Second-line Maintenance Therapy in Ovarian Cancer: PARP Inhibitors - Episode 4

Patient Eligibility for the Use of PARP Inhibitors in Ovarian Cancer

Bhavesh Shah, RPh, BCOP; and Thomasina Morris, RPh, MHA, BCOP, detail what makes a patient eligible to receive PARP inhibitors as second-line maintenance for the management of ovarian cancer.

Bhavesh Shah, RPh, BCOP: Are PARP inhibitors only active in patients who are platinum-sensitive? Or can you use them in patients who are also platinum-refractory?

Thomasina Morris, RPh, MHA, BCOP: Most of the data out there have been for platinum-sensitive. With the platinum sensitivity, it also shows that they have a better progression-free survival with a PARP inhibitor if they are BRCA mutated. Platinum resistance or refractory is a lot harder; in essence, they’re going to recur much quicker. You want to get them to a point where you can say they’re stable. You don’t want to switch them to something if it’s working; if you feel like you put them on another treatment and you haven’t exhausted what you’re already giving them, where are you truly giving them the benefit? The studies aren’t looking at platinum-refractory currently. They probably have small cohorts in the study, or supplemental material that says we looked at it, but the numbers are small. I think when we look at platinum-refractory, we don’t really think about PARP inhibitors as an option right now.

However, there’s an ARIEL4 study with rucaparib that also talks about giving platinum in platinum-sensitive patients, and paclitaxel in platinum-resistant patients, and doing a comparative in there. It’s coming, but it’s just not as fast as what we have seen with the platinum sensitivity. It’s interesting because when you talk about biomarkers, when patients with breast cancer are treated, they go through a number of biomarkers now, more so than they ever did in the past; everybody else is catching up. They’re trying to do as much as breast does, but breast has been doing it for a long time. With ovarian cancer, the GYN [gynecologist] oncologist is excited, saying, “We get to do more than just a CA 125 [cancer antigen 125].” They’re just thrilled that they can now look and talk to these patients and say, “I can give you more options at the time of diagnosis.” I think that’s what’s so important.

Bhavesh Shah, RPh, BCOP: I totally agree. There is subset analysis with a small number of patients, not recommending this, but in the Rubraca [rucaparib] trial, there was a small subset of platinum-refractory patients who were included. It’s hard to extrapolate the benefit in the general platinum-refractory patient population; based on the mechanism, it may not be as active as patients who are platinum-sensitive.

This transcript has been edited for clarity.