Targeted Delivery: Peptide–Drug Conjugates, Antibody–Drug Conjugates and Nanoparticles

The idea of targeted delivery

Many drugs reach the whole body when only one tissue needs them. Targeted delivery tries to steer a medicine to where it is needed. A conjugate is a two-part design: one part finds the target, and the other part, the payload, does the work. The targeting part can be an antibody, a peptide or a coated particle. This page is a short summary of an adjacent field, not a guide to any product. It is mostly about cancer medicine, where these designs began, and it does not describe anything for personal use.

Evidence labels used here

Plain labels are used across this library: approved medicine, established, promising but limited, mixed, insufficient evidence, preclinical (cells or animals only), no good evidence of benefit, evidence of harm and marketing claim. Each label applies to one specific design and use.

Antibody-drug conjugates

Antibody-drug conjugates (ADCs) combine the specificity of a monoclonal antibody with a highly cytotoxic (cell-killing) payload, aiming to reduce side effects by delivering the payload preferentially to the tumor. [1] A 2023 review says many ADCs have now been approved or are in late-phase trials, but toxicity remains a key issue. [1] Evidence label: approved medicine for the specific cancers where they have been approved, per the review, and each one has to be judged for its own indication.

Peptide-drug conjugates

Peptide-drug conjugates (PDCs) use a peptide as the guide instead of an antibody. A 2026 review of PDCs in breast cancer says they may offer better tumor penetration, lower immune reaction and flexible chemical synthesis compared with antibody-based systems. [2] The same review adds that, despite encouraging preclinical outcomes, translation to the clinic is hindered by limited stability in the body, rapid clearance and suboptimal pharmacokinetics (how a drug moves through the body). [2] Evidence label for most new PDCs: preclinical (cells or animals only), with the stated advantages still to be shown in patients.

A separate review warns that "anticancer peptide" covers molecules doing very different jobs: killing tumor cells directly, modulating targets inside cells, homing to tumors, or carrying another drug. [3] It says many potent peptides fail during development because charge, shape, cell entry, stability, tissue exposure and manufacturability all have to work together. [3]

An established example: peptide receptor radionuclide therapy

Peptide receptor radionuclide therapy (PRRT) uses lutetium-177 DOTATATE, a radioactive agent used for tumors that carry somatostatin receptors. A 2026 review calls it an established treatment option for gastroenteropancreatic neuroendocrine tumors, with trials such as NETTER-1 and NETTER-2 showing gains in progression-free survival and response rates. [4] The same review lists uncertainties about the best sequencing and the effect on overall survival. [4] On safety, the NETTER-1 registration trial reported therapy-related myeloid neoplasms, a type of blood cancer, in about 1% of patients. [5] A single-center retrospective study of 173 patients found 10 cases (5.8%) at a median of 23 months after the first cycle. [5] Different designs and follow-up lengths make those two figures hard to compare. The point is that a successful targeted peptide can still carry serious late risks, and this is a specialist cancer treatment, not a wellness product.

Targeted nanoparticles and carriers

Nanoparticles are carriers on a scale of billionths of a meter. Peptides can be attached to them, or to nucleic acid drugs, to help them reach cells. A 2026 review says clinical translation of such delivery still faces barriers, including difficulty crossing cell membranes and being broken down inside cells. [6] Another 2026 review describes bone-homing antibodies, built by attaching bone-binding motifs including acidic peptides, as validated in multiple preclinical disease models. [7] Evidence label: preclinical.

What this means for consumer claims

A word like "targeted" or "liposomal" on a product page does not show that anything reached the right tissue or worked. Delivery science for one molecule does not carry over to another. For consumer claims, see encapsulation, liposomes and nanoparticles and topical and transdermal delivery claims. To see how approved medicines differ from research-only products, read approved medicines vs research peptides. A broader map of related fields is on the adjacent research map.