Makino Koji, Tilden Dominic, Guarnieri Carmel, Mudge Mia, Baguley Ian J
THEMA Consulting, Sydney, NSW, Australia.
Brain Injury Rehabilitation Service, Westmead Hospital, Sydney, NSW, Australia.
Pharmacoecon Open. 2019 Mar;3(1):93-102. doi: 10.1007/s41669-018-0086-z.
In Australia, the reimbursement of botulinum neurotoxin-A (BoNT-A) on the Pharmaceutical Benefits Scheme for the treatment of moderate to severe spasticity of the upper limb following a stroke (PSS-UL) is restricted to four treatment cycles per upper limb per lifetime. This analysis examined the cost effectiveness of extending the treatment beyond four treatments among patients with an adequate response to previous treatment cycles.
A Markov state transition model was developed to perform a cost-utility analysis of extending the use of incobotulinumtoxin-A beyond the current restriction of four treatment cycles among patients who have shown a successful response in previous treatment cycles ('known responders'). The Markov model followed patients in 12-weekly cycles for 5 years, estimating the proportion of patients with or without response over this period in each of the modelled treatment arms. Post hoc analysis of an open-label extension phase study informed the Markov model. The perspective of the analysis was the Australian healthcare system, meaning only direct healthcare costs were included. Utility values by response status were derived from EQ-5D data from a published double-blind, placebo-controlled study. The primary outcome measure was the incremental cost per quality-adjusted life-year (QALY). Univariate and probabilistic sensitivity analyses were conducted.
The open-label extension study data demonstrated the probability of treatment response after four injections was greater among 'known responders' than those without prior response. The incremental cost per QALY gained of continued use of incobotulinumtoxin-A beyond the current restriction of four treatments was A$59,911.
Limiting BoNT-A treatment to four cycles per patient per lifetime is likely to be suboptimal in many patients with PSS-UL. Treatment response beyond four cycles is highest among known responders, and allowing such patients to continue treatment beyond four cycles appears cost effective.
在澳大利亚，肉毒杆菌神经毒素A（BoNT-A）在药品福利计划中用于治疗中风后上肢中度至重度痉挛（PSS-UL）的报销限制为每只上肢终身四个治疗周期。本分析探讨了在先前治疗周期有充分反应的患者中，将治疗周期延长至四个以上的成本效益。
开发了一个马尔可夫状态转移模型，以对在先前治疗周期有成功反应的患者（“已知有反应者”）中，将incobotulinumtoxin-A的使用从当前的四个治疗周期限制延长进行成本效用分析。马尔可夫模型以12周为周期跟踪患者5年，估计每个模拟治疗组在此期间有反应或无反应的患者比例。一项开放标签扩展阶段研究的事后分析为马尔可夫模型提供了信息。分析的视角是澳大利亚医疗保健系统，这意味着只包括直接医疗成本。根据一项已发表的双盲、安慰剂对照研究的EQ-5D数据得出按反应状态划分的效用值。主要结局指标是每质量调整生命年（QALY）的增量成本。进行了单变量和概率敏感性分析。
开放标签扩展研究数据表明，在“已知有反应者”中，四次注射后治疗有反应的概率高于无先前反应者。在当前四个治疗周期限制之外继续使用incobotulinumtoxin-A所获得的每QALY增量成本为59,911澳元。
对于许多PSS-UL患者，将BoNT-A治疗限制为每人终身四个周期可能不是最佳选择。在已知有反应者中，四个周期以上的治疗反应最高，允许这些患者在四个周期后继续治疗似乎具有成本效益。
