Longer Time to Post–PARP Inhibitor Therapy Associated with Better Tolerance to Subsequent Therapy

In women with ovarian cancer, a longer period of time between discontinuation of PARP inhibitor therapy and initiation of post–PARP inhibitor therapy was associated with better tolerance of the subsequent therapy, according to data presented in a poster by Brandon Michael Roane, MD, at the Society of Gynecologic Oncology (SGO) Annual Meeting on Women’s Cancer. In addition, waiting longer to initiate subsequent therapy did not have a negative impact on progression-free survival (PFS) on post–PARP inhibitor therapy, nor did it impact the number of subsequent lines of therapy patients could tolerate.

Dr Roane and colleagues from the University of Alabama at Birmingham queried the specialty pharmacy database at their institution for patients with ovarian cancer who received PARP inhibitor therapy followed by post–PARP inhibitor therapy from January 2016 to August 2019.

Patients were classified as having poor tolerance to post–PARP inhibitor therapy if they had a treatment-related hospitalization or a delay in treatment due to cytopenia. The investigators calculated the number of days between patients’ last dose of a PARP inhibitor and their first dose of subsequent therapy, and PFS was defined as the number of days from the first day of post–PARP inhibitor therapy until progression.

A total of 39 patients met inclusion criteria: 16 (41%), 13 (33%), and 10 (26%) patients were treated with rucaparib, niraparib, and olaparib, respectively. Post–PARP inhibitor therapy included platinum doublets in 46% of patients, single-agent therapies in 44%, or treatment on a clinical trial in 10% of patients. Patients received a median of 3 lines of therapy prior to initiation of a PARP inhibitor (range, 1-10), which did not differ among the study groups.

Twenty-two (56%) patients in the trial tolerated post–PARP inhibitor therapy, whereas 17 (44%) patients were classified as having poor tolerance.

The median number of days between discontinuation of a PARP inhibitor and initiation of post–PARP inhibitor therapy was 16 for those with poor tolerance, ranging from 6 to 28, versus 47 for those with tolerance, ranging from 13 to 142 (P <.01). The most common adverse event was bone marrow suppression, observed in 41% of patients.

The investigators observed no significant difference in median PFS on post–PARP inhibitor therapy between patients with poor tolerance compared with patients with tolerance (4.0 vs 41 months). After PARP inhibitor therapy, patients received a median of 2 lines of therapy (range, 1-7), which did not differ among groups.

Importantly, for each additional day counted prior to starting post–PARP inhibitor therapy, the researchers observed a 14% increase in the odds of a patient tolerating the subsequent therapy.

Based on these findings, Dr Roane and co-investigators concluded that longer time between discontinuation of PARP inhibitor and post–PARP inhibitor therapy did not negatively impact tolerance of post–PARP inhibitor therapy, and had no negative impact on clinical outcomes.


  • SGO 2020 Annual Meeting on Women’s Cancer. Abstract 239.

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