Clinical indications treated with unregistered antimicrobials: Regulatory challenges of antimicrobial resistance and access to effective treatment for patients

Increasing antimicrobial resistance and a concurrent paucity of new antimicrobials marketed increases the risk that patients will develop infections resistant to currently available drugs. This study aimed to determine the range of clinical indications for which unregistered antimicrobials are prescribed at two tertiary hospitals in South Australia to identify any trends over a 2-year period. The effects of recent regulatory changes to the Special Access Scheme (SAS) were assessed. Methods: Data were extracted from application forms submitted to the Therapeutic Goods Administration to access unregistered antimicrobials via the SAS pathway at two Australian tertiary hospitals for the period July 2015-June 2017. Average weighted antimicrobial prices were retrieved from the hospital iPharmacy (DXC Technology, Macquarie Park, NSW, Australia) dispensing system. To estimate the effect of a new access pathway (Category C), the SAS classification for each application was retrospectively assessed over time with each regulatory change. Results: Between July 2015 and June 2017, 477 SAS applications for 29 different antimicrobials were submitted for 353 patients at the two hospitals. The most common indications were tuberculosis (43.6%) and refractory Helicobacter pylori (10%). Regulatory changes reduced the proportion of applications requiring preapproval for access. Conclusions: Although the introduction of a new pathway has decreased the administrative burden when accessing unregistered antimicrobials, this study highlights the range of clinical conditions for which there are no registered drugs available in Australia. What is known about the topic?: With increasing antimicrobial resistance and a paucity of novel antimicrobials entering the market, access to older, previously less-used antimicrobials is increasingly important in clinical practice. Accessing unregistered antimicrobials is common practice in Australian hospitals, but the range of clinical indications for which they are used is unclear. What does this paper add?: Increasing antimicrobial resistance and a concurrent paucity of new antimicrobials being marketed globally is increasing the risk that patients may develop infections that cannot be treated with registered products. This study describes the range of clinical conditions for which registered antimicrobials are not available or appropriate, illustrating the challenges associated with sustainable access to effective treatments. What are the implications for practitioners?: Access to effective antimicrobials in a timely manner is essential for optimal patient outcomes. Reliance on unregistered products is associated with increased risks regarding timely access to safe, quality-assured, effective medicines.