# PROTACs (targeted protein degradation)

Bifunctional small molecules that recruit an E3 ubiquitin ligase to a disease protein, tagging it for proteasomal destruction — an event-driven, catalytic drug modality approaching its first approval with Arvinas's estrogen-receptor degrader vepdegestrant, and a deep pipeline across IRAK4, IKZF and BTK targets.

Source: https://en.bioecon.ru/technology/protacs/
Updated: 2026-08-18



## Overview and value chain

Markers: [EC: Directive 2001/83/EC + FDA targeted protein degradation guidance | OECD: Bio-pharma | Regulator: FDA (USA), EMA (European Union), NMPA (China)]

PROTACs (proteolysis-targeting chimeras) and related targeted-protein-degradation (TPD) molecules are bifunctional small molecules: one end binds a disease target protein and the other an E3 ubiquitin ligase, bringing the two together so the ligase tags the target for proteasomal destruction. Because a single PROTAC molecule catalytically destroys many target copies (event-driven pharmacology), it can drug proteins that conventional inhibitors cannot — scaffolds, transcription factors, aggregated proteins. Arvinas's vepdegestrant (ARV-471) is a first-in-class estrogen-receptor PROTAC approaching FDA approval for breast cancer (co-developed with Pfizer); Kymera's KT-474 (IRAK4 degrader, with Sanofi) has the structural basis of its potency and selectivity published in Nature Communications; C4 Therapeutics reported first-in-human Phase 1 results for cemsidomide (CFT7455, MonoDAC IKZF1/3 degrader) in non-Hodgkin's lymphoma; Nurix's NX-5948 is a CNS-penetrant BTK degrader that breaks established CNS-drug design rules; and BeiGene's BGB-16673 BTK chimeric degrader reported CaDAnCe-101 Phase 1 data in relapsed/refractory CLL/SLL at EHA 2026.

The key directions of PROTACs are:
1. **Estrogen-receptor PROTACs (Oncology Degrader):** first-in-class ER degrader for ER+ breast cancer, the modality's lead asset approaching approval — Arvinas (vepdegestrant/ARV-471, with Pfizer).
2. **Immunology degraders (Immunology Degrader):** IRAK4 and IKZF1/3 degraders for autoimmune and haematological disease — Kymera (KT-474 IRAK4, with Sanofi), C4 Therapeutics (cemsidomide/CFT7455 IKZF).
3. **BTK degraders (BTK Degrader):** catalytic BTK destruction for B-cell malignancies, including CNS-penetrant designs — Nurix (NX-5948), BeiGene (BGB-16673).
4. **Degrader chemistry platforms (Degradation Platform):** cereblon- and VHL-recruiting E3 ligands, MonoDAC/CEpD scaffolds, and the linker/warhead design that enables catalytic, sub-stoichiometric destruction.

### Sectoral value chain

```
[disease protein + E3 ligase] ──> [bifunctional degrader design + synthesis] ──> [oral small-molecule degrader]
                                              │
                                     (catalytic proteasomal destruction)
                                              │
                                              ▼
[clinical candidate] <─── [degradation PD/PK + Phase 1-3 trials] <─────┘
```

### Value chain levels

| Level | Description | Key inputs/outputs |
|:---|:---|:---|
| **Target & E3 Selection** | identify the disease protein and a recruiting E3 ligase (CRBN, VHL) | **In:** target biology.<br>**Out:** target-ligand pair. |
| **Degrader Design** | linker, target-binding warhead and E3-ligand engineering into a bifunctional molecule | **In:** ligands.<br>**Out:** degrader molecule. |
| **Synthesis & CMC** | medicinal-chemistry scale-up, oral-bioavailability optimisation, GMP manufacture | **In:** synthesis, CDMO.<br>**Out:** drug substance. |
| **Preclinical & Clinical** | degradation PD/PK, IND-enabling studies and human trials | **In:** drug, subjects.<br>**Out:** clinical data. |
| **Regulatory & Approval** | NDA (US) / MAA (EU) under the small-molecule pathway | **In:** data, dossier.<br>**Out:** approval. |
| **Launch & PV** | market access and post-market pharmacovigilance | **In:** approval, field.<br>**Out:** revenue, safety. |

Cross-cutting technologies of the sector:
- **E3 ligase recruitment (E3 Ligase Recruitment):** cereblon (CRBN) and von Hippel-Lindau (VHL) are the dominant recruited E3 ligases; the choice governs which tissues and targets are addressable.
- **Event-driven pharmacology (Catalytic Degradation):** because one degrader molecule destroys many target copies, PROTACs can work at lower exposure and against scaffolds and aggregation-prone proteins undruggable by inhibitors.
- **Oral small-molecule profile (Oral Degrader):** unlike antibody or cell therapy, PROTACs aim for oral bioavailability, the central CMC and medicinal-chemistry challenge.

---

## US

The US owns the PROTAC field commercially — Arvinas, Kymera, C4 Therapeutics and Nurix are all US-based, and Arvinas's vepdegestrant is on track to be the first approved PROTAC.

### Arvinas, Kymera, C4, Nurix, FDA
- **Arvinas:** vepdegestrant (ARV-471) is a first-in-class estrogen-receptor PROTAC approaching FDA approval for ER+ breast cancer, co-developed with Pfizer; it is the modality's lead regulatory asset and would be the first approved targeted-protein-degradation drug.
- **Kymera Therapeutics:** KT-474 is an IRAK4 degrader (co-developed with Sanofi) whose structural basis for selective and potent IRAK4 degradation was published in Nature Communications, underpinning dermatology and autoimmunity indications.
- **C4 Therapeutics:** reported initial Phase 1 first-in-human results for cemsidomide (CFT7455), a novel MonoDAC IKZF1/3 degrader, in patients with non-Hodgkin's lymphoma.
- **Nurix Therapeutics:** NX-5948 is a CNS-penetrant catalytic BTK degrader that breaks established design rules for CNS drugs, opening B-cell malignancies with CNS involvement.
- **FDA framework:** PROTAC degraders are reviewed as small-molecule NDA drugs under FDA guidance; vepdegestrant's approaching approval would establish the first targeted-protein-degradation regulatory precedent.

---

## CN

China's targeted-protein-degradation field is anchored by BeiGene's BGB-16673 chimeric degrader, with a broader pipeline of CRBN-recruiting degraders from domestic biotechs.

### BeiGene, NMPA, domestic pipeline
- **BeiGene:** BGB-16673 is a BTK chimeric degrader (CEpD platform) whose CaDAnCe-101 Phase 1 data in relapsed/refractory CLL/SLL was reported at EHA 2026, extending BeiGene's global haematology franchise into degradation.
- **Domestic pipeline:** Chinese biotechs (e.g. Cullgen and peers) are building CRBN- and VHL-recruiting degrader pipelines, with several entering clinical development behind the US leaders.
- **NMPA framework:** degraders are reviewed under the NMPA small-molecule drug framework, with China's deeper biotech investment pulling the modality forward domestically.

---

## EU

Europe's role in PROTACs is mainly through partnership — Sanofi's co-development of Kymera's KT-474 — and the basic-science origin of the modality, with EU regulators preparing for the first degrader MAA.

### Sanofi-Kymera partnership, EMA, basic-science origin
- **Sanofi-Kymera partnership:** Sanofi (France) co-develops Kymera's KT-474 IRAK4 degrader, making Europe a commercial partner on one of the modality's lead immunology assets even though the originator is US-based.
- **EMA framework:** degraders will be reviewed as small-molecule MAA drugs by the European Medicines Agency under Directive 2001/83/EC; no degrader is yet EU-approved.
- **Basic-science origin:** the PROTAC concept rests on academic ubiquitin-proteasome biology, and EU pharma (Boehringer Ingelheim, Novartis) maintains early-stage degrader R&D alongside partners.

---

## Leading companies and research institutes

| Company / Institute | Country | Key products / platforms | Tech features | Status 2026 |
|:---|:---|:---|:---|:---|
| **Arvinas** | 🇺🇸 USA | *vepdegestrant (ARV-471)* | ER PROTAC, with Pfizer | operating |
| **Kymera Therapeutics** | 🇺🇸 USA | *KT-474 (IRAK4)* | IRAK4 degrader, with Sanofi | operating |
| **C4 Therapeutics** | 🇺🇸 USA | *cemsidomide (CFT7455)* | MonoDAC IKZF1/3 degrader | operating |
| **Nurix Therapeutics** | 🇺🇸 USA | *NX-5948 (BTK)* | CNS-penetrant BTK degrader | operating |
| **BeiGene** | 🇨🇳 China | *BGB-16673 (BTK)* | CEpD chimeric degrader | commercial |

---

## Tech stack and innovations

The stack pairs target- and E3-ligand selection with bifunctional linker engineering and oral small-molecule CMC, delivering catalytic destruction of a disease protein.

1. **Estrogen-receptor PROTACs (Oncology Degrader):**
   - Arvinas's vepdegestrant (ARV-471) is a first-in-class ER PROTAC approaching FDA approval for ER+ breast cancer, co-developed with Pfizer — the modality's lead asset and first regulatory test.
2. **Immunology degraders (Immunology Degrader):**
   - Kymera's KT-474 (IRAK4, with Sanofi) has the structural basis for its selective, potent degradation published in Nature Communications; C4's cemsidomide (CFT7455 MonoDAC IKZF1/3 degrader) reported initial Phase 1 results in non-Hodgkin's lymphoma.
3. **BTK degraders (BTK Degrader):**
   - Nurix's NX-5948 is a CNS-penetrant catalytic BTK degrader that breaks established CNS-drug design rules, and BeiGene's BGB-16673 (CEpD platform) reported CaDAnCe-101 Phase 1 data in relapsed/refractory CLL/SLL at EHA 2026.
4. **Degradation platforms (Degradation Platform):**
   - Cereblon- and VHL-recruiting E3 ligands, MonoDAC (C4) and CEpD (BeiGene) scaffolds embody the linker/warhead engineering that makes a single molecule catalytic and orally bioavailable.

---

## Value chains and production pipelines

### Industrial pipeline of a PROTAC degrader drug (NDA / MAA, Directive 2001/83/EC)

```
┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Target & E3 selection  │ ───> │ 2. Degrader design        │
└───────────────────────────┘      └───────────────────────────┘
                                                   │
                                                   ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Preclinical & clinical │ <─── │ 3. Synthesis & CMC        │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. Regulatory & approval  │ ───> │ 6. Launch & PV            │
└───────────────────────────┘      └───────────────────────────┘
```

#### Stage 1: Target and E3 selection
A disease protein (ER, IRAK4, IKZF1/3, BTK) is identified as undruggable-by-inhibition or where catalytic removal is advantageous, and a recruiting E3 ligase (CRBN or VHL) is chosen based on target expression and tissue access.

#### Stage 2: Degrader design
A target-binding warhead and an E3-ligand (e.g. cereblon or VHL ligand) are joined by a tuned linker into a bifunctional molecule, optimised for ternary-complex formation, cooperativity and degradation efficiency.

#### Stage 3: Synthesis and CMC
Medicinal chemistry scales the bifunctional molecule under small-molecule GMP, optimising oral bioavailability and DMPK — the central challenge that distinguishes a degrader drug candidate from a tool compound.

#### Stage 4: Preclinical and clinical
IND-enabling degradation PD/PK, safety and efficacy studies support first-in-human trials; cemsidomide (CFT7455), NX-5948 and BGB-16673 are all in Phase 1, and vepdegestrant is approaching approval.

#### Stage 5: Regulatory and approval
A NDA (US) or MAA (EU) is filed as a small molecule under Directive 2001/83/EC; vepdegestrant's approaching FDA approval would establish the first targeted-protein-degradation regulatory precedent.

#### Stage 6: Launch and pharmacovigilance
Following approval, the degrader launches under the small-molecule pharmacovigilance regime, with real-world degradation-PD monitoring that the modality has not yet seen at scale.