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ADC Linkers

Antibody-drug conjugates (ADCs), consisting of monoclonal antibodies (mAb), cytotoxic payloads and linkers, have evolved rapidly in recent years and are progressively revolutionizing clinical cancer therapy. To fight cancer, the antibodies attach to proteins on the surface of tumor cells. Once the ADC is there, the tumor cells engulf the ADC; rip apart the linker through chemical, enzymatic or biological processes; and release a small molecule payload. The payload then kills the tumor cells. These therapies are envisioned to act like guided missiles, delivering a killing drug specifically to cancer cells without harming healthy cells. Currently, dozens of ADCs have been approved and over hundreds are in various stages of clinical trials.

The linker connects antibody to cytotoxic payload and is a key component of ADC. Linkers provide ADC with the following characteristics. (1) high stability in the circulation, and (2) specific release of the payload in the target tissue. To meet these requirements, various linkers have been developed and can be classified into two types based on their cleavage method - cleavable and noncleavable linker. Cleavable linker has a chemical trigger in its structure that can be efficiently cleaved to release cytotoxic payload in the tumor. More than 80% of clinically approved ADCs employ cleavable linkers. For example, Trodelvy is an anti-TROP-2 mAb conjugated to SN-38 via a cleavable maleimide linker (acidity) with a short pegylated unit.  In contrast to cleavable linkers, there is no chemical trigger in the structure of the noncleavable linker, and it is part of the payload. Most of the non-cleavable linkers are based on maleimidocaproyl  (MC) and 4-maleimidomethyl cyclohexane-1-carboxylate (MCC). Recently, researchers have been developing hydrophilic non-cleavable linkers containing PEG with alkynes and piperazines. However, this new technology has not yet reached clinical maturity. 

Trodelvy-formula-ADC

The use of PEGs as a linker between the antibody and payload molecules allows for higher ADC loading. PEGs create a protective shield that wraps the ADC payload from its microenvironment, improving solubility and stability. Other benefits include reduced aggregation and thus lower immunogenicity, improved pharmacokinetics, increased circulation time and reduced toxicity. Biopharma PEG offers a variety of PEG linkers to facilitate antibody-drug conjugate (ADC) development projects. All PEG linkers are of >95% purity and they are the basic building blocks for a successful ADC.

Technique support: GMP standard production support, impurity control. Contact for Technical Files.

References:
​1. Zheng Su, Dian Xiao, Fei Xie, Lianqi Liu, Yanming Wang, Shiyong Fan, Xinbo Zhou, Song Li, Antibody–drug conjugates: Recent advances in linker chemistry, Acta Pharmaceutica Sinica B, Volume 11, Issue 12, 2021,Pages 3889-3907, ISSN 2211-3835, https://doi.org/10.1016/j.apsb.2021.03.042.
2. Joubert, N.; Beck, A.; Dumontet, C.; Denevault-Sabourin, C. Antibody–Drug Conjugates: The Last Decade. Pharmaceuticals 2020, 13, 245. https://doi.org/10.3390/ph13090245

Catalog No. Name Structure M.W. Purity
MD006005 N3-PEG2-NH2 N3-PEG2-NH2 174.2 ≥95%
MD006005 N3-PEG4-NH2 N3-PEG4-NH2 262.31 ≥95%
MD006016 N3-PEG2-COOH N3-PEG2-COOH 203.19 ≥95%
MD006016 N3-PEG3-COOH N3-PEG3-COOH 247.3 ≥95%
MD006016 N3-PEG4-COOH N3-PEG4-COOH 291.301 ≥95%
MD006016 N3-PEG5-COOH N3-PEG5-COOH 335.35 ≥95%
MD006016 N3-PEG6-COOH N3-PEG6-COOH 379.41 ≥95%
MD006016 N3-PEG8-COOH N3-PEG8-COOH 467.51 ≥95%
MD006016 N3-PEG9-COOH N3-PEG9-COOH 511.56 ≥95%
MD006025 N3-PEG3-SPA N3-PEG3-SPA 344.3 ≥95%
MD006025 N3-PEG4-SPA N3-PEG4-SPA 388.37 ≥95%
MD002002 OH-PEG8-OH OH-PEG8-OH 370.436 ≥95%
MD002002 OH-PEG9-OH OH-PEG9-OH 414.488 ≥95%
MD002002 OH-PEG24-OH OH-PEG24-OH 1075.28 ≥95%
MD002038 OH-PEG4-Tos OH-PEG4-Tos 348.412 ≥95%
MD001002 mPEG12-OH mPEG12-OH 560.67 ≥95%
MD001005 mPEG3-NH2 mPEG3-NH2 163.2 ≥95%
MD001005 mPEG36-NH2 mPEG36-NH2 1616.95 ≥95%
MD001025 mPEG7-SPA mPEG7-SPA 509.5 ≥95%
MD001025 mPEG10-SPA mPEG10-SPA 645 ≥95%
MD001025 mPEG11-SPA mPEG11-SPA 685.75 ≥95%
MD001025 mPEG25-SPA mPEG25-SPA 1301 ≥95%
MD005002 NH2-PEG4-OH NH2-PEG4-OH 193.2 ≥95%
MD005002 NH2-PEG12-OH NH2-PEG12-OH 545.667 ≥95%
MD005016 NH2-PEG4-COOH NH2-PEG4-COOH 265.3 ≥95%
MD005016 NH2-PEG6-COOH NH2-PEG6-COOH 353.4 ≥95%
MD005016 NH2-PEG24-COOH NH2-PEG24-COOH 1146.37 ≥95%
MD005016 NH2-PEG36-COOH NH2-PEG36-COOH 1674.99 ≥95%
MD005067 NH2-PEG2-CH2CH2COOtBu NH2-PEG2-CH2CH2COOtBu 233.3 ≥95%
MD005067 NH2-PEG4-CH2CH2COOtBu NH2-PEG4-CH2CH2COOtBu 321.4 ≥95%
MD005067 NH2-PEG6-CH2CH2COOtBu NH2-PEG6-CH2CH2COOtBu 409.5 ≥95%
MD006300 2-((Azido-PEG8-carbamoyl)methoxy)acetic acid 2-((Azido-PEG8-carbamoyl)methoxy)acetic acid 554.6 ≥95%
MD136016 CBZ-NH-PEG3-COOH CBZ-NH-PEG3-COOH 355.383 ≥95%
MD069016 Fmoc-NH-PEG2-COOH Fmoc-NH-PEG2-COOH 399.44 ≥95%
MD069016 Fmoc-NH-PEG3-COOH Fmoc-NH-PEG3-COOH 443.5 ≥95%
MD069016 Fmoc-NH-PEG4-COOH Fmoc-NH-PEG4-COOH 487.5 ≥95%
MD069016 Fmoc-NH-PEG8-COOH Fmoc-NH-PEG8-COOH 663.8 ≥95%
MD069016 Fmoc-NH-PEG12-COOH Fmoc-NH-PEG12-COOH 839.963 ≥95%
MD141016 Mal-PEG4-COOH Mal-PEG4-COOH 345.3 ≥95%
MD141025 Mal-PEG1-SPA Mal-PEG1-SPA 310.26 ≥95%
MD141025 Mal-PEG2-NHS Mal-PEG2-NHS 354.3 ≥95%
MD141025 Mal-PEG4-NHS Mal-PEG4-NHS 442.4 ≥95%
MD000019 N-(acid-PEG3)-N-bis(PEG3-azide) N-(acid-PEG3)-N-bis(PEG3-azide) 623.7 ≥95%
MD000017 N-(ACID-PEG3)-N-BIS(PEG3-AMINE) N-(ACID-PEG3)-N-BIS(PEG3-AMINE) 571.704 ≥95%
MD000019 N-(Hydroxy-peg3)-n-boc-peg4-t-butyl ester N-(Hydroxy-peg3)-n-boc-peg4-t-butyl ester 597.74 ≥95%
MD001212 mPEG8-CH2CH2CHO mPEG8-CH2CH2CHO 396.5 ≥95%
MD002067 OH-PEG4-CH2CH2COOtBu OH-PEG4-CH2CH2COOtBu 322.39 ≥95%
MD005121 NH2-PEG4-CH2COOH NH2-PEG4-CH2COOH 251.3 ≥95%
MD016050 COOH-PEG24-NH2.HCl COOH-PEG24-NH2.HCl 1182 ≥95%
MD022016 Mal-NH-PEG8-COOH Mal-NH-PEG8-COOH 592.6 ≥95%
MD023023 NHS-PEG3-NHS NHS-PEG3-NHS 444.4 ≥95%
MD007005 Alkyne-PEG2-NH2 Alkyne-PEG2-NH2 143.2 ≥95%
MD007005 Alkyne-PEG8-NH2 Alkyne-PEG8-NH2 407.5 ≥95%
MD007016 Alkyne-PEG3-COOH Alkyne-PEG3-COOH 216.2 ≥95%
MD056006 Br-PEG2-N3 Br-PEG2-N3 238.08 ≥95%
MD056006 Br-PEG3-N3 Br-PEG3-N3 282.1 ≥95%
MD056067 Br-PEG4-CH2CH2COOtBu Br-PEG4-CH2CH2COOtBu 385.29 ≥95%
MD056068 Br-PEG4-NH-Boc Br-PEG4-NH-Boc 400.31 ≥95%
MD068002 Boc-NH-PEG6-OH Boc-NH-PEG6-OH 381.5 ≥95%
MD068005 BOC-NH-PEG4-NH2 BOC-NH-PEG4-NH2 336.4 ≥95%
MD068121 Boc-NH-PEG2-CH2COOH Boc-NH-PEG2-CH2COOH 263.3 ≥95%
MD115006 Aminooxy-PEG3-N3 Aminooxy-PEG3-N3 234.3 ≥95%
MF001024 mPEG-SCM mPEG-SCM ≥95%
HE002121 OH-PEG-AA OH-PEG-AA ≥95%
HE002005 OH-PEG-NH2 OH-PEG-NH2 ≥95%
HE002016 OH-PEG-PA OH-PEG-PA ≥95%
HO017017 COOH-PEG-COOH COOH-PEG-COOH ≥95%
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