Slee Ann-Louise, Coutsouvelis John, Tong Bianca, Poole Susan, Zalcberg John
Pharmacy Department, Alfred Health, Melbourne, Victoria, Australia.
Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
J Oncol Pharm Pract. 2025 Jul;31(5):687-692. doi: 10.1177/10781552241255287. Epub 2024 May 23.
BackgroundPembrolizumab, an immune checkpoint inhibitor, indicated to treat multiple cancers, was initially approved in Australia as weight-based dosing at 2 mg/kg every 3 weeks (Q3W). Subsequent approvals used 'fixed' dosages of 200 mg Q3W or 400 mg every 6 weeks (Q6W). Pharmacokinetic equivalence was demonstrated between dosing strategies, with no significant differences in efficacy or toxicity. Fixed dosing regimens are routinely used in Australia.AimTo model and compare the cost of weight-based dosing of pembrolizumab to standard fixed dosing regimens.MethodA single centre, retrospective review was conducted. Patients, identified from dispensing software, who commenced on pembrolizumab between January and December 2022 were included. Patient demographic and treatment data was extracted from electronic medical records. Costs of weight-based doses were calculated and compared to the cost of fixed dosing. Variables such as acquisition cost, funding mechanisms and 'vial sharing' were considered.ResultsFifty-two patients were included (63% male, median age 68 years). Of the 211 doses of pembrolizumab administered (average 4.1 doses/patient), 161 were Q3W doses, and 50 were Q6W doses. The acquisition cost for a fixed 200 mg and 400 mg dose was $7646, and $15,292, respectively. The average patient weight was 77.6 kg (SD 19 kg), which equated to $5933 for a weight-based Q3W dose, and $11,867 for the Q6W dose; a potential cost avoidance of $1965 and $3930 per dose, respectively. This represented a possible 23.5% avoidance in medication acquisition cost. Over the study period of 1 year, using weight-based dosing for pembrolizumab had the potential to reduce medication expenditure by $467,996.DiscussionSignificant cost avoidance could be achieved via weight-based pembrolizumab dosing. Given the substantial total cost of pembrolizumab, the growing number of indications and the expected equivalent treatment outcomes with weight-based pembrolizumab, the potential cost reductions of weight-based pembrolizumab at both institution and government level should be further explored.
背景
帕博利珠单抗是一种免疫检查点抑制剂，被批准用于治疗多种癌症，最初在澳大利亚获批的给药方式是基于体重，每3周（Q3W）给药2mg/kg。随后的批准采用了“固定”剂量，即每3周200mg或每6周（Q6W）400mg。已证明不同给药策略之间具有药代动力学等效性，疗效和毒性无显著差异。在澳大利亚，常规使用固定给药方案。
目的
对帕博利珠单抗基于体重给药与标准固定给药方案的成本进行建模和比较。
方法
进行了一项单中心回顾性研究。纳入从配药软件中识别出的2022年1月至12月开始使用帕博利珠单抗的患者。从电子病历中提取患者的人口统计学和治疗数据。计算基于体重给药的成本，并与固定给药成本进行比较。考虑了采购成本、资助机制和“药瓶共享”等变量。
结果
共纳入52例患者（63%为男性，中位年龄68岁）。在使用的211剂帕博利珠单抗中（平均每位患者4.1剂），161剂为每3周给药一次，50剂为每6周给药一次。固定200mg和400mg剂量的采购成本分别为7646美元和15292美元。患者平均体重为77.6kg（标准差19kg），这相当于基于体重每3周给药一次的剂量为5933美元，每6周给药一次的剂量为11867美元；每剂分别可节省成本1965美元和3930美元。这意味着药物采购成本可能节省23.5%。在1年的研究期间，使用基于体重的帕博利珠单抗给药方式有可能减少药物支出467996美元。
讨论
通过基于体重的帕博利珠单抗给药可实现显著的成本节省。鉴于帕博利珠单抗的总成本巨大、适应证不断增加以及基于体重给药预期具有等效的治疗效果，应进一步探索基于体重的帕博利珠单抗在机构和政府层面潜在的成本降低情况。
