February 23, 2013
New Drug To Treat Breast Cancer Approved By US Regulatory Agency
April Flowers for redOrbit.com - Your Universe Online
The Food and Drug Administration (FDA) has approved a brand new type of breast cancer medication this week that targets tumor cells while sparing healthy surrounding tissues. In U.S. women, breast cancer is the second most deadly form of cancer and is expected to kill more than 39,000 Americans this year alone, the National Cancer Institute reports.
Kadcyla, from Roche, is a combination of a powerful chemotherapy drug, the established drug Herceptin, and a third chemical to link the first two together. The chemical maintains the coherence of the cocktail until it binds itself to a cancer cell to deliver a potent dose of anti-tumor poison.
Kadcyla is seen as an important step in the fight against breast cancer because it delivers more medication while reducing the side effects of traditional chemotherapy.
"This antibody goes seeking out the tumor cells, gets internalized and then explodes them from within. So it's very kind and gentle on the patients — there's no hair loss, no nausea, no vomiting," Dr. Melody Cobleigh of Rush University Medical Center, said in a HuffPost interview. "It's a revolutionary way of treating cancer."
According to Forbes, traditional chemotherapy is akin to a nuclear weapon- it indiscriminately destroys massive amounts of healthy cells along with the cancerous ones. The new drug, and other targeted treatments are more like cruise missiles — programmed to detonate only when they reach a specified target.
The new drug has been approved by the FDA for about 20 percent of breast cancer patients — those with a form of the disease typically more aggressive and less responsive to hormone therapy. The tumors present in these patients overproduce a protein known as HER-2.
Herceptin (trastuzumab) targets HER-2 positive cells, reports MedPage Today, allowing the chemotherapeutic molecule — DM1 — to attack the cancerous cells.
"This provides a significant leap to a whole other group of drugs, not only for HER2 because this adds a new drug for people who've already seen their tumor grow through trastuzumab as well as some of the other antibodies such as pertuzumab or ... the tyrosine kinase inhibitors such as lapatinib," said Jennifer Litton, MD, of the University of Texas MD Anderson Cancer Center (MDAnderson) in Houston.
Kadcyla (ado-trastuzumab emtansine) is the fourth approved therapy meant to target HER-2 proteins. Two of the other three, Herceptin and Perjeta, are Genentech products as well. The fourth drug, Tykerb, is marketed by GlaxoSmithKline.
The approval of Kadcyla will build on the blockbuster success of Herceptin for Roche's Genentech unit. Herceptin has dominated the breast cancer marketplace, with sales of approximately $6 billion last year.
Kadcyla will be expensive, with a cost of $9,800 a month. That's more than double the cost of Herceptin, which is $4,500 a month. A full course of Kadcyla, the company estimates, will run about nine months at a cost of $94,000.
The FDA's approval was based on company studies showing Kadcyla delays the progression of the disease by several months. Last year, researchers reported that patients treated with Kadcyla lived an average of 9.6 months before death or the disease spreading. Patients treated with two standard drugs, Tykerb and Xeloda, live an average of 6.4 months before death or the spread of the disease.
Overall, study participants treated with Kadcyla lived approximately 2.6 years, compared to 2 years for those taking other drugs.
The drug has been specifically approved for patients with advanced breast cancer who have already been treated with Herceptin and taxane, a widely used chemotherapy treatment. Doctors, however, are not required to follow FDA prescribing guidelines.
Cancer researchers say Kadcyla could have great potential in patients with earlier forms of breast cancer.
Kadcyla is not without side effects, however. The packaging will carry a boxed warning — the most severe kind — to alert doctors and patients alike that the drug can cause liver toxicity, heart problems and potentially death. Severe birth defects are also side effects of Kadcyla. It should not be used by pregnant women.
Other forms of targeted therapy are in development as well. Scientists have been working on the concept of anti-cancer drug "delivery" to targeted tumors for well over 20 years, but in the last few years the technologies have seen exceptional progress. The next phase of research will probably involve nanoparticle technology. Nanoparticles are smaller-than-microscopic transport vehicles injected into the body. They would then deliver their payload of toxic anti-cancer chemicals only to the cancerous cells.
Different materials have been considered to create nanoparticles since the 1990s. Lipids — naturally occurring molecules that include fats and waxes — were the first promising candidates. Lipids proved to be too large to penetrate tumors effectively, as well as being removed from the body too quickly.
Current candidates are polymers, or synthetic molecules, that can be tailored to the type of medication they are meant to deliver.
Dr. Juntoa Luo, a researcher working on polymer nanoparticles at the Upstate Medical University of New York, says, “The general concept is that one nanoparticle may not be able to deliver different types of medications. You may need to design a nanoparticle for each medication.”
He adds that "nanoparticles may need to be further tailored to individual patients, who may respond differently to medications depending on the stage and markers of their cancer. Polymer nanoparticles carry the medication to the tumor site within 24 hours. Remnants of the nanoparticles are flushed from the body through the kidneys. While they are designed to work most effectively in solid tumors, nanoparticles may also help fight some cancers of the blood.”
Polymer delivery vehicles are not the only nanoparticles being explored. AstraZeneca recently announced significant advances in using gold as a payload vehicle for targeted cancer treatments. Gold flecks are durable and can carry a large amount of a given drug. They are also incredibly tiny, with 5000 flecks fitting on the width of a human hair.
The upshot of all of this is that we may have reached a turning point in our war with cancer. With FDA approval of targeted drug therapies like Kadcyla, and human trials of nanoparticle delivery technology in the offing, mankind might just have gained the upper hand with cancer.