CRDMO: H1 2025 Review of Targeted Protein Degraders

Targeted protein degraders (TPDs) offer a novel therapeutic approach by leveraging the body’s own protein degradation systems to eliminate disease-associated target proteins. This strategy opens new avenues for addressing previously “undruggable” targets. Nearly a decade ago, when this technology was still in its infancy, WuXi AppTec began building relevant capabilities. Since then, the company has established a comprehensive, integrated platform encompassing discovery, synthesis, purification, analysis, and testing. To date, this platform has supported the development of more than 120 TPD molecules, with over 20 advancing to clinical stages. This article summarizes key developments in the TPD landscape during the first half of 2025. It also presents a case study demonstrating how WuXi AppTec’s integrated CRDMO platform efficiently overcomes TPD development challenges, including preparing IND-enabling materials for a PROTAC candidate within just 12 months for first-in-human (FIH) trials.

Clinical Advances: First PROTAC (proteolysis-targeting chimera ) Phase 3 Results and Progress in Extracellular Degraders

In March 2025, Pfizer and Arvinas jointly announced top-line results from the first-ever Phase 3 clinical trial of a PROTAC therapy—vepdegestrant. In HR+, HER2- breast cancer patients with ESR1 mutations, vepdegestrant reduced the risk of disease progression or death by more than 40% compared to the active control (hazard ratio < 0.60). Arvinas and Pfizer have recently submitted a new drug application (NDA) for the drug.

Arvinas' second PROTAC candidate, ARV-102, also showed promise in Phase 1 studies, achieving significant reductions in LRRK2 protein levels in both the central nervous system and peripheral tissues of healthy volunteers—laying the groundwork for future clinical trials in LRRK2-related neurodegenerative diseases.

Meanwhile, Kymera Therapeutics reported positive Phase 1 results for KT-621, a potential first-in-class oral STAT6 degrader. Once-daily administration achieved over 90% average degradation of STAT6 in the blood at doses above 1.5 mg. Complete degradation in both blood and skin was observed in all multiple ascending dose (MAD) cohorts at doses ≥50 mg.

Beyond PROTACs, extracellular protein degradation therapies are also gaining traction. Biohaven’s BHV-1300 and BHV-1400 demonstrated rapid and robust reductions in target protein levels—achieving 70–80% decreases within hours. These molecules bind target proteins on one end and the asialoglycoprotein receptor (ASGPR) on the other, thereby facilitating internalization and degradation via endocytosis.

Financing and Collaborations: Molecular Glues Attract Major Deals

Alongside bifunctional degraders, molecular glues—small molecules that induce or stabilize interactions between E3 ligases and target proteins—continue to draw significant interest. In 2024, multiple major pharmaceutical companies signed R&D deals for molecular glue technologies worth over $1 billion.

That momentum has carried into 2025, with several multinational pharmaceutical companies announcing collaborations focusing on molecule glues-based degraders, targeting undruggable targets in oncology, immunology, and more diseases with unmet medical needs. In addition, novel proximity-inducing mechanisms are being explored to target disease-relevant tissues with high precision.

In parallel, several emerging companies in the TPD space completed new funding rounds during H1 2025.

The potential of targeted protein degradation continues to expand. A recent article in Nature Medicine noted, the ability to degrade proteins with orally available small molecules is fundamentally reshaping drug discovery—liberating scientists from traditional “druggability” constraints and allowing them to focus on the targets that matter most in disease biology. As the field progresses, more TPD therapies are expected to achieve clinical milestones and ultimately bring benefits to patients worldwide.

However, the promise of TPDs comes with unique development challenges. For example, due to their large molecular weight and structural complexity, PROTACs often suffer from poor solubility and suboptimal pharmacokinetics. The following case study illustrates how WuXi STA, an integral part of WuXi AppTec, collaborated with a partner to address these challenges effectively.

Addressing Key Bottlenecks in TPD Drug Development

Several years ago, a biotech company developing a PROTAC candidate faced synthetic challenges and turned to WuXi STA for support. The goal was to complete the production of drug substance and clinical trial material production within 14 months to support an IND filing and FIH trial. However, the original synthesis route involved 24 steps and yielded only 0.3%. Crystallization and purification proved difficult due to the compound’s unique structure.

Compounding the challenge, the candidate’s high molecular weight and poor solubility resulted in oral bioavailability of just 0.9%. Moreover, three steps in the synthesis relied on a palladium (Pd) catalyst, raising safety concerns and increasing production costs.

To resolve these issues, WuXi STA’s process chemistry, biocatalysis, and crystallization teams worked in concert to redesign the synthesis route, reducing the number of steps from 24 to 16 and replaced palladium with biocatalysts in two steps. To tackle crystallization bottlenecks, high-throughput crystallization screening identified suitable conditions that met both purity and yield requirements. These changes significantly improved the scalability and efficiency of the synthetic route while reducing costs.

Simultaneously, WuXi STA’s formulation team addressed the low oral bioavailability by exploring a range of enabling technologies and ultimately selected spray-dried dispersion (SDD) to prepare a solid dosage form. SDD disperses poorly soluble compounds in an amorphous state within a polymer matrix and has been successfully used in several approved drugs. With this approach, the candidate’s oral bioavailability improved approximately 30-fold—supporting further clinical advancement.

Thanks to WuXi STA’s integrated CRDMO model, API process development and formulation were advanced in parallel by multiple teams working seamlessly together. Ultimately, they delivered IND-enabling materials and clinical trial materials within just 12 months—two months ahead of schedule.

As one of the industry’s leading platforms enabling targeted protein degradation, WuXi AppTec’s integrated services extend beyond PROTACs to a wide array of bifunctional modalities, including:

• LYTACs (lysosome-targeting chimeras): for degrading extracellular or membrane proteins via lysosomes
• DACs (degrader-antibody conjugates): combining antibodies with protein degraders
• AUTACs (autophagy-targeting chimeras): small molecules inducing autophagic degradation
• RIBOTACs (ribonuclease-targeting chimeras): targeting and degrading specific RNA sequences

As targeted protein degradation continues to evolve, WuXi STA remains committed to leveraging its integrated CRDMO platform to empower the development of targeted protein degraders, helping partners translate scientific innovation into transformative medicines for patients around the world.

Reference:

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[13] Fraser Therapeutics Secures $29 Billion Series B from J&J and 8 Others. Retrieved May 15, 2025, from http://prazertx.com/pages/board/view.php?menu_code=477&board_sid=16&data_sid=261&page_num=&skey=&sval=&category_code1=

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