Invited discussant Ernst Lengyel, MD, PhD, of University of Chicago Medicine, found the results of ATHENA-MONO promising. “I think it is encouraging that in the BRCA-mutation subgroup of patients, we see such a clear increase in progression-free survival compared to the intention-to-treat population. In addition, patients with wild-type BRCA but loss of heterozygosity also benefited from rucaparib maintenance,” Dr. Lengyel said.

However, he expressed some caution, questioning the high discontinuation rate among the patients assigned to rucaparib. “Only about 55% of all patients were able to stay on the initial 600-mg dose after 6 months, some of them [discontinuing rucaparib] because of side effects. This is important because normally after surgery and chemotherapy, patients are in remission. Given the recurrence rate in this population is around 70%, patients need to maintain a high quality of life during this period of respite and not be experiencing adverse events,” he pointed out.

Ernst Lengyel, MD, PhD

As Dr. Monk showed in his slides, the rate of discontinuation of therapy due to adverse events in the rucaparib arm was 12.6%, and it was 5.4% in the placebo arm.

“I think we have to be careful with patients who are homologous recombination–proficient, to give them a PARP [poly (ADP-ribose) polymerase] inhibitor in the maintenance situation. These patients, especially if they had a complete radiologic and CA-125 response, will have a good chance to do well. Adding a PARP inhibitor for these patients who don’t have any residual disease after front-line treatment will lead to the significant side effects we see with PARP inhibitors,” Dr. Lengyel stated. 

DISCLOSURE: Dr. Lengyel has received institutional funding from AbbVie and grants from the National Cancer Institute and the Ovarian Cancer Research Alliance.