Avastin

Avastin is the brand name for a chemotherapy drug called bevacizumab. It was made by Genentech and was approved for several types of cancer by the U.S. Food and Drug Administration (FDA) in 2004. Avastin is one of the most commonly used chemotherapy drugs, for cancers like colorectal and non-small cell lung cancer. It is most recently being tested for use in treating patients with mesothelioma.

Early clinical trials with Avastin and mesothelioma patients have shown that the drug has the potential to extend life expectancies. On the other hand, there are some very serious side effects that go beyond the typical nausea and fatigue that chemotherapy patients often experience. Some studies are even showing that this drug may increase death rates, especially in certain drug combinations. More research is needed to determine if it is both a safe and effective treatment for mesothelioma.

What is Bevacizumab?

Avastin, bevacizumab, is a chemotherapeutic agent that was approved by the FDA in 2004. It acts on tumors by inhibiting the growth of blood vessels and is administered intravenously, circulating throughout the bloodstream. Avastin is only approved for use in certain types of cancer, although doctors can use discretion in prescribing it for other patients.

Approved uses include metastatic colorectal cancer, non-squamous non-small cell lung cancer, glioblastoma, metastatic renal cell carcinoma, cervical cancer, and for some patients with epithelial peritoneal, fallopian tube, and ovarian cancers. Intravenous doses are given over a period of 60 to ninety minutes every two to three weeks.

How it Works

Most chemotherapy drugs work by being circulated through the blood and attacking any rapidly growing and dividing cells. This mostly targets fast-growing tumor cells, but also targets some healthy cells, resulting in some of the characteristic side effects of chemotherapy, like hair loss. While Avastin is called a chemotherapy drug, and is used in a similar way, it doesn’t work the same as most others.

Avastin works by inhibiting a process in tumors called angiogenesis. Angiogenesis is the growth of blood vessels that supply tumors with blood carrying oxygen and nutrients. By cutting off this process, it slows and stops the growth of the tumor, and eventually the cancer cells begin to die, being starved of oxygen and other nutrients. While this is an effective way to destroy the cancer, it is not specific to the tumor. The inhibition of angiogenesis can affect healthy systems and cause or worsen high blood pressure, coronary artery disease, and other complications.

Side Effects

As with any other chemotherapy drug, there is the risk of side effects with Avastin. The side effects are different, though, because this drug works in a different way. There is also a greater potential for more serious and severe side effects than with most other chemotherapy medications. The most common side effects of Avastin are nosebleeds, headaches, nasal congestion, high blood pressure, excessive amounts of protein in the urine, changes in the ability to taste, back pain, dry skin, peeling skin, and rectal hemorrhage.

Avastin comes with several warnings and precautions because it has been found to cause serious adverse effects in some patients. Some of these are listed in a black box warning, the FDA’s most serious warning label. These serious side effects include gastrointestinal perforation, which occurs in over three percent of patients treated with Avastin. Another complication is bleeding and difficulty healing in wounds and after surgery. Hemorrhaging is a serious concern as well, and may occur in the brain and other parts of the body and may become fatal.

Avastin for Mesothelioma – Ongoing Trials

Several years after Avastin was first approved by the FDA, researchers began serious investigations into how this drug might help patients with mesothelioma. Some studies have found little improvement in patients when including Avastin in combination with other drugs like cisplatin and gemcitabine. Others have showed that the introduction of Avastin can help, including a case study in which a man with peritoneal mesothelioma did not respond well to other treatment regimens, but saw improvements with Avastin.

Clinical trials using Avastin in patients with mesothelioma have been conducted and some are ongoing, with mixed results. These include studies combining it with pemetrexed and cisplatin, combining it with Tarceva, and comparing combinations of chemotherapy drugs including Avastin to the same combinations without Avastin. All of these have been conducted with participating mesothelioma patients.

The Risk of Death

There have been many clinical trials using Avastin, either alone or in combination, and from a meta-analysis of several of these, researchers discovered a disturbing trend: there is a serious risk of death when Avastin is combined with more standard chemotherapy drugs. The results of the meta-study were published in 2011 and showed that the risk of death was very serious with this drug.

The analysis included more than 10,000 patients in clinical trials. Fatalities that occurred during the trials were not common, but showed a trend. In patients who received Avastin, 2.5 percent died. This is as compared to the 1.7 percent of patients not receiving Avastin who died. The increase is even more significant when comparing deaths among patients who received Avastin in combination with other chemotherapy drugs to those who did not. The death rate in these cases was tripled for those who received Avastin. The most common cause of death in these instances was hemorrhaging, followed by infections, and gastrointestinal perforations.

The study authors ultimately concluded that for most patients the risks of these harmful side effects that can be fatal are outweighed by the benefits of combining Avastin with chemotherapy. They did point out, though, that knowing the risks is important, for both patients and doctors.

Avastin is a targeted drug that is used in a similar way as chemotherapy drugs and often combined with these drugs to help a variety of cancer patients. Many of these patients have undergone other treatments with limited success and are turning to an alternative, in spite of the risks of serious adverse events. For mesothelioma patients, research is ongoing, but Avastin may prove to be a novel treatment for this otherwise difficult to treat cancer.