Sample Submission Guidelines
The Rise of TIL Therapy and Its Quality Control Challenge
Tumor-infiltrating lymphocyte (TIL) therapy represents one of the most significant recent advances in adoptive cell immunotherapy. In February 2024, the FDA approved Amtagvi (lifileucel) — the first TIL therapy product — for unresectable or metastatic melanoma, marking a pivotal moment for immune repertoire sequencing as a precision quality tool in the CGT space.
TIL therapy works by harvesting T cells that have naturally infiltrated a patient's tumor, expanding them ex vivo to large numbers, and reinfusing them to achieve targeted anti-tumor killing. Unlike CAR-T therapy, TIL products carry a diverse, pre-existing set of T cell receptor (TCR) clones that have already encountered tumor antigens — a property that is both their therapeutic strength and their quality control challenge.
The manufacturing process spans tumor resection and TIL isolation, a rapid expansion protocol (REP) lasting two to three weeks, and final product formulation. Each stage can alter cellular composition. Current quality release testing typically evaluates cell count, viability, sterility, and basic phenotype markers — metrics that confirm a product is alive and expandable, but reveal nothing about whether the functionally relevant, tumor-reactive clones survived and were enriched throughout the process.
Why TCR Clonotype Analysis Is the Missing CQA
EMA guidance documents increasingly identify TCR clonotype composition as a strongly recommended critical quality attribute (CQA) for TIL products. The biological rationale is clear: a product's clinical efficacy depends not on how many cells it contains, but on whether the cells with the right TCR specificities are present, at adequate frequency, and retained through manufacturing.
| Quality Dimension | Conventional Testing (Count / Viability / Flow) | TCR Clonotype Analysis (T-Track) |
|---|---|---|
| Identity / Molecular Fingerprint | Cannot confirm tumor origin of T cells | Establishes unique TCR clonal signature traceable to tumor biopsy |
| Potency Surrogate | IFN-γ release or nonspecific cytotoxicity assay | Clonotype abundance as surrogate for tumor-reactive clone frequency |
| Process Consistency | Fold expansion and viability ratios | TCR repertoire shift detection across manufacturing steps |
| Clinical Outcome Prediction | No validated correlate | TCR diversity and clonality metrics correlate with PD1 response and survival |
| Regulatory Alignment | Accepted but insufficient per recent guidance | Addresses EMA CQA recommendation directly |
| PK Monitoring | Not feasible from peripheral blood by flow | Sensitive clone-level tracking in blood post-infusion |
Our TCR sequencing platform delivers the molecular depth that cell-count-based testing cannot. It answers the questions regulators and clinical teams are increasingly asking: Does this product contain the same T cell identities as the original tumor? Have the dominant functional clones been preferentially expanded — or accidentally diluted?
T-Track TILs: Full Life-Cycle Clonal Tracking
T-Track is CD Genomics' dedicated solution for TIL therapy TCR quality control, built around the regulatory and manufacturing demands of clinical-stage CGT programs — not a general-purpose research TCR-seq service.
Clone-Level Molecular Identity
- Establishes unique TCR clonal fingerprint at tumor baseline
- Proves manufactured product retains patient's tumor T cell repertoire
- Provides molecular evidence of product identity that counts and viability cannot
Manufacturing Process Consistency Monitoring
- Profiles TCR clonal composition at every critical manufacturing step
- Tracks clones present at >1% frequency from pre-REP through final product
- Detects process-driven clonal selection or depletion events quantitatively
Clinical Response-Predictive Metrics
- Delivers validated diversity indices: Shannon entropy, clonality, CDR3 richness
- Higher pre-infusion TCR diversity and tumor-specific clone frequency associate with durable responses
- Supports retrospective responder/non-responder analysis and patient stratification
Peripheral Blood PK Monitoring
- Tracks infused clones in serial peripheral blood samples post-infusion
- Confirms in vivo expansion and persistence of therapeutic clones
- Critical data for IND submission pharmacology sections
Validated Methodology for Regulatory Submission
- Full method validation completed for precision, accuracy, sensitivity, and linearity per ICH Q2(R1)
- Validation documentation formatted for inclusion in IND CMC sections
- Report format designed to support direct regulatory filing — not raw research output
Service Workflow
From consultation and study design to IND-ready data package — our T-Track team guides every step.
Step 1 — Consultation & Study Design: We review your TIL manufacturing process, IND timeline, and regulatory strategy. We define the sampling plan — which timepoints to profile (biopsy, pre-REP, post-REP, final product, PK blood draws), what reference samples are needed, and how to align the data package with EMA expectations.
Step 2 — Sample Collection & QC: We accept tumor biopsy tissue, TIL suspension (fresh or frozen), PBMC from peripheral blood, and final product aliquots. Each sample undergoes nucleic acid extraction and strict QC — concentration, integrity, and input adequacy — before library preparation begins.
Step 3 — TCR Library Preparation & Sequencing: Bulk TCR-seq is performed using validated multiplex PCR or 5' RACE amplification of CDR3 regions (TCRα and TCRβ chains), followed by high-depth NGS. Library preparation includes built-in spike-in controls for quantitative accuracy. Single-cell TCR sequencing is available for individual-cell-level resolution.
Step 4 — Bioinformatics Analysis: Our validated pipeline calls CDR3 sequences, assigns V(D)J gene usage, quantifies clonotype frequency, and computes diversity metrics. Cross-timepoint clone matching identifies specific clones tracked from biopsy to product to blood. Longitudinal clonal abundance plots and comparative diversity analyses are generated.
Step 5 — Results Delivery & Regulatory Report: You receive raw sequencing files, per-sample QC metrics, clone frequency tables, longitudinal tracking figures, and a formatted analytical report written to support IND submission. A scientific debrief session is included to discuss findings and follow-up strategy.
Key Applications
T-Track delivers actionable TCR data across the full TIL therapy development and clinical cycle.
TIL Product Lot Release Testing
T-Track delivers TCR clonotype composition data as a supplementary release criterion alongside conventional cell count and viability. The data confirms molecular product identity and documents process consistency across batches — directly supporting regulatory filing and lot comparability.
Manufacturing Process Development & Optimization
During process development, T-Track reveals whether REP protocol changes — cytokine cocktail, feeder cell ratios, duration — preferentially expand or deplete specific TCR clones. This enables data-driven process optimization before locking a manufacturing method for IND submission.
Clinical Outcome Correlation & Patient Stratification
Baseline TCR diversity metrics from tumor biopsy or pre-REP product can serve as biomarkers of clinical response. Teams use T-Track data to analyze responder versus non-responder patterns and design patient selection criteria for clinical trials. Integration with single-cell sequencing extends this to full transcriptome-coupled clone characterization.
Pharmacokinetic & Persistence Monitoring
Post-infusion peripheral blood sampling with T-Track quantifies the in vivo expansion, peak frequency, and decay of infused TCR clones — providing immune PK data required in clinical trial protocols and IND pharmacology sections. Clone detection sensitivity reaches frequencies as low as 0.01% in peripheral blood with enhanced sequencing depth.
Sample Requirements
All samples should be collected using sterile technique and documented per chain-of-custody requirements. We provide a sample submission form and pre-analytical handling SOP upon project initiation.
| Sample Type | Manufacturing Timepoint | Recommended Input | Minimum Input | Notes |
|---|---|---|---|---|
| Tumor biopsy (fresh tissue) | Baseline | 50–100 mg | 20 mg | Single-cell suspension on-site or ship in cold media |
| TIL suspension (pre-REP) | Day 0 | ≥1×106 cells | 5×105 cells | Fresh or cryopreserved; PBMC-compatible media |
| TIL suspension (post-REP / final product) | Day 14 / release | ≥1×106 cells | 5×105 cells | Final product aliquot acceptable |
| Peripheral blood (PK monitoring) | Post-infusion (Day 7, 14, 28+) | 10 mL whole blood | 5 mL whole blood | PBMC isolation at site or ship in Streck tubes |
| Genomic DNA (pre-extracted) | Any | ≥500 ng | 200 ng | OD 260/280 ≥ 1.8 |
| Total RNA (pre-extracted) | Any | ≥1 µg | 500 ng | RIN ≥ 7; dissolved in RNase-free water |
- Contact us before shipping: Please reach out to our project team before submitting samples for cold-chain coordination, custom handling protocols for rare or limited samples, and chain-of-custody documentation for GMP-adjacent workflows.
Bioinformatics Analysis & Deliverables
Our T-Track bioinformatics pipeline is purpose-built for clinical TIL quality data, not research-grade exploratory output. Every deliverable is formatted to support direct inclusion in regulatory submission packages.
- Raw Data & QC: FASTQ files with per-sample QC metrics — read depth, mapping rate, unique clonotype count per sample.
- CDR3 Sequence Tables: Full clonotype list with V(D)J gene assignments, amino acid and nucleotide sequences, and absolute/relative frequency per timepoint.
- Longitudinal Clone Tracking Matrix: Cross-timepoint clone matching, abundance at each sampling point, ranked by pre-REP frequency — the core T-Track deliverable.
- Diversity Metrics Report: Shannon entropy, clonality index, CDR3 richness, CL50 — with intra-lot and inter-lot comparisons and statistical testing.
- Visualization Package: Stacked bar plots, clonality landscape plots, Lorenz curves, and peripheral blood PK clone tracking figures (if PK samples included).
- Analytical Validation Summary: Precision, accuracy, sensitivity, linearity per ICH Q2(R1) — available in submission-ready format for IND CMC sections.
Additional options include V gene usage profiling, CDR3 motif analysis, and integration with CRISPR off-target validation or other CGT safety datasets for comprehensive IND packages.
References
- Rohaan MW, Borch TH, van den Berg JH, et al. Tumor-infiltrating lymphocyte therapy or ipilimumab in advanced melanoma. N Engl J Med. 2022;387(23):2113–2125. https://doi.org/10.1056/NEJMoa2210233
- Ramsden DA, Marais R, et al. The T cell receptor repertoire of tumor infiltrating T cells is predictive and prognostic for cancer survival. Nat Commun. 2021;12:4098. https://doi.org/10.1038/s41467-021-24343-x
- Tsai SQ, Zheng Z, Nguyen NT, et al. GUIDE-seq enables genome-wide profiling of off-target cleavage by CRISPR-Cas nucleases. Nat Biotechnol. 2015;33(2):187–197. https://doi.org/10.1038/nbt.3117
For Research Use Only. Not for use in diagnostic or clinical procedures.
Demo Results
TCR clonotype frequency distribution across 10 representative TIL products — proportion of reads in top 1, 10, and 100 clones. Extended REP duration correlates with increased clonality.
Longitudinal tracking of top 20 TCR clones across four manufacturing timepoints: tumor biopsy → pre-REP Day 0 → post-REP Day 14 → final product. Clone-level expansion and depletion events are quantitatively resolved.
Diversity metrics (Shannon entropy, clonality, CDR3 richness) comparing pre-REP vs. post-REP across a clinical lot series (n=8). Error bars show inter-lot variability; statistically significant REP-driven changes are flagged for process reproducibility assessment.
References
- Ramsden DA, Marais R, et al. The T cell receptor repertoire of tumor infiltrating T cells is predictive and prognostic for cancer survival. Nat Commun. 2021;12:4098. https://doi.org/10.1038/s41467-021-24343-x
T-Track TILs FAQs
1. Is TCR clonotype analysis required or only recommended by EMA for TIL products?
Current EMA guidance documents list TCR clonotype composition as a strongly recommended critical quality attribute for TIL products — not yet a mandatory lot release test in all jurisdictions, but increasingly expected in IND submissions and product license applications. As the regulatory landscape matures following the Amtagvi approval in 2024, TCR clonotype analysis is moving from "strongly recommended" toward expected standard practice. Establishing this measurement now positions your program for smoother regulatory review and reduces the risk of data deficiency requests.
2. Can you track the same TCR clones from tumor biopsy through manufacturing to peripheral blood PK?
Yes — longitudinal clone-level tracking across all manufacturing timepoints and post-infusion blood samples is the central design principle of T-Track. We assign a unique identifier to every CDR3 clonotype detected at baseline biopsy and follow its abundance through pre-REP, post-REP, final product, and peripheral blood draws. The resulting longitudinal tracking matrix is a standard deliverable in every project data package, and the methodology is validated for quantitative accuracy at each step.
3. What is your detection sensitivity for low-frequency clones in bulk TIL products?
Our T-Track assay detects clonotypes present at frequencies as low as 0.01% of the total T cell population in bulk products, depending on input cell number and sequencing depth. For peripheral blood PK monitoring, where infused clone frequencies may be very low after dilution in systemic circulation, we offer enhanced sequencing depth options with corresponding limits of detection defined in the method validation documentation — available for inclusion in IND submissions.
4. Is the T-Track method validated per ICH Q2(R1) analytical method validation guidelines?
Yes. T-Track has undergone full analytical method validation for the key performance parameters required for clinical CQA testing: precision (intra-run and inter-run repeatability), accuracy (spike-in recovery), sensitivity (limit of detection and limit of quantification), and linearity across the relevant input cell number range. Validation documentation is available in a format suitable for direct inclusion in IND CMC sections, supporting its use as part of GMP-adjacent quality documentation.
5. How does TCR clonality add value over standard flow cytometry phenotyping?
Flow cytometry phenotyping reveals the proportions of T cell subsets — CD4+, CD8+, PD-1+, TIM-3+ — but cannot distinguish individual TCR clones. Two TIL products with identical flow phenotypes can have radically different clonal compositions, and therefore different potentials for tumor recognition. TCR-seq identifies each clone by its unique CDR3 amino acid sequence, tracks it quantitatively through manufacturing, and links its abundance to published biomarkers of clinical response. Flow and TCR-seq are complementary; T-Track fills the functional identity gap that flow cytometry cannot address.
T-Track TILs Case Studies
Published Research Highlight
The T Cell Receptor Repertoire of Tumor Infiltrating T Cells Is Predictive and Prognostic for Cancer Survival
Journal: Nature Communications
Volume: 12, Article 4098
Published: July 2, 2021
Background
A key unresolved question in TIL therapy and checkpoint immunotherapy has been whether the properties of the TCR repertoire within tumor-infiltrating T cells — rather than simply their density — can predict patient outcomes. If TCR diversity and clonality carry prognostic or predictive value, then quantifying these metrics would justify their inclusion as a clinical CQA in TIL product quality assessments. Ramsden, Marais, and colleagues at the University of Manchester set out to test this hypothesis systematically across multiple cancer types and to determine whether baseline TCR clonality could predict response to anti-PD1 immunotherapy in metastatic melanoma.
Materials & Methods
Sample Preparation
- Pre-treatment tumor biopsy samples across multiple cancer histologies
- TCGA cohort for pan-cancer prognostic analysis
- 16 metastatic melanoma patients receiving anti-PD1 therapy
Sequencing
- Targeted TCR beta chain CDR3 sequencing
- High-throughput NGS of TIL repertoires
- Bulk TCR-seq from tumor biopsy tissue
Data Analysis
- Shannon entropy (diversity) calculation per sample
- TCR clonality index measurement pre-treatment
- Correlation with clinical response and overall survival
Results
- TCR Diversity as a Pan-Cancer Prognostic Biomarker
- Higher baseline TCR diversity of tumor-infiltrating T cells was associated with significantly improved overall survival across cancer types in the TCGA cohort (Fig. 1).
- TCR repertoire metrics provided prognostic information independent of T cell density, confirming that molecular composition of TIL products matters beyond simple cell counts.
Fig. 1 — TCR repertoire diversity of tumor-infiltrating T cells is prognostic for cancer survival across tumor types. Higher baseline Shannon entropy correlates with improved overall survival. (Ramsden DA, Marais R et al., Nat Commun, 2021)
- TCR Clonality Predicts Anti-PD1 Immunotherapy Response
- In 16 metastatic melanoma patients receiving anti-PD1 therapy, patients whose pre-treatment TILs showed higher TCR clonality — indicating a more oligoclonal, antigen-driven T cell response — demonstrated significantly better response to PD1 blockade.
- This finding establishes clonality as a predictive biomarker for checkpoint therapy response, independent of total TIL count or flow phenotype.
- TCR Metrics Outperform Cell-Count-Based Quality Assessment
- TCR diversity and clonality provided prognostic and predictive information that cell density measurements could not capture.
- These results directly support the scientific rationale for including TCR clonotype analysis as a CQA in TIL product characterization, as increasingly recommended by EMA guidance.
Conclusion
This study provided rigorous clinical evidence that TCR repertoire properties — specifically diversity and clonality — are prognostic for survival and predictive for immunotherapy response, beyond what cell density or phenotypic markers can reveal. For TIL therapy developers, these findings establish the scientific foundation for incorporating TCR clonotype analysis as a CQA: a product rich in tumor-reactive, clonally expanded T cells is measurably better, and TCR-seq can quantify this. The T-Track TILs Solution delivers exactly this measurement in a validated, CMC-ready format.
Reference
- Ramsden DA, Marais R, et al. The T cell receptor repertoire of tumor infiltrating T cells is predictive and prognostic for cancer survival. Nat Commun. 2021;12:4098. https://doi.org/10.1038/s41467-021-24343-x
