Cell and Gene Therapy Answers: Top considerations for ocular cell and gene therapies

As the field of ocular cell and gene therapies advances, biopharma companies face unique challenges in bringing these innovative treatments from the lab to the clinic. To shed light on the complexities and opportunities in this growing area of therapeutic research, we sat down with Labcorp Study Director and Nonclinical Ocular Toxicology Lead, Peter Sonnentag, to discuss four crucial aspects of ocular cell and gene therapies: the preclinical development process, regulatory requirements for ophthalmic gene therapy programs, the role of immune suppression in both cell and gene therapies and the distinct characteristics that contribute to a successful preclinical program. Here’s what to know. 

Receptor occupancy analysis with solid tumor: Measurement with flow cytometry

China Bioanalysis Forum 2024 -- Drug-target engagement studies are essential to understand molecular pharmacology and pharmacokinetic/pharmacodynamic (PK/PD) relationships. The ability of drugs to penetrate the tumor and bind their target is critical for the successful treatment of solid tumors. Flow cytometry-based receptor occupancy (RO) assays are frequently used for measuring and quantifying the binding of a drug, which is regarded as a critical PD biomarker for the quantitative evaluation of PK/PD relationships and can provide useful information for initial dose range finding in early phases of clinical trials. RO assays are typically performed on fresh blood specimens. However, evaluating RO for the drugs that target receptors on solid tumor tissues (such as ADC drugs) is perceived to be very difficult if not impossible. In this study, we explored the feasibility of flow cytometry-based RO assay with solid tumor tissue samples in clinical trials through a CDX mouse model.

Using in-vivo samples to aid assay transfer of an ADC PK assay: Lesson learned from a case study

China Bioanalysis Forum 2024 -- Antibody-drug conjugates (ADCs) represent a rapidly evolving area of drug development and hold significant promise. It combines the target specificity of monoclonal antibodies with the anticancer activity of small-molecule therapeutics. Method transfers occur for a number of reasons. Typically, when a program is in early clinical states, there is usually only a single lab supporting the clinical bioanalysis for the study. However, if the program expands into multiple clinical studies and multiple countries, the bioanalytical work needs may exceed the support of a single lab. Therefore, it could be necessary to establish the bioanalytical assay in other labs, including in other countries. Per M10, cross-validation is required to demonstrate how the reported data are related when multiple bioanalytical labs are involved in one study or across studies that are going to be combined or compared to support special dosing regimens, or regulatory decisions regarding safety, efficacy and labelling. ADC is a complex modality in structure. Biotransformation in vivo can lead to additional changes in drug-to-antibody ratios resulting in dynamically changing mixtures. It makes that cross-validation for ADC more challenging as compared to other biologics. This poster proposes to use in-vivo samples as an effective approach to guide the assay transfer for an ADC PK assay.

Hybrid (LBA)-LC-MS/MS methodology covers the different dimensions of ADC bioanalysis

China Bioanalysis Forum 2024 -- An antibody-drug conjugate (ADC) is generally composed of a small-molecule drug, also known as a payload, and an antibody or antibody fragment, conjugated together by a chemical linker. In accordance with recommended guidelines, it is advised to primarily detect the conjugated antibody/Ab-conjugated payload (ADC), total antibody (conjugated antibody and unconjugated antibody), and free small molecule compounds in pharmacokinetic (PK) studies of ADCs. So, three bioanalytical methods are typically employed in ADC bioanalysis: free toxin PK assay, ADC PK assay (Ab-conjugated payload), total antibody PK assay. Recently the hybrid (LBA)-LC-MS/MS has been used on ADC bioanalysis and has covered ADC PK assay and total antibody PK assay, plus regular LC-MS/MS method for free toxin assay, LC-MS/MS platform provides additional valuable solutions for ADC bioanalysis.

Developing and validating a neutralizing Ab assay to AAV9 based on cell-based platform

China Bioanalysis Forum 2024 -- Gene therapy brings the promise of a one-time treatment option that will fix the errors in patient genetic coding. Recombinant viruses are highly efficient vehicles for in vivo gene delivery. Adeno-associated virus (AAV) is one of the most actively investigated delivery tool in clinical gene therapy owing to its minimal pathogenicity and ability to establish long-term gene expression in different tissues. Assessment of the neutralizing antibodies (NAbs) of AAV in patients prior to/after systemic gene therapy administration is an important consideration regarding efficacy and safety of the therapy.

Minimizing target interference in PK assays: An approach for sample heat pre-treatment

China Bioanalysis Forum 2024 -- Quantitation of total levels of monoclonal antibody (mAb) biotherapeutics in serum using ELISA may be hindered by soluble targets. Interfering molecules can form complexes with the analyte and inhibit the specific binding characteristics used for either capture or detection of the analyte in an assay. Based on Bead-Extraction and Heat-Dissociation (BEHD) which uses heat pre-treatment to minimize drug interference in ADA assay when the drug with lower melting temperature than full 150-kDa antibody (Xu et al. Immunological Methods, 2018), we hypothesized that target interference in PK assay can be dissociated or removed by sample heat pre-treatment. 

Quantitative bioanalysis of oligonucleotides in tissue

China Bioanalysis Forum 2024 -- An antisense oligonucleotide (ASO) is a single-stranded ribonucleotide therapeutic, typically 16-20 nucleotides long, designed to bind complementary to the target RNA via Watson-Crick base pairing. Determination of oligonucleotides in biological tissues yields information which assists investigators in pharmacokinetic studies and may help to avoid potential organ toxicity. Compound A, a novel unconjugated ASO was designed to treat chronic hepatitis B for a functional cure. Through a global development strategy, Compound A is advancing rapidly towards the goal of HBV cure. To support a toxicity study of Compound A, a robust method was set up for the quantification of Compound A in different types of tissue homogenate, including kidney, liver, spleen, placenta, milk and in different species including mouse, monkey and rabbit.

How your employees can quit smoking and help reduce COPD risk

Learn about the impact and causes of chronic obstructive pulmonary disease (COPD). And, as the Great American Smokeout approaches on Nov. 21, see how a wellness coach can assist with a smoking cessation program.

Clinical considerations of drug testing in the primary care setting

Drug testing plays a critical role in monitoring patients who are prescribed controlled substances, including opioid pain medications, anti-anxiety medications, stimulants and drugs to treat substance use disorder. Testing choices have expanded in recent years and choosing the most appropriate drug testing involves considering many factors. Join Labcorp’s toxicology experts to gain insights into the fundamentals of clinical drug testing to help inform patient treatment decisions.

What to know about ocular cell and gene therapies

Cell and gene therapy (CGT) development for the eye differs from CGT development for other parts of the body. Discover more of the unique traits, regulatory guidelines and strategies necessary for ocular CGTs in our new Cell and Gene Therapy Answers video.