Sequenom Announces New Positive Data on Down Syndrome Detection and Unveils Breakthrough DNA Approach to Prenatal Diagnostics

Sequenom, Inc. (NASDAQ:SQNM) today announced new positive data from the prospective clinical studies using the Company’s noninvasive SEQureDx™ technology, enabling the detection of fetal aneuploidy from maternal blood. The data presented today consist of 459 new, high prevalence samples from the prospective, blinded studies performed at Sequenom, bringing the total number of samples studied to 858. Based on the results from the total study samples, including samples as early as 8 weeks of pregnancy, the Sequenom SEQureDx RNA-based technology demonstrated a 100% positive predictive value (PPV) and a 99.9% negative predictive value (NPV). The SEQureDx technology achieved a better than 99% detection rate, with less than a 1% false positive rate. The current standard of care, screening tests, perform at less than a 99% detection rate; however, statistically, if these screening tests could perform at a 99% detection rate, their false positive rate would be in the 10% to 25% range. SEQureDx compares favorably to the current invasive procedures, such as amniocentesis.

In addition to data on the RNA-based technology, the Company unveiled a breakthrough technology which further enhances Sequenom’s SEQureDx technology. This new DNA approach has demonstrated in early studies universal ethnic coverage, high sensitivity and specificity, and the ability to detect Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau syndrome) in a single test. This technology is being developed as a "reflex test” for unresolved results from the current SEQureDx Trisomy 21 technology will be available at the time of the launch of the Trisomy 21 laboratory developed test (LDT) in June 2009.

"We are very pleased with the completion of the R&D studies for our Trisomy 21 RNA-based technology,” stated Harry Stylli, Ph.D., President and Chief Executive Officer of Sequenom. "Our highly sensitive and specific Down syndrome technology will be transferred to the Sequenom Center for Molecular Medicine (SCMM) to complete the development and validation phases necessary for launch in June as an LDT. Our pioneering DNA approach is proving to be a powerful approach to detecting a wide range of aneuploidies. We are very excited by these early findings and believe it will play a key role in our prenatal diagnostics franchise as it eliminates unresolved results due to ethnic coverage and has shown sensitivity as early as eight weeks, similar to the current RNA approach. Furthermore, we believe it will have broad applicability in other areas such as cancer aneuploidies and other genetic disorders. This new approach and other approaches being developed by the Company are covered by existing and recently filed patents.”

Overview of Data from Screening Studies Evaluating RNA-based Trisomy 21 Technology

Elizabeth Dragon, Ph.D., Senior Vice President of Research and Development at Sequenom, presented data from blinded studies performed at Sequenom involving 459 new, high prevalence clinical samples collected prospectively, which brings the total number of samples studied to 858. The data from the 459 new samples show that Sequenom’s proprietary technology for Down syndrome correctly identified all eight first trimester Down syndrome samples (i.e. sensitivity or detection rate) with no false positives and no false negatives, as confirmed by chorionic villus sampling (CVS). Of the 15 second trimester confirmed Down syndrome samples, the Sequenom RNA-based technology detected 14 samples, with one unresolved result reflexed to the new DNA-based method. The DNA-based method accurately detected the Down syndrome. There was one false positive in the second trimester samples, which would be reflexed for confirmatory genetic testing per American College of Obstetricians and Gynecologists (ACOG) guidelines.

"These results represent a significant advance in noninvasive prenatal screening,” stated Allan T. Bombard, M.D., Chief Medical Officer of Sequenom. "In light of these outstanding results, the SEQureDx RNA-based Trisomy 21 technology clearly represents a paradigm-shifting approach. I am encouraged by the single false-positive result in this study representing one tenth of one percent of the total samples tested to-date, and the detection rate is notably superior to the current standard of care, biochemical screening tests. As an ob-gyn, I am confident the simplicity of the SEQureDx approach will be invaluable to physicians and the patients they care for and will result in substantially fewer invasive procedures."

Breakthrough DNA Approach to Detection of Trisomy 21 and Other Aneuploidies

In addition, Dennis Lo, M.D. Ph.D., Li Ka Shing Professor of Medicine at The Chinese University of Hong Kong, presented insights in future opportunities for noninvasive prenatal diagnostics, including pioneering work in a novel DNA approach to the detection of fetal aneuploidy, an approach which Sequenom is already evaluating in R&D studies.

Dr. Dragon from Sequenom presented early findings regarding this promising technology from 359 samples. These findings showed that the DNA-based method correctly identified all 68 unresolved results reflexed from the RNA method, including one confirmed positive Trisomy 21 sample. In addition, this method correctly identified four confirmed positive Trisomy 13 samples and four confirmed positive Trisomy 18 samples.

"We believe this technology represents a breakthrough approach for detecting chromosomal aneuploidies,” stated Dr. Dragon. "This method provides a universal method for detecting all chromosomal aneuploidies. The simple integration into RNA lab workflow of this MassARRAY-based technology does not impact timelines or costs. We will continue to evaluate this technology in parallel to the RNA method and plan to incorporate the DNA-based method into our launch plans.”

Future Applications in Detection of Monogenic Diseases

During his presentation, Dr. Lo focused on the future potential for Sequenom’s technology to address the unmet needs in detection of monogenic diseases. Currently, monogenic diseases, such as cystic fibrosis, B-thalassemia and sickle cell anemia, can only be definitively diagnosed prenatally through invasive procedures following extensive carrier screening testing on both parents. In the United States, cystic fibrosis screening is recommended for all women of child bearing age (more than 10 million individuals in the U.S. are carriers of the CF mutated gene, including one in every 29 Caucasian Americans) and in certain regions of the world, B-thalassemia affects anywhere from three to 16 percent of the population.

Data presented by Dr. Lo demonstrate that when individual mutant or normal DNA sequences are counted in maternal plasma using digital PCR technology, the number of mutant genes inherited by an unborn fetus, and hence its disease status, can be determined. He further demonstrated that a 'molecular counting' strategy can be made more efficient by taking into account the length of the DNA molecules in maternal plasma, as fetal DNA molecules are known to typically be shorter than the maternally derived molecules in maternal plasma. This digital counting approach enables the noninvasive diagnosis of B-thalassemia and hemoglobin E disease from maternal plasma—forms of inherited anemias that affect millions of people worldwide. This molecular counting strategy can, in principle, be applicable to all forms of monogenic diseases, namely paternally or maternally inherited, autosomal dominant diseases and autosomal recessive diseases with any combination of parental mutations. Thus, the complete diagnosis of monogenic diseases can be achieved noninvasively. Sequenom holds exclusive rights to this breakthrough technology representing a new approach that could potentially eliminate the need for paternal testing and significantly reduce the use of invasive tests.

"This new diagnostic approach addresses a problem that has been puzzling investigators in the field of noninvasive prenatal diagnostics over the last 10 years," stated Dr. Lo, study co-author. "Digital PCR technologies have enabled us to measure the minute imbalance of mutant and normal DNA sequences in maternal plasma. This has freed us from the past restriction for monogenic disease analysis where we could only look at the paternally-inherited mutations noninvasively. This research represents a significant paradigm shift in the way we approach plasma DNA-based diagnostics, and offers substantial promise for bringing noninvasive prenatal diagnosis of monogenic diseases closer to reality."

"Sequenom is committed to developing the next generation of prenatal diagnostic tools that will provide physicians with the capabilities they need to noninvasively diagnose genetic disorders early in a woman's pregnancy," commented Dr. Stylli. "We believe these unique, noninvasive digital technologies have the potential to dramatically impact the prenatal diagnostic market and we look forward to advancing these innovative approaches as part of our long-term strategy to expand our prenatal diagnostics franchise."

Sequenom’s analyst briefing included the following speakers and topics:

• Sequenom Business Overview and Update, Harry Stylli, Ph.D., President and Chief Executive Officer
• Trisomy 21 R&D Study Results, Elizabeth Dragon, Ph.D., Senior Vice President of Research and Development
• Glimpse into the Future of Aneuploidy Screening, Elizabeth Dragon, Ph.D., Senior Vice President of Research and Development
• Impact on Clinical Practice, Allan T. Bombard, M.D., Chief Medical Officer
• Understanding the Regulatory Landscape, Gary Riordan, Vice President, Regulatory Affairs and Quality
• Future Applications in Noninvasive Prenatal Diagnostics, Dennis Lo, M.D. Ph.D., Professor of Medicine at The Chinese University of Hong Kong

A webcast of the presentation will be available for 90 days following the event on the Company’s Web site at www.sequenom.com.

Sequenom’s Proprietary Noninvasive Prenatal Diagnostics

Sequenom’s commercial opportunities in prenatal diagnostics are built upon its SEQureDx technologies and are enabled by the pioneering inventions and associated intellectual property rights that it has exclusively licensed from Isis Innovation Ltd., the technology transfer company of the University of Oxford, as well as The Chinese University of Hong Kong. Sequenom’s portfolio of noninvasive prenatal diagnostic patent rights and patent applications is platform-independent, includes genetic-analysis methods using circulating cell-free fetal nucleic acids from maternal serum, plasma or whole blood, and also includes a portfolio of methylation and nucleic-acid markers. Sequenom holds exclusive rights in territories including the United States, Europe, Australia, Canada, Japan and Hong Kong. Sequenom is actively expanding its intellectual property position with new technology and new territories. Because Sequenom’s license rights are platform-independent, the rights provide exclusivity (with the narrow exception in Europe for RT-PCR-based RhD tests) for development and commercialization of noninvasive prenatal screens and tests on any platform and are not limited to the Company’s MassARRAY platform.

About SEQureDx Technology

Sequenom’s SEQureDx Technology is a novel approach to genetic screening. Unlike current standards of harvesting placental tissue cells as is required for CVS, or entering the uterus to sample the amniotic fluid surrounding the baby as is performed with amniocentesis, SEQureDx Technology extracts fetal nucleic acid material safely and comfortably from a simple blood specimen collected from the mother to determine the genetic status of the fetus. This breakthrough suggests that effective screening may be accomplished in the future without the risks associated with disturbing the amniotic fluid that surrounds the baby in the uterus. In December 2007, the Company, through its laboratory partner, introduced a laboratory-developed RhD genotyping test using RT-PCR in the United States. In February 2008, Sequenom announced progress with its noninvasive Trisomy 21 test based on multiple RNA fetal markers, including the PLAC4 gene as previously published by Dr. Dennis Lo, The Chinese University of Hong Kong.

About Down Syndrome

Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 21st chromosome, either in whole (Trisomy 21) or in part (such as due to translocations). The effects of the extra copy vary greatly among people, depending on the extent of the extra copy, genetic history and pure chance. In 2007, the American College of Obstetricians and Gynecologists (ACOG) endorsed guidelines that offer risk assessment to all pregnancies for fetal chromosomal abnormalities, including Down syndrome. The ACOG recommendation includes screening before the 20^th week of pregnancy using a less-invasive screening option that includes ultrasound in conjunction with the measurement of certain blood hormones. It is estimated that approximately 70% of all births, or 2.7 million pregnancies, undergo Down syndrome screening in the United States each year.

About Sequenom

Sequenom is committed to providing the best genetic analysis products that translate the results of genomic science into solutions for noninvasive prenatal diagnostics, biomedical research, translational research and molecular medicine applications. The Company's proprietary MassARRAY^® system is a high-performance (in speed, accuracy and cost efficiency) nucleic acid analysis platform that quantitatively and precisely measures genetic target material and variations. The Company has exclusively licensed intellectual property rights for the development and commercialization of noninvasive prenatal genetic tests for use with the MassARRAY system and other platforms. Sequenom maintains a Web site at www.sequenom.com to which Sequenom regularly posts copies of its press releases as well as additional information about Sequenom. Interested persons can subscribe on the Sequenom Web site to email alerts or RSS feeds that are sent automatically when Sequenom issues press releases, files its reports with the Securities and Exchange Commission (the "SEC”) or posts certain other information to the Web site.

Sequenom^®, MassARRAY^® and SEQureDx™ are trademarks of Sequenom, Inc.

Forward Looking Statements

Except for the historical information contained herein, the matters set forth in this press release, including statements regarding the Company’s SEQureDx Technology and a novel DNA-based approach to the detection of fetal aneuploidy, including the potential applications, benefits and impact of such technologies, the sensitivity and specificity of such technologies, the continuing development, validation and commercialization of such technologies and the expected availability of diagnostic tests utilizing such technologies, future opportunities for and benefits of noninvasive prenatal diagnostic tests, including potential applications for the diagnosis of monogenic diseases and other diseases, the expansion of Sequenom’s intellectual property position, and Sequenom’s ability to develop and commercial diagnostic tests on multiple platforms, are forward-looking statements within the meaning of the "safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially, including the risks and uncertainties associated with demand for and market acceptance of Sequenom’s products, services, and technologies, new technology and product development and commercialization, reliance upon the collaborative efforts of other parties, research and development progress, competition, government regulation particularly with respect to diagnostic products and laboratory developed tests, obtaining or maintaining regulatory approvals, and other risks detailed from time to time in the Company’s SEC reports, including the Company’s Annual Report on Form 10-K for the year ended December 31, 2007 and subsequent filings. These forward-looking statements are based on current information that is likely to change and speak only as of the date hereof. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement, and the Company undertakes no obligation to revise or update any forward-looking statement to reflect events or circumstances after the issuance of this press release.