Raptor Pharmaceutical (RPTP) Announces Phase 2a NASH Study Meets Primary Endpoints

NOVATO, Calif., May 3, 2010 (GLOBE NEWSWIRE) — Raptor Pharmaceutical Corp. (“Raptor” or the “Company”) (Nasdaq:RPTP), announced positive Phase 2a clinical trial results from its pilot study of delayed-release cysteamine bitartrate in 11 adolescent patients with non-alcoholic steatohepatitis (“NASH”), a progressive form of liver disease believed to affect 5% to 11% of the U.S. population. The results were presented at the Digestive Disease Week 2010 conference in New Orleans, LA on May 2, 2010.

The open-label Phase 2a clinical trial was conducted under a collaboration agreement between Raptor and the University of California, San Diego (“UC San Diego”) at UC San Diego’s General Clinical Research Center. Eligible patients with baseline levels of the liver enzymes alanine transaminase (“ALT”) and aspartate aminotransferase (“AST”) that were at least twice normal levels were enrolled to receive twice-daily, escalating oral doses of up to 1,000 mg of delayed-release cysteamine bitartrate (a prototype of Raptor’s DR Cysteamine) for six months, followed by a six-month post-treatment monitoring period.

Patients showed a marked decline in ALT levels during the treatment period with 7 of 11 patients achieving a greater than 50% reduction and 6 of 11 reduced to within normal range. AST levels also saw significant improvements with patients averaging 41% reduction by the end of the treatment phase. The reduction in liver enzymes was largely sustained during the 6 month post-treatment monitoring phase. Other important liver function markers showed positive trends. Levels of cytokeratin 18, a potential marker of disease activity in Non-alcoholic Fatty Liver Disease (“NAFLD”), decreased by an average of 45%. Adiponectin levels increased by an average of 35% during the treatment period. Reduced adiponectin levels are thought to be a marker of the pathogenesis and progression of NASH.  Body Mass Index (“BMI”) did not change significantly during both the treatment and post-treatment phases.  Delayed-release cysteamine bitartrate demonstrated a strong, favorable safety profile, with mean gastrointestinal symptom scores of 1.1 at baseline and 0.7 after 6 months of treatment using a rating system in which the maximum score of 14 indicates most severe gastrointestinal symptoms.

Joel Lavine, M.D., Ph.D., pediatric gastroenterologist at UC San Diego and principal investigator for the NASH study, said, “While NASH and NAFLD have long been a growing health concern, we have not seen many drugs reach this stage of clinical testing while continuing to show such a favorable safety profile and encouraging efficacy after six months. The trial results are consistent with ALT and AST reductions seen in patients that achieve a 10% weight loss, even though study participants did not show a significant change in body mass index. DR Cysteamine appears to be a promising candidate for further testing in the potential treatment of NASH.”

Raptor’s chief medical officer, Patrice Rioux, M.D., Ph.D., said, “We are very excited about the results of this delayed-release cysteamine bitartrate pilot study in NASH patients. NASH is already an area of significant unmet medical need in adults and with the growing numbers of obese children diagnosed with the disorder, its importance is anticipated to grow rapidly in the coming years. While we are very pleased with the substantial impact seen on liver transaminases, we are particularly encouraged by the rapid drug effect we saw during the early phases of the study as well as the sustained liver enzyme reductions following drug withdrawal.  Supported by the long-term safety profile of this compound in cystinosis, this suggests the potential for a longer term, sustainable benefit to overall liver function in NASH patients with DR Cysteamine treatment.”

NASH is a more aggressive form of NAFLD, and is the most common cause of chronic liver disease in North America. Although most patients are asymptomatic and feel healthy in early phases of the disease, NASH causes decreased liver function and can lead to cirrhosis, liver failure and end-stage liver disease. While NASH is most common in insulin-resistant obese adults with diabetes and abnormal serum lipid profiles, its prevalence is increasing among juveniles as obesity rates rise within this patient population. There are no currently approved drug therapies for NASH; patients are limited to lifestyle changes such as diet, exercise and weight reduction to manage the disease.

Under a license with UC San Diego, Raptor is developing DR Cysteamine for cystinosis, NASH, Huntington’s Disease and other potential therapeutic indications. Cysteamine is known to be a scavenger of reactive oxygen species and potent antioxidant, most likely through its ability to increase intracellular glutathione levels.

About Raptor Pharmaceutical Corp.

Raptor Pharmaceutical Corp. (Nasdaq:RPTP) (“Raptor”) is dedicated to speeding the delivery of new treatment options to patients by working to improve existing therapeutics through the application of highly specialized drug targeting platforms and formulation expertise. Raptor focuses on underserved patient populations where it can have the greatest potential impact. Raptor currently has product candidates in clinical development designed to potentially treat nephropathic cystinosis, non-alcoholic steatohepatitis (“NASH”), Huntington’s Disease (“HD”), aldehyde dehydrogenase (“ALDH2”) deficiency, and a non-opioid solution designed to potentially treat chronic pain.

Raptor’s preclinical programs are based upon bioengineered novel drug candidates and drug-targeting platforms derived from the human receptor-associated protein (“RAP”) and related proteins that are designed to target cancer, neurodegenerative disorders and infectious diseases.

For additional information, please visit www.raptorpharma.com.

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FORWARD LOOKING STATEMENTS

This document contains forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements relate to future events or our future results of operation or future financial performance, including, but not limited to the following statements: the Phase 2a clinical trial results may suggest the potential for a longer term, sustainable benefit to overall liver function in NASH patients treated with DR Cysteamine; that DR Cysteamine appears to be a promising candidate for, or that there will be, further testing of DR Cysteamine in NASH patients; and Raptor’s ability to successfully develop any of its product candidates. These statements are only predictions and involve known and unknown risks, uncertainties and other factors, which may cause the Company’s actual results to be materially different from these forward-looking statements. Factors which may significantly change or prevent the Company’s forward looking statements from fruition include that Raptor may be unsuccessful in developing any products or acquiring products; that Raptor’s technology may not be validated as it progresses further and its methods may not be accepted by the scientific community; that Raptor is unable to retain or attract key employees whose knowledge is essential to the development of its products; that unforeseen scientific difficulties develop with the Company’s process; that Raptor’s patents are not sufficient to protect essential aspects of its technology; that competitors may invent better technology; that Raptor’s products may not work as well as hoped or worse, that the Company’s products may harm recipients; and that Raptor may not be able to raise sufficient funds for development or working capital. As well, Raptor’s products may never develop into useful products and even if they do, they may not be approved for sale to the public. Raptor cautions readers not to place undue reliance on any such forward-looking statements, which speak only as of the date they were made. Certain of these risks, uncertainties, and other factors are described in greater detail in the Company’s filings from time to time with the Securities and Exchange Commission (the “SEC”), which Raptor strongly urges you to read and consider, including Raptor’s current report on Form 8-K filed with the SEC on February 5, 2010; and Raptor’s quarterly report on Form 10-Q filed with the SEC on April 9, 2010, all of which are available free of charge on the SEC’s web site at http://www.sec.gov. Subsequent written and oral forward-looking statements attributable to Raptor or to persons acting on its behalf are expressly qualified in their entirety by the cautionary statements set forth in Raptor’s reports filed with the SEC. Raptor expressly disclaims any intent or obligation to update any forward-looking statements.