PARP inhibitors are a type of cancer drug. PARP stands for poly adenosine diphosphate-ribose polymerase, a type of enzyme that helps repair DNA damage in cells.
PARP inhibitors work by preventing cancer cells from repairing, allowing them to die.
These drugs are a type of targeted therapy. They target cancer cells and mostly avoid affecting healthy cells.
Below, we explore the uses of PARP inhibitor targeted therapy. We also describe the side effects and other considerations.
A PARP inhibitor is a type of prescription drug that helps treat certain types of cancer. It blocks the PARP enzymes in cells.
PARP enzymes help repair DNA damage. Blocking them can keep cancer cells from repairing, and this allows them to die.
There are four main PARP inhibitors:
PARP inhibitors block the action of the PARP enzymes: PARP-1, PARP-2, and PARP-3. These all help repair damaged DNA in cells.
PARP inhibitors can keep cancer cells from repairing, and if they cannot repair, they die.
These drugs target cancer cells specifically, and manufacturers are currently developing other PARP inhibitors that may better home in on tumor cells.
The Food and Drug Administration (FDA) have approved PARP inhibitors for certain uses in cancer treatment.
Learn about the general uses in the following table, and find more information below.
| Olaparib | Niraparib | Rucaparib | Talazoparib | |
| Breast cancer | X | X | ||
| Fallopian tube cancer | X | X | X | |
| Ovarian cancer | X | X | X | |
| Pancreatic cancer | X | |||
| Peritoneal cancer | X | X | X | |
| Prostate cancer | X | X |
A doctor may prescribe talazoparib for adults with BRCA 1 or 2 mutations and metastatic breast cancer.
Rucaparib can treat certain types of ovarian, fallopian tube, primary peritoneal,and prostate cancer. Doctors may use it if other treatments, such as chemotherapy, have failed, or in the maintenance period that follows chemotherapy.
Niraparib has similar uses to rucaparib for ovarian cancer, fallopian tube cancer, and primary peritoneal cancer — but not prostate cancer.
Doctors may prescribe niraparib after at least three rounds of chemotherapy. And more recent studies support the use of this drug as a maintenance treatment after front-line chemotherapy.
Olaparib has the most extensive uses. It, too, can help treat ovarian cancer, fallopian tube cancer, or primary peritoneal cancer. This drug can also help treat BRCA-associated metastatic breast cancer.
Each PARP inhibitor works in the same way. But doctors use these drugs for different purposes, and they can cause some different side effects and interactions.
PARP inhibitors are
In general, all PARP inhibitors can cause the following
- nausea
- vomiting
- diarrhea
- fatigue
- a loss of appetite
- changes in taste
- stomach pain
- muscle and joint pain
- reduced levels of red blood cells, white blood cells, and platelets
In rare cases, these treatments cause cancer to develop in the blood.
It is important to discuss the possible side effects and interactions of any PARP inhibitor with the doctor before starting the treatment.
They can describe how to manage any side effects, what to do if side effects are severe, and in which circumstances it is a good idea to stop the treatment.
A person might also ask about drug label warnings and any other risks involved.
In addition, the doctor can provide information about how well the drug has worked for people with similar cases of cancer. They might describe this as the “effectiveness of the treatment.”
It is crucial to let the doctor know about any other medications, remedies, or supplements, as some may interfere with the effectiveness and safety of PARP inhibitors.
PARP inhibitors interfere with certain enzymes that help cancer cells repair. Blocking these enzymes allows the cancer cells to die.
These inhibitors are targeted therapies — they target cancer cells and have less effect on healthy cells than traditional chemotherapy.
A doctor may prescribe a PARP inhibitor to treat ovarian, fallopian tube, primary peritoneal, breast, prostate, or pancreatic cancer. Four of these drugs are currently on the market, and more are in development.