What are the drugs being studied in treatment for colorectal cancer?

This paper looks at the various research into treatment for colorectal cancer. 

There are various proteins (large molecules) involved in the development of colorectal cancer. Drugs have been and are being developed to target these proteins and stop cancer from growing.

Activation of the Wnt protein, and the proteins it signals, leads to the initiation and growth of cancer.  Several new inhibitors such as sphingadiene can block Wnt activity.

Activation of epidermal growth factor receptor encourages cancer growth. Drugs are being developed to block this receptor. Cetuximab (Erbitux) and panitumumab (Vectibix) are such FDA-approved drugs. 

mTOR is a protein that, when over-produced can lead to tumor growth. Rapamycin (Sirolimus) is a drug that blocks the mTOR pathway, and is currently being studied.

Activation of vascular endothelial growth factor leads to the formation of new blood vessels needed for cancer growth. Thus, drugs are being developed to block blood vessel growth. Bevacizumab (Avastin) inhibits vascular endothelial growth factor. It is used in colorectal cancer that has metastasized (spread to other parts of the body). One study showed that adding bevacizumab chemotherapy improved progression-free survival by 17.1%. However, another study showed that it did not improve survival.  It was also associated with side effects such as diarrhea and high blood pressure.

Aflibercept (Regeneron) also blocks blood vessel growth. Clinical trials show that aflibercept is effective and safe in metastatic colorectal cancer.  In patients previously treated with oxaliplatin (Eloxatin), treatment with aflibercept in combination with irinotecan (Campto) and fluorouracil (Adrucil) improved survival.

One study concluded that a combination of endostar (a drug that inhibits blood vessel growth) and chemotherapy was safe and effective in patients with metastatic colorectal cancer.  Another study showed that patients with metastatic colorectal cancer who received regorafenib (Stivagra) had improved outcomes, with 23% decreased risk of death.

Studies have shown that the regular use of non-steroidal anti-inflammatory drugs (drug to reduce inflammation) was associated with decreased occurrence of colorectal cancer. However, it might be associated with side effects. 

The authors concluded that research into treatment for colorectal cancer is ongoing. New drugs are still needed.