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Avastin/Irinotecan

So a decision has been made.

Next week Kai will start on Avastin/Irinotecan.

This protocol will be an IV infusion every two weeks at the clinic.

It is disappointing to be starting all over again, but tonight I am relieved that the decision has been made.  I went into today still not knowing which way to go and really they made it pretty clear that there is no right answer and we will end up trying most of these options at some point.  I guess I better get used to this.

While there is not statistical evidence that this treatment is any better than the rest, I have spoken to many optic glioma families who have had good results from this protocol.  I have been told their kids had very few side effects while on this and had good shrinkage and stability.  They also warned me that when they come off the drugs the tumor does tend to come back fairly quickly and sometimes even more aggressively than before.  At most we can hope that his will buy us some time, we can wish for shrinkage which will hopefully allow for some developmental gains, but we also have to be prepared for what treatment comes next.

This protocol is 1 year, but many people stay on it for up to two years if they are getting good results.  After that we are on to the next one.

The technical side: 

Avastin works differently than most chemo drugs, in-fact it is technically not a chemotherapy at all.  Typically chemotherapy drugs work to disrupt DNA replication at different points, causing rapidly dividing  cells to die.

How does this drug work?

Bevacizumab (avastin) is a type of targeted therapy known as a monoclonal antibody. A monoclonal antibody is a man-made version of an immune system protein that fits like a lock and key with a certain protein in the body.

Bevacizumab attaches to a protein called vascular endothelial growth factor (VEGF), which is required by the body to grow blood vessels. It is thought that by doing this, the drug stops tumors from being able to create new blood vessels to feed the tumor. This limits the tumors’ supply of nutrients, which in turn may slow or stop their growth. For this reason, bevacizumab is sometimes referred to as an anti-angiogenic drug. Another theory is that it may help by making tumor blood vessels (which are usually leaky) more stable, allowing chemotherapy to get into cancer cells more effectively.

http://www.cancer.org/Treatment/TreatmentsandSideEffects/GuidetoCancerDrugs/bevacizumab

I am hoping that because this drug works in a completely different way than the ones we previously tried, we will see better results…

The ‘common’ side effects of this Avastin are similar to what we have already been dealing with (and again anecdotally I have heard many kids have little to no side effects on this treatment)

  • high blood pressure* (this is a new one for us, and will be treated with medication if it does occur)
  • headache
  • mouth sores
  • diarrhea
  • loss of appetite
  • feeling tired
  • feeling weak
  • ovarian failure (when given with chemotherapy)*

The Irinotecan is a more traditional chemotherapy and will be given along with the Avastin.

How does this drug work?

Irinotecan is a chemotherapy drug made from a type of plant alkaloid known as a topoisomerase I inhibitor. It is thought to work by blocking the action of an enzyme in cells called topoisomerase I. Cells need this enzyme to keep their DNA in the proper shape when they are dividing into 2 cells. Blocking this enzyme leads to breaks in the DNA, which leads to cell death. Because cancer cells divide faster than normal cells, they are more likely than normal cells to be affected by irinotecan.

http://www.cancer.org/Treatment/TreatmentsandSideEffects/GuidetoCancerDrugs/irinotecan

There are many terrible and frightening side effects to this drug, but Kai is most likely to face loosing his hair, having lowered blood counts, and reacting with severe diarrhea; which will then be treated by yet another drug.

  • diarrhea*
  • nausea/vomiting*
  • lowered white blood cell count with increased risk of infection*
  • hair thinning or loss, including face and body hair*
  • abdominal (belly) pain
  • loss of appetite
  • feeling weak

Now that the decision has been made, we will be doing our best to enjoy this week before having to start up again.

 We plan to spend lots of time watching Kai’s hair blowing in the wind, while we still have it!  While loosing his hair is the least worrisome of the side effects it is the one that, to the rest of the world make it undeniable HE HAS CANCER.  It will take some time for us to adjust to the new changes, but today I am hopeful that he will tolerate this well, have good results, and I am hoping beyond HOPE that we will continue to see those smiles and laughs he has been dishing out the past few weeks!

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