Niraparib is an oral poly-adenosine diphosphate-ribose polymerase (PARP) inhibitor developed to treat ovarian and related cancers by exploiting DNA repair weaknesses in tumour cells. Research into PARP inhibition began in the late 1990s, with Niraparib being designed to selectively block PARP enzymes, leading to cancer cell death due to accumulated DNA damage.

The U.S. FDA first approved Niraparib in March 2017 as a maintenance treatment for recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer in patients who achieved a complete or partial response to platinum-based chemotherapy. In April 2020, it received expanded FDA approval for first-line maintenance treatment of advanced ovarian cancer regardless of BRCA mutation status. It is also approved in the European Union, India, and other regions for similar uses.

Niraparib is used in the treatment of:

• Maintenance therapy for adult patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who have responded to platinum-based chemotherapy.

• Maintenance treatment of recurrent ovarian cancer in patients (with or without BRCA mutation) who achieved a complete or partial response after platinum-based chemotherapy.

• Investigational and off-label studies are also exploring its use in endometrial cancer, prostate cancer, and breast cancer with homologous recombination deficiency (HRD).

Cancer cells rely on DNA repair mechanisms to survive. Niraparib inhibits PARP enzymes, which play a crucial role in repairing damaged DNA. When PARP is blocked, DNA damage accumulates in cancer cells, leading to their death, a process called synthetic lethality.

This mechanism is particularly effective in cancers with BRCA1/BRCA2 mutations or homologous recombination deficiency (HRD), but Niraparib also benefits patients without these mutations.

• Form: Oral tablets.

• Typical Dose: Once daily, with or without food.

• Administration: Swallow whole, do not crush or chew.

• Individualisation: The starting dose may vary depending on body weight and baseline platelet count.

• Dose adjustments may be required if side effects occur, particularly low blood counts or high blood pressure.

Common (mild to moderate):

• Nausea, vomiting

• Fatigue

• Constipation or loss of appetite

• Insomnia

• Headache or dizziness

• Stomach pain

Serious (seek urgent medical attention):

• Severe anaemia (pale skin, extreme tiredness, shortness of breath).

• Thrombocytopenia (unexplained bruising, bleeding gums, nosebleeds).

• Hypertension (severe headache, chest pain, blurred vision).

• Bone marrow suppression (frequent or severe infections).

• Rare but serious: Myelodysplastic syndrome (MDS) or acute myeloid leukaemia (AML)

• Allergic reactions (swelling, rash, breathing difficulty)

• Bone marrow suppression: Regular monitoring of blood counts is essential.

• High blood pressure: Can worsen or develop during treatment.

• Heart effects: May cause palpitations or cardiovascular strain in some patients.

• Pregnancy/Breastfeeding: May harm the unborn or nursing baby; not recommended.

• Secondary cancers: Rare cases of MDS/AML have been reported.

• Blood pressure monitoring: Required regularly during therapy.

• Routine blood tests: For blood counts, kidney, and liver function.

• Avoid pregnancy: Effective contraception during and after treatment.

• Inform your doctor: If you have a history of heart disease, blood disorders, or uncontrolled hypertension.

• Alcohol: Limit intake, as it may worsen dizziness, nausea, or liver effects.

• Drug interactions: Always share your complete medication list.

• Do not start Niraparib if your blood counts are very low. Your doctor will check before treatment.

• Regular monitoring of blood pressure and complete blood counts is required during therapy.

• If you miss a dose, take it as soon as you remember. Skip the dose if it is almost time for the next one. Do not double up.

• Inform your doctor if you experience persistent fatigue, unusual bleeding, or sudden changes in blood pressure.

• Continue follow-up visits as advised to monitor treatment response and side effects.

1. Mansoor Raza Mirza et al., “Niraparib Maintenance Therapy in Platinum-Sensitive, Recurrent Ovarian Cancer,” The New England Journal of Medicine, [Dec 2016], showing significant improvement in progression-free survival with niraparib https://www.nejm.org/doi/full/10.1056/NEJMoa1611310
   

2. Bradley J. Monk et al., “Niraparib in Patients with Newly Diagnosed Advanced Ovarian Cancer,” The New England Journal of Medicine, [Jun 2019], PRIMA trial establishing niraparib as frontline maintenance therapy https://www.nejm.org/doi/full/10.1056/NEJMoa1910962

3. U.S. Food and Drug Administration (FDA), “FDA approves niraparib for first-line maintenance of advanced ovarian cancer,” [April 2020] https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-niraparib-first-line-maintenance-advanced-ovarian-cancer
   

4. European Medicines Agency (EMA), “Zejula (niraparib): EPAR – Product Information,” [Accessed Sept 2025], regulatory details for EU approval https://www.ema.europa.eu/en/medicines/human/EPAR/zejula

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.