Implementation of Systematic Bioanalysis of Antibody–Drug Conjugates for Preclinical Pharmacokinetic Study of Ado-Trastuzumab Emtansine (T-DM1) in Rats

Versatile intact LC-MS method for evaluating the drug-antibody ratio and drug load distribution of antibody-drug conjugates in human plasma

The average drug-antibody ratio (DAR) and drug load distribution (DLD) of an antibody-drug conjugate (ADC) can be altered by biotransformation after administration. In addition, drug loading affects the clearance and exposure of the ADC. Evaluating alterations in the average DAR and DLD of an ADC in vivo would provide valuable information to better understand of the pharmacokinetic (PK) profile of the ADC. Although the quantitation of antibodies/ADCs using LC-MS is often coupled with affinity capture methods, here, we aimed to develop a versatile intact LC-MS method for evaluating the average DAR and DLD of ADCs in human plasma. The development of the affinity purification process and method validation were performed using healthy human pooled plasma spiked with the model ADCs, commercially available trastuzumab emtansine (T-DM1) and brentuximab vedotin (B-MMAE), and the recombinant proteins HER2 and CD30 were used to capture T-DM1 and B-MMAE, respectively. As unique points of this study, initially, a two-step gradient was established for the sensitive detection of a small amount of ADC. The ADC elution conditions after affinity capture were also optimized considering its application for LC-MS analysis. Furthermore, a validation study of the intact LC-MS approach for analyzing the average DAR and DLD of ADCs in human plasma sample was proposed for the first time. Using the validation study, our analytical method was validated by verifying its performance characteristics, including sensitivity, intermediate precision, accuracy, carryover and autosampler stability. In addition, the feasibility of applying our method was demonstrated by a collaborative study with six laboratories. Finally, our method was shown to be versatile for evaluating the average DAR and DLD of ADCs in human plasma.

Preparation and anti-tumor ability evaluation of anti-PD-L1 conjugated curcumin in colon cancer

Immune checkpoint inhibitors have been approved for various solid tumor treatments but have shown poor efficacy on colon cancer. Curcumin has been proven as an anti-tumor agent that inhibits cell cycle and tumor cell proliferation. Moreover, curcumin has also been reported to have the ability to inhibit PD-L1 expression, which might benefit the therapeutic efficacy of immune checkpoint inhibitors. Therefore, we proposed using antibody-drug conjugate (ADC) could effectively inhibit tumor proliferation and reverse the immunosuppression in colon cancer. We prepared an anti-PD-L1 conjugated curcumin with a ROS-responsive linker of phenylboronic acid carbamate, which provides chemo-drug active targeting ability and tumor environment-responsive release. Both in vitro and in vivo data confirm the improved cytotoxicity of anti-PD-L1-PBA-Cur and inhibited cell invasion. More importantly, the PD-L1 expression on the tumor surface was significantly reduced after being treated with ADC. The in vivo inhibition of tumor progression and PD-L1 expression was confirmed in both subcutaneous and in-suit mouse models. This study provides an effective colon treatment strategy with the advantages of high tumor targeting efficiency and immunopotentiation potential.

Simultaneous Quantification of Total Antibody and Conjugated Payload for DS001 in Rat Serum Using a Hybrid Immuno-Capture LC-MS/MS

Antibody-drug conjugates (ADCs) are intricate compounds that pose significant challenges in bioanalytical characterization. Therefore, multiple bioanalytical methods are required to comprehensively elucidate their pharmacokinetic (PK) profiles. In this study, we investigated DS001, an ADC consisting of a humanized monoclonal antibody (hRS7), a cleavable chemical linker, and the microtubule inhibitor monomethyl auristatin E (MMAE), with a drug-to-antibody ratio (DAR) of 8. This study established a rapid and sensitive hybrid immunoaffinity liquid-chromatography-tandem-mass-spectrometry (LC-MS/MS) approach for the simultaneous quantification of the total antibody and the enzymatically cleavable conjugated payload of DS001. This method is capable of monitoring fluctuations in average DAR values during PK assessments. The sample preparation procedure involved immunocapture, denaturation, trypsin digestion, papain digestion, and termination, all completed within a total processing time of less than 4 h. The method demonstrated linearity for the total antibody in the range of 100 ng/mL (lower-limit-of-quantification, LLOQ) to 100,000 ng/mL, and for the conjugated payload from 3.495 ng/mL (LLOQ) to 3495 ng/mL in rat serum. Both analytes exhibited standard curve correlation coefficients (r) greater than 0.990 within their respective linear ranges. The precision and accuracy of the method were within ± 15% (± 20% for LLOQ). The verified LC-MS/MS approach was successfully employed in the PK analysis following intravenous administration of 0.2 mg/kg DS001 in rats via tail vein injection.

Antibody-drug conjugates: A review of cutaneous adverse effects

Antibody-drug conjugates (ADCs) are an emerging class of anticancer agents that combine targeting antibodies with potent cytotoxic agents. Their molecular configuration allows for increased therapeutic efficacy and reduced adverse-effect profiles compared to monoclonal antibodies or cytotoxic chemotherapy alone. ADCs cause off-target toxicities through several mechanisms, including premature deconjugation of the cytotoxic agent in the serum and the presence of the targeted antigen on normal tissues. Given cutaneous adverse events comprise 31.3% of all-grade adverse events in clinical trials involving ADCs, dermatologists are increasingly called upon to manage the cutaneous toxicities caused by these drugs. In this review, we summarize known cutaneous toxicities of the ADCs that have been approved for use by the US Food and Drug Administration to date. Dermatologists can play a key role in recognizing cutaneous reactions associated with ADCs, contributing to guidelines for their management, and aiding during clinical trials to generate detailed morphologic and histopathologic descriptions of cutaneous toxicities caused by ADCs.

Development and validation of bioanalytical assays for the quantification of 9MW2821, a nectin-4-targeting antibody-drug conjugate

We designed and developed 9MW2821, an anti-Nectin-4 antibody-drug conjugate (ADC) with an enzymatically cleavable valine-citrulline linker and monomethyl auristatin E (MMAE) as the payload. Four bioanalytical assays for total antibodies, conjugated antibodies, conjugated payload, and free payload were then developed and validated for the comprehensive evaluation of the multiple drug forms of 9MW2821. Specific sandwich enzyme-linked immunosorbent assays were used to quantify total antibodies and conjugated antibody, showing good drug-to-antibody ratio (DAR) tolerance. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine free MMAE, and conjugated MMAE was quantified using a combination of ligand-binding assay (LBA) and LC-MS/MS. Based on these four assays, we studied the serum stability and monkey pharmacokinetic profiles of 9MW2821, and the in vivo DAR of 9MW2821 was calculated and dynamically monitored. In conclusion, we developed and validated series of bioanalytical assays to quantify multiple forms of 9MW2821, a new ADC, and used the assays to evaluate the serum stability and monkey pharmacokinetic characteristics. The results indicate good linker stability and suggest that the developed assays can be further used in clinical settings.

Development and validation of bioanalytical methods to support clinical study of disitamab vedotin

Disitamab vedotin (RC48), a humanized anti-HER2 antibody conjugated with monomethyl auristatin E (MMAE), is the first antibody-drug conjugate in China with an approved biological license application. A bioanalytical method was established for three analytes (total antibody, conjugate antibody and free payload) to help characterize their pharmacokinetic behavior in clinical settings. The bioanalytical methods were validated according to M10 guidance. Electrochemiluminescence assay methods were used for the quantitative measurement of total antibody and conjugated antibody in human serum. A LC-MS/MS method was used to quantify the concentration of MMAE in human serum. The method had high specificity and sensitivity with a quantitative range of 19.531-1250.000 ng/ml (total antibody), 39.063-5000.000 ng/ml (conjugated antibody) and 0.04-10.0 ng/ml (MMAE), respectively.

Monoclonal Antibodies and Antibody-drug Conjugates as Emerging Therapeutics for Breast Cancer Treatment

When breast cells divide and multiply out of control, it is called breast cancer. Symptoms include lump formation in the breast, a change in the texture or color of the breast, or a discharge from the nipple. Local or systemic therapy is frequently used to treat breast cancer. Surgical and radiation procedures limited to the affected area are examples of local management. There has been significant worldwide progress in the development of monoclonal antibodies (mAbs) since 1986, when the first therapeutic mAb, Orthoclone OKT3, became commercially available. mAbs can resist the expansion of cancer cells by inducing the destruction of cellular membranes, blocking immune system inhibitors, and preventing the formation of new blood vessels. mAbs can also target growth factor receptors. Understanding the molecular pathways involved in tumor growth and its microenvironment is crucial for developing effective targeted cancer therapeutics. Due to their unique properties, mAbs have a wide range of clinical applications. Antibody-drug conjugates (ADCs) are drugs that improve the therapeutic index by combining an antigen-specific antibody with a payload. This review focuses on the therapeutic applications, mechanistic insights, characteristics, safety aspects, and adverse events of mAbs like trastuzumab, bevacizumab, pertuzumab, ertumaxomab, and atezolizumab in breast cancer treatment. The creation of novel technologies utilizing modified antibodies, such as fragments, conjugates, and multi-specific antibodies, must be a central focus of future studies. This review will help scientists working on developing mAbs to treat cancers more effectively.