Review and Formulation Analysis of 14 Antibody Drug Conjugates (ADCs) Approved by FDA Up To 2022

Review and Formulation Analysis of 14 Antibody Drug Conjugates (ADCs) Approved by FDA Up To 2022

Since 2000, the research and development of precision therapy represented by small molecule targeted drugs and antibodies has made great progress and become the main targeted therapy for tumors. However, since small molecules and antibody drugs can specifically target tumor signaling pathways or antigens on the surface of tumor cells, and the heterogeneity between tumor cells is strong, precision therapy is very important for precision therapy. ADCs combine the dual advantages of small molecule and antibody drugs compared to antibody or small molecule drugs alone. Many ADCs have demonstrated impressive activity against treatment-refractory cancers, resulting in their approval for both hematologic malignancies and solid tumorindications.

Antibody Drug Conjugates (ADCs) Approved by FDA

After decades of research and troubleshooting, significant technological advancements and an improved mechanistic understanding of ADC activity culminated in the FDA approval of 14 ADCs, each providing demonstrable therapeutic benefit to cancer patients. Currently, about 297 ADCs are in preclinical/clinical development, indicating that the world is ushering in a new era of targeted cancer therapy.

ADCCommon NameTargetmAbLinkerPayloadPayload ActionDARConjugationCompany
MylotargGemtuzumab OzogamicinCD33IgG4Acid CleavableOzogamicin/ CalicheamicinDNA Cleavage2-3LysinePfizer
AdcetrisBrentuximab VedotinCD30IgG1Enzyme CleavableMMAE/ AuristatinMicrotubule Inhibitor4CysSeattle


HER2IgG1Non-CleavableDM1/ MaytansinoidMicrotubule Inhibitor3.5LysineRoche


CD22IgG4Acid CleavableOzogamicin/ CalicheamicinDNA Cleavage6LysinePfizer


CD79bIgG1Enzyme CleavableMMAE/ AuristatinMicrotubule Inhibitor3.5CysRoche


CD22-Enzyme CleavablePseudomonas Exotoxin A--CysAstrazeneca


Nectin4IgG1Enzyme CleavableMMAE/ AuristatinMicrotubule Inhibitor3.8CysSeattle
EnhertuFamtrastuzumab DeruxtecannxkHER2IgG1Enzyme CleavableDXd/ CamptothecinTOP1 Inhibitor8CysDaiichi Sankyo


TROP2IgG1Acid CleavableSN-38/ CamptothecinTOP1 Inhibitor7.6CysImmunomedics


BCMAIgG1Non-CleavableMMAF/ AuristatinMicrotubule Inhibitor4CysGSK


CD19IgG1Enzyme CleavableSG3199/ PBD DimerDNA Cleavage2.3CysADC Therapeutics
AkaluxCetuximab SaratolacanEGFR-----LysineRakuten Medical
AidixiDisitamab VedotinHER2IgG1Enzyme CleavableMMAEMicrotubule Inhibitor4CysRemeGen
TivdakTisotumab VedotintftvTissue FactorIgG1Enzyme CleavableMMAE/ AuristatinMicrotubule Inhibitor4CysSeagen

Table 1. FDA approved ADCs currently on the market.

ADC Formulation Analysis

A typical antibody formulation contains ADC, excipients (sugars or salts), buffers, surfactants (Tween) and other metal ion chelators. Table 2 lists the formulations of 14 ADCs, which show that even with the same linker-payload, the final formulation buffer used by different antibodies will be different.

ADCSpecification/BottleConcentrationBuffer Salt/mLExcipients/mLSurfactants/mLpH
Mylotarg4.5mg1mg/ml5mM Phosphate14mg Sucrose, 8mg Glucan 40, 5.2mg Sodium Chloride-7.4
Adcetris50mg5mg/ml20mM Citrate70mg Trehalose Dihydrate0.2mg Tween806.6
Kadcyla100mg, 160mg20mg/ml10mM Succinic acid60mg Sucrose0.2mg Tween805.0
Besponsa1mg0.25mg/ml18mM Tromethamine45mg Sucrose, 5.2mg Sodium Chloride0.1mg Tween808.0
Lumoxiti1mg1mg/ml25mM Phosphate40mg Sucrose, 80mg Glycine0.2mg Tween807.4
Polivy140mg20mg/ml8mM Succinic Acid40mg Sucrose1mg Tween805.3
Padcev23mg, 33mg10mg/ml20mM Histidine55mg Trehalose Dihydrate0.2mg Tween806.0
Enhertu100mg20mg/ml25mM Histidine90mg Sucrose0.3mg Tween805.5
Trodelvy180mg10mg/ml18mM MES7.8mg Trehalose Dihydrate0.1mg Tween806.5
Blenrep100mg50mg/ml20mM Citrate75.6mg Trehalose Dihydrate0.2mg Tween806.2
Akalux250mg5mg/ml10mM Sodium Phosphate90mg Trehalose0.2mg Tween807.1
Zynlonta10mg5mg/ml20mM Histidine59.9mg Sucrose0.2mg Tween806.0
Aidixi60mg10mg/ml10mM Histidine43.72mg Mannitol, 20.54mg Sucrose0.2mg Tween806.1
Tivdak40mg10mg/ml30mM Histidine30mg Mannitol, 30mg Sucrose-6.0

Table 2. ADCs formulation analysis.

The Screening Process and Evaluation Index Analysis of ADC Preparations

pH and Buffer Screening

Among the 14 ADCs on the market, most ADCs have pH values between 6.0 and 6.9. Among them, histidine salt was the most important buffer type. Among the 14, 5 were histidine, 3 phosphate, 2 citrate, 2 succinate, 1 tromethamine and 1 MES. Generally, the selection of ADC buffer needs to follow the following principles: according to the buffer range of different buffer pairs, the pH gradient was set from 4.0-8.0 to prepare the ADC concentration for clinical use. Then, they were placed at 25°C and 40°C for 7 days, observed and sampled on day 0, day 1, day 3 and day 7, respectively, including observation of clarity, BCA detection concentration, SEC-HPLC detection of purity, DSC detection of thermal stability, etc.

When the suitable pH range is determined, two buffers at the pH can be selected. For example, when the suitable pH is 6.0, 30 mM histidine or 20 mM citric acid can be selected as the buffering agent of the preparation, and then the next step is screened.

ADCBuffer Salt/mLConfiguration/mLpH
Mylotarg5mM Phosphate0.52mg disodium hydrogen phosphate anhydrous, 0.09mg sodium dihydrogen phosphate monohydrate7.4
Adcetris20mM Citrate5.6mg sodium citrate dihydrate, 0.21mg citric acid monohydrate6.6
Kadcyla10mM Succinic Acid-5.0
Besponsa18mM Tromethamine2.15mg tromethamine8.0
Lumoxiti25mM Phosphate3.4mg water sodium bicarbonate phosphate7.4
Polivy8mM Succinic Acid1mg Succinic Acid5.3
Padcev20mM Histidine1.40mg L-histidine, 2.31mg L-histidine hydrochloride6.0
Enhertu25mM Histidine0.89mg L-histidine, 4.04mg L-histidine hydrochloride5.5
Trodelvy18mM MES3.8mg MES6.5
Blenrep20mM Citrate0.42mg citric acid, 6.7mg disodium and trisodium citrate dihydrate6.2
Akalux10mM Sodium Phosphate-7.1
Zynlonta20mM Histidine1.4mg L-histidine, 2.3mg L-histidine hydrochloride6.0
Aidixi10mM Histidine2.1mg histidine hydrochloride (adjusted with NaOH)6.1
Tivdak30mM Histidine2.11mg L-histidine, 3.44mg L-histidine hydrochloride6.0

Table 3. ADCs pH and buffer analysis.

Surfactant Screening

Surfactants reduce aggregate production primarily by reducing surface tension. Of the 14 ADCs, 7 used 0.01-0.02% (W/V) Tween 80, 3 used 0.01-0.02% (W/V) Tween 20, and 1 used 0.03% Tween 80, 1 used 0.1% Tween 20, and the other 2 did not add surfactant. Generally, there are two screening principles for surfactants.

  • Common processing method: stir the sample horizontally at 250-300 rpm on an orbital shaker at 25°C for 8 hours or longer. After stirring, some samples will aggregate and the solution will become cloudy.
  • Reference detection methods: visual observation of solution clarity, concentration determination, SEC-HPLC detection of aggregate content, turbidity meter detection of turbidity, HIAC automatic liquid particle counter detection of particle number.

Excipient Screening

Among the 14 ADC formulations, various sugars or salts were added as excipients mainly. When setting different sugars and salts, there are many combinations and types. 10% trehalose, 9% sucrose, 5% sorbitol, etc. can be used as the basic formula for preliminary screening. When it is necessary to combine, the content of the two is halved. After 14 days of storage at 4°C, 25°C, and 40°C, characterizations were performed for transparency observation, BCA concentration detection, SEC-HPLC purity detection, DSC thermal stability detection, CIEF pH detection, etc.


  1. Kavianinia, I. et al. An insight into FDA approved antibody-drug conjugates for cancer therapy. Molecules. 2021, 26: 5847.
* Only for research. Not suitable for any diagnostic or therapeutic use.

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