Evaluating Bevacizumab and PARP Inhibitors as Impo...
Ovarian Cancer
Evaluating Bevacizumab and PARP Inhibitors as Important Treatment Options
If you’ve been diagnosed with ovarian cancer, you’ll probably need to decide whether to enroll in “maintenance therapy” after chemotherapy and surgery. Ovarian cancer often recurs in women who’ve been through an initial round of treatment, and maintenance therapy seeks to keep the cancer from coming back for as long as possible.
Maintenance therapy often involves using drugs to keep the cancer in remission longer. Two options for maintenance are a drug known as a PARP inhibitor or another drug known as Bevacizumab (or Avastin). To understand what these two drugs are and which to choose for maintenance therapy, we spoke to Dr. Michael Birrer, Senior Scientist of the O’Neal Comprehensive Cancer Center at UAB, who underscored the importance of the question:
“How do you decide what patients should get Bevacizumab vs PARP? That’s really the million dollar question,” says Birrer.
What is a PARP inhibitor and when should a woman use it?
PARP inhibitors work by blocking an enzyme—known as PARP—used by cells to repair damage to their DNA. Without normal functioning PARP, tumor cells will accumulate more and more DNA damage, and eventually die. So when should you use it? According to Dr. Birrer, PARP inhibitors are most effective in women with a BRCA mutation. “If patients have either germline or somatic BRCA1/2 mutations that, when possible, they should get a PARP inhibitor,” he says. Why? Women who have a BRCA mutation are more receptive to treatment with a PARP inhibitor. Tumor cells with BRCA mutations have problems repairing DNA already, and the PARP inhibitors make that worse, causing cancer cells to die. Learn more about the side effects of PARP inhibitors here.
However, not all women have a BRCA mutation, says Birrer. “You need to recognize that you’re looking at about 20 percent of the patient population.” So what about the rest? For women without a BRCA mutation, PARP inhibitors have still been shown to have benefit.
Indeed, the three major PARPs have been shown to be effective in the 80 percent of ovarian cancer patients who don’t have BRCA mutations. According to Dr. Oliver Dorigo, Director of Gynecologic Oncology at Stanford University Medical Center, the PARP Inhibitor Niraparib, also known as Zejula, can benefit a wide range of women with ovarian cancer. “We have trials that have shown that Niraparib in any patient with [ovarian cancer] can be beneficial in the maintenance setting…independent of a BRCA mutation,” he says.
What is Bevacizumab (Avastatin) and when should it be used
Bevacizumab 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. The drug works by targeting a protein called vascular endothelial growth factor, a critical protein for blood vessel growth. This targeting blocks angiogenesis, the process by which new blood vessels are formed out of ones already in existence.
When should women use Bevacizumab? It’s quite simple and clear-cut, says Dr. Birrer: Most women without a BRCA mutation should use the drug. There are a few that shouldn’t, such as those with cancer spreading into the bowel, but that’s a relatively small number of women, says Birrer.
What about both?
Right now, Dr. Birrer says there are clinical trials underway to test whether taking both drugs at the same time will be even more effective than taking either one alone. “There are several ongoing trials looking at the combination of Olaparib (one type of PARP inhibitor) and Bevacizumab,” says Birrer. He predicts that the results of the trial will likely be quite promising. “If I were to give an educated guess, I would say we’ll be treating with both agents in the near future,” concludes Birrer.
Learn more about SurvivorNet's rigorous medical review process.
If you’ve been diagnosed with ovarian cancer, you’ll probably need to decide whether to enroll in “maintenance therapy” after chemotherapy and surgery. Ovarian cancer often recurs in women who’ve been through an initial round of treatment, and maintenance therapy seeks to keep the cancer from coming back for as long as possible.
Maintenance therapy often involves using drugs to keep the cancer in remission longer. Two options for maintenance are a drug known as a PARP inhibitor or another drug known as Bevacizumab (or Avastin). To understand what these two drugs are and which to choose for maintenance therapy, we spoke to Dr. Michael Birrer, Senior Scientist of the O’Neal Comprehensive Cancer Center at UAB, who underscored the importance of the question:
“How do you decide what patients should get Bevacizumab vs PARP? That’s really the million dollar question,” says Birrer.
What is a PARP inhibitor and when should a woman use it?
PARP inhibitors work by blocking an enzyme—known as PARP—used by cells to repair damage to their DNA. Without normal functioning PARP, tumor cells will accumulate more and more DNA damage, and eventually die. So when should you use it? According to Dr. Birrer, PARP inhibitors are most effective in women with a BRCA mutation. “If patients have either germline or somatic BRCA1/2 mutations that, when possible, they should get a PARP inhibitor,” he says. Why? Women who have a BRCA mutation are more receptive to treatment with a PARP inhibitor. Tumor cells with BRCA mutations have problems repairing DNA already, and the PARP inhibitors make that worse, causing cancer cells to die. Learn more about the side effects of PARP inhibitors here.
However, not all women have a BRCA mutation, says Birrer. “You need to recognize that you’re looking at about 20 percent of the patient population.” So what about the rest? For women without a BRCA mutation, PARP inhibitors have still been shown to have benefit.
Indeed, the three major PARPs have been shown to be effective in the 80 percent of ovarian cancer patients who don’t have BRCA mutations. According to Dr. Oliver Dorigo, Director of Gynecologic Oncology at Stanford University Medical Center, the PARP Inhibitor Niraparib, also known as Zejula, can benefit a wide range of women with ovarian cancer. “We have trials that have shown that Niraparib in any patient with [ovarian cancer] can be beneficial in the maintenance setting…independent of a BRCA mutation,” he says.
What is Bevacizumab (Avastatin) and when should it be used
Bevacizumab 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. The drug works by targeting a protein called vascular endothelial growth factor, a critical protein for blood vessel growth. This targeting blocks angiogenesis, the process by which new blood vessels are formed out of ones already in existence.
When should women use Bevacizumab? It’s quite simple and clear-cut, says Dr. Birrer: Most women without a BRCA mutation should use the drug. There are a few that shouldn’t, such as those with cancer spreading into the bowel, but that’s a relatively small number of women, says Birrer.
What about both?
Right now, Dr. Birrer says there are clinical trials underway to test whether taking both drugs at the same time will be even more effective than taking either one alone. “There are several ongoing trials looking at the combination of Olaparib (one type of PARP inhibitor) and Bevacizumab,” says Birrer. He predicts that the results of the trial will likely be quite promising. “If I were to give an educated guess, I would say we’ll be treating with both agents in the near future,” concludes Birrer.
Learn more about SurvivorNet's rigorous medical review process.