prodchem
Aug 17, 2026
Antibody-drug conjugates are one of the fastest growing categories in oncology, with more than 200 candidates in active clinical development and over 40 already in Phase III trials. But C&EN's recent reporting flags a sourcing problem behind that growth. Only a handful of drug services firms currently have the capacity to manufacture ADCs start to finish, from antibody through payload, linker, conjugation and fill-finish, under one roof.
That gap matters more than it sounds. Most biotech and pharma companies developing ADCs do not have in-house manufacturing for any of the three components, let alone all three combined.
An ADC is not one molecule made in one process. It is three separate technical disciplines stitched together.
The antibody is produced through mammalian cell culture and purification, the same core biologics expertise used for monoclonal antibodies.
The payload and linker are synthesized through small-molecule chemistry, often involving highly potent active pharmaceutical ingredients (HPAPIs) with occupational exposure limits as low as 1 nanogram per cubic meter.
Conjugation chemically attaches the payload-linker unit to the antibody at controlled sites, followed by purification and sterile formulation into a finished vial or syringe.
Very few organizations run all three disciplines internally. Most drug services firms specialize in one or two pieces and rely on partnerships or customer-coordinated handoffs to complete the rest.
According to C&EN's reporting, Lonza stands out as a CDMO that can perform every step in-house, drawing on capabilities that span small molecules, large biologics and highly potent compounds at its Visp, Switzerland site. That kind of integration is the exception industry-wide, not the norm.
Lonza has also built out a proprietary ADC technology platform, acquired through its 2023 purchase of Synaffix, covering site-specific conjugation chemistry, spacer technology and a portfolio of linker-payloads. Combined with its end-to-end manufacturing footprint, that positions it as one of the few genuinely single-source options in the market.
Most other major players remain strong in specific segments rather than the full chain:
MilliporeSigma has invested heavily in payload, linker and conjugation capacity across its Saint Louis and Madison, Wisconsin sites.
Catalent offers full-service development through commercial-scale ADC production, positioned as a major full-chain competitor.
WuXi Biologics continues expanding large-scale antibody and bioconjugation capacity, particularly serving Asia-Pacific demand.
Sterling Pharma Solutions and Veranova have both expanded dedicated bioconjugation suites, but as component specialists rather than fully integrated providers.
The practical effect of this concentration is longer lead times and earlier capacity reservation. Experts cited in the C&EN piece expect demand to outpace the current base of integrated providers as more ADC candidates move toward regulatory filing.
Pharmaceutical companies without in-house ADC capability, which is most of the field, are left with two sourcing paths. They can work with one integrated provider capable of running the full process, or they can coordinate multiple specialist firms across antibody production, payload-linker synthesis and conjugation themselves.
The second path adds coordination risk. Every handoff between firms introduces additional shipping, quality-system alignment and scheduling dependencies, all of which can slow a program down at exactly the stage when speed to clinic matters most.
The scale of demand explains why this bottleneck is drawing attention now. The global ADC contract manufacturing market was valued at roughly $10.8 billion in 2026 and is projected to grow toward $16.5 billion within the next several years.
North America accounted for an estimated 42 to 45 percent of the ADC CDMO market in 2025, while China represented a growing share of Asia-Pacific capacity, driven by domestic innovators alongside expanding international bioconjugation infrastructure. That regional spread means buyers increasingly have options outside their home market, but not necessarily options with full start-to-finish capability.
CDMOs across the board have responded with fresh capital. Recent expansions have targeted conjugation suites, high-potency containment infrastructure and integrated quality systems designed to bring antibody production, linker-payload synthesis, bioconjugation and fill-finish under a single roof, exactly the kind of integration that remains rare today.
Given how few firms currently offer true end-to-end capability, timing and supplier diversification both matter more than usual in this category.
Engage early: Capacity reservation agreements are becoming standard as demand tightens, so late-stage sourcing conversations start from a weaker negotiating position.
Map the full chain: Know which of your prospective suppliers can genuinely handle all three ADC components versus which require you to coordinate additional partners.
Watch regional buildout: Expansion activity in North America, Europe and Asia-Pacific is shifting where integrated capacity becomes available first.
Budget for containment costs: HPAPI handling requirements add real cost and lead time regardless of which supplier structure is chosen.
The ADC pipeline is growing faster than the pool of firms that can manufacture these molecules from start to finish. That imbalance is likely to persist for at least the next few years, even as CDMOs across regions invest in new capacity. Buyers evaluating ADC manufacturing partners should treat true end-to-end capability as a scarce resource, not an assumed baseline, and plan sourcing timelines accordingly.
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