GSK's Tykerb just received priority FDA review, meaning that if everything goes right, it will be on the market in about 6 months - initially for breast cancer.
The linked article suggests Tykerb will peak at $2B in annual revenue, which seems a bit large.
A small molecule dual EGFR + Her2/neu inhibitor, Tykerb could supplant Herceptin (~$750M in 2005 sales) and potentially Tarceva, meaning that Genentech is solidly in GSK's cross hairs (not to mention other EGFR product makes like ImClone/BMS, and Amgen.)
IMHO, DNA needs to rev up Tarceva marketing ASAP.
Thursday, November 16, 2006
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Is Tykerb better than Herceptin?
Maybe, for these reasons.
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, the monoclonal antibodies like Herceptin and Erbitux 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.
Exciting results have come from studies of multitargeted tyrosine kinase inhibitors, "small" molecules that act on multiple receptors in the cancerous cells, like Tykerb and Sutent. Targeted "small-molecule" therapies ruled at the recent annual ASCO meeting of oncologists. The trend is away from the monoclonals to the small molecules, a trend in which a new predictive test may be able to hasten.
The EGFRx™ assay is able to test molecularly-targeted anti-cancer drug therapies like Iressa, Tarceva, Tykerb, Sutent and possibly Nexavar, because of being small molecules. The EGFRx™ assay relies upon a technique known as Whole Cell Profiling, in which living tumor cells are removed from an individual cancer patient and exposed in the laboratory to the new drugs.
Basically, Whole Cell Profiling measures the response of the tumor cells to drug exposure. Following this exposure, it measures both cell metabolism and cell morphology. The effect of drugs on the whole cell, resulting in a cellular response to the drug, measures the interaction of the entire genome.
A variety of metabolic and apoptotic measurements are then used to determine if a specific drug was successful at killing the patient's cancer cells. The whole cell profiling method differs from other tests in that it assesses the activity of a drug upon combined effect of all cellular processes, using several metabolic (cell metabolism) and morphologic (structure) endpoints, at the cell "population" level (rather than at the "single cell" level).
Other tests, such as those which identify DNA or RNA sequences or expression of individual proteins often examine only one component of a much larger, interactive process. Whole Cell Profiling measures genes before and after drug exposure. Gene Expression Profiles measures the gene expression only in the "resting" state, prior to drug exposure.
The EGFRx™ Assay is the only assay that involves direct "visualization" of the cancer cells at endpoint. This allows for accurate assessment of drug activity, discriminates tumor from non-tumor cells, and provides a permanent archival record, which improves quality, serves as control, and assesses dose response in vitro.
Source: http://weisenthal.org/ex_targeted_egfr_kinase.pdf
Oncologists Not Yet Ready To Use Tykerb As A Replacement For Herceptin
Although oral tyrosine kinase inhibitors, like Tykerb, offer patients a well-tolerated, conveniently administered alternative to intravenous (IV) therapy, Decisions Resources, one of the world's leading research and advisory firms for pharmaceutical and healthcare issues, found that oncologists are not yet ready to use Tykerb as a replacement for Herceptin. Ninety-one percent of surveyed oncologists stated that intravenous (IV) cancer therapies are more profitable than oral therapies. And fifty-eight percent of oncologists say they would favor IV Herceptin over oral Tykerb because administration of IV drugs remains an important source of income for their practices.
Selling cancer chemotherapy with concessions creates conflicts of interest for oncologists
http://www.healthyskepticism.org/news/2007/Jun.php
A precursor to the modern Chemotherapy Concession going on in the United States had been forbidden in Germany since the 13th century, as a result of a very visionary German ruler, Frederick II of Hohenstaufen, Emperor of the Holy Roman Empire of the Germanic Nation, and his visionary law (Edict of Salerno) regarding the separation of the professions of Physician and Pharmacist.
His 1241 Edict of Salerno (sometimes called Constitution of Salerno) made the first legally fixed separation of the occupations of physician and apothecary. Physicians were forbidden to double as pharmacists and the prices of various medicinal remedies were fixed. This became a model for regulation of the practice of pharmacy throughout Europe.
Medical oncologists should be taken out of the retail pharmacy business and force them be doctors again.
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