The Phase 3 clinical trial of Nexavar® (sorafenib) tablets in patients with advanced hepatocellular carcinoma (HCC) or primary liver cancer, has met its primary endpoint.
Clinical data demonstrated that treatment with Nexavar® (sorafenib) tablets has significantly extended overall survival (OS) of the particular patient population.
An independent data monitoring committee (DMC) that reviewed the clinical data has attested to the safety and efficacy of the product and therefore recommended early conclusion of the said study.
As a result of this recommendation, Bayer and Onyx will stop the trial and allow all patients enrolled in this trial access to Nexavar. Given that there are limited approved systemic therapies for this disease, the companies will continue discussions with health authorities worldwide, including the U.S. Food and Drug Administration (FDA) and European health authorities regarding the next steps in filing for approval for the treatment of HCC.
Nexavar® is a small molecule drug that has been approved for the treatment of advanced kidney cancer. The product is being co-developed by Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) with Bayer Pharmaceuticals Corporation (NYSE: BAY).
Find more details from the press release.
[Photo Credit: emaxhealth]
Do Targeted Cancer Drugs Always Work?
The "targets" that the new "smart drugs" go after can be located on the "inside" or "outside" of a cancer cell. The most common targets on the outside are receptors, proteins that help relay chemical messages. And many targets on the inside are enzymes, proteins that help speed up chemical reactions in the body.
What Nexavar, Iressa, Tarceva, Sutent and Tykerb have in common is that they are small molecule drugs. Exciting results have come from studies of multitargeted tyrosine kinase inhibitors, small molecules that act on multiple receptors in the cancerous cells.
Cells are the most basic structure of the body. Cells make up tissues, and tissues make up organs, such as the lungs or liver. Each cell is surrounded by a membrane, a thin layer that separates the outside of the cell from the inside.
For a cell to perform necessary functions for the body and respond to its surroundings, it needs to communicate with other cells in the body. Communication occurs through chemical messages in a process called signal transduction. The purpose of these signals is to tell the cell what to do, such as when to grow, divide into two new cells, and die.
Targeted cancer therapies use drugs that block the growth and spread of cancer by interfering with specific molecules involved in carcinogenesis (the process by which normal cells become cancer cells) and tumor growth. By focusing on molecular and cellular changes that are specific to cancer, targeted cancer therapies may be more effective than current treatments and less harmful to normal cells.
However, monoclonal antibodies are "large" molecules. These very large molecules don't have a convenient way of getting access to the large majority of cells. Plus, there is multicellular resistance, the drugs affecting only the cells on the outside may not kill these cells if they are in contact with cells on the inside, which are protected from the drug. The cells may pass small molecules back and forth.
Even if clinical trials end early, each of these new targeted drugs are not for everybody. The study of cell function analysis tells us that even when the disease is the same type, different patients' tumors respond differently to the same agents. So it doesn't matter if there is a "target" molecule in the cell that the "targeted" drug is going after, if the drug either won't "get in" in the first place or if it gets pumped out/extruded or if it gets immediately metabolized inside the cell, drug resistance is multifactorial.
Posted by: Gregory D. Pawelski | February 17, 2007 3:08 PM | Permalink to Comment