Xeris Pharmaceuticals has selected medmix’s Drug Delivery business, formerly known as Haselmeier, to provide the injection device for XP-8121, an investigational once-weekly subcutaneous formulation of levothyroxine for hypothyroidism. The companies are developing XP-8121 as a drug-device combination that pairs Xeris’ proprietary high-concentration XeriSol levothyroxine formulation with medmix’s D-Flex disposable pen injector. The adjustable device is designed to provide precise fixed-dose administration tailored to the requirements of the therapy.

According to medmix, D-Flex exceeded the dose-accuracy requirements specified in ISO 11608-1 during recent design verification testing. The standard covers dose accuracy for needle-based injection systems. The companies say the results are relevant to development programs involving NTI medicines, where the delivery system needs to provide reliable dosing as part of the overall drug-device combination.

D-Flex also incorporates a patented dosing mechanism intended to restrict users to the specified dose settings. Intermediate settings cannot be selected, a design feature intended to reduce the possibility of inadvertent dosing. The platform can accommodate multiple fixed-dose configurations while maintaining a common device architecture. It is designed to deliver dose increments as small as 0.005 mL and can be adapted for volumes of up to 0.75 mL, depending on the application.

For Xeris, the collaboration brings together its high-concentration levothyroxine formulation technology with a pen system designed around fixed-dose delivery. The approach reflects a broader trend in drug development toward delivery platforms engineered around the specific dosing and administration requirements of individual therapies.

Pete Valentinsson, Senior Vice President of Global Technical Operations at Xeris, says that D-Flex was selected following an evaluation of available device options and demonstrated the dose accuracy required for XP-8121. The selection also gives the XP-8121 program access to a device platform that is already in commercial and clinical use.

Dr. Oliver Haferbeck, Head of the Drug Delivery Business Unit at medmix, says precise delivery is particularly important for therapies involving NTI drugs and that the company is supporting Xeris’ development program with the D-Flex platform.

D-Flex has been marketed since 2023 and has an established manufacturing and supply infrastructure. According to medmix, the technology is already used in an approved European product variant and in an ongoing US clinical program.

For more information, visit www.medmix.com.