Strengthening the public downstream SLD supply chain for MDR-TB : lessons learnt from a Western Cape case study

[摘要] ENGLISH ABSTRACT: Systemic problems in the supply chain of second-line anti-TB drugs (SLDs) for multidrug-resistant tuberculosis (MDR-TB) are well documented and contributesignificantly to the difficulties preventing successful control of the disease.Though literature contains a wealth of proposed changes to global SLD supply chain policies, there is a significant research gap related to quantitative modelling of the SLD supply chain to accurately predict the expected impactof these proposed changes on the availability and delivery of SLDs. The global SLD supply chain consists of two components: (i) the 'upstream component which includes all activities from the manufacturing of the active pharmaceutical ingredient through to the warehousing of drugs prior to shipment; and (ii) the 'downstream component which includes in-country warehousing anddelivery of drugs to various healthcare facilities. In this research study, a downstream SLD supply chain is modelled using real-world data. The model is built for one SLD used in the MDR-TB treatment regimen, namely amikacin. Thisresearch forms part of a bigger study that will eventually incorporate both the upstream and the downstream components of the supply chain into a singlemodel. A model of the current downstream segment of the supply chain for SLDs in the Western Cape was developed using a System Dynamics modelling approach. The model has been built and validated using real-world data providedby the Western Cape Department of Health (WCDoH). This model has been used as a platform for: (i) studying the behaviour and stability of the downstream component of the global SLD supply chain; and (ii) testing the impact of various supply chain policy changes that have been proposed. In addition to the modelling results, an analysis of the WCDoH data has also produced a number of insights into the function of the downstream supply chain, examples of these include:• 13% of SLDs ordered by the Cape Medical Depot (CMD) are only received more than three months after the order date by suppliers; and• 267% more units of amikacin than what is required on average are available at the CMD every month, leading to ineffective inventory management.The modelling results show that the factor that will most likely lead to the biggest improvement in the performance of the SLD supply chain is reduced lead time. Therefore, selecting suppliers that provide shorter lead times shouldbe a priority. Furthermore, the results show that significant opportunities could be unleashed by adjusting the policy for determining the desired minimum and maximum levels of stock at the CMD. This research makes a contributionby: (i) increasing the understanding of the strengths and weaknesses of the SLD supply chain; (ii) quantitatively evaluating the expected impact of suggested changes to the global SLD supply chain; and (iii) proposing a methodology that can be used to model and evaluate other downstream medication supply chains.

[发布机构] Stellenbosch University