General

About Circulating Tumor Cells (CTCs)

Where can CTCs be detected?

CTCs can be detected in all solid tumors.

Are CTCs different in different patients?

Yes, CTCs can be different in different patients.

What is the difference between CTCs and ctDNA (circulating tumor DNA)? Why is ctDNA not enough?

1. ctDNA are short DNA fragments coming from cancer cells (primary tumor and metastases). If different cancer cells are present in the patient (this is usually the case), then ctDNA is a mix of DNA-fragments of the different cancer cells. ctDNA is part of cfDNA (cell-free DNA) which is present in all people. The very low frequency of ctDNA in the cfDNA fraction influences the sensitivity of the ctDNA detection. Detection/analysis of ctDNA gives information about i) tumor y/n, ii) tumor-specific mutation, iii) presence of MRD, and potentially iv) location of the tumor.

2. CTCs are whole cancer cells coming from the primary tumor and metastases. They contain the complete omics (complete genome, the complete proteome, and the complete transcriptome) specific for each CTC. Different CTCs show different omics. Detection/analysis of CTCs gives information about i) tumor y/n, ii) complete tumor-DNA sequence resulting in a comprehensive analysis of tumor-specific mutations, iii) tumor-specific protein and transcriptome markers e.g., available drug-targets iv) location of the tumor and v) presence of MRD. CTCs can be differentiated from WBCs (white blood cells) by certain markers. The detection of CTCs usually shows no background.

Technology

How do we prove that all CTCs can be detected/isolated?

We spike healthy blood with a known number of cancer cells and analyze the recovery via microcopy after workup and immobilization of the cells.

How reproducible are our results?

The recovery of spiked cells is reproducibly between 95% and 100% using the same blood sample and analyzed by different team members.

How long does it take to isolate and analyze blood samples?

It currently takes 3 days – our goal is to bring it down to 2 days.

How many samples can you handle in parallel?

6 samples at once, 12 samples per day.

What is unique of our technology?

Several steps along our workflow are unique:

• our blood stabilizer keeps the blood stable for over 48 hours at ambient temperature
• lysis reagent to eliminate the red blood cells – recovery of white blood cells (WBC) > 97%
• preparation of the cells for detection and immobilization of the cells – no cells are lost

How do you distinguish CTCs from WBCs?

We distinguish CTCs from WBCs in the same manner as other CTC companies: CTCs are Dapi-positive, CK-positive, and CD-45 negative.

Do the detected number of CTCs have a clinical relevance for the outcome?

Although there are publications which suggest a worse outcome if more CTCs are detected, we think the correct characterization of all present CTCs will be the base to judge the outcome.

What is fundamentally different comparing our technology with existing CTC approaches?

Current technologies

• cannot reliably detect every CTC in each patient
• cannot characterize every CTC based on multiple proteomic and genomic markers
• cannot analyze other rare cells (e.g. T-cells for immune therapy)

The reasons for this depend on the technology used. For example,

• if the CTCs are captured by magnetic beads coated with specific antibodies against cell surface marker(s) (e.g., CellSearch®) then only those CTCs are isolated which have this/these marker(s) on the surface in enough density. All other CTCs which do not have this marker on the surface or not in enough density will be lost.
• if the CTCs are isolated by size exclusion (e.g., filtration, microfluidic systems), all smaller CTCs or quite deformable CTCs will not be isolated.

Why has no one solved this before?

Many people asked this question. We are not sure but we assume that

1. many companies hoped that it would be sufficient to detect subfractions/certain phenotypes of CTCs,
2. nobody had the time and budget to deeply evaluate the diversity of CTCs (within the same patients but also between different patients)
3. nobody had the time and budget to deeply compare the different technologies using the same blood samples in a quantitative manner to evaluate which CTCs are not detected/captured using different technologies

Clinical

What is the clinical relevance of our test?

In principle, our test allows to access all omics (proteomics (drug targets), transcriptomics, genomics (mutations, resistances), methylomics (location of the tumor). However, so far we worked only on proteomics and genomics for breast cancer.

Has the technology been tested in clinical studies?

No, because we first needed to solve the problem of i) capture all CTCs, ii) isolation of each CTC etc.

Has the technology been tested using clinical samples?

Yes. Telexos technology was tested in a prospective pilot study on 26 breast cancer patients in which a comparison between tissue diagnostics (pathologist) and CTCs (based on Telexos technology) was done. We were able to demonstrate that Telexos technology detects >20% more Her2-positive patients than tissue diagnostics. These patients can then undergo an antibody-based therapy which is more smooth and more specific than a chemo therapy.

In another pilot study, we compared our technology with CellSeach(R) using breast cancer samples. We detected >3x as many CTCs and, more importantly, found many false-negatives.

What happens if you detect more CTCs but outcomes don’t change?

Depends on the meaning of this question:

An general: If the therapy is not working then the CTCs are still present and can even increase in numbers. In this situation the CTCs should be thoroughly analyzed using our kit for this kind of tumor in order to identify the reason for this phenomenon (e.g., resistance)

What decision does a doctor make differently using your products?

This depends on each case. A general answer can not be given here.

Using our technology to analyze CTCs as the analyte allows

• to characterize the cancer in great detail (e.g., available drug targets, available mutation/resistances etc.)
• to monitor the therapy closely (advantage of Liquid Biopsy) but also in great detail in order to intervene and help to adapt the personalized therapy
• (theoretically) to detect cancer ealier (e.g., pancreatic cancer) but this has to be proven.

Business

Who are our customers?

Our customers are cancer clinics and cancer research centers as well as pharamceutical companies.

What are our first products? And for which application?

Our first products will be

• CTC detection kit, breast cancer (for the stratification of patients with metastatic breast cancer and their therapy monitoring)
• CTC detection kit, colorectal carcinome (CRC) (for the stratification of patients with metastatic CRC and their therapy monitoring)

Each of those products can detect cancer-specific drug targets and the mutations responsible for resistances.

What is our path to market?

We focus on the following criteria:

• Each cancer-specific product will be first introduced into the clinical RUO market. Then clinical studies will be performed to qualify for the IVD market
• We will start with the introduction of CTC products for breast and colorectal cancer in 2027
• The first products will be introduced into a limited market

Who will pay for the test?

• For RUO products: split between health insurances and patients
• For IVD products: Health insurances after approval

How often is the test used per patient?

For stratification usually only once. For therapy monitoring/MRD detection: At least 2 times, we recomment 3 times – in the end, this is the oncologist’s decision.