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Organ Specific Toxicity Assays

Organ specific toxicity assays are an essential part of early-stage preclinical development, allowing researchers to identify and mitigate organ-targeted safety risks before progressing to animal studies or clinical trials.

Purpose: To provide early, human relevant targeted insights into how a drug candidate may adversely affect specific human organs or systems. These assays help developers make informed decisions, reduce costs, and improve safety before advancing to clinical trials. These in vitro assays are faster, lower-cost, and reduce reliance on animal testing.

Target Organ Assay Principle Application FDA Context
Liver ALT/AST Release Assay Measures leakage of liver enzymes from damaged hepatocytes Screens for hepatocellular injury (acute or chronic DILI) Common in hepatotoxicity panels; supports in vivo liver findings
Liver CYP450 Inhibition/Induction Evaluates metabolism and enzyme regulation (CYP1A2, 2C9, 3A4, etc.) Assesses drug–drug interaction (DDI) and metabolic liability Required in FDA IND packages
Liver BSEP Inhibition Assay Detects interference with bile acid transport via BSEP transporter Screens for cholestatic injury risk Recommended for DILI risk assessment; especially if hepatobiliary toxicity is suspected
Liver Liver Organoid Toxicity Assay Uses 3D organoids to mimic liver architecture and bile canaliculi Long-term hepatotoxicity, mitochondrial dysfunction, steatosis Emerging tool for mechanistic and human-specific DILI profiling
Heart hERG Channel Inhibition Assay Measures blockade of the potassium ion channel (IKr) Predicts QT prolongation and torsades de pointes Mandatory under ICH S7B for small molecules
Heart iPSC-Derived Cardiomyocyte Assays Measures beating rate, Ca²⁺ flux, contractility, and cell viability Screens for functional and structural cardiotoxicity Accepted in biologics, ADCs, and oncology; used as mechanistic or supplemental safety data
Heart Cardiac Organoid Assay 3D cardiac tissue constructs simulate cardiac Advanced modeling of drug-induced arrhythmia and cardiotoxicity Emerging application; increasingly used in FDA pre-IND
Kidney KIM-1 / NGAL Expression Measures kidney injury biomarkers secreted by renal epithelial cells Early indicator of nephrotoxicity Recognized biomarkers in FDA/EMA; used in renal toxicity packages
Kidney RPTEC-Based Cytotoxicity Assays Viability or function assessment in proximal tubule epithelial cells Detects proximal tubule damage and accumulation toxicity Accepted in mechanism-based screening or in vitro–in vivo correlation studies
Kidney Kidney Organoid Assay iPSC-derived 3D nephron-like structures modeling kidney filtration/barrier Models glomerular and tubular toxicity, albuminuria, oxidative stress Used in advanced nephrotoxicity screening; growing FDA interest
Brain/CNS Neurite Outgrowth Assay Measures axonal and dendritic extension after exposure Screens for neurotoxicity and developmental neural disruption Recommended when BBB is crossed or neuroactive potential exists
Brain/CNS iPSC-Neuron or Brain Organoid Models 2D/3D models of functional neurons, astrocytes, glial cells Detects synaptic disruption, oxidative stress, neurotransmitter imbalance Accepted as investigative tools; valuable for CNS-active compounds
Immune System PBMC Cytokine Release Assay Measures inflammatory cytokines (e.g., IL-6, TNF-α, IFN-γ) released from PBMCs Detects cytokine storm or immune overstimulation Required for biologics (e.g., CAR-T, T-cell engagers, bispecifics); critical safety tool
Immune System T Cell Activation Assay Flow cytometric analysis of CD69, CD25, IFN-γ expression Characterizes immune activation or suppression Supports immunotoxicity profiling under CBER guidance
Lung Air–Liquid Interface (ALI) Lung Model Cultured airway cells exposed to aerosols in physiologically relevant manner Evaluates inhalation toxicity, mucociliary clearance, barrier damage Used for inhaled formulations and aerosols; accepted in IND-supporting packages
Lung Lung Organoid Assay 3D bronchioalveolar organoids derived from human stem cells Assesses chronic pulmonary toxicity, surfactant function Applied in inhalation tox and viral/immune-modulated respiratory products
Skin Reconstructed Human Epidermis (RHE) 3D model simulating epidermal barrier, tested for viability post exposure Detects skin irritation and corrosion FDA-accepted animal alternative per OECD TG 439
GI Tract Caco-2 / TEER Assays Measures epithelial permeability and barrier integrity Screens for intestinal toxicity or absorption-related issues Included in oral tox packages and bioavailability studies
GI Tract Intestinal Organoid Assay 3D gut structures mimicking villi, crypts, and barrier function Evaluates GI irritation, inflammation, or ulceration Emerging assay for oral drugs, especially in immuno-oncology or NSAID screening
Bone Marrow CFU (Colony Forming Unit) Assay Measures progenitor cell proliferation and colony differentiation Screens for myelotoxicity and marrow suppression Recommended for cytotoxic drugs (e.g., chemotherapy, antivirals)