63P A real-world comparison of the tolerability and toxicity of niraparib in older and younger women with high-grade serous ovarian carcinoma

Patients with newly diagnosed or recurrent platinum-sensitive advanced ovarian cancer benefit from maintenance Niraparib as per the PRIMA and NOVA trials. These trials recruited younger patients (median age 57 and 63 respectively) as compared to real-world clinical practice. A single centre retrospective analysis was carried out on all high grade serous ovarian cancer patients commenced on Niraparib in the first or subsequent line setting between January 2020 and June 2022 in the Edinburgh Cancer Centre. 111 patients were included in this study; 61 patients ≥70 years and 50 patients <70 years. The median number of cycles in both groups was 7 and median follow up time was 28.9 and 26.9 months in the older and younger groups respectively. A significantly greater proportion of older than younger patients started on the lowest dose of Niraparib (100mg) (13.1% vs 2.0%, P=0.0361). The 3 most common toxicities experienced in the older and younger groups were nausea/vomiting, haematological toxicity and fatigue (59.0% vs 60.0%, 52.5% vs 54.0%, 59.0% vs 50.0%). All incidences of nausea/vomiting and fatigue were Grade 1-2 in severity. Grade 3-4 haematological toxicity was seen in 19.6% and 30.0% of the older and younger groups respectively (P=0.184). Dose interruptions and reductions were seen similarly in the older and younger groups (85.2% vs 82.0%, 60.7% vs 62.0%). Haematological toxicity was the main reason for both. More older than younger patients stopped Niraparib due to toxicity (20.4% vs 7.5%, P=0.0948). No significant difference in median PFS was seen across the older and younger groups (7.0 vs 6.0 months, P=0.33). This median PFS is shorter than reported in clinical trials. There was no significant difference in incidence of toxicities, dose interruptions or reductions across the older and younger groups. This may be confounded by a significantly larger proportion of older patients initiated on the lowest dose of Niraparib to improve tolerability. There was also a trend to more older than younger patients stopping treatment due to toxicity. This may reflect a distinction in management due to patient fitness and wishes as well as treatment intent.