2SPD-013 Economic impact of the use of flat dose vs personalised dose of pembrolizumab

Background Pembrolizumab is a highly selective anti-PD-1, approved for the treatment of metastatic melanoma, lung cancer and other advanced malignancies. The dosage was changed from a personalised dose to a flat dose. We suspected that using a newly approved dose of 200 mg for all patients may be an unnecessarily high dose, given the average weight of our patients, 70 kg. Purpose The objective of this study is to demonstrate the economic impact of the use of a flat dose (200 mg) vs personalised dosing (2 mg/kg) vs dose banding. Material and methods We collected data from all pembrolizumab’s prescriptions, between March and August 2018, from our software. The data were processed: by date, weight, diagnosis and number of therapies prepared. Then we calculated the actual number of milligrams used and the related economic impact value of the 3 strategy. Results From March to August 2018, 81 patients were treated, 56 men and 25 women. The most frequent diagnosis was melanoma (43) and lung cancer (38). The mean weight of the patients was 71.8 kg. In this 6 months’ period we prepared a total of 372 preparations in a personalised dose (2 mg/kg), 53424 mg were prescribed, for a value of €1.118.9218,24. Simulating the same preparation with a flat dose, would have prescribed 74400 mg, with a value of €1,656,144.00, an increase of 39% (€466,925.76). Simulating the same situation with dose banding (we use NHS table banding as an example), 51 775 mg would be prescribed, with a value of €1,152,511.00, a small decrease of 3%. Conclusion Our analysis shows how the introduction of the flat dose can undermine the sustainability of these high-cost therapies. The Food and Drug Administration determined, on the basis of pharmacokinetic models, that the 200 mg dose is comparable to that of 3 mg; but the same studies show that there are no clinically significant effects on safety and efficacy between the two doses. From our perspective it is important to consider strategies to minimise wastage without compromising the efficacy, such as dose banding, or organisation of the Pembrolizumab’s Day, which could help to alleviate pressure on drug budgets. Reference and/or acknowledgements Ogungbenro K. Dose rationalisation of pembrolizumab and nivolumab using pharmacokinetic modelling and simulation and cost analysis . doi:10.1002/cpt.875 No conflict of interest.