Clinical-Grade tTMB Ref Std for Cancer I-O

Product Overview

The Clinical-Grade Tumor Mutation Burden (tTMB) Reference Standard is a meticulously engineered tool to validate next-generation sequencing (NGS) assays measuring tTMB, a pivotal biomarker for predicting response to immune checkpoint inhibitors (ICIs) in cancer immunotherapy (I-O). This reference standard comprises cell line-derived DNA with a characterized mutational landscape, spanning 20,000+ somatic mutations across 500+ cancer-related genes, calibrated to mimic high, intermediate, and low tTMB phenotypes (≥20, 10-19, and <10 mutations/Mb, respectively) .

Developed in alignment with FDA and EMA guidelines for I-O biomarker validation, this standard enables laboratories to assess the accuracy, precision, and reproducibility of their tTMB assays. Its design reflects key findings from landmark studies like CheckMate 227, which demonstrated improved progression-free survival (7.2 vs. 5.5 months) in patients with tTMB ≥10 mut/Mb treated with dual immunotherapy . By providing a benchmark for assay performance, it ensures reliable identification of patients most likely to benefit from ICIs.

Product Features

• Clinically Relevant Mutational Spectrum: Includes mutations in genes frequently altered in NSCLC, melanoma, and colorectal cancer, with 98% concordance with whole-exome sequencing (WES) results .

• Quantitative Gradient Design: Three distinct tiers of tTMB levels allow verification of assay linearity across the clinically meaningful range, critical for distinguishing between responders and non-responders.

• Stability Guarantees: Lyophilized DNA remains stable for 24 months at -80°C; rehydrated aliquots stored at -20°C retain integrity for up to 6 months with minimal degradation .

• Traceability: Each lot is validated against international reference materials, with a comprehensive certificate of analysis detailing mutation counts, allele frequencies, and performance characteristics.

Usage

Reconstitution and Handling:

• Rehydrate lyophilized DNA with molecular-grade water to a final concentration of 50 ng/µL, vortex gently, and incubate at room temperature for 10 minutes.

• Aliquot into single-use portions to avoid repeated freeze-thaw cycles, which can introduce artificial mutations.

Assay Validation Workflow:

• Include the reference standard in NGS runs alongside clinical samples, following the same library preparation and sequencing protocols.

• Calculate tTMB using the laboratory’s standard bioinformatics pipeline, ensuring alignment with the expected values provided in the certificate of analysis.

Performance Monitoring:

• Track inter-run variability using the coefficient of variation (CV) for each tTMB tier; a CV <5% indicates robust assay performance.

• Use results to troubleshoot issues such as insufficient sequencing depth or bioinformatics pipeline errors.

FAQ

How does this standard account for different panel sizes?

It is optimized for 500+ gene panels, the minimum size shown to correlate with WES-derived tTMB, but can be used to validate smaller panels by adjusting mutation count thresholds .

Can it detect assay-specific biases?

Yes. Its diverse mutational landscape includes insertions, deletions, and substitutions, enabling identification of platform-specific limitations in variant calling.

What is the shelf life after reconstitution?

Rehydrated DNA stored at -20°C is stable for 6 months, but for best results, use within 3 months of reconstitution .

How does tTMB correlate with other I-O biomarkers like PD-L1?

tTMB and PD-L1 expression are independent biomarkers; this standard focuses solely on tTMB, allowing laboratories to validate this metric without confounding variables .