Niraparib - A promising drug with hematological toxicity

Ovarian cancer is the second most common and the most lethal gynecological malignancy in the western world. Unfortunately, there are lack of methods for early screening and diagnosis of the disease. Because of this, most of the cases are diagnosed at an advanced stage and have poor prognosis. The standard treatment of ovarian cancer is maximal cytoreductive surgical debulking followed by platinum-based chemotherapy. There are new molecular agents available for maintenance therapy of ovarian cancer including anti-angiogenic therapies, poly adenosine diphosphate ribose polymerase inhibitors, inhibitors of growth factor signaling, or folate receptor inhibitors, as well as several immunotherapeutic approaches. Niraparib is a poly adenosine diphosphate ribose polymerase inhibitor that has shown to be clinically effective as maintenance therapy in patients with platinum sensitive, recurrent ovarian cancer. Studies have shown the median duration of progression-free survival was significantly longer among those receiving niraparib than among those receiving placebo, regardless of presence or absence of BRCA gene mutations or homologous recombination deficiency status. Studies have shown that treatment-emergent Grade 3 or Grade 4 hematological events were observed in patients receiving niraparib including thrombocytopenia (33.8%), anemia (25.3%) and neutropenia (19.6%). Most of the hematological laboratory abnormalities occurred within the first three treatment cycles. After dose adjustment, the incidence of hematological abnormalities was infrequent beyond cycle 3. We are reporting two cases of Grade III/IV neutropenia and thrombocytopenia in patients treated with niraparib in our institution. Unfortunately, one of the patients succumbed to septic shock secondary to right lower lobe pneumonia while severely neutropenic. The second patient's blood counts improved after discontinuing the medication and with supportive transfusions during the hospitalization.