For most of its history, "a drug" meant one thing: a small molecule — a compact chemical you could make in a plant and press into a pill. That assumption is now badly out of date, and the change is one of the biggest forces shaping where demand goes.
From the Knitify Pharma Demand Radar — our running read on where pharmaceutical demand is heading. We publish the observations; the method behind them stays in-house.
The science: many kinds of medicine for the same disease
The same target, in the same disease, can now be attacked in radically different ways. A small molecule blocks it. A peptide mimics or disrupts it. An antibody binds it from outside the cell. An antibody-drug conjugate uses that antibody to deliver a toxin. A degrader deletes the protein entirely. A radioligand carries radiation to it. An RNA drug switches off the gene that makes it. Each of these has appeared, or is appearing, across the themes in this series.
None of this was true a generation ago, when the toolkit was, in practice, two families — chemicals you synthesised and, later, proteins you grew in living cells. What has changed is that we can now attack the same target from several directions at once: a protein that resisted a pill because it offered no deep pocket to bind might still be reachable by an antibody, a degrader, or an RNA drug. The disease stays the same; the ways to intervene have multiplied.
And crucially, each of those answers is a completely different factory. A small molecule, a peptide and an antibody share almost nothing in how they're made, who makes them, or what they cost — different equipment, different raw materials, different skills, and regulatory expectations written around a different kind of risk. To see why the supply chains don't overlap, walk through how each is built.
The classic chemistries: pills and peptides
The small molecule is the original template and still the workhorse. It is made by chemical synthesis: a sequence of reactions run in steel reactors, each step building or modifying the molecule, then purified and crystallised into a solid. The supplier base is the fine-chemical and active-ingredient industry — plants that think in kilograms and tonnes. This is the cheapest, most scalable, most mature corner of the landscape, and it sets the cost expectations every other modality is measured against.
A peptide is a short chain of amino acids, and although it is still "chemistry", it is made in a distinctly different way. The dominant method is solid-phase synthesis: the chain is built one amino acid at a time on a solid support, each addition requiring a cycle of coupling and deprotection before the next unit goes on. The longer the peptide, the more cycles are needed, the more side-products accumulate, and the harder purification becomes. Peptide makers therefore live and die on coupling efficiency and purification capacity — a different craft from running a reactor, with its own specialised resins and reagents.
The living factories: antibodies and their conjugates
An antibody is not synthesised at all — it is grown. Living mammalian cells, engineered to secrete the desired protein, are cultured in large bioreactors under tightly controlled conditions, then the antibody is harvested and purified through a series of chromatography steps. This is biomanufacturing, and it has almost nothing in common with a chemical plant: the inputs are cell lines and growth media rather than solvents, and the product is a large, fragile molecule that must generally be kept cold from factory to patient. The capital and expertise required are enormous, which is why antibody capacity is a scarce and jealously guarded resource.
An antibody-drug conjugate stacks two of these worlds together and adds a third. You need the biologic — the antibody, grown in cells. You need a highly potent small-molecule payload, a toxin so poisonous it must be made in a dedicated high-containment plant. And you need the linking chemistry that joins the two precisely, so the finished conjugate pairs the antibody's homing ability with a payload far too toxic to give on its own.[1] An ADC is, in effect, three supply chains stitched together under one quality system — which is why so few manufacturers can make one end to end.
The frontier platforms: degraders, radioligands, and RNA
A degrader is a small molecule again, but a strange one. Rather than blocking a target, it is bifunctional: one end grabs the target protein, the other recruits the cell's own disposal machinery, so the protein is tagged and destroyed rather than merely inhibited. Chemically this is still organic synthesis, so it borrows part of the small-molecule supply chain, but these molecules are larger, more elaborate and harder to make and formulate than a classic pill. The approach has been moving steadily from concept toward the clinic.[2] Its promise is that it can reach targets a blocking drug never could, which gives demand for this chemistry a trajectory of its own.
A radioligand is a targeting molecule bolted to a radioactive isotope, so it delivers radiation directly to the cells it binds. Its supply chain is unlike anything else, because the active ingredient is decaying from the moment it is made. Isotopes are produced in reactors, cyclotrons or generators, attached to the targeting molecule, and shipped and administered before too much of the signal has decayed away. That turns manufacturing into a just-in-time logistics problem with a cold chain and a clock running the whole time — nuclear supply and time-critical distribution a tablet maker never has to think about.
An RNA or oligonucleotide drug is built from yet another chemistry. The strands are assembled by phosphoramidite synthesis — again a cycle-by-cycle, solid-phase build, but with its own specialised building blocks. Naked RNA is fragile and struggles to get into cells, so it usually has to be delivered: either dressed with a targeting conjugate that steers it to a specific tissue, or wrapped in a lipid nanoparticle that carries it inside cells. The delivery layer is a discipline in itself, and the raw materials — the modified nucleotides and the lipids — are a supply chain that barely existed at scale until recently.
Why one factory can't become another
Put these side by side and the central fact becomes obvious: a contract manufacturer built for one modality usually cannot serve another. A fine-chemical plant tooled for small molecules has no bioreactors and no way to grow an antibody; a biologics site has no high-containment suite for cytotoxic payloads and no licence to handle radioactive material. The equipment, the people, the quality systems and the regulatory playbooks are all specific to the modality. You cannot repurpose one into another with a weekend of retooling; you build, staff and qualify a new kind of plant.
That is why the manufacturing landscape is fragmenting into modality specialists — contract organisations that go deep on peptides, or ADCs, or oligonucleotides, or radioligands, rather than trying to do everything. At the same time, the drug developers themselves increasingly run a portfolio across several modalities at once, chasing the same disease areas with whatever chemistry fits best. A single company may have a small-molecule programme, an antibody, a conjugate and an RNA candidate in the same building — each reaching out to a completely different set of suppliers.
The demand: which chemistry, not just which target
This is why "what's the hot target?" is no longer a complete question. The follow-up — "and in which modality?" — determines an entirely different supply chain, a different set of suppliers, a different capital base. A target heating up as a small molecule sends demand to fine-chemical makers; the same target heating up as an ADC or a peptide sends it somewhere else entirely. The value in reading the patent record isn't only spotting which biology is accelerating; it's seeing which kind of chemistry that demand is flowing into. In a seven-modality world, that is half the game — and it's exactly what the whole of this series has been tracing, one modality at a time.
For the people who place bets, this reframes the question. A contract manufacturer reading a wave of demand has to ask whether it lands in a modality it can actually make — if not, that demand is someone else's business. An investor sizing a market can no longer treat "the drug" as one industry; a surge in a disease might flow to antibody capacity, to isotope supply, or to oligonucleotide building blocks, and those are different companies with different economics. And for business development, the modality is the difference between a partner who can build the thing and one who simply can't — a distinction a target name alone hides.
The caveats: immature modalities and moving targets
None of this means the modalities are equal or fixed. Some are decades old and industrial; others are still early, with thin manufacturing bases, few qualified suppliers and processes far from settled. A modality can be scientifically exciting and still be capacity-constrained, so a genuine surge in demand can run straight into a wall of limited supply — itself worth noticing, just a different signal. Enthusiasm on the science side and readiness on the manufacturing side do not always arrive together.
It is also a mistake to assume a disease belongs to one modality forever. The same condition may be served first by one chemistry and later by another as the tools mature — a target best drugged today as an antibody might be better addressed tomorrow as a degrader or an RNA drug. The factories are not fixed lanes so much as a shifting map, and the useful skill is less about crowning a single winner than about reading, at any given moment, which kind of chemistry a wave of demand is actually flowing toward.
Editorial commentary from the Knitify Pharma Demand Radar. Not investment, legal, regulatory, or medical advice.