Niraparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, has been approved in the United States for the treatment of recurrent ovarian cancer, maintenance treatment of platinum-sensitive recurrent ovarian cancer, and maintenance treatment in newly diagnosed ovarian cancer. Niraparib is administered at an individualized starting dose of 200 mg or 300 mg daily, depending on body weight and platelet count. Researchers assessed the incidence of hematologic adverse events in real-world patients with ovarian cancer treated with niraparib.
In this retrospective study, the medical records of patients with ovarian cancer treated with an individualized starting dose of niraparib between February 2019 and January 2020 were reviewed. Data regarding treatment-emergent hematologic adverse events, including leukopenia, anemia, and thrombocytopenia, were collected and analyzed.
A total of 43 patients with ovarian cancer were included in the study. Patients had a median body weight of 50.5 kg, with a range of 33 kg to 75 kg. All patients received the individualized starting dose of niraparib of 200 mg once daily. Of the included patients, 27 (62.8%) were of BRCA wild-type, 14 (32.6%) had BRCA mutations, and the BRCA status of 2 (4.6%) patients was unknown. In 25 (58.1%) patients, niraparib was administered as maintenance treatment in newly diagnosed ovarian cancer, and as treatment for recurrent ovarian cancer in 14 (32.6%) patients. In 4 (9.3%) patients, niraparib was given as maintenance treatment for platinum-sensitive recurrent disease.
Overall, 28 (65.1%) patients experienced a hematologic adverse event of grade ≥1. These events included leukopenia (37.2%), anemia (34.9%), and thrombocytopenia (39.5%). Grade 3 or 4 adverse events occurred in 10 (23.3%) patients, including leukopenia (9.3%), anemia (7.0%), and thrombocytopenia (11.6%). At the time of the most recent follow-up, the median time until occurrence of leukopenia was 30 days, anemia 34 days, and thrombocytopenia 20 days. Most of the hematologic adverse events occurred within 3 months. No deaths were reported.
Of patients who experienced adverse events during treatment, the dose was reduced in 4 (14.3%) patients and treatment was interrupted in 9 (32.1%) patients. Treatments for adverse events included recombinant human granulocyte colony-stimulating factor in 17.9%, erythrocytes in 7.1%, and recombinant human thrombopoietin in 17.9%. Following intervention, 8 (18.6%) patients restarted treatment, and only 1 (2.3%) patient discontinued treatment.
Researchers found that the incidence of hematologic adverse events in this real-world experience was lower than that reported with treatment with niraparib 300 mg daily in the ENGOT-OV16/NOVA trial. They note that in addition to maintenance therapy in first-line treatment, patients receiving niraparib in the treatment of platinum-sensitive recurrence and for later-line treatment may benefit from an individualized starting dose.
Abstract 418. ESGO 2020.