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Ultragenyx Announces Collaboration With Kyowa Hakko Kirin to Develop and Commercialize Phase 2-Stage KRN23 for X-Linked Hypophosphatemia

NOVATO, Calif., Sept. 3, 2013 (GLOBE NEWSWIRE) -- Ultragenyx Pharmaceutical Inc. today announced it has entered into a collaboration and license agreement with Kyowa Hakko Kirin Co., Ltd. (KHK), to develop and commercialize KRN23. KRN23 is a recombinant fully human monoclonal IgG1 antibody intended to treat X-linked hypophosphatemia (XLH). KHK is currently completing a Phase 1/2 study in adults with XLH in the US and Canada. The two companies plan to initiate a pediatric XLH program in 2014.

XLH is a rare metabolic bone disorder caused by excessive loss of phosphate in the urine leading to severe hypophosphatemia and poor bone growth and mineralization. XLH patients have low serum phosphate levels due to high levels of FGF23, a hormone that represses the reabsorption of phosphate from the urine. KRN23 is intended to bind to and render FGF23 inactive, leading to an increase in kidney tubular absorption of phosphate and increased serum phosphate levels. KRN23 is potentially the first specific treatment that addresses the underlying problem of excess FGF23 production in XLH.

Under the terms of the agreement, Ultragenyx and KHK will collaborate on the development of KRN23 for the US, Canada and European Union (EU), with Ultragenyx leading development efforts in the XLH indication and the parties sharing development costs. If KRN23 is approved, Ultragenyx and KHK will share commercial responsibilities and profits in the US and Canada, KHK will commercialize KRN23 in the EU and Ultragenyx will develop and commercialize KRN23 in Mexico, Central and South America. KHK will manufacture and supply KRN23 for clinical and commercial use globally.

"We are excited to enter into this collaboration with KHK on KRN23, a promising clinical-stage product to treat a rare and debilitating bone disease," said Emil D. Kakkis, MD, PhD, Chief Executive Officer of Ultragenyx. "The collaboration combines KHK's broad antibody-based discovery, manufacturing and development capabilities with our expertise in the clinical development of novel therapeutics for rare genetic diseases. We look forward to working closely with the KHK team, investigators, and patients on continuing development of KRN23, a much needed new therapy for XLH patients."

KHK has successfully completed a Phase 1 (US-02) and a Phase 1/2 (INT-001) study with a Phase 1/2 extension (INT-002) study ongoing in adults with XLH. Data from the Phase 1 (US-02) study will be presented at an upcoming scientific meeting. Under the collaboration, Ultragenyx and KHK plan to continue the development of KRN23 in adult XLH patients while initiating a pediatric XLH program in 2014.

"KRN23 is a strategically important product for Kyowa Hakko Kirin to expand its business into global markets," commented Yoichi Sato, Executive Managing Officer, Vice President, Head, Development Division at KHK. "We believe that the collaboration with Ultragenyx will accelerate the development and commercialization of KRN23 and maximize its value in global markets. Through the collaboration, Kyowa Hakko Kirin will continue to use its best efforts to bring KRN23 to XLH patients who need the new therapy the most."

About X-linked Hypophosphatemia (XLH)

XLH is a disorder of phosphate metabolism caused by phosphate wasting in the urine leading to severe hypophosphatemia. XLH is the most common heritable form of rickets that is inherited as an X-linked dominant trait affecting both males and females, though the disease in males by some reports may be more severe. XLH is a distinctive bone disease characterized by inadequate mineralization of bone that leads to a spectrum of abnormalities, including progressive bowing of the leg, osteomalacia, bone pain, waddling gait, short stature, gross motor impairment, muscle weakness, osteopenia, frequent/poorly healing microfractures, spinal stenosis and osteoarthritis.

Most patients are managed using oral phosphate replacement and vitamin D (calcitriol) therapy, which is poorly tolerated and only partially effective at restoring bone physiology and growth. Current treatment with oral phosphate requires extremely close monitoring and can result in complications such as secondary hyperparathyroidism, hypercalciuria, hypercalcemia and nephrocalcinosis. XLH was originally called vitamin D-resistant rickets, because doses of vitamin D effective for the treatment of vitamin D-deficient nutritional rickets did not have an impact on phosphate levels in these patients.

About KRN23 and FGF23

KRN23 is a recombinant fully human monoclonal IgG1 antibody discovered by KHK and being developed to treat X-linked hypophosphatemia (XLH). KRN23 is designed to bind to and thereby reduce the biologic activity of fibroblast growth factor 23 (FGF23). FGF23 is a hormone that promotes phosphate excretion by the kidney and suppresses vitamin D production. FGF23 also reduces the expression of the enzyme that is required to synthesize a hormone that normally increases renal tubular absorption of both phosphate and calcium. Therefore, FGF23 induces profound reductions in serum phosphate levels. Phosphate wasting in XLH is caused by excessive levels and activity of FGF23.

About Ultragenyx

Ultragenyx is a privately held, clinical-stage biotechnology company committed to bringing to market life-transforming therapeutics for patients with rare and ultra-rare metabolic genetic diseases. Founded in 2010, the company is rapidly building a diverse portfolio of product candidates with the potential to address diseases for which the unmet medical need is high, the biology for treatment is clear, and for which there are no effective treatments.

The company is led by a management team experienced in the development and commercialization of rare disease therapeutics. Ultragenyx's strategy is predicated upon time and cost-efficient drug development, with the goal of delivering safe and effective therapies to patients with the utmost urgency.

For more information on Ultragenyx, please visit the company's website at www.ultragenyx.com.

About Kyowa Hakko Kirin

Kyowa Hakko Kirin is a leading biopharmaceutical company in Japan focusing on its core business areas of nephrology, oncology and immunology/allergy. Kyowa Hakko Kirin leverages antibody-related leading-edge technologies to discover and develop innovative new drugs aiming to become a global specialty pharmaceutical company contributing to the health and well-being of people around the world.

For more information, please visit the company's website at www.kyowa-kirin.com.

CONTACT: For Media inquiries: Susan Kinkead, Kinkead Communications susan@kinkeadcomm.com For Investor inquiries: Shalini Sharp, Ultragenyx Pharmaceutical Inc. ssharp@ultragenyx.comSource:Ultragenyx Pharmaceutical Inc.