Subcutaneous Self-Administration: 3 Key Market Drivers, 3 Key Delivery Challenges

By Fran DeGrazio, executive editor, Drug Delivery Leader

Of major impact on market growth in drug-led or biologic-led combination products are the rapidly accelerating  efforts to enable patient self-administration of therapies and medications. Among routes of administration with significant potential for enablement across a  broader range of therapeutic targets and patient populations, subcutaneous delivery (SC) is high on the list.

Within this general trend toward self-administration, what are specific market drivers for subcutaneous delivery approaches? What delivery challenges will need to be addressed? Top of mind for me, frankly, are these key drivers and challenges, three of each:

Market Driver #1: The Desire For Alternatives To Intravenous Delivery

One key driver comes in the delivery of biopharmaceutical formulations for which intravenous (IV) administration has historically been the preferred – if not the only – option. IV has generally required administration in a clinical setting by trained clinicians. Compared to IV-based methods, SC delivery offers benefits such as improved cost effectiveness, greater mobility for the patient, less potential for infection, and, generally, less invasiveness.

Furthermore, on the effectiveness front, SC injections can deliver biologics-based therapies locally, provide targeted delivery to the lymphatics, and have the potential for prolonging system exposure.

Many antibody drugs are designed for self-administration through SC injection. 40% of the antibodies approved by the FDA in 2024 were administered by SC. For biologics that may be initially commercialized for IV delivery, the move to SC can be  part of product lifecycle management. Of course, a key aspect when evaluating the move from IV to SC must be pharmacokinetic comparability that can be proven.

An example of SC delivery's contribution to lifecycle planning is ZYMFENTRA™ (infliximab-dyyb), sold by Celltrion, Inc. for maintenance treatment of ulcerative colitis. The recently approved SC version, which is in an autoinjector format, is intended for bi-weekly, in-home administration.

Market Driver #2: The Increase In Geriatric Patient Populations

Another key driver behind SC delivery growth is the increasing size of the geriatric population. Per the World Health Organization (WHO), the global population of people aged 80 and older is expected to more than triple between 2015 and 2050. Common conditions with high potential to amplify as people age include age-related macular degeneration (AMD), diabetes, cancer, dementia, and infection management needs.

In addition to the benefit of in-home treatment options for a generally less mobile segment of the population, SC injections can help overcome a common delivery challenge – the difficulty of accessing veins for IV administration. Per a paper published during 2024 in the Journal of the American Geriatrics Society, older patients receiving antibiotics by SC vs IV injection had fewer adverse events by subcutaneous delivery.

Market Driver #3: Convenience In Treating Chronic Conditions

Given the often higher frequency of treatment administration events required for chronic conditions, SC injections offer obvious benefits in addressing them at home. Imagine the impact on quality of life if, for instance, GLP-1 receptor agonists such as Trulicity, Ozempic, and Mounjaro could not be self-administered.

Delivery by SC injection also has the potential to contribute significantly to transforming life-threatening chronic diseases into manageable illnesses. One key opportunity for both the industry and patients is employing SC injections for delivering cancer therapies. Granted, targeting this therapeutic area brings complex delivery challenges such as larger injection volumes and weight-based dosing.

Nonetheless, there are promising developments in the oncology space. In January 2025, Sanofi announced topline results showing that the SC-administered formulation of the anti-CD38 monoclonal antibody isatuximab met coprimary end points in a phase 3 study compared with the IV version. Of major significance was that the results stemmed from the first-ever global phase 3 study to evaluate SC administration of a cancer therapy by using an on-body injector (OBI) delivery system. Importantly, efficacy and safety of the SC version was shown to be comparable to IV delivery, a potentially  significant step in providing a more patient-centric administration option.

Of course, the move to subcutaneous injection is not without its challenges, as there is an assortment of factors that can impact successful delivery through a subcutaneous route of administration. Consider these:

Delivery Challenge #1: Handling Larger And More Complex Formulations

Driven by efforts to move biologics into more convenient and self-administered delivery regimens, dosage concentrations, viscosities, and volumes are increasing. In 2024, over 20% of approved monoclonal antibody formulations had protein concentrations >100 mg/ml. Based on a review published in 2024 in the journal mAbs, a review of clinical stage and approved IV and  SC biopharmaceuticals identified over 180 candidates that would fall into a category of high-volume injections (delivery greater than 2ml).

These increases can have significant impact on deliverability and on patient response/adoption. Formulation characteristics such as pH and viscosity, as well as the buffers or preservatives used, can all have an influence on aspects of the patient experience such as delivery time and pain perception.

Approaches to addressing these challenges of delivering higher volumes via injection include permeation enhancers and on-body injection (OBI) systems. The commercial market includes examples of both.

Delivery Challenge #2: Determining Appropriate Device Type

Deciding which type of device will enable effective subcutaneous delivery of the formulation involves several considerations. Is the best fit a prefilled syringe, an autoinjector, a pen, an on-body injector, or some other kind of combination product? What type and design of needle will be used? These kinds of decisions are critical to ensuring accurate delivery of the drug to the patient and will have an influence on the patient’s commitment to self-administration on an ongoing basis.

A peer-reviewed paper published in 2024 by Elsevier in the Journal of Hospital Pharmacy entitled “Patient Preference after Switching Guselkumab from Prefilled syringe to Autoinjection Pen in Psoriasis and Psoriatic Arthritis Patients” reported on a study comparing self-administration using a prefilled syringe system vs a one-press pen system. The study showed that pain at the site was significantly reduced with the one-press pen system and that all 40 patients in the study found the pen to be easier to use.

Delivery Challenge #3: Keeping The Mind Of The Patient In Mind

In developing drug-led or biologics-led, injection-based combination products, the patient’s perspective is always critical, especially if the expectation is for self-administration. Pain perception and the likelihood of successful training on use are just two such examples of patient-centric factors to consider.

In 2017, the FDA introduced patient-focused drug development (PFDD) under the 21st Century Cures Act. As a part of this initiative, FDA has released a series of guidances to provide directions on how to collect patient input and incorporate into decision-making.

Active feedback loops with the patient community can help with injection device decisions such as the amount of back pressure during the injection process – just one of the factors in making sure that choice and design of device aligns with patient preferences. (I identified the voice of the patient as “Wave #2” in a recent trends article on Drug Delivery Leader.)

One example of efforts to ensure a positive patient experience is the work being done to develop long-acting injectable formulations. In theory, these versions will release slowly into the bloodstream over time, allowing for a steady level of medication in the blood and potentially reducing the number of injections needed.

Frankly, biopharma organizations considering or already working on developing SC formulations and injection devices should prioritize the relationship between drug delivery and patient quality-of-life perhaps even more so than ever before. That’s because, for those key patient populations I identified earlier, self-administration has the potential to bolster quality-of-life perhaps even more than for less challenged groups.