22 PROTAC / Targeted Protein Degrader CRO and CDMO vendors

What does it take to develop and manufacture a PROTAC / Targeted Protein Degrader drug?

A PROTAC is a bifunctional molecule: one end binds your target protein, the other recruits an E3 ubiquitin ligase, and a linker holds the two together. The biology you are paying for is event-driven, not occupancy-driven. The degrader pulls the target into a productive ternary complex, tags it for the proteasome, then lets go and does it again. That mechanism is the whole reason the modality exists (it can hit targets small molecules call undruggable), and it is also why a generalist small-molecule CRO will struggle. The design space sits in the linker and the ternary complex, and neither shows up in a standard binding assay.

Discovery work here is its own discipline. You need a CRO that can run linker chemistry at scale, swap E3 ligase handles (CRBN and VHL are the workhorses, but IAP, DCAF15, and newer ligases matter when you want tissue selectivity or want to dodge resistance), and read out degradation directly. That means DC50 and Dmax from Western blot or quantitative proteomics, HiBiT or NanoBRET ternary-complex assays, ubiquitination and proteasome-dependence controls, and a washout experiment to prove catalytic, sub-stoichiometric activity. A vendor who only reports target binding has measured the wrong thing. Watch for the hook effect too, where too much compound forms unproductive binary complexes and degradation falls off at high dose. A team that has not designed around that curve has not really worked in degraders.

The harder, less glamorous half is CMC and DMPK, and it is where specialist degrader CDMOs separate from generalists. PROTACs are big (molecular weights routinely north of 800 to 1,000 Da), greasy, and firmly in beyond-Rule-of-Five space, which punishes solubility, permeability, and oral bioavailability. Synthesis is a long convergent route with an expensive E3 ligand and a linker coupling that has to be clean and reproducible. You want a CDMO that has solved degrader-specific problems: enabling formulations (amorphous solid dispersions, lipid systems) to rescue exposure, analytical methods that resolve regioisomers and linker-related impurities, polymorph and salt screening on a sticky molecule, and GMP scale-up of a route with several chiral and amide-coupling steps. The analytical burden is real because the impurity profile of a bifunctional molecule is more complex than a conventional small molecule of the same dose.

How do you choose a CRO or CDMO for PROTAC / Targeted Protein Degrader?

Fit to the modality beats brand and beats price. The fastest filter is to ask what degraders the team has actually moved forward, not how many small molecules they make a year. A group that has taken at least one PROTAC from linker optimization through a degradation-driven SAR campaign, or a CDMO that has run GMP synthesis of a beyond-Rule-of-Five bifunctional, is in a different league from a competent generalist learning on your program. Run two or three vendors against the same written scope and compare on the points below.

• Relevant platform and track record: degrader-specific medicinal chemistry, an E3 ligand and linker toolkit (CRBN, VHL, and ideally beyond), ternary-complex and degradation assays in house (HiBiT, NanoBRET, quantitative proteomics), and named programs they have advanced. Ask whether the scientists you would work with have run degrader SAR, not just heard of it.
• GxP and analytical capability for this modality: for IND-enabling and clinical supply, GLP bioanalysis and GMP manufacturing that can handle a large, lipophilic molecule. Confirm they can develop stability-indicating methods that resolve linker-related and regioisomeric impurities, run polymorph and salt screening, and build enabling formulations to fix solubility and exposure.
• Capacity and scale: realistic queue and lead time, plus a credible path from milligram discovery batches to kilogram GMP without re-inventing the route. A long convergent synthesis with a costly E3 ligand makes early route and supply planning matter more than it would for a simple small molecule.
• Regulatory experience: degraders are still a newer class, so regulators ask sharper questions on impurities, genotoxic risk, and off-target degradation. Favor a vendor that has supported an IND or CTA for a degrader or an unconventional small molecule and can speak to those expectations.
• IP and confidentiality: linker designs, E3 ligand choices, and the degrader composition are the crown jewels. Settle ownership of compounds, methods, and any platform-derived IP in writing, and have a CDA in place before you disclose target or chemistry.