What Modern High-Concentration Monoclonal Antibodies Taught Us – And How Lipid Nanoparticle Therapeutics Must Adapt

Lipid nanoparticle (LNP) therapeutics have revolutionised nucleic acid medicine, yet currently approved products remain relatively low in active nucleic acid payload concentration compared with modern high-concentration monoclonal antibody (mAb) therapies.

The evolution of high-concentration mAbs demonstrates how clinical demands for subcutaneous delivery, reduced injection volumes, and self-administration drove advances in formulation design, manufacturing and analytical characterisation, while also introducing challenges related to viscosity, aggregation and particulate matter.

As LNP therapeutics expand toward protein replacement, gene editing and chronic dosing, analogous formulation, manufacturability and characterisation challenges may emerge. This perspective discusses how lessons from three decades of mAb development can help proactively guide the formulation and characterisation of next-generation LNP therapeutics.

Why Biologics Evolved Toward Higher Concentrations

The next challenge for lipid nanoparticle (LNP) therapeutics may not be whether they can deliver nucleic acids, but whether they can do so at clinically practical concentrations, volumes and manufacturing scales.

The history of therapeutic monoclonal antibodies (mAbs) demonstrates that biologic formulations rarely remain static after market approval. Instead, they evolve in response to clinical needs, advances in formulation science and an increasing emphasis on patient-centered drug delivery.

The earliest marketed antibodies in the late 1990s, including rituximab in 1997 (Rituxan) and trastuzumab in 1998 (Herceptin), were supplied as relatively dilute intravenous formulations (typically 10–25 mg/ml) administered by prolonged infusion in healthcare settings.

As biologic therapies became established for chronic diseases, the expectations of both patients and healthcare providers evolved. Reducing infusion time, minimising injection volume, enabling subcutaneous (SC) administration and ultimately facilitating self-administration at home became increasingly important drivers of product development.

These changing clinical priorities stimulated a steady rise in API concentration over the following two decades. By the early 2010s, products such as adalimumab (Humira, 100 mg/ml) and golimumab (Simponi, 100 mg/ml) exemplified the transition toward high-concentration formulations suitable for SC injection.

More recently, next-generation biologics have pushed formulation concentrations even further, with products including risankizumab (Skyrizi, 150 mg/ml), tezepelumab (Tezspire, around 110 mg/ml), and the subcutaneous formulation of amivantamab (Rybrevant, around 160 mg/ml) illustrating the continued trend toward increasingly concentrated biologics.

This evolution has enabled lower injection volumes, improved patient convenience, greater treatment adherence and reduced reliance on infusion centres. It also shows that concentration is not simply a formulation parameter; it can reshape product design, manufacturability, analytical control and patient experience.

The Concentration Challenge

Increasing protein concentration fundamentally alters the physicochemical environment of an active pharmaceutical ingredient (API) by reducing intermolecular distance and increasing protein-protein interactions.

These largely reversible interactions can significantly influence rheological and colloidal behaviour, most notably through a nonlinear increase in solution viscosity (Yadav et al, 2010), particularly above approximately 100 mg/ml. However, viscosity is highly molecule-dependent and is also influenced by molecular surface properties, charge distribution, pH, ionic strength and excipient composition.

Consequently, antibodies formulated at identical concentrations may exhibit markedly different viscosities, highlighting that concentration acts as a key contributor but not the sole determinant of formulatability (Mahler et al, 2009).

Molecular crowding increases the likelihood of protein self-association and aggregation. Reversible association does not inevitably lead to irreversible aggregation, but it increases the probability of interactions between partially unfolded molecules, particularly under manufacturing and storage stresses.

Aggregation remains a multifactorial process influenced by temperature, agitation, freeze-thaw cycles, oxidation and interfacial exposure, making elevated concentration an important risk amplifier rather than an independent cause.

Similarly, increasing concentration may promote subvisible and visible particle formation by enhancing protein-protein and protein-surface interactions during mixing, filtration, filling, transportation and administration, although air-liquid interfaces, silicone oil, container-derived particles, surfactant degradation and mechanical stresses also contribute significantly (Kannan et al, 2021; Messick et al, 2020).

High concentration further affects syringeability by increasing injection forces and limiting subcutaneous administration while complicating ultrafiltration, mixing, pumping and fill-finish operations.

These challenges have driven advances in formulation design, excipient selection, process engineering, container-closure systems, and orthogonal analytical characterisation.

Collectively, the experience with high-concentration monoclonal antibodies demonstrates that concentration narrows the formulation and manufacturing design space, making robust formulation and analytical strategies essential for successful biologic product development.

From mRNA-Based Vaccines To mRNA-Based Therapeutics: Is The Evolution Of LNPs Following A Similar Path?

The evolution of high-concentration monoclonal antibody (mAb) formulations represents far more than a formulation success story – it provides a valuable framework for anticipating the future development of LNP therapeutics.

Although proteins and lipid nanoparticles differ fundamentally in their physicochemical behaviour, both technologies are ultimately shaped by similar clinical demands, including reduced injection volumes, improved patient convenience, subcutaneous administration and scalable manufacturing.

The clinical success of LNP technology has transformed nucleic acid therapeutics from an experimental concept into a clinically validated drug delivery platform.

To date, only a limited number of LNP-based products have received regulatory approval, including mRNA vaccines:

• Comirnaty
• Spikevax
• mRESVIA
• mCOMBRIAX
• mFLUSIVA
• Onpattro (siRNA therapeutic patisiran)

Unlike modern mAb products, these therapies deliver relatively smaller mass doses of nucleic acids and therefore do not require highly concentrated formulations.

Large-scale manufacturing relies on rapid microfluidic or impingement mixing followed by tangential flow filtration, sterile filtration and fill-finish, producing formulations that maintain nanoparticle stability, encapsulation efficiency and manufacturability while remaining suitable for current dosing requirements.

This paradigm is reflected in clinical dosing. As summarised in Table 1, approved mRNA vaccines typically administer 30–100 μg of mRNA per dose, whereas early clinical protein replacement programmes are already evaluating doses ranging from 0.5 to 5 mg mRNA.

Unlike vaccines, which rely on transient antigen expression to stimulate an amplified immune response, therapeutic applications such as protein replacement, gene editing, genome engineering and chronic repeat-dose therapies require sustained production of functional proteins or genome-editing machinery (Mitchell et al, 2021).

These increasing payload requirements, together with the growing demand for subcutaneous administration and self-administration, are driving the development of increasingly concentrated LNP formulations capable of delivering larger doses within clinically acceptable injection volumes (Chander et al, 2023; Shkodra et al, 2025).

Table 1: Comparison Of Typical mRNA Doses Across Approved Vaccines And Emerging Therapeutic Applications

Application	mRNA dose	Dosing frequency
Pfizer COVID vaccine	30 μg	Once/booster
Moderna Spikevax	100 μg (primary), now 50 μg boosters	Once/booster
Influenza/combination vaccines	10–100 μg	Annual
Protein replacement (early clinical trials, for example NCT07544420)	0.5–5 mg depending on indication	Repeated

LNP Concentrations

Importantly, greater therapeutic protein requirements do not necessarily translate directly into higher LNP concentrations.

mRNA-LNP therapeutics remain relatively early in their technological evolution, with considerable opportunity to increase protein expression per administered dose.

Intracellular delivery remains inefficient, with only a fraction of internalised nucleic acid reaching the cytosol for productive translation (Gilleron et al, 2013).

Improved tissue targeting, cellular uptake, endosomal escape, alternative delivery systems, self-amplifying RNA and sequence optimisation could substantially increase protein expression without proportionally increasing the administered dose.

Thus, high concentration is not an inevitable trajectory for all LNP therapeutics, but one of several complementary strategies for achieving therapeutic exposure.

This article focuses specifically on that high-concentration pathway. As higher payloads, limited administration volumes, and patient-centric delivery drive the development of concentrated LNP formulations, new formulation, manufacturing, and analytical challenges are likely to emerge.

Although mAbs and LNPs are fundamentally different systems, decades of high-concentration biologics development offer valuable principles – not a direct platform – for anticipating and addressing these challenges.

Unlike protein therapeutics or oligonucleotide conjugates, such as antisense oligonucleotides, which may more directly recapitulate the concentration-dependent viscosity pathway observed for mAbs but are beyond the scope of this article, particulate formation in LNP systems is more commonly associated with nanoparticle aggregation, lipid phase separation, cryogenic stress, mechanical processing, container interactions and extrinsic contaminants.

Current evidence suggests that these phenomena are governed by multiple interacting variables – including lipid composition, PEG-lipid content, buffer chemistry, freeze-thaw history and manufacturing conditions – rather than concentration alone.

Nevertheless, emerging studies indicate that increasingly concentrated LNP formulations may also experience greater challenges related to colloidal interactions, suspension viscosity, manufacturability, nanoparticle stability, and subvisible particulate formation (Schober et al, 2024).

Emerging evidence also suggests that increasing payload loading in lipid nanoparticle systems may already be exposing formulation challenges analogous to those encountered during the development of high-concentration monoclonal antibody products.

For example, Hogarth et al (2024) demonstrated that formulation robustness became increasingly dependent on lipid composition as lipid loading increased, with conventional PEGylated surfactants alone providing insufficient stabilisation at higher loading levels (Hogarth et al, 2024).

Incorporation of unPEGylated helper lipids significantly improved colloidal stability, reduced aggregation tendencies and enabled substantially greater nanoparticle loading while maintaining acceptable physicochemical properties.

These observations highlight an important principle for future high-concentration LNP therapeutics: increasing payload density is unlikely to be achieved simply by concentrating existing formulations.

Rather, higher-concentration LNPs will likely require increasingly sophisticated lipid and excipient optimisation strategies to balance loading capacity, colloidal stability, manufacturability and long-term storage performance.

Notably, silicone oil droplets – well recognised as a source of subvisible particles in high-concentration monoclonal antibody formulations – have also been identified as a contributor to particle formation in LNP systems (Hada et al, 2023).

In parallel, advances in orthogonal analytical characterisation have improved the accurate identification of subvisible particles in LNP formulations (Accurate Particle Characterisation in Lipid Nanoparticle Therapies, 2025) while new formulation and process optimisation strategies are being developed to mitigate these challenges (Hada et al, 2023; Kersten et al, 2026; Optimize LNP Formulations Through Ultrafiltration: Amicon® Ultra Devices, n.d.).

This emerging parallel suggests that certain formulation and container-closure challenges are already converging between the two modalities, reinforcing the value of applying lessons learned from biologics to the development of increasingly concentrated LNP therapeutics.

These lessons are not directly interchangeable across modalities, but they highlight recurring development pressure points that LNP programmes can address earlier rather than rediscover during late-stage development.

As therapeutic mRNA applications move toward larger doses and more patient-centric routes of administration, formulation design space may similarly narrow, making helper lipid selection, nanoparticle stabilisation strategies and process robustness critical determinants of successful high-concentration LNP development.

Table 2: Lessons From Three Decades Of High-Concentration Monoclonal Antibody Development And Their Potential Implications For Future Lipid Nanoparticle Therapeutics

Challenge in high-concentration mAbs	Potential implication for future LNPs
Increased viscosity	Injectability
Aggregation	Nanoparticle instability
Subvisible particles	Orthogonal particle characterisation
Excipient optimisation	Lipid/excipient design
Container interactions	Device compatibility
Process robustness	Scalable manufacturing

Future Outlook

The transition toward increasingly concentrated LNP therapeutics has thus already begun.

Although advances in mRNA design, targeting, cellular uptake and endosomal escape may increase protein expression without requiring proportionally higher doses, concentration remains an important strategy for delivering larger payloads within practical administration volumes.

Decades of high-concentration antibody development provide valuable lessons in formulation optimisation, orthogonal particle characterisation, container-closure compatibility, process robustness and scalable manufacturing.

Rather than repeating the iterative development path of monoclonal antibodies, the LNP community can proactively apply these principles while recognising the fundamental differences between the two modalities.

Integrating these lessons during early formulation, analytical and process development may help address concentration-related challenges and accelerate the translation of robust, scalable and patient-centric LNP therapeutics.

Key Takeaways

• High-concentration mAb development demonstrates how increasing concentration can reshape product design, manufacturability, analytical control and patient experience.
• LNP therapeutics may face similar development pressures as they expand from vaccines toward higher-dose applications, although the underlying formulation risks are modality-specific.
• Higher LNP concentration is only one route to therapeutic exposure; improved targeting, uptake, endosomal escape, sequence optimisation and self-amplifying RNA may reduce dose requirements.
• Concentrated LNPs will require deliberate optimisation of lipids, excipients, processes and container-closure systems rather than simply concentrating existing formulations.
• Orthogonal particle characterisation and early process-robustness studies will become increasingly important as LNP concentration and administration constraints increase.
• The key lesson from high-concentration biologics is not to replicate mAb formulation strategies, but to anticipate a narrowing formulation and manufacturing design space before late-stage development.