NEW YORK – Startup MiCareo Rare Cell Diagnostics has developed a fluorescent cell sorting instrument that it claims can filter millions of cells in minutes from a patient's blood sample to detect circulating tumor cells (CTCs), immune cells, and other rare cell types.
The firm plans to publish data that show the instrument's prognostic value in colorectal cancer (CRC), as well as launch a new version, by this summer.
Researchers typically use flow cytometry or similar methods to isolate CTCs from a patient's blood sample. Companies like Italy-based Menarini Silicon Biosystems and UK-based Angle have commercialized instruments that use epithelial biomarkers or morphological features to detect cells, respectively.
Perry Schiro, MiCareo cofounder and chief technology officer, argued that these types of methods require difficult workflows and several instruments to isolate, purify, and analyze target cells. His team at the University of Washington instead began developing a workflow that only required a single instrument and minimal hands-on time.
Schiro and Daniel Chiu, a professor of chemistry, analytical chemistry, and bioengineering at UW, left the university in 2011 to launch MiCareo as a UW spinout to commercialize an instrument based on his academic research.
"We found that Taiwan had both good software technology, as the method uses a lot of artificial intelligence [and] machine learning to identify cell types and look for changes, [and] had researchers that we know [whose resources] we could tap into," Schiro said.
MiCareo's MiSelect R workflow applies a method called "ensemble-decision aliquot ranking" (eDAR), which initially breaks down a patient's blood sample into several different aliquots. After labeling a patient's blood sample with a cocktail of surface antibodies (such as EpCAM, CD44, and CD45, PD-L1), the firm then loads each aliquot into the instrument.
Whole blood from each aliquot travels through an inlet and is scanned with a laser to identify fluorescent antibody markers. When eDAR spots the fluorescent marker, the instrument uses flow displacement to sort the rare cell into separate collection chambers for downstream processing and purification. Meanwhile, the rest of the sample flows into a waste chamber.
The instrument then enriches and filters out blood cells from the sample using the "SelectChip Dual" microfluidic chip in the chamber containing the target cell. Isolated cells are incubated and stained with two rounds of pre-loaded antibodies directly in the chip and imaged at seven different wavelengths.
"The SelectChip Dual chip doubles the sample flow rate, allowing for a significantly shorter overall experiment time, particularly for larger 16-ml samples," Schiro said. "The cell collection chamber ... [is designed] to capture smaller nucleated cells, such as nucleated red fetal blood cells and smaller immune cells."
Using a specialized "SelectChip Retrieval" cartridge, the instrument purifies rare cells that are collected in microcentrifuge tubes for downstream analysis, including with next-generation sequencing, PCR, and other methods. MiCareo offers users the option to view and analyze single retrieved cells using high-resolution image capture and software bundled with the instrument.
Schiro said that MiSelect R can purify and collect a single cell in as little as 8 ml of blood within two to three hours.
While MiSelect R only labels and detects up to 13 different antibodies per run, Schiro highlighted that the instrument can use about 100 markers to identify different cells depending on the tumor type.
Most of MiCareo's business — including manufacturing and research and development — is in Taiwan. However, the firm also launched its North American collaboration service center in Seattle in 2019.
Schiro noted that MiCareo has explored using MiSelect R to purify CTCs and rare cells from nine solid tumor types, including prostate, CRC, breast, and lung cancer.
"We have done hundreds of experiments where we've taken a single cell, cultured it into 8 ml of blood, and more than 95 percent of the time, we've found the cell at the end of the workflow," Schiro explained. "We're confident that no matter who runs the instrument, you'll find the one cell."
Researchers have previously used the MiSelect R System to investigate the driving factors behind tumor growth, dissemination, and the establishment of distant tumor sites in breast cancer metastasis.
MiCareo also recently submitted a paper to an undisclosed journal regarding the use of MiSelect R to look at the prognostic value of CTCs in CRC patients. In the study, the team found that patients identified with more than five CTCs presented significantly worse overall survival. The researchers also saw that patients with a low level of carcinoembryonic antigen — a protein that acts a cancer marker — and CTCs also trended toward a worse overall survival.
While MiCareo initially developed MiSelect R to isolate CTCs, Schiro pointed out the firm has launched trials in recent years to identify rare cells like immune and T cells that act as precursors to certain diseases due to interest from academic collaborators.
"We can come in and say that we're finding 50 cells instead of five because we haven't performed any preprocessing and we are gentle with the samples," Schiro said. "We can say 'here are the cells, what they look like … and their related biomarkers,' [correlating] that with disease outcomes or drug efficacy that work with the patient's response and [indicate] they have some clinical significance."
The sample prep space is bustling with firms attempting to help researchers capture and sort CTCs and other rare cells in a patient's blood sample. While companies like Menarini and Angle currently offer commercial assays, startups like Tethis and Akadeum Life Sciences are also developing cell capture platforms to identify CTCs and other molecules for downstream applications.
Schiro pointed out that eDAR offers several advantages over standard fluorescence-activated cell sorting (FACS), including its higher cell recovery rate, automated workflow, and the use of a disposable chip.
"You're not doing that upfront workflow, where you're performing fancy centrifugation, lysis, purification, or a whole bunch of calibration," Schiro explained. "FACS requires calibration steps to prevent cross-bleeding from one [step] to another."
He also pointed out that Angle's Parsortix/HyCEAD workflow requires multiple instruments, which can lead to discrepancies due to human error during transfer between the instruments.
While MiCareo initially licensed the MiSelect R's core patents from UW, Schiro said the firm has since received additional patents related to the technology: the single-use microfluidic chip; the mechanism for isolating the rare cell using fluorescence; and processing the cell in a gentle matter that does not cause shear stress.
MiCareo is applying for a CE mark for the instrument for all rare cell applications, followed by an eventual 510(k) application with the US Food and Drug Administration. However, he acknowledged that the firm has not yet begun specific clinical trials for the 510(k) submission.
For now, MiCareo sells the system as an RUO product for US customers out of its Seattle-based location, with a price tag of $195,000 for customers interested in using the system to create laboratory-developed tests. The company also offers an RUO service, the cost of which depends on the type of analysis the user wants the firm to perform.
"If you want us to do a fairly simple CTC analysis, and look at a few biomarkers, maybe it'd be $600 [per sample]," Schiro said. "If you want us to run a next-generation sequencing analysis on a single-cell level on 20 different cells, then we're going to be talking about a couple thousand [dollars]."
He also noted that the upcoming MiSelect R II System, which the firm expects to launch this summer, will cost substantially less than the original instrument. The iteration will also need only about a third of the time of the current platform to produce results for downstream applications. He noted that the firm will eventually phase out the original instrument once it has fully launched the R II system.
Schiro said that MiCareo's customer base includes academic institutions working on foundational research and pharma companies interested in using MiSelect R as part of their clinical trials.
"Rather than scrapping [potential drug candidates], we can go back and say [to pharma that] 'there's a strong correlation between this immune cell type and the drug," Schiro said. "If we use it as a companion diagnostic to look at this immune cell subtype … it allows them to have a safety net and redesign the trial [for next time]."
While Schiro declined to mention how much funding MiCareo has raised since it was launched, he said that the firm's angel investors have continued to participate in several financing rounds.