Informasi yang harus Anda ketahui

Oral Targeted Therapies for Cancer

Iressa, Tarceva, Erbitux, Avastin, Herceptin ….

 

The Dream drugs or Smart Bombs are currently designed to target the cancer cells and block or slow the growth of certain types of cancer. They minimise damage to healthy cells. Of course, molecular targeted therapies also cause side effects, but these are generally more moderate than those caused by chemotherapy or radiotherapy.

The common side effects of molecular targeted therapy may include diarrhea, fever, loss of appetite, nausea, rash, and weakness.

Serious side effects may include severe allergic reactions, inflammation or scarring in the lungs, bleeding inside the body, irregular heartbeat, heart failure, blood clots, and dangerously low blood pressure.

The Smart Bombs

Targeted therapies include the use of monoclonal antibodies and small molecule inhibitors such as:

1.      Gleevec (imatinib mesylate) for chronic leukemia and gastrointestinal stromal tumour (GIST).

2.      Iressa (gefitinib) for non-small cell lung cancer.

3.      Tarceva for metastatic non-small cell lung cancer.

4.      Velcade (bortezomib) for multiple myeloma.

5.      Rituximab for Non-Hodgkin’s lymphoma.

6.      Herceptin (trastuzumab) for breast cancer.

7.      Erbitux (cetuximab) for colon cancer and non-small cell lung cancer.

8.      Avastin (bevacizumab) for cancers of the colon, breast, sarcoma and non-small cell lung cancer.

9.      Nexavar (sorafenib) for advanced kidney cancer.

10.  Sutent (sunitinib) for advanced kidney cancer and GIST.

11.  Torisel (temsirolimus) for advanced kidney cancer.

And there shall be many more smart bombs to come. 

Expensive Smart Bombs That Prolong Life By Few Months

Targeted therapies are incredibly expensive. Are they worth the expense?

Most of these new cancer drugs improve survival by only a few weeks or months.

They don’t cure cancer.

Ask your oncologist what you can expect from the smart drug he is prescribing you. 

Drug Cost per month in US Dollars

  • Zevalin $ 24,000 (most expensive!)
  • Erbitux $ 10,000Avastin $ 8,800 (breast /lung)Avastin $ 4,400 (colon)
  • Naxavar $ 4,300
  • Rituxan $ 4,200 to $13,000
  • Sutent $ 4,000
  • Herceptin $ 3,000
  • Gleevec $ 2,600
  • Tarceva $ 2,400 to $ 2,700

Reference:  http://www.usatoday.com/news/health/2006-07-10-cancer­drugs_x.htm http://www.iht.com/articles/2006/02/15/business/DRUG.php

Strange Medicine, Astonishing Prices

Why are these drugs so expensive? It’s hard to know exactly, since drug pricing is a sacred prerogative protected by acts of Congress and the details remain shrouded in trade secrets.

Drug makers have typically defended high prices citing high cost of developing new medicines. But now, they are saying: If society wants the benefits, it must be ready to spend more for the treatments.

William Burns, the chief executive of Roche’s pharmaceutical division, said: As we look at Avastin and Herceptin pricing, right now the health economics hold up, and therefore I don’t see any reason to be touching them. The pressure on society to use strong and good products is there.

Dr. Susan Desmond-Hellmann, the president of product development of Genentech, said the company had set Avastin’s price based on the value of innovation, and the value of new therapies.

Reference: Robert Bazell, http://slate.msn.com/id/2102844/ http://www.iht.com/articles/2006/02/15/business/DRUG.php 

Iressa: The First SmartBomb That Backfired

AstraZeneca informed the FDA of a study involving 1,700 lung cancer patients:

  • Patients who took Iressa lived for 5.6 months.
  • Those given a placebo (inactive, dummy pill) lived for 5.1 months.

The study shows by taking Iressa, patients live longer by TWO weeks.

As a result, Iressa was withdrawn in Western countries.

However, patients of Asian origin responded slightly better. They lived FOUR months longer.

  • With Iressa lung cancer patients lived 9.5 months.
  • Without Iressa patients lived only 5.5 months.

As a result, Iressa is still being prescribed to patients in Asian countries.  Iressa costs RM 215 per tablet or RM 6,450 per month in Malaysia.

Reference: American Cancer Society News Today, 21 Dec. 2004. 

Lethal Lung Cancer Drug … 444 deaths

In July 2002, Japan was the first country in the world to approve Iressa for lung cancer. In less than 2 years later, 1,151 cases of side effects were reported and 444 were thought to have died of Iressa in Japan.

The most common side effects of Iressa are: diarrhoea, rash, acne, dry skin, nausea, vomiting, interstitial lung disease (ILD), which involves scarring and inflammation of the lungs that can cause breathing problems, and pneumonia (causing difficulty breathing, coughs, fevers).

Reference:  The Japan Times, 25 March 2004

http://news.bbc.co.uk/2/hi/health/2605109.stm

http://www.boston.com/news/science/articles/2005/04/05/smart_drug_for_lung_cancer_may_be_pulled_from_market/

http://www.telegraphindia.com/1050418/asp/knowhow/story_4588836.asp

Tarceva for Lung Cancer

If Iressa cannot help you, then your oncologist may recommend Tarceva.

  • Patients with lung cancer taking Tarceva lived 9.5 months.
  • Lung cancer patients not taking Tarceva (on placebo) lived 6.7 months.

Increased survival after taking Tarceva was 2.8 months. Nowhere in the medical literature is a claim that Tarceva cures lung cancer!

Patients have to decide if it is worth spending RM 8,000 per month on medication that never cures but is said to only prolong life by 2.8 months.

Reference:  http://www.tarceva.net/survivalresults.aspx

Erbitux 

Erbitux is a monoclonal antibody, used to treat metastatic colorectal cancer, and head and neck cancer. It is given with irinotecan (another chemo-drugs) or by itself. It is not known whether Erbitux will improve symptoms of colorectal cancer or help patients live longer. It has been shown to shrink tumours.

Besides the hefty price tag, Erbitux comes with the following side effects: allergic reactions, skin reactions (shedding of the outer layer of the skin), headache, diarrhoea, kidney failure, lung disease, shortness of breath, blood clots in the lung, stomach pain, infection without abnormal decrease in white blood cell count.

Reference:  http://www.fda.gov/cder/drug/infopage/erbitux/erbituxQA.htm  http://www.erbitux.com/erbitux/erb/home/index.jsp?BV_UseBVCookie=Yes

Avastin

Avastin is used to treat cancers of the colon, breast, sarcoma and non-small cell lung cancer. Avastin will not cure metastatic colorectal cancer.

Patients given Avastin survived about fivemonths longer.In 2008, the FDA approved Avastin for treatment of advanced breast cancer on the basis that it doubled the number of women whose tumors shrank significantly.

But it did not extend overall survival rates. It caused more serious side effects, including perhaps half a dozen deaths.

Avastin delays tumour growth by five and a half months. The big question is whether such response is worth the toxic side effects and its high cost! 

Note: Now research has shown that Avastin spreads and makes cancer more aggressive.

Reference:

http://www.fda.gov/cder/drug/infopage/ avastin/avastinQ&A.htm http://www.nytimes.com/2008/03/10/opinion/10mon2.html?_r=1&oref=slogin

The Side Effects of Avastin

Holes in the colon requiring surgery to repair (gastrointestinal perforation). This can occur throughout the course of treatment and in some cases resulted in death.

Slow or incomplete wound healing, e.g. surgical incision has trouble healing or staying closed.

Severe bleeding leading to stroke or death, especially in lung cancer patients.

Heart failure in certain patients.

Clot in the vein (thrombophlebitis).

Other side effects are: kidney damage, high blood pressure, tiredness/weakness, diarrhoea, decreased white blood cells, headache, loss of appetite and mouth sores.

Reference:  http://www.fda.gov/cder/drug/infopage/avastin/ avastinQ&A.htm

http://www.avastin.com/avastin/index.jsp?p=Avastin&vc=&fr=yfp-t­501&toggle=1&cop=mss&ei=UTF-8&fp_ip=MY 

Herceptin

Herceptin is used with the usual chemotherapy regimen like doxorubicin, cyclophosphamide, and paclitaxel, or as single agent.

This is what patients can expect from the drug:

  • Clincal trial with HER2-positive metastatic breast cancer showed:

Herceptin + chemotherapy – Median survival is 25.1 months.
Chemotherapy without Herceptin – Median survival is 20.3 months.
Conclusion: Prolong survival by 4.6 months if Herceptin is added to the chemo-regimen. Take note, Herceptin does not cure breast cancer.

  • After one year women treated with:

Herceptin + chemotherapy – 79% of patients were alive. Chemotherapy without Herceptin – 68 % of patients were alive.

Conclusion: 11% more patients are alive after one year if Herceptin is added to the chemo-regimen.

  • After three-and-a-half years women treated with:

Herceptin plus chemotherapy – 87% were disease-free. Chemotherapy without Herception – 71% were disease free.

Conclusion: 16% more women are disease free after 3.5 years if Herceptin is added to the chemo-regimen.

Reference: http://www.gene.com/gene/products/information/oncology/ herceptin/factsheet.html

http://www.herceptin.com/herceptin/patient/index.jsp

The Side Effects of Herceptin

Herceptin treatment can result in heart problems, including those without symptoms (reduced heart function) and those with symptoms (congestive heart failure).

The risk and seriousness of these heart problems were highest in people who received both Herceptin and a certain type of chemotherapy (anthracycline).

Some patients may have serious infusion reactions and lung problems. Such reactions may occur during or within 24 hours of receiving Herceptin.

Worsening of low white blood cell counts associated with chemotherapy has also occurred.

Other side effects are: chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling; feeling short of breath, even with mild exertion; swelling, rapid weight gain, coughs or wheezing, white patches or sores inside the mouth or on the lips, fevers, chills, body aches, flu symptoms, nausea, vomiting, diarrhoea, headache, tired feeling.

Reference:  http://www.gene.com/gene/products/information/oncology/ herceptin/factsheet.html

http://www.herceptin.com/herceptin/patient/index.jsp

http://health.yahoo.com/breastcancer-medications/trastuzumab-injectable/ healthwise—d04357a1.html#d04357a1-sideeffects