patients 6 months or older with PFIC. We received a rare pediatric disease priority review voucher from the FDA in connection with the U.S. approval.
The precise prevalence of PFIC is unknown, and we are not aware of any patient registries or other method of establishing with precision the actual number of patients with PFIC in any geography. PFIC has been estimated to affect between one in every 75,000 children born worldwide. Based on the published incidence, published regional populations, and estimated median life expectancies, we estimate the prevalence of PFIC across the spectrum of the disease to be approximately 15,000 patients worldwide, not including China and India, but we are not able to estimate the prevalence of PFIC with precision. We hold global rights to Bylvay unencumbered. Our current plan is to commercialize Bylvay ourselves in the United States and Europe. We have entered into a Co-Promotion Agreement with Travere Therapeutics, Inc. for the co-promotion of Bylvay in the United States. The initial term of the arrangement is two years from launch of Bylvay, terminable at will by either party after one year following launch. We have also entered into license agreements with third parties to commercialize Bylvay in certain other jurisdictions, subject to regulatory approval in those jurisdictions including, Medison Pharma Ltd. in Israel, Gen İlaç ve Sağlık Ürünleri Sanayi ve Ticaret A.Ş. in Turkey and Genpharm Services for Saudi Arabia, Bahrain, Kuwait, Oman, Qatar, and the UAE, and we are identifying potential partners for other regions. Bylvay is currently the only approved drug for the treatment of PFIC. Ursodeoxycholic acid, or UDCA, is approved in France only for PFIC type 3, and in the United States and elsewhere for the treatment of primary biliary cholangitis, or PBC. However, many PFIC patients do not respond well to UDCA, undergo partial external bile diversion, or PEBD, surgery and often require liver transplantation. PEBD surgery is a life-altering and undesirable procedure in which bile is drained outside the body to a stoma bag that must be worn by the patient 24 hours a day.
Other Indications Under Development for Bylvay.
We are also pursuing the development of Bylvay in patients with biliary atresia, another rare, life-threatening disease that affects the liver and for which there is no approved pharmacologic treatment option. In December 2018, the European Commission granted orphan designation to Bylvay for the treatment of biliary atresia, and in January 2019, the FDA granted orphan drug designation to Bylvay for the treatment of biliary atresia. We initiated the BOLD clinical trial, a global pivotal trial and the largest prospective intervention trial ever conducted in biliary atresia, in the first half of 2020. We continue to enroll patients in the trial and expect topline results in 2024. We believe biliary atresia is one of the most common rare pediatric liver diseases, and is the leading cause of liver transplants in children. Our double-blind, placebo controlled pivotal trial in biliary atresia is designed to enroll approximately 200 patients at 70 sites globally. Patients will receive either placebo or high-dose (120µg/kg) Bylvay once daily. The primary endpoint is survival with native liver after two years of treatment.
Biliary atresia is a partial or total blocking or absence of large bile ducts that causes cholestasis and resulting accumulation of bile that damages the liver. The estimated worldwide incidence of biliary atresia is between 6 and 10 for every 100,000 live births. We estimate the prevalence of biliary atresia to be approximately 18,100 patients across the U.S. and Europe, and approximately 27,000 combined in other jurisdictions worldwide, but we are not able to estimate the prevalence of biliary atresia with precision. There are currently no drugs approved for the treatment of biliary atresia. The current standard of care is a surgery known as the Kasai procedure, or hepatoportoenterostomy, in which the obstructed bile ducts are removed and a section of the small intestine is connected to the liver directly. However, only an estimated 25% of those initially undergoing the Kasai procedure will survive to their twenties without need for liver transplantation.
In addition, we initiated a pivotal trial of Bylvay in ALGS, the ASSERT trial, in the fourth quarter of 2020. The trial is expected to enroll approximately 45 patients aged 0 to 17 years of age with a genetically confirmed diagnosis of ALGS across 35 sites in North America, Europe, Middle East and Asia Pacific. We expect topline data to be available in 2022, before the announcement of the topline results from the BOLD trial. ALGS is a genetic condition associated with liver, heart, eye, kidney and skeletal abnormalities. In particular, ALGS patients have fewer than normal bile ducts inside the liver, which leads to cholestasis and the accumulation of bile and causes scarring in the liver. ALGS is estimated to affect between one in every 50,000 children born worldwide. We estimate the prevalence of ALGS to be approximately 11,700 patients across the U.S. and Europe, and approximately 13,000 combined in other jurisdictions