Microarrays for studying microRNAs first hit the market around four years ago, but the market for these products is still on the ascent, according to manufacturers and customers. Some microRNA array vendors say the market for their tools continues to grow, and users say that there continues to be compelling reasons to add miRNA-expression profiling to their research.
Between 2005 and 2008, there was a flurry of entries to the space. First comers Exiqon, Invitrogen, and CombiMatrix were joined later by Agilent Technologies, Febit, Miltenyi Biotech, LC Sciences, Asuragen, Illumina, Affymetrix, and others. Citing growing numbers of miRNA-related publications, these miRNA array vendors looked to capitalize on demand from researchers for access to the biomolecules, which have been shown to play an important role in gene regulation.
"Although the growth rate of the market may have seen a temporary setback due to the financial crisis … we still see significant growth," Exiqon CEO Lars Kongsbak told BioArray News recently.
He referred to the firm's financial results for the first half of 2009, which showed 21-percent organic growth in its Life Science business year over year. The segment includes its line of miRCURY miRNA arrays. Exiqon's other business units are Pharma Services and Diagnostics.
According to the financials, total Life Science revenues grew 31 percent to DKK 36.7 million ($7.3 million) compared to DKK 28.1 million in the same period of 2008. Exiqon posted H1 '09 revenues of DKK 58.4 million.
The company did not break out receipts for its miRCURY miRNA arrays.
Kongsbak said that researchers interested in studying cancer are the largest group of miRNA array customers, but added that "all [research] areas are growing." Recent publications that cite the use of Exiqon arrays concern investigations into cancer, cell development, and obesity, among other indications.
According to Exiqon, one of the features that makes its arrays different from competitors is its use of locked nucleic acids, modified RNA nucleotides that the firm claims enable its arrays to be more sensitive and specific.
"The platform is very robust and sensitive and we do not need to apply any advanced software tools to extract data from the images," Kongsbak said of the platform. "This provides [our customers with] comfort."
Like Exiqon, Heidelberg, Germany-based Febit has also seen continuous growth in demand for its miRNA Geniom biochips, according to Chief Scientific Officer Peer Stähler. The company synthesizes its microfluidic arrays using its Geniom system and sells them either as catalog arrays or via a service.
"We just started two pilot studies with large pharma companies last week," Stähler told BioArray News recently. "I think [the business] is going in a very good direction and I think that miRNAs are an interesting tool to develop biomarkers."
According to Febit, its arrays are superior to those of its rivals because they can synthesize new miRNAs as soon as they are published in miRBase, the public database of miRNAs hosted by the University of Manchester. MiRBase is typically updated twice a year, and Febit has updated its arrays twice in 2009 to cover miRBase versions 13.0, released in April, and 14.0, released last month.
Exiqon's Kongsbak agreed that "coverage is important." He said that Exiqon has "hundreds of validated human miRNA on our array [that] you cannot find in miRBase."
"There [are] only a few thousand [miRNAs] at this point," Stähler said of the content. "It's large enough to be very information-rich and small enough [that it] can be handled in easy assays," he said. "I think it's a promising area to work on for biomarkers. People understand that miRNAs are useful molecules beyond fundamental biology."
According to Stähler, the market for miRNAs is saturated by competing platforms, and vendors that sell miRNA arrays have to differentiate themselves to gain market share, Febit has decided to differentiate itself by focusing on playing a role in clinical studies.
"We are working with real patient samples," Stähler said. "A lot of this is done in service mode, but we have simplified protocol a lot, trying to keep the parameters of experiments very fixed and we have invested heavily in bioinformatics. You are then able to identify miRNAs that are most significant for a certain differentiator that you would like to have," Stähler added. "That creates a lot of interest from customers."
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'Biological Real Estate'
According to Enal Razvi, an industry analyst affiliated with Select Biosciences, there is "still a lot of interest in miRNAs."
Razvi, who recently authored a report on microRNA research trends, said most analysts estimate the miRNA research market — including sales of other technologies like RT-PCR — to be worth just under $100 million and growing between 20 percent and 25 percent annually.
"It is definitely much smaller than the existing gene expression-analysis market," Razvi said. "It depends in what you include in market size. It depends how you cut it. But I think it's about $100 million in terms of reagent sales," he told BioArray News recently.
Though the market is still comparatively small, Razvi said that interest in miRNA research, coupled with array vendors' need to sell more chips, is driving the market forward.
"I think the reason people have been so interested in the whole miRNA field is because first of all, there is such a deep and profound effect that miRNA has in regulating gene function," said Razvi.
"There is also strong association of miRNAs with several different diseases — cancer, muscular and skeletal disorders, obesity," he said. "By and large, it appears that the miRNA space is an area [that] is probably very fundamental to biological research. Given that profound nature, it is what is driving companies to get into the space."
Cancer research is "by far" the greatest contributor to the market, though stem cell research projects are also increasing, he said. "Cancer is the one driver of this field," he said. "If the cancer and miRNA links were soft, you wouldn't see this level of interest from the research community."
Though still nascent, the demand to survey miRNA expression has been attractive to array companies looking to enter new markets. According to Razvi, array companies "need new content, they need new biological real estate that they can employ onto their platforms in order to effect what their goal is, which is to sell more instruments and consumables and grow their revenues that way."
That need is what prompted such diverse companies to enter the space. While companies like Exiqon and Febit see no plateau in sight for miRNA demand, Razvi said that the market is changing as Exiqon, Rosetta Genomics, and others seek to apply miRNA content for personalized medicine.
Rehovot, Israel-based Rosetta, for instance, last year launched three array-based miRView cancer-related diagnostic tests that San Diego-based Prometheus Laboratories in April licensed for commercialization in the US. Rosetta has inked similar deals with collaborators in other countries. The company has also developed an assay for detection of colorectal cancer recurrence called miRScreen. Exiqon also has plans to introduce a colon cancer-detection test via its diagnostics subsidiary in Tustin, Calif. However, none of the assays is being deployed on arrays.
These initial forays into molecular diagnostics are just another sign of the market moving from discovery projects to finding functions for the content, Razvi said.
"Academic labs are moving towards biological functions of miRNAs in different diseases and companies are offering tools for functional analysis and so on," he said. "It's moving more downstream."
Picking a Platform
There are at least a dozen companies offering miRNA array catalog products and services on the market today. Razvi said that there are multiple attributes that lead customers to choose one platform over another for their research purposes.
"Whether a different platform is chosen depends on a variety of factors," said Razvi. "Does a core facility carry a particular platform? Does a lab carry part of a platform? Have they worked with a platform before in a certain scenario, especially in gene expression? These are all relevant questions," he said.
Razvi added that a customer's choice depends on how a vendor positions its product. "If arrays are designed to look at cancer-specific miRNAs, then, if I am a researcher getting into this, I can see the value in using that platform," he said. "A lot of vendors very specifically frame their offering in light of the big picture – what they can offer compared to other companies."
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For Alan Dombkowski, director of the microarray and bioinformatics facility core at Wayne State University in Michigan, one reason he chose to adopt Agilent's miRNA platform over others is that the core was already set up to run Agilent arrays.
"We have an Agilent scanner and system, so it was a natural progression," Dombkowski told BioArray News. "We have considered other alternatives, but the Agilent arrays, when they first came out, provided excellent concordance with confirmatory methods like qRT-PCR," he said. "It was an easy platform to work with, low input RNA requirements, and you can work with total RNA as opposed to fractionated RNA selected for small RNA species. That's really why we settled with that platform."
According to Dombkowski, the "major factor" involved in a customer's choice of miRNA platform is reproducibility. Other factors include price, simple assay workflow, probe design, and coverage.
"The platforms that demonstrate good reproducibility and keep up with those Sanger [database updates] are going to be the ones that stay at the top of market and the other ones will fall to the wayside," Dombkowski predicted.
He added that he welcomed the interest of so many vendors, as it tends to keep the price of arrays down. "There is pressure on these companies to keep pace with one another and to offer cost-effective solutions," said Dombkowski. "That has benefited researchers immensely. Competition among these vendors drives the technology."
As for research areas, Dombkowski said he's used miRNA arrays in toxicogenomics and stem cell research projects. He has also used Agilent arrays in breast cancer and leukemia studies.
Like Dombkowski, Kathryn Scott, manager of the Laboratory of Cancer Genomics at Thomas Jefferson University in Philadelphia, said that previous experience with the Affymetrix platform led the lab to adopt the firm's GeneChip miRNA array platform.
"As we already have an Affymetrix system in house, when the arrays were released, we were interested in validating them for our customers," she told BioArray News. "The arrays are multi-species, which are needed for our facility customers, as we have a range of species submitted for analysis."
Scott also had previous experience with the Genisphere labeling kit that is part of Affy's miRNA array offering, she said. Though the lab had been using Invitrogen's NCode arrays, the firm decided to switch to Affy after evaluating its platform, which debuted last year.
"When validating, the inherent issues with using the slide-based systems were not observed with the Affy arrays such as background issues either from insufficient washing or non-specific binding," she said. "These issues being gone, combined with the pricing and that we already have an Affy system, allowed us to make the switch."
Scott's lab has been busy. She said there has been a "definite increase" in the amount of samples submitted for miRNA analysis to the facility compared to the same time one year ago.
"There was always an interest in miRNAs, but as there are now more platforms available and more papers in high-impact journals, there are more researchers looking at miRNAs in their studies," Scott said. "We are getting more samples submitted for both mRNA and miRNA profiling."
According to Scott, cancer is the most common area of research in her facility.
Xisong Ke, a researcher at the Gade Institute at the University of Bergen in Norway, agreed that the miRNA array market will continue to grow. At the Gade Institute, Ke has used Febit miRNA biochips in cancer-related studies. Ke said he chose Febit because its chips are less expensive than rival platforms and because "the quality was really good.
"MiRNAs are known to be very important in most research fields," Ke told BioArray News this week. Ke said that arrays are popular among researchers because "it is not easy to detect miRNAs individually by PCR since [the molecules are] too short and need special primers."
He also said that miRNA arrays have satisfied quality control and the results are "very reliable," another factor spurring their adoption. Finally, he said that miRNA array use is growing because vendors have made their platforms available for an "acceptable" price.