A recent study found that treatment with PARP inhibitors significantly increases the risk of hematologic toxicities and warrants frequent clinical monitoring by clinicians.
Various hematologic toxicities—including neutropenia, thrombocytopenia, and anemia—have proven to be major adverse effects of PARP inhibitors (olaparib, veliparib, and niraparib). However, the incidence rate and overall risk of treatment with PARP inhibitors have not been systematically studied.
A trio of Chinese researchers examined the incidence and relative risks of high-grade hematologic events in patients with cancer treated with PARP inhibitors. The meta-analysis included phase II and III randomized controlled studies from PubMed, Embase, and oncology conference proceedings. A total 2479 patients with cancer treated with PARP inhibitors and with adequate safety data on hematologic toxicities from 12 clinical trials were included.
Results of the study were published in Drug Design, Development and Therapy (October 2017;2017:3009-3017).
Researchers found that the incidence of neutropenia was 32.9%, 15.9% for thrombocytopenia, and 9.1% for anemia. Additionally, they observed a correlation between treatment with olaparib and increased risk of high-grade neutropenia, veliparib and an increased risk of high-grade neutropenia and thrombocytopenia, and niraparib and an increased risk of high-grade thrombocytopenia, anemia, and neutropenia.
After stratifying by combination therapy, researchers further found a significantly increased risk of hematologic toxicities for patients receiving PARP monotherapy and PARP inhibitors combined with a single-agent chemotherapy.
“Although the experience of severe hematologic toxicities is one of the main toxicity challenges of PARP inhibitor treatment, there are currently no methods to predict patients at higher risk, therefore regular monitoring of complete blood counts is recommended,” authors of the study wrote.
Clinicians need to be aware of the hematologic risks associated with PARP inhibitors and monitor patients in order to improve treatment outcomes and the quality of life, authors concluded.—Zachary Bessette