Key points
- Surgery and chemotherapy are still the foundation: removing all visible tumour, and 6 cycles of carboplatin and paclitaxel [3, 4].
- Every woman with the common type of ovarian cancer should have a BRCA test, ideally at diagnosis; the result guides treatment and also helps her family [13, 3].
- In women with a BRCA mutation, two years of olaparib tablets after chemotherapy delayed the return of the disease by years: seven years later, 2 in every 3 were alive [6].
- These tablets help most when given early and to the right patient: their use instead of chemotherapy in patients treated several times before was withdrawn, and after a relapse they remain only for women with a BRCA mutation [11].
How was ovarian cancer treated, and what changed?
Until the mid-1990s, advanced ovarian cancer was treated with surgery and chemotherapy with two drugs, cisplatin and cyclophosphamide. In 1996 a large study showed that when paclitaxel was given instead of cyclophosphamide, the disease came back later and patients lived longer [1]. A few years later, carboplatin was found to work just as well with fewer side effects [2]. The combination of carboplatin and paclitaxel has remained the standard treatment ever since [3].
But one big problem remained: most women responded well to chemotherapy [1], yet in many of them the disease came back after a while. For example, among women with a BRCA mutation who were only monitored after chemotherapy, after 3 years only about 1 in every 4 was still free of relapse [5].
A new path came from understanding the BRCA genes. These genes help the cell repair damage to its DNA. Tumours with a BRCA mutation or a similar weakness in DNA repair (called "HRD-positive") depend on another enzyme, called PARP, to survive. "PARP inhibitor" tablets block this route as well, and the cancer cell dies [17].
In 2018, a large study in women with advanced ovarian cancer and a BRCA mutation gave a striking result: two years of olaparib tablets after the end of chemotherapy cut the risk of the disease returning or progressing to less than a third [5]. Seven years later, 2 in every 3 women who had taken the tablets were alive, and almost half of all of them had still not needed any new treatment; more than twice as many as among women who had not taken the tablets [6].
In another large study, almost half of the patients had HRD-positive tumours, with or without a BRCA mutation [9]. In these women, olaparib together with bevacizumab almost doubled the time the disease stayed under control, and five years later 2 in every 3 were alive [7, 8]. Another tablet, niraparib, also delayed relapse, especially in HRD-positive tumours, but after about 6 years of follow-up it did not lengthen patients' lives [9, 10]. Today the US label allows its use after the first treatment only for HRD-positive tumours [12].
Why did the place of these tablets change?
In the early years, PARP tablets were also given in more situations: instead of chemotherapy in women who had been treated several times, and after a relapse for all patients, whether or not they had a mutation. When the long-term results came in, the picture changed: in several studies, patients' lives in these situations may even have been shortened. So in 2022 and 2023 the US Food and Drug Administration withdrew the use of these tablets instead of chemotherapy and limited their use as maintenance after a relapse to women with a BRCA mutation [11].
The lesson is simple: these tablets help most when they are given early, that is after the first course of chemotherapy, and to the right women (those with a BRCA mutation or an HRD-positive tumour) [3, 6, 8]. If your tumour has neither a BRCA mutation nor HRD, the benefit of these tablets is small; in that case continuing bevacizumab, or sometimes niraparib, may be considered, and the decision is one to make with your doctor [3, 10].
Treatment today, step by step
- 1
- 2
Chemotherapy
Carboplatin and paclitaxel every 3 weeks for 6 cycles; in stage 3 and 4 disease, sometimes together with bevacizumab [3].
- 3
- 4
- 5
If the disease comes back
If the relapse comes more than 6 months after the last chemotherapy, platinum chemotherapy is usually given again, and further surgery is sometimes considered [3]. In women with a BRCA mutation who have not had a PARP tablet before, olaparib after this chemotherapy kept the disease under control far longer [16, 11].
BRCA testing: for you and for your family
American and European guidelines recommend that every woman with the common (epithelial) type of ovarian cancer has genetic testing at diagnosis: a blood test for an inherited mutation in BRCA1, BRCA2 and several other genes and, if no inherited mutation is found, a BRCA test on the tumour sample [13, 3].
An inherited mutation is not only about you. If your test is positive, close blood relatives, including sisters, daughters, your mother and even the men in the family, can be tested after genetic counselling [13]. A woman with a BRCA mutation has a high risk of breast and ovarian cancer: about 4 in every 10 women with a BRCA1 mutation, and about 2 in every 10 with a BRCA2 mutation, develop ovarian cancer by age 80 [14]. For these women, breast screening starts at a younger age and uses MRI as well as mammography, and removing the ovaries and fallopian tubes at the right age lowers the risk of ovarian cancer [15]. Read more: Is cancer hereditary?
When should I call my doctor?
Regular blood tests are needed while you take PARP tablets, because these tablets can lower blood cells and platelets [18, 12]. Tell your doctor early about: severe tiredness, paleness or breathlessness (anaemia), unusual bruising or bleeding, fever or signs of infection, and a new cough [18]. With niraparib, blood pressure also needs to be checked regularly [12]. Do not stop the tablets yourself or change the dose.
Frequently asked questions
Does every woman with ovarian cancer get a PARP tablet?
How long do I take the tablets?
If I have a BRCA mutation, will my daughter definitely get cancer?
Do these tablets cause blood cancer?
My disease has come back several times; can these tablets still help?
These tablets are no longer used instead of chemotherapy in patients who have been treated several times [11]. After a relapse that has responded to platinum chemotherapy, they have a role as maintenance tablets only in women with a BRCA mutation who have not had a PARP tablet before [11, 3]. Other treatments exist; see Ovarian cancer: a complete guide.
For physicians
Show detailsHide
Foundation of treatment: GOG-111 (410 patients, stage III–IV with residual disease larger than 1 cm): cisplatin-paclitaxel versus cisplatin-cyclophosphamide, response 73% versus 60%, median PFS 18 versus 13 months and OS 38 versus 24 months [1]. GOG-158 (792 patients, optimally resected stage III): carboplatin-paclitaxel non-inferior to cisplatin-paclitaxel (median PFS 20.7 versus 19.4 months; RR for progression 0.88), with less gastrointestinal, renal and metabolic toxicity [2]. EORTC 55971: neoadjuvant chemotherapy and interval debulking non-inferior to primary surgery in bulky IIIC–IV disease (HR for death 0.98); complete resection of all macroscopic disease was the strongest independent predictor of survival [4]. Doses: carboplatin and paclitaxel in ovarian cancer.
First-line maintenance: SOLO-1 (391 patients, BRCA mutation, complete or partial response to platinum): HR for progression or death 0.30; progression-free at 3 years 60% versus 27% [5]. Seven-year follow-up: OS 67.0% versus 46.5% (HR 0.55; P=0.0004; the prespecified threshold of P<0.0001 was not met), alive without subsequent therapy 45.3% versus 20.6%, MDS/AML 1.5% versus 0.8% [6]. PAOLA-1 (806 patients, first line with bevacizumab): median PFS overall 22.1 versus 16.6 months (HR 0.59), HRD-positive 37.2 versus 17.7 months (HR 0.33), and HRD-positive without a BRCA mutation 28.1 versus 16.6 months (HR 0.43) [7]; final OS overall 56.5 versus 51.6 months (HR 0.92), and in HRD-positive disease HR 0.62 with 5-year OS 65.5% versus 48.4% (exploratory) [8]. PRIMA (733 patients, 373 HRD-positive): median PFS in HRD-positive disease 21.9 versus 10.4 months (HR 0.43) and overall 13.8 versus 8.2 months (HR 0.62) [9]; final OS (median follow-up 73.9 months): HR overall 1.01, HRD-positive 0.95 and HR-proficient 0.93; subsequent PARPi in the placebo group 37.8% [10]. The current FDA label restricts first-line niraparib to HRD-positive disease (BRCA mutation and/or genomic instability) [12]. Doses: olaparib maintenance · olaparib + bevacizumab · niraparib.
Withdrawn indications: In 2022–2023 the FDA withdrew or narrowed the six indications for PARPi in advanced EOC that it had granted between 2014 and 2019, after a potential detrimental effect on OS was seen in four randomised trials: the treatment indications for niraparib, olaparib and rucaparib in BRCA-mutated or HRD-positive advanced EOC were withdrawn, and maintenance in recurrent disease was restricted to BRCA mutations [11]. SOLO2 (platinum-sensitive relapse with a BRCA mutation): median PFS 19.1 versus 5.5 months (HR 0.30); grade ≥3 anaemia 19% [16].
Testing and monitoring: ESMO Pan-Asian 2025: germline and/or somatic BRCA testing for all non-mucinous high-grade cancers at diagnosis [I, A] and HRD testing in advanced high-grade disease [I, A]; PARPi maintenance ± bevacizumab for BRCA-mutated or HRD-positive disease [I, A]; in HRD-negative disease, bevacizumab [I, A] or niraparib [I, B] may be considered [3]. ASCO 2020: germline testing for all EOC; somatic BRCA1/2 testing in germline-negative patients; dMMR testing in clear cell, endometrioid and mucinous types; evaluation and testing of first- and second-degree relatives of carriers; no clinical decisions based on a VUS [13]. Olaparib: CBC at baseline and monthly; for prolonged cytopenia that has not recovered 4 weeks after interruption, refer to haematology for bone marrow assessment [18]. Niraparib: CBC weekly for the first month and monthly for the next 11 months; blood pressure and heart rate at least weekly for the first 2 months, then monthly for the first year [12].
Scientific evidence
Show detailsHide
Scientific evidence
10 itemsOverall Survival With Maintenance Olaparib at a 7-Year Follow-Up in Patients With Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation: The SOLO1/GOG 3004 Trial
Olaparib plus bevacizumab first-line maintenance in ovarian cancer: final overall survival results from the PAOLA-1/ENGOT-ov25 trial
Olaparib plus Bevacizumab as First-Line Maintenance in Ovarian Cancer
Olaparib tablets as maintenance therapy in patients with platinum-sensitive, relapsed ovarian cancer and a BRCA1/2 mutation (SOLO2/ENGOT-Ov21): a double-blind, randomised, placebo-controlled, phase 3 trial
Phase III Trial of Carboplatin and Paclitaxel Compared With Cisplatin and Paclitaxel in Patients With Optimally Resected Stage III Ovarian Cancer: A Gynecologic Oncology Group Study
Cyclophosphamide and Cisplatin Compared with Paclitaxel and Cisplatin in Patients with Stage III and Stage IV Ovarian Cancer
Pan-Asia adapted ESMO Clinical Practice Guideline for the management of patients with newly diagnosed and relapsed epithelial ovarian cancer
Niraparib first-line maintenance therapy in patients with newly diagnosed advanced ovarian cancer: final overall survival results from the PRIMA/ENGOT-OV26/GOG-3012 trial
Niraparib in Patients with Newly Diagnosed Advanced Ovarian Cancer
Maintenance Olaparib in Patients with Newly Diagnosed Advanced Ovarian Cancer
Read more
Related cancer types
References
18 referencesShow all references, 13 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
- 1
- 2Phase III Trial of Carboplatin and Paclitaxel Compared With Cisplatin and Paclitaxel in Patients With Optimally Resected Stage III Ovarian Cancer: A Gynecologic Oncology Group Study
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16Olaparib tablets as maintenance therapy in patients with platinum-sensitive, relapsed ovarian cancer and a BRCA1/2 mutation (SOLO2/ENGOT-Ov21): a double-blind, randomised, placebo-controlled, phase 3 trial
- 17Epithelial ovarian cancer
- 18
This page is based on reputable scientific sources and was last updated on 28 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
Printed from the website; the full and up-to-date version: https://drdabiri.com/en/articles/ovarian-cancer-parp-inhibitors/
