered not good candidates to get another anthracycline because of heart risks.
Overall, the decline in heart function in this study was less than and slower than what would have been expected with a standard anthracycline formulation. None of the women in the study developed heart failure.
The results suggest that Myocet could be a safer alternative to traditional forms of doxorubicin or other anthracyclines. Still, since Myocet is made in a different way, it will be important for more research to show that Myocet works at least as well as the other anthracyclines against breast cancer. Researchers are currently studying using Myocet in combination with Herceptin to treat women diagnosed with HER2-positive breast cancer.
Myocet isn't currently approved or available for use in the United States, but is approved for use in some other countries. The U.S. Food and Drug Administration has been evaluating information about Myocet.
Stay tuned to Research News for the latest information on Myocet.