Why precision drug delivery could change everything

When you hear the phrase precision medicine, you might picture futuristic treatments tailored to your DNA, or advanced tests that reveal the unique fingerprints of your illness. For years, scientists and doctors have described precision medicine as standing on two sturdy pillars: precision diagnosis (figuring out what’s wrong at the most detailed level possible) and precision therapy (crafting treatments targeted to that exact problem).

But Dr. Avnesh Thakor, a physician-scientist at Stanford University’s School of Medicine, believes there’s a third, equally important pillar that has been overlooked: precision delivery, and he lays out this vision in an article published in MedComm. And once you hear the reasoning, it’s hard to imagine precision medicine without it. His perspective is simple but profound: even the best-designed therapies won’t work if they don’t reach the right cells, at the right time, in the right amounts.

In research labs, experimental therapies often look like miracle cures. They’re tested directly on disease cells in petri dishes, and the results can be stunning. But when those same treatments are tried in people, many fall short. Why? The problem is delivery. In clinical practice, drugs are often given in the most convenient ways, swallowed as a pill or injected into a vein. These routes send medicine coursing through the entire body. But as the author explains, that means most of the drug never reaches its intended target. Along the way, it gets diluted, destroyed by the liver or stomach acids, or trapped in organs that weren’t meant to be treated.

The solution, traditionally, has been to crank up the dosage. But higher doses come with side effects: nausea, fatigue, damage to healthy tissues, or worse. It’s like shouting louder in a noisy room instead of walking over to talk directly to the person you want to reach. This is where precision delivery comes in, bringing the medicine right to the doorstep of the cells that need it, without disturbing the rest of the neighborhood.

The three modules of precision delivery

The paper proposes that precision delivery has three interconnected “modules,” each tackling a different part of the challenge. Let's think of precision medicine as if it were a package delivery.

The first module is targeted delivery, that is, getting to the right address. Imagine you have a package that must be delivered to a specific apartment in a huge city. If you simply toss it from a helicopter, chances are slim that it will land at the right door. Instead, precision delivery uses specialized “delivery routes” to place therapies exactly where they’re needed. Doctors are already experimenting with this in clever ways. For example, endovascular approaches guide catheters through blood vessels, delivering drugs directly into tumors in the liver or brain; endoluminal approaches use scopes to access hollow organs like the lungs or intestines; percutaneous approaches rely on needles or minimally invasive tools inserted through the skin; Implantation approaches place small devices, patches, or scaffolds inside the body to release therapies slowly and locally. In fact, for certain liver cancers, doctors inject radioactive beads directly into the arteries feeding the tumor. This not only delivers a lethal dose to cancer cells but spares most of the healthy liver tissue. Survival rates improve, and side effects shrink.

The second module of precision medicine is microenvironment modulation. Even when medicine reaches the right neighborhood, it can still be blocked from entering the house. Biological barriers like the blood–brain barrier protect the brain from toxins, but they also keep out potentially life-saving drugs. Researchers are developing ways to temporarily “open the door.” Focused ultrasound, for instance, uses sound waves and microbubbles to safely loosen the blood–brain barrier in a specific spot, letting cancer drugs or Alzheimer’s treatments slip through. Other techniques tweak the local environment, using electricity, changes in acidity, or even tiny chemical adjustments, to help medicines cross barriers and reach their targets.

The third module of precision medicine is all about cellular interactions, that is, making sure the package is opened. So, once a drug finally gets inside the right cell, it must interact properly to have an effect. Scientists are finding creative ways to ensure this: coating drugs with molecules that help them stick to cell surfaces, packaging them in nanoparticles that protect them until they’re inside, or designing them to activate only in certain environments (like low oxygen inside a tumor). In short, targeted delivery gets the drug to the right place, microenvironment modulation helps it move through the terrain, and cellular interactions ensure it does its job once it arrives.

The idea of precision delivery is already changing treatments. In clinical trials, delivering chemotherapy directly into arteries that feed tumors has improved survival for patients with liver cancer, melanoma, and other hard-to-treat cancers. Also, by pairing focused ultrasound with targeted drug delivery, researchers are making progress against glioblastoma (a deadly brain cancer) and Alzheimer’s disease, both notorious for being resistant to standard treatments. Precision delivery is even being used to place drugs directly into the spinal fluid for conditions like spinal muscular atrophy, a breakthrough that has given some children their mobility back.

What’s exciting is that these techniques don’t just reduce side effects, but they can also make previously impossible therapies feasible. Gene editing tools like CRISPR, for instance, hold enormous promise but struggle with safe, effective delivery. Precision delivery could unlock their potential.

Of course, bringing this third pillar into everyday medicine won’t be easy. Precision delivery requires advanced imaging, specialized equipment, and highly trained operators, resources often concentrated in big academic hospitals. There are also regulatory hurdles: many existing drugs were approved based on how they behave when taken orally or intravenously. Delivering them directly to tissues may require new safety studies and new rules. Finally, there’s cost. Catheter-based procedures, implantable devices, and guided ultrasound aren’t cheap. But as technology improves and becomes more widespread, much like MRI scans once did, costs are likely to fall.

For decades, medicine has focused on what to give patients: which drug, which gene therapy, which cell transplant. But as the article makes clear, to leap forward, we must also focus on how we give it.

If you want to learn more, read the original article titled "The Third Pillar of Precision Medicine — Precision Delivery" on MedComm at http://dx.doi.org/10.1002/mco2.70200.