Illumina Launches Gene Expression Product Line On SentrixTM Multi-Array Platforms

September 16, 2003

Launch Follows Two NIEHS Toxicogenomics Studies and Offers Flexible Probe Content, Superior Performance, and Low Per-Sample Pricing

SAN DIEGO, CALIFORNIA, September 16, 2003 -- Illumina, Inc. (NASDAQ: ILMN) announced today that it has launched a focused-content, quantitative gene expression product line on two complementary Array of ArraysTM platforms - the SentrixTM Array Matrix and the SentrixTM BeadChip. The commercial launch follows completion of two separate pilot studies, involving over 350 samples and replicates, with the National Institute of Environmental Health Sciences (NIEHS), an NIH institute charged with understanding how environmental exposures and genetic susceptibility interact to affect individuals' health.

The first NIEHS study was designed to process and measure expression levels of nearly 650 genes in a lymphoblast cell line to determine differential response to oxidative stress.

The second study was designed to identify and measure expression profile changes of selected mouse genes following exposure to immunosuppressive compounds. The two studies were directed, respectively, by Douglas Bell, Ph.D., a Senior Investigator at NIEHS, and by Nigel Walker, Ph.D., an NIEHS Staff Scientist. All experiments in both NIEHS projects used Sentrix Array Matrices to analyze sets of target genes, in parallel, across 96 different samples or replicates. Following delivery of data from the two studies, NIEHS placed an order for an Illumina system on which to continue and expand its toxicogenomics research using Sentrix Array Matrices.

"We're excited by the work we've done with NIEHS and delighted that the Institute will be investing in our gene expression system," according to Jay Flatley, Illumina President and CEO. "Sentrix Array platforms offer life scientists experimental flexibility at per-sample costs that will enable larger and more meaningful gene expression studies such as those required in toxicology. We're leveraging dense platform geometries and efficient probe manufacturing to deliver RNA profiling solutions with combined per-sample array and labeling costs that are lower than competitive costs for sample labeling alone."

Flexible Formats; Flexible Content; Flexible Access
Illumina's Sentrix gene expression arrays are based on the Company's BeadArrayTM technology. The arrays are manufactured by introducing pools of microscopic beads, each with hundreds of thousands of identical probe sequences attached, to etched substrates with the highest feature densities of any platform available today. The arrays are configured into multi-sample Array of Arrays formats, an approach that Illumina introduced to the high-throughput genomics market. Bead-based pools of probe sequences can be deployed interchangeably on high-density Sentrix Array Matrices with 96 individual arrays or on moderate-throughput Sentrix BeadChips, which enable parallel processing of eight discrete samples.

Illumina's focused array program offers three flexible options for probe content. For specific disease areas and key model organisms, Illumina will offer arrays with a standard set of probes. Customers can add probe content to a standard bead pool to interrogate supplemental genes of interest in each array cluster. Finally, researchers may order bioinformatically screened probe designs and fully customized arrays with rapid delivery turnaround.

Sentrix Arrays are available as part of two integrated expression profiling solutions. For high-throughput projects, the Illumina system includes a BeadArray Reader with sub-micron resolution for imaging Sentrix Array Matrices (6-micron feature-to-feature spacing), a hybridization chamber, software for scanner operation and data extraction, and extensive documentation. For research projects that require moderate throughput, the Sentrix BeadChip analyzes 8 samples in parallel and can be scanned on the extensive installed base of Axon Instruments' 4000B GenePixTM scanners, which have been certified to provide high-quality detection and imaging.

To encourage early trial of Sentrix Arrays and enable potential customers to experience the benefits of BeadArray technology, Illumina has made available a trio of BeadChip Samplers, respectively for human, mouse and arabidopsis. Each sampler contains a set of probes to query 528 genes, with two 50-mer probes per gene. The Human and Mouse BeadChip Samplers are designed to interrogate representative genes from common areas of study such as immunology, apoptosis, drug metabolism and cancer. The Arabidopsis Sampler includes probes for genes associated with pathogen response, transcription factors, and reproduction/development among others.

Industry-Leading Array Performance
Sentrix Arrays offer strong cross-platform concordance for critical performance criteria like sensitivity and selectivity, along with high array-to-array reproducibility. High correlation values (r2 > 0.97 for log-transformed expression ratios) are exhibited in comparison of Sentrix array data to the "gold standard" of expression analysis, low-multiplex quantitative PCR.

"We attribute performance results to the inherent benefits of BeadArray technology and its redundant probe features, our probe design strategy, and our low manufacturing variability," explains Todd Dickinson, Ph.D. Illumina's Market Manager for Gene Expression. "Equally important, our BeadArray technology has the flexibility to scale to include whole genomes in future product configurations," Dickinson added.

Upcoming Web Seminars
Illumina will be hosting a series of live web seminars to provide more detail about array platforms, performance metrics and custom content options. Visit http://www.illumina.com/webinars/gex.htm to find out more about these educational sessions and to preregister for convenient, desktop viewing.

For more information about Illumina's Expression offerings or about other products and services for high-throughput, high-performance, array-based expression profiling, contact Illumina Customer Solutions at +1.858.202.4566.

Additional information about the National Institute of Environmental Health Sciences can be found at www.niehs.nih.gov/ .

For more information on Axon Instrument's 4000B scanner, visit http://www.axon.com/gn_GenePix4000.html

Illumina (www.illumina.com) is developing next-generation tools that permit large-scale analysis of genetic variation and function. The Company's proprietary BeadArrayTM technology -- now used in leading genomics centers around the world -- provides the throughput, cost effectiveness and flexibility to enable researchers in the life sciences and pharmaceutical industries to perform the billions of tests necessary to extract medically valuable information from advances in genomics and proteomics. This information will help pave the way to personalized medicine.

"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995: this release may contain forward-looking statements that involve risks and uncertainties. Among the important factors which could cause actual results to differ materially from those in the forward-looking statements are Illumina's ability to continue to develop and improve its BeadArray and Oligator technologies, the Company's ability to reproducibly manufacture Array Matrices and BeadChips and to reconfigure these platforms to other geometries, the Company's ability to successfully build out international sales and support organizations, the Company's ability to develop and deploy new applications for its platform technology, and other factors detailed in the Company's filings with the Securities and Exchange Commission including its recent filings on Forms 10-K and 10-Q or in information disclosed in public conference calls, the date and time of which are released beforehand. Illumina disclaims any intent or obligation to update these forward-looking statements beyond the date of this release.