It07:Herceptin
| It07:Herceptin | |
|---|---|
| |
| General | |
| Other Names | Trastuzumab |
| Drug Type | Therapeutic monoclonal antibody |
| Drug Function | HER2-positive metatsatic breast cancer treatment |
| Molecular formula | C6470H10012N1726 O2013S42 |
| CAS number | 180288-69-1 |
| PubChem Identifier | 736684 |
| Drug Bank Identifier | BTD00098 |
| Properties | |
| Molar mass | 145531.5 gmol-1 |
| Melting point | 61 oC (FAB fragment), 71 oC (whole mAb)-Vermeer, A.W.P. & Norde, W., Biophys. J. 78:394-404 (2000) |
| Logp/Hydrophobicity | -0.415 |
| pKa/Isoelectric Point | 8.45 |
| Appearance (State) | Liquid |
| Metabolism | Most likely removed via the reticuloendothelial system |
| Half Life | 2-12 days |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Herceptin (also Trastuzumab)
General
'Herceptin' is the trade-name of a molecule called Trastuzumab, which is a humanized monoclonal antibody. It is particularly well known for its use as an anti-cancer agent, specifically in breast cancer.
This molecule targets the HER2/neu receptor, and if too much of this receptor is produced, which occurs in some cases of breast cancer tumours, then Herceptin can be used to tre
Herceptin cannot be taken orally, as it would be destroyed by the stomach. Instead, it is injected directly into the vein via a drip.
Using Herceptin
Herceptin is most commonly used when there has been found to be an over-expression of the HER2 receptor. This over-expression can be detected by immunohistochemistry or either chromogenic or fluorescent in situ hybridisation. Alternative ways of detecting this over-expression include various polymerase chain reaction methods.
Herceptin has been found to be unsuitable for patients with pre-existing heart problems, and has had unwanted cardiac effects on around 5% of patients used upon.
After taking Herceptin, some patients suffered from unwanted side-effects, including nausea, vomiting, headaches and fatigue.
Pharmacological Action
Herceptin acts in a different way to other standard treatments for cancer, including hormone replacement and chemotherapy. It is thought to have three main functions.
- In most cases of breast cancer the cancerous cells have too many copies of an oncogene, a gene which causes cells to rapidly grow and divide. The gene (part of the c-erbB-2 family) results in the expression of the HER2 receptor on the cell surface, thus allowing the cell to communicate and replicate. This receptor is targeted by Herceptin, which binds to it stopping communication and division.
- Once Herceptin is bound to the receptor it can be recognised by the body's Natural Killer immune cells (NK). These can then attack and destroy the unhealthy cells.
- Herceptin can be used in conjunction with chemotherapy, as the drugs work together and can be more effective than either treatment alone.
For detailed discussion of biopharmacological action..
Herceptin's success
Despite the unwanted side-effects, Herceptin has been found to be very useful in assisting the treatment of breast cancer. Recent clinical trials stated that Herceptin reduces the risk of relapse in breast cancer patients by 50% when given to them after breast cancer surgery, but before the cancer has spread any further, for one year.
However, the fact that Herceptin can cause heart disease means that its use as an anti-cancer drug has become limited.
Side effects
The Herceptin is believed to have several side effects for the women who had taken it.
One significant complications of Herceptin is that is causes heart failure. Cardiac dysfunction is associated with herceptin in 2~7% [citation needed] of the cases. In very few cases, about 5% of the patients experienced stroke or life-threatening congestive heart failure—a condition in which the heart can't pump effectively. Therefore, 10% of the patients with pre-existing heart disease have limitations of tolerating this drug.
Another complication of Herceptin is the allergic-like reactions and lung reactions. According to the record from the company make Herceptin, 62 of the approximately 25,000 women who had taken Herceptin as of 2001 had a serious reaction to the medication. Symptoms of the allergic–like reactions included hives, wheezing, and trouble breathing because of swelling and muscle spasms of the airways. Lung reactions included swelling of the lung, low blood pressure, or pleural effusions.
In most cases, about 40% of the women have the mild effects as flu-like symptom, which includes fever, chills, muscle aches and nausea in the first 24hour of the first dose. These effects usually become less severe after the first treatment.
Costs
As well as Hercpetin's unwanted side-effects, its cost plays an important role in its issue to patients. It has been reported that Herceptin costs around £35,000 for a full course of treatment - a price that some public health services, including those of England and New Zealand, have been unwilling to pay for a drug with such major defects. However, after much campaigning, the Ontario Ministry of Health said in July 2005 that it would pay for the treatment.