Translation of a-t 2025; 56: 15

Fourth dose of tirzepatide (MOUNJARO KwikPen) cannot be released – quality defect or application error?

Between May and September 2024, the Drug Commission of German Pharmacists (Arzneimittelkommission der Deutschen Apotheker [AMK]) received 149 reports of suspected quality-related defects regarding the twincretin tirzepatide pre-filled pen (MOUNJARO KwikPen), which was only launched on the market in May 2024. It is claimed that the fourth (i.e. last) and, in some cases, also the third weekly dose of the pen, which has been approved for use in type 2 diabetes and obesity, could not be released.¹ According to the AMK, the supplier, Lilly, attributes the complaints to patient-side application errors: misinterpretation of the technically required overfilling of the pen as a subsequent dose, which can still be administered, excessive venting prior to use causing the pen to lock prematurely and prevent the delivery of a subsequent dose, and failure to accurately remember the number of weekly applications already delivered – hence users may assume that they have only injected three doses instead of four in reality.¹ The Central Laboratory of German Pharmacists (Zentrallaboratorium Deutscher Apotheker [ZL]) was unable to reproduce incorrect release of the fourth dose. However, it cannot be concluded from this, that – as the Drug Commission of the German Medical Association (Arzneimittelkommission der deutschen Ärzteschaft [AkdÄ]) points out² – a manufacturer-related problem can be ruled out. Given the conspicuous accumulation of complaints, the AMK also sees manufacturer-related factors that may cause/contribute to medication errors and has suggested improvements. These include, for example, highlighting the drug calendar contained in the package leaflet and using an unambiguous numerical scale on the body of the pen. The latter should then make it easier to see how many doses have already been administered. In our opinion, Lilly is obliged to optimise the way in which the pen works and should provide clearer and more concise instructions for use. In response to our enquiry, the company informed us that it is working on updating the existing patient information in relation to residual quantities of medicinal product and new frequently asked questions.³ However, there is no mention of improvements to the pen per se, –Ed.

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