Use of PARP Inhibitors in Recurrent Ovarian Cancer
Erin Crane, MD, discusses the role of PARP inhibitors in the treatment of ovarian cancer.
Erin Crane, MD: For this patient, niraparib was definitely the right choice. Had we known about the results of the PRIMA or PAOLA trials when she was initially treated, we probably would have put her on it in the first-line maintenance setting. We know, at that point especially, that we can extend progression-free survival significantly for this patient population. It has also been FDA approved for use in the recurrent setting. It was definitely the right choice for this patient. We often have long discussions among ourselves and with the patients about how long to continue PARP inhibitors. Some studies continue them for up to 2 years. Niraparib has been continued for up to 3 years. I think, at that point, if patients are without evidence of disease, it is reasonable to discontinue that course of treatment, but some patients get it very nervous about discontinuing it.
It is important to talk to our patients about the fact that we do not really have any long-term safety data beyond the 3-year mark. If we decide to continue as a physician and patient together, then the patient needs to accept that there may be risks that we are unaware of, such as myelodysplastic syndrome, and they need to be monitored over time. I think, as more of these studies come out and time goes on, we will have a better idea of how long to keep patients on treatment. One of the other questions that has come up relates to the fact that the trials that were first released were in the recurrent setting; we were putting everyone with platinum-sensitive disease on PARP inhibitors.
Now, we have all these data from the SOLO-1 and the PRIMA trials, both of which concluded that it was very effective in the upfront setting. So if a patient has had a PARP inhibitor in the upfront setting, and it was successful, and they still have platinum-sensitive disease, do you rechallenge? Do you rechallenge after that patient has had a response to a platinum-based regimen in the recurrent setting? The answer, of course, is that we do not know. There are trials ongoing that are looking at that right now. I think it has to be taken on a case-by-case basis.
This transcript was edited for clarity.
Case: A 63-Year-Old Woman With Recurrent Ovarian Cancer
Initial Presentation
- A 63-year-old female presented with early satiety and abdominal discomfort
- PMH: unremarkable, postmenopausal; no known family history of cancer
- PE: left lower quadrant tenderness on palpation
- ECOG PS 1
Clinical work-up
- Pelvic exam with transvaginal ultrasound showed a left ovarian mass
- Transvaginal U/S showed a left ovarian mass
- Chest/abdomen/pelvis CT with contrast confirmed a left adnexal 4.4-cm mass with paraaortic lymph node involvement and ascites
- Paracentesis (1000 cc) cytology confirmed high-grade epithelial ovarian cancer
- Germline molecular testing: HRD+, BRCA1/2-
- CA-125, 370 U/mL
- Diagnosis: Stage III, high-grade epithelial ovarian cancer
Treatment
- Patient underwent TAH/BSO, lymph node dissection, with optimal debulking; R0
- Paclitaxel/carboplatin q3 weeks for 6 cycles; CA-125 decreased; PR
- At 7-month post treatment follow-up imaging showed progression of disease
- Paclitaxel/carboplatin + bevacizumab was initiated q3 weeks for 6 cycles
- At 14-months CA-125 had increased
- Cisplatin/gemcitabine was initiated, PR
- Initiated niraparib maintenance
