Kyowa Kirin to Present New Research on X-linked Hypophosphatemia (XLH) at ASBMR Annual Meeting

  • Five poster presentations provide greater understanding of patient profiles and real-world experiences of people living with XLH
  • Princeton, N.J., October 12, 2023— Kyowa Kirin, Inc., an affiliate of Kyowa Kirin Co., Ltd. (Kyowa Kirin, TSE: 4151), a global specialty pharmaceutical company based in Japan, will share new research that advances understanding about the real-world experiences and clinical characteristics of children, adolescents, and adults living with X-linked hypophosphatemia (XLH), a rare genetic metabolic bone disease. The findings will be presented in a series of poster presentations at the American Society for Bone and Mineral Research (ASBMR) 2023 annual meeting, which takes place October 13-16 in Vancouver, BC, Canada.

    “Individuals living with XLH face a lifelong struggle of managing their disease and progressively worsening morbidities, which negatively impact their life,” said Zhiyi Li, MA, MBA, Director of Health Economics and Outcomes Research at Kyowa Kirin North America. “The breadth of the research we are presenting at ASBMR reflects our commitment to helping inform a more complete understanding of XLH and its’ management.”

    Kyowa Kirin will present the following posters at the ASBMR annual meeting:

    “Real-world characteristics and disease history of patients with X-linked hypophosphatemia treated with burosumab: a United States claims database study” (Poster #SAT-493)

    • Lead author: Kathryn Dahir, MD, Vanderbilt University Medical Center
    • Poster Session I; Saturday, October 14, 1:30 – 3:00 pm PDT

    “Clinical and treatment characteristics of pediatric and adult patients with familial hypophosphatemia compared with demographically matched controls” (Poster #SAT-519)

    • Lead author: Zhiyi Li, MA, MBA, Kyowa Kirin North America
    • Poster Session I; Saturday, October 14, 1:30 – 3:00 pm PDT

    “Association between work productivity and characteristics of adults with X-linked hypophosphatemia: an analysis of the XLH Disease Monitoring Program” (Poster #SAT-496)

    • Lead author: Aliya Khan, MD, McMaster University
    • Poster Session I; Saturday, October 14, 1:30 – 3:00 pm PDT

    “Age at diagnosis of XLH amongst children with and without a family history: findings from the International XLH Registry” (Poster #SUN-500)

    • Lead author: Suma Uday, MBBS, FRCPCH, PhD, Birmingham Women’s and Children’s Hospital (UK)
    • Poster Session II; Sunday, October 15, 1:30 – 3:00 pm PDT

    “A patient-centered and multi-stakeholder co-designed, mixed method, observational, prospective study protocol: Example of the adolescent experience of treatment for X-linked hypophosphatemia (XLH)” (Poster #SUN-496)

    • Lead author: Vrinda Saraff, MD, Birmingham Women’s and Children’s Hospital (UK)
    • Poster Session II; Sunday, October 15, 1:30 – 3:00 pm PDT

    About X-linked hypophosphatemia

    X-linked hypophosphatemia is a rare, lifelong, genetic disease that can impact the bones and muscles in both children and adults. In individuals with XLH, the body doesn't hold on to enough phosphorus, which is an essential mineral for bone health. This is due to the production of excess fibroblast growth factor 23 (FGF23), causing the body to release too much phosphorus through the urine. When phosphorus levels are too low (hypophosphatemia), it can cause the softening and weakening of growing bones in children (rickets) and of mature bones in adults (osteomalacia).

    In children, XLH typically appears as bowed legs or knock knees. Over time, bone weakening can also lead to bone abnormalities in the legs, delayed growth, and short stature. In adults, XLH may cause osteomalacia, fractures and pseudo-fractures, and hypophosphatemia.

    About CRYSVITA® (burosumab-twza) Injection

    CRYSVITA is a recombinant fully human monoclonal IgG1 antibody, discovered by Kyowa Kirin, which binds to and inhibits the biological activity of FGF23, the underlying cause of hypophosphatemia in XLH. By blocking FGF23, CRYSVITA helps to restore phosphorus reabsorption in the kidneys and increase the production of active vitamin D, which enhances intestinal absorption of phosphate and calcium.

    U.S. CRYSVITA Indication

    CRYSVITA is a fibroblast growth factor (FGF23) blocking antibody indicated for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients 6 months of age and older.

    Important Safety Information


    CRYSVITA is contraindicated:

    • In concomitant use with oral phosphate and/or active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) due to the risk of hyperphosphatemia.
    • When serum phosphorus is within or above the normal range for age. In patients with severe renal impairment or end stage renal disease because these conditions are associated with abnormal mineral metabolism.



    • Hypersensitivity reactions (e.g., rash, urticaria) have been reported in patients with CRYSVITA. Discontinue CRYSVITA if serious hypersensitivity reactions occur and initiate appropriate medical treatment.

    Hyperphosphatemia and Risk of Nephrocalcinosis

    • Increases in serum phosphorus to above the upper limit of normal may be associated with an increased risk of nephrocalcinosis. For patients already taking CRYSVITA, dose interruption and/or dose reduction may be required based on a patient’s serum phosphorus levels.

    Injection Site Reactions

    • Administration of CRYSVITA may result in local injection site reactions. Discontinue CRYSVITA if severe injection site reactions occur and administer appropriate medical treatment.


    Pediatric Patients

    • Adverse reactions reported in 10% or more of CRYSVITA-treated pediatric XLH patients across three studies are: pyrexia (55%, 44%, and 62%), injection site reaction (52%, 67%, and 23%), cough (52%), vomiting (41%, 48%, and 46%), pain in extremity (38%, 46%, and 23%), headache (34% and 73%), tooth abscess (34%, 15%, and 23%), dental caries (31%), diarrhea (24%), vitamin D decreased (24%, 37%, and 15%), toothache (23% and 15%), constipation (17%), myalgia (17%), rash (14% and 27%), dizziness (15%), and nausea (10%).
    • Postmarketing experience reported in CRYSVITA-treated pediatric XLH patients: blood phosphorus increased.

    Adult Patients

    • Adverse reactions reported in more than 5% of CRYSVITA-treated adult XLH patients and in at least 2 patients more than placebo in one study are: back pain (15%), headache (13%), tooth infection (13%), restless legs syndrome (12%), vitamin D decreased (12%), dizziness (10%), constipation (9%), muscle spasms (7%), and blood phosphorus increased (6%).
    • Spinal stenosis is prevalent in adults with XLH, and spinal cord compression has been reported. It is unknown if CRYSVITA therapy exacerbates spinal stenosis or spinal cord compression.


    • There are no available data on CRYSVITA use in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Serum phosphorus levels should be monitored throughout pregnancy. Report pregnancies to the Kyowa Kirin, Inc. Adverse Event reporting line at 1-844-768-3544.
    • There is no information regarding the presence of CRYSVITA in human milk or the effects of CRYSVITA on milk production or the breastfed infant. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for CRYSVITA and any potential adverse effects on the breastfed infant from CRYSVITA or from the underlying maternal condition.


    • Advise patients not to use any oral phosphate and/or active vitamin D analog products.
    • Instruct patients to contact their physician if hypersensitivity reactions, injection site reactions, and restless legs syndrome induction or worsening of symptoms occur.

    You may report side effects to the FDA at (800) FDA-1088 or You may also report side effects to Kyowa Kirin, Inc. at 1-844-768-3544.

    For important risk and use information, please see the full Prescribing Information for CRYSVITA.

    About Kyowa Kirin

    Kyowa Kirin strives to create and deliver novel medicines with life-changing value. As a Japan-based Global Specialty Pharmaceutical Company with a more than 70-year heritage, we apply cutting-edge science including expertise in antibody research and engineering, to address the needs of patients and society across multiple therapeutic areas including Nephrology, Oncology, Immunology/Allergy and Neurology. Across our four regions – Japan, Asia Pacific, North America and EMEA/International – we focus on our purpose, to make people smile, and are united by our shared values of commitment to life, teamwork/Wa, innovation, and integrity. You can learn more about the Kyowa Kirin North America at:

    Kyowa Kirin North America:
    Susan Thiele
    Sr. Director, Communications & Advocacy, Global Commercial Franchises
    Phone: +1 (908) 736-4514

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