PARP Inhibitors for Ovarian Cancer - What You Need to Know
- There are currently three PARP inhibitors approved to treat women with ovarian cancer.
- PARP inhibitors are oral pills that can be taken at home.
- Follow-up with your medical team is still important throughout the process.
- There are common side effects some of which include nausea and fatigue.
While initially, women with a BRCA-1 or BRCA-2 genetic mutation had been shown to respond especially well to PARP inhibitors after recurrence, newer research has shown that women with the BRCA gene mutation (and indeed almost all women), can consider using PARP inhibitors throughout their treatment.
Which PARP Inhibitors Are Approved?
Read MoreWho Should Use Them?
However Dr. Amanika Kumar of The Mayo Clinic who spoke to SurvivorNet, cautioned that women still need to speak with their doctor to evaluate the benefit of taking a PARP inhibitor to extend life, because there are very real side effects due to the toxicity of the drug. "Patients with HRD (homologous recombination deficiency) have a far better response than those without and those with BRCA mutations even more so. It is on us as clinicians to help patients understand the risks and benefits of treatment. Patients that have no mutation or HRD may choose not to go on maintenance (in fact I recommend they don't) because there is real toxicity to these meds."There are currently three different types of PARP inhibitors approved for women with ovarian cancer. All three medications — Lynparza (olaparib), Zejula (niraparib) and Rubraca (rucaparib) — are taken orally, but there is some variation in how often the drugs are taken and what dosage, Dr. Stephanie Wethington, a gynecologic oncologist at Johns Hopkins University in Baltimore, Maryland, tells SurvivorNet.
How Do PARP Inhibitors Work?
PARP (or poly ADP ribose polymerase) inhibitors work by preventing cancer cells that have been damaged — often during a course of chemotherapy treatment — from naturally healing. To accomplish this, which, in turn, effectively kills the cancer cell, the PARP-inhibitor drug blocks the necessary mechanism of repair, the PARP enzyme, which the cancer cell requires to fix single-strand breaks in its DNA. Recent studies have shown the drugs to provide benefit for patients with ovarian cancer as part of an initial plan of treatment.
RELATED: Should PARP Inhibitors be Given to All Women With Ovarian Cancer?
Even though PARP inhibitors are drugs that can be taken at home, Dr. Wethington says, patients will still be required to follow up with their medical team throughout the treatment process to make sure everything is going according to plan.
“You still follow up with your physicians, your chemo nurses, your outpatient nurses or your nurse practitioners,” Dr. Wethington says. “So, you still see your providers to touch base, to get labs, to follow symptoms.”
What Are The Side Effects?
Dr. Wethington notes that no matter which of the three approved PARP inhibitors a woman is taking, fatigue and nausea are very common side effects.
“Fortunately, those two symptoms, which are very, very common when patients first start PARP inhibitors, decrease in severity over time,” Dr. Wethington says. “So, we find that the severity of those symptoms starts as a common event, and becomes less common over time.”
RELATED: Differences Between Different Types of PARP Inhibitors
Dr. Wethington also notes that even in the beginning, the side effects tend to be mild for most patients.
“These aren’t side effects of nausea and vomiting where patients are unable to get up and do the things they want to do, they’re just more pesky,” she says. “They’re sort of there, sitting in the background, distracting you from what you want to do as opposed to keeping you in bed or keeping you in the house. For most patients, that’s the case.”
When deciding which of the three approved PARP inhibitors to use, women will need to discuss the risks/benefits of each with their doctor to make the best choice. The three medications are largely similar in how they work, but do have slight differences in side effects for the different stages of ovarian cancer. There is also no clear agreement among doctors who treat ovarian cancer about which of three drugs is the best choice in certain situations, so your doctor may recommend one drug over another based on their own personal preferences and experience.
Your doctor’s experience will be a valuable resource in making the right choice when it comes to PARP inhibitors.
Learn more about SurvivorNet's rigorous medical review process.