SPECIALTY TOPICS · GUIDE

Targeted Delivery and Tissue Specificity

How gene and RNA medicines are steered to the right tissue, with examples from FDA labels of local delivery, liver-targeting tags and cell-based approaches, plus the barriers that remain.

Content last updated October 22, 2026. This page has not been medically reviewed.

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Quick answer

A gene or RNA medicine only works if it reaches the right cells in enough amount and nowhere it should not. Researchers use several strategies: put the medicine near the target, add a tag that cells in one organ recognize, use genetic switches that work only in one tissue, or edit cells outside the body and return them. Each approved product uses its own strategy for its own disease, and none of these strategies is a general solution.

Tools that narrow the target

Where you give it. Local routes limit how much medicine reaches the rest of the body, though a procedure can carry its own risks. The LUXTURNA label warns of permanent decline in visual acuity after subretinal injection. [4]
Tissue-specific promoters. A promoter is a genetic "on switch." The HEMGENIX construct uses one that is liver-specific. [12] The label still warns that integration of liver-targeting AAV vector DNA could lead to liver cancer, so specificity does not remove safety questions. [12]
Targeting tags (ligands). GalNAc is one example for liver cells. [13] Reviews describe other ligand strategies for lungs, spleen, brain and more as engineering approaches under study; their abstract does not report human outcomes. [1]
Cell selection and ex vivo editing. The FDA explains that some products take a patient's cells, modify them and return them. [18] That solves targeting for blood stem cells but requires specialized procedures.
Patient screening. Some labels require checking for pre-existing antibodies against the vector before treatment, which indirectly affects whether a vector can reach its target. See Immune Responses to Gene Therapy and Delivery Vehicles. [19]

What "tissue specific" does not prove

A good laboratory delivery result is not a treatment. A biomarker or expression signal does not equal a clinical benefit. See Mechanism vs Demonstrated Benefit.
Delivery studies in animals do not transfer directly to people. The review on extrahepatic LNPs names species differences as a bottleneck. [1] See Cell Studies vs Animal Studies vs Human Trials.
Approval of one product does not extend to another that uses similar words such as "targeted" or "nanoparticle." Each is approved for a named indication only. [20]
Other kinds of carriers, such as peptide-drug and antibody-drug conjugates, are covered in Targeted Delivery: Peptide-Drug Conjugates, Antibody-Drug Conjugates and Nanoparticles.

Frequently asked questions

Can a medicine be aimed at one organ only?

Partly. Approved products narrow the target by local administration, tissue-specific promoters, liver-targeting tags and ex vivo cell editing, as shown in the table above. Reviews say delivery beyond the liver and cell-type targeting remain barriers. [2]

Why do so many approved RNA medicines act in the liver?

LNPs naturally favor the liver [1], and GalNAc tags direct RNA to liver cells. [13]

Is brain gene therapy available?

One FDA-listed example is KEBILIDI for AADC deficiency, which the label says is given by infusion into a brain structure and approved under accelerated approval based on a motor milestone measure. [5] Whether delivery methods developed for the brain in preclinical work will reach patients was uncertain in a 2021 review. [3]

Does "targeted" mean "safer"?

Not automatically. The HEMGENIX label includes warnings about liver effects and a theoretical cancer risk despite its liver-specific design. [12]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

How to read the evidence labels

Labels used on this page: approved medicine (US FDA, as read), established, promising but limited, insufficient evidence.

Why delivery is hard

Reviews of the field describe the same barriers again and again. LNPs tend to collect in the liver, which limits their use elsewhere. [1] Cell-type targeting, delivery beyond the liver and tolerability of repeat doses are listed as barriers for non-viral carriers. [2] For brain disease, a 2021 review explains that the blood-brain barrier makes intravenous delivery of AAV vectors to the brain highly inefficient, and that higher doses raise the risk of immune-mediated toxicity. [3] That review also described several advanced strategies as preclinical, with none in clinical trials at the time. [3] It is from 2021, so check newer sources before drawing conclusions about today's pipeline.

Strategies seen in approved products

The table shows how FDA-listed products reach their target. These are descriptions of labeled products, not recommendations.

Strategy	Example (US FDA)	What the label or FDA page shows
Local injection into the eye	LUXTURNA	Subretinal injection of an AAV vector [4]
Directly into a brain region	KEBILIDI	Label states it is for intraputaminal infusion only (a brain structure, by stereotactic surgery) [5]
Into the spinal fluid	SPINRAZA (antisense)	Given intrathecally [6]
Into the bladder	ADSTILADRIN	Adenoviral vector instilled into the bladder [7]
On the skin	VYJUVEK	Topical gel applied to wounds [8]
Into a tumor lesion	IMLYGIC	Local treatment of skin and lymph node melanoma lesions [9]
Into the inner ear	OTARMENI	Hearing-loss gene therapy for people with confirmed OTOF variants and no prior implant in that ear [10]; the label ties treatment to access to the inner ear [11]
Liver-specific genetic switch	HEMGENIX	AAV vector with a liver-specific promoter, given by infusion [12]
Liver-targeting tag on the RNA	GIVLAARI, OXLUMO, LEQVIO	RNA linked to a GalNAc group to deliver it to liver cells [13][14][15]
Particle that favors the liver	ONPATTRO	siRNA formulated as a lipid complex for delivery to liver cells [16]
Edit the patient's cells outside the body	CASGEVY	Autologous (the patient's own) genome-edited stem cells [17]

The common pattern: most systemic RNA medicines approved so far aim at the liver, while products for other organs are given locally or built from the patient's own cells. For the siRNA side, see RNA Interference and siRNA Therapies; for antisense, see Antisense Oligonucleotides.

Safety note

Treatments described here are prescription products delivered by trained teams, sometimes through surgery or specialist infusions. This page contains no instructions and cannot tell any person whether a treatment suits them. Questions belong with a specialist. See Talking With a Health Professional.

References

Liu Y et al. Overcoming hepatic tropism: precision engineering of lipid nanoparticles for extrahepatic RNA delivery. Mater Today Bio 2026. PubMed 42677161. Read 2026-10-22.
Yang Y et al. Recent advances in non-viral vectors for gene therapy and gene delivery: from lipid nanoparticles to engineered extracellular vesicles. Pharmaceutics 2026. PubMed 42797269. Read 2026-10-22.
Fischell JM, Fishman PS. A multifaceted approach to optimizing AAV delivery to the brain for the treatment of neurodegenerative diseases. Front Neurosci 2021. PubMed 34630029. Read 2026-10-22.
US FDA prescribing information, LUXTURNA (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, KEBILIDI (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, SPINRAZA (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, ADSTILADRIN (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, VYJUVEK (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, IMLYGIC (label data via openFDA). Read 2026-10-22.
US FDA, OTARMENI product page. Read 2026-10-22.
US FDA prescribing information, OTARMENI (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, HEMGENIX (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, GIVLAARI (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, OXLUMO (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, LEQVIO (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, ONPATTRO (label data via openFDA). Read 2026-10-22.
US FDA prescribing information, CASGEVY (label data via openFDA). Read 2026-10-22.
US FDA, What is Gene Therapy?. Read 2026-10-22.
US FDA prescribing information, ZOLGENSMA (label data via openFDA). Read 2026-10-22.
US FDA, Approved Cellular and Gene Therapy Products. Read 2026-10-22.

Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.