An Ovarian Cancer Drug That Cuts Tumor Growth

Bevacizumab, known commercially as Avastin, is a drug your oncologist may suggest during your treatment journey.

The drug works by preventing blood flow to tumors. It blocks the tumor from growing blood vessels, which cuts off the oxygen supply to the tumor. This can stop the tumor from growing and ultimately kill it.

Women Likely to Benefit From Avastin

Avastin is particularly helpful for women with high-risk cases of ovarian cancer. This includes:

• Widely metastatic cases that could have spread to the other areas, such as the liver and chest
• Cases where a tumor cannot be fully removed surgically
• Patients with recurrent ovarian cancer

The drug has had a meaningful effect on recurrent cases that are both platinum sensitive (where cancer recurs some time after completing platinum-based treatment that was effective), and platinum resistant (cases that did not have a meaningful response to platinum-based chemotherapy.)

When Avastin Can Be Used

• In combination with the first chemotherapy treatment
• As a form or maintenance therapy after the first chemotherapy treatment
• With chemotherapy after cancer has come back
• As maintenance after cancer has come back

Avastin is often used as a first line treatment, especially for women in the advanced stages of the disease. However, it should be part of chemotherapy when used as front line. It is often given along with chemotherapy drugs Carboplatin and Taxol.

When treating recurrent cancer cases, it is generally used with Carboplatin, Doxil, Taxol or Topotecan.

Patients can continue using Avastin alone as maintenance after chemotherapy, as long as cancer doesn’t recur, and the patient tolerates the drug well.

Using Avastin with PARP Inhibitors

Avastin has also been approved for use in combination with the PARP inhibitor, Lynparza (olaparib), for women whose cancer cells have a high degree of homologous recombination deficiency (HRD).

The combination, which was approved in 2020, can be used as a first-line maintenance therapy for women with advanced ovarian cancer who have had either a complete or partial response to chemotherapy.

PARP inhibitors work by blocking an enzyme—known as PARP—used by cells to repair damage to their DNA, which can lead to cancer cells dying off.

How Avastin Works

Drugs targeting the angiogenic process were not originally developed for ovarian cancer. But they’ve proven an effective treatment for ovarian and other cancers and have therefore been integrated into treatment regimens.

Avastin works by targeting a protein called vascular endothelial growth factor, a critical protein for blood vessel growth. It blocks angiogenesis, the physiological process through which new blood vessels are formed out of ones already in existence.

There are other promising cancer treatment drugs that try and cut off the tumor’s growth or survival processes, such as PARP inhibitors, which block DNA-repairing PARP enzymes from repairing malignancies, causing them to die, and immune checkpoint inhibitors, which help the immune system fight cancer cells. But Avastin has been studied more than these other classes of drugs, making them preferable to some oncologists.

One of the first anti-angiogenic drugs was Thalidomide, but it was not developed as a cancer drug.

“The story of Thalidomide is one of the most fascinating stories in all of medicine,” remembers Dr. Vincent Rajkumar, medical oncologist at the Mayo Clinic, who was instrumental in getting the anti-angiogenic drug Lenalidomide approved. “Thalidomide was developed as a sleeping pill in the late 50s. And when it was developed nobody knew its precise mechanism of action. They just knew that if you took it, you felt sleepy.”

But the drug fell out of favor when pregnant women who used it gave birth to babies with birth defects.

However, it came back in popularity after the concept of anti-angiogenesis was discovered in 1971.

“Thalidomide was thought to be an anti-angiogenic drug. That is, it prevented the growth of new blood vessels,” said Dr. Rajkumar.  “The theory was that cancers can grow only until one millimeter in size, unless they are able to induce new blood vessels. And if they are not able to induce new blood vessel formation, the cancer will shrink and die.” Thalidomide, and then a similar drug, Lenalidomide, became approved for widespread treatment of the blood cancer multiple myeloma in the late 2000s. Lenalidomide, also known as its trade name Revlimid, is considered and effective treatment for multiple myeloma. Similarly to Avastin, it can be used shortly after a diagnosis and after treatment for maintenance.

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