Apalutamide toxicity and tolerability: A real-world multicentre experience in metastatic hormone-sensitive prostate cancer (MHSPC) in the United Kingdom (UK).

Abstract

107 Background: Apalutamide became available for mHSPC along with androgen deprivation treatment (ADT) in the UK in November 2021. We present here, to our best knowledge the first real world multicentre experience of Apalutamide use in mHSPC patients from three tertiary cancer centres from the UK. Our primary aim was to assess for toxicity and tolerability at this stage. Methods: We collected retrospective data from hospital prescription registries including all patients with mHSPC receiving Apalutamide between November 2021 and January 2023. Median period of follow up in our cohort was 14 months. Results: Two hundreds and ten patients received Apalutamide for mHSPC from three centres. The median age was 73 years. A total of 16.4% of the patients had recurrent mHSPC previously treated for localised PC and 83% were de novo metastatic. Of all patients, 43.3% had high-volume disease, and 56.7% had low-volume disease. The median presenting Prostate Specific Antigen (PSA) was 62 ng/l at diagnosis (range 0.87 to 5580). Undetectable PSA achieved in 43.3% of patient after starting Apalutamide and ADT. For those who have detectable PSA, median value was 0.22. Ninety percent of patients maintained their performance status (PS) at 0 or 1 on treatment. Most common side effects were fatigue (35.7%) and rash (11.4%). Cardiac adverse effects were recorded in 1.9% and thromboembolic events in 0.4%. Overall grade 3 and 4 toxicity was 5.2% across all symptoms assessed. To date, 83.3% patients continue on Apalutamide, 7.6 % discontinued due to toxicity and 9.1% had progressive disease (PD). Three deaths were recorded and all due to PD. Conclusions: In this multicentre retrospective analysis we found that Apalutamide and ADT is well tolerated in the real-world setting. Our patients are older and had lower volume metastasis compared with patients from the registry Trial (TITAN). Fatigue is more prevalent. Majority patients continue on Apalutamide with manageable side effects and good PS.