As subcutaneous biologics increase in volume and complexity, the demand for wearable injectors enabling safe, effective at-home delivery continues to grow. Yet unlike the autoinjector and pen segments, which have largely converged on common standards, wearable injectors remain highly diverse in design. This article explores how YpsoDose, a pre-filled and ready-to-use large-volume wearable injector developed by Ypsomed, reflects a deliberate design philosophy that differentiates it within the fragmented design landscape of wearable injectors. It also provides an overview of the differing approaches shaping the large-volume wearable category. In doing so, it highlights how YpsoDose prioritizes consistent delivery, low residual volume, and ease of use.
IV league dropouts
Over the past decade, the biopharmaceutical industry has shifted toward higher-volume subcutaneous (SC) drug delivery. Driven by the rise of monoclonal antibodies, bispecifics, antibody-drug conjugates, and other complex biologics, SC injection is increasingly seen as a preferred alternative to intravenous (IV) infusion in many indications. Compared to IV, SC administration offers faster dosing, greater flexibility in treatment location, and improved patient experience. One widely cited example is daratumumab, which transitioned from a 3-to-7-hour IV infusion to a SC version deliverable in under five minutes, now accounting for around 93 % of usage in the US.
This trend is made possible by advances in drug formulation, permeation enhancers, and injection devices. As more therapies move into the home or outpatient setting, there is a growing need for delivery systems capable of handling volumes well beyond the 2 mL traditionally supported by autoinjectors. Ypsomed’s systematic review found that over 100 large-volume SC candidates aim for doses of 5 mL or above. With more biologics entering the pipeline and patient care moving closer to home, the need for devices that support safe, convenient SC administration continues to grow.
This evolution concerns more than just dosing increase, it is a shift in how and where care happens. For device developers, the challenge is to design large-volume injection systems that not only meet clinical and technical requirements but also fit seamlessly into the realities of selfcare, delivering efficiency, reliability, and usability.
Patch work: The fragmented design landscape of wearable injectors
Pen injectors and autoinjectors have, over time, coalesced around a set of widely accepted design norms. Since the 1980s cartridge-based pen injectors have evolved from prefilled reusable to prefilled multidose disposable, geared devices with easy-to-read displays, that are either manually or spring-driven. Single-use autoinjectors were first launched in 2006 and are today usually based on 2-step push-on-skin mechanisms that are activated once the needle is fully inserted into the skin. The volumes delivered by single use autoinjectors have increased to cover 1 mL, 2.25 mL and most recently 5.5 mL prefilled syringes.
Traditionally, larger-volume subcutaneous injections relied on reusable infusion pumps for delivering drugs in niche applications, such as apomorphine for treating Parkinson’s disease or gamma-globulins for immunomodulatory therapies. The emergence of new antibody therapies over the past 10–15 years has driven the need for larger-volume subcutaneous injections in the 5–20 mL range. In response, wearable injection devices have evolved alongside large-volume handheld autoinjectors to meet the requirements of these new treatment regimens.
It is the wearable nature of these systems, and the relatively recent emergence of the segment in comparison to pens and autoinjectors, that has led to considerable design divergence. While pens and autoinjectors tend to center on faster injection times, simplified hand-held actuation, and integrated sterile drug paths (cartridge and pen needle or staked needle syringe), wearable injectors show a remarkable diversity in design. Differences span device shape, fluid path, patch technology, drive mechanisms, filling methods, user-assembly requirements, and sterilization strategies.
Against this backdrop, selecting the right design is more critical than ever. With so many design directions being followed in parallel by different design manufacturers, the implications for usability, reliability, cost-effectiveness and scalability are significant, making it even more critical for pharmaceutical companies to carefully consider their options when deciding on potential delivery devices.
Faced with this open design space, Ypsomed pursued a focused, pragmatic approach. Rather than following completely novel but unproven architectures, Ypsomed made foundational decisions that reflect real-world use cases and pharmaceutical constraints. The first such decision was to create a consistent injection experience for every dose.
Force majeure: injection consistency and external variables
While mechanical injection systems may appear simple and cost-efficient, they can introduce inconsistency into the drug delivery process. Spring-driven mechanical devices often exhibit declining force profiles as the spring decompresses, leading to fluctuating flow rates during the injection. In hand-held autoinjectors we can already see time variances in injection time, though the variance is negligible given the injection event lasts a matter of a few seconds. These limitations naturally become more pronounced with large-volume or high-viscosity formulations, where an injection may last up to 30 minutes.
YpsoDose avoids these pitfalls through its motor-driven push-on-plunger system. Unlike spring-based systems, the motor delivers consistent force throughout the injection event, independent of the external conditions. This design enables a steady, controlled flow profile even under assumed worst-case conditions, and reliable delivery of 10 mL at viscosities up to 50 cP in 10 minutes. The result is a system that delivers not just the correct volume, but a consistent experience.
External factors like variations in temperatures, orientations, and injection sites can also adversely affect delivery. YpsoDose is motor-driven and sensor-supported, ensuring it performs reliably across a range of environmental and patient-specific variables. Skin-contact sensors verify correct placement before initiating the injection, reducing the risk of user error, and its motor drive allows for delivery across a wider range of temperatures. This stability translates into a smoother experience for patients and more dependable outcomes for healthcare providers. For treatments requiring long-term therapy adherence, this consistency supports trust and ongoing engagement. While this represents real value for patients, there is another key aspect which provides more direct value for pharma customers, and that is minimizing residual drug volume.
Residual volume: the silent drain on drug delivery
Two major factors contribute to drug loss in wearable injectors. Firstly, manual filling or transfer steps introducing variability and loss, and secondly, residual drug left in the device after injection due to fluid path design. These factors can lead to significant cumulative waste, particularly for high-cost biologics.
In contrast to, for example, suction-based delivery, YpsoDose was designed from the outset to minimize residual volume. YpsoDose integrates a pre-filled cartridge with a simplified, optimized fluid path consisting of two cannulas and short connecting tube. The result is a total residual volume for the system of <0.262 mL (<0.015 mL device fluid path, <0.245 mL cartridge), and zero waste from manual patient filling.
These numbers matter for pharma, and this efficiency is not a secondary feature; it is integral to the device’s value. By minimizing drug waste, YpsoDose reduces the overfill requirement and helps preserve valuable active pharmaceutical ingredients. Yet the implications extend beyond pharmacoeconomics. Reduced residual volume contributes to environmental sustainability by minimizing chemical waste and reducing the carbon footprint associated with manufacturing and disposal. For pharmaceutical companies facing cost pressures and ESG expectations, this design choice makes a compelling case.
More than just volume and flow
While minimal residual volume and consistent injection performance are foundational, they are only part of what makes YpsoDose a complete solution. Usability, safety, and reliability are also central to the device’s value, each informed by human factors testing and industrial design decisions made to reduce user burden and improve confidence.
YpsoDose incorporates several other features designed to improve usability and confidence for both patients and pharmaceutical partners. An example of core patient-centricity is the audio and visual feedback features, providing real-time cues that guide the user through the injection process, making it intuitive and reassuring. Likewise, electronic skin-contact sensors ensure that the injection is only initiated when proper contact with the skin is detected, reducing the risk of improper use and providing peace of mind. Flexibility is also built in, with the device supporting programmable injection speeds of up to 3.0 mL/min, allowing for the accommodation of different formulations and individual patient tolerances, and built-in sterility enables final assembly outside a cleanroom, reducing manufacturing and integration complexity for pharmaceutical companies.
Taken together, these design choices deliver not only a technically advanced device but one that is practical, scalable, and aligned with the real-world demands of pharmaceutical development and patient use. YpsoDose offers a solution that balances innovation with reliability, revolutionizing selfcare and helping partners bring therapies to market with confidence.
Conclusion
As the number of large-volume subcutaneous biologics increases, careful evaluation of device design is critical. YpsoDose addresses primary sources of delivery inefficiency - residual volume and injection inconsistency - with a platform built for reliability. Yet advanced features alone are not enough. YpsoDose is part of a broader solution ecosystem, supported by partnerships across the supply chain, including the primary container (SCHOTT Pharma), fill-finish, and final assembly (ten23 health), ensuring a smooth, integrated path to clinic and market for customers. Clinically and commercially ready, YpsoDose enables easier adoption and faster market access for pharmaceutical partners.
Authors
Reto Jost
Reto Jost is Category Lead for Large Volume Injectors at Ypsomed Delivery Systems. He has been with Ypsomed since 2014 in various roles in product management and business development, working with pharmaceutical companies to develop and bring to market innovative self-injection systems. Since 2018 his main focus has been on new product innovation, with a particular focus on large volume injections. Mr Jost holds an MSc in Mechanical Engineering from ETH Zurich, Switzerland, and a CAS in Business Administration from HES-SO, Fribourg, Switzerland. He has broad experience in medical devices, having worked in the industry since 2006.
Daniel Käser
Daniel Käser is Manager Product Management for Large- Volume Injectors at Ypsomed. Mr Käser has held various positions in project and product management throughout his career. Since joining Ypsomed in 2022, he has served as Product Manager and since 2024, has overseen product management for large-volume injectors, including YpsoDose and YpsoMate 5.5.
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