A rare, inherited disease that affects the body’s ability to metabolize fat, cholesterol and lipids within cells can now be treated by Xenpozyme, a drug approved by the U.S. Food and Drug Administration (FDA).
Adults and children with non-central nervous system (non-CNS) manifestations of acid sphingomyelinase deficiency (ASMD) can now take healthcare company Sanofi’s Xenpozyme (olipudase alfa-rpcp) – the first therapy and only approved treatment.
Executive vice president and head of specialty care at Sanofi, Bill Sibold, said: “Sanofi teams have been dedicated to bringing hope to patients living with ASMD and their families. This is a devastating and extremely rare disease that affects both children and adults. The approval of Xenpozyme represents the culmination of bold work done in research and development, and our unwavering commitment to this historically overlooked community.”
ASMD, historically known as Niemann-Pick disease types A, A/B, and B, is an extremely rare, progressive genetic disease with significant morbidity and mortality.
It has been estimated that there are fewer than 120 patients diagnosed with ASMD in the U.S. Approximately two-thirds of patients with ASMD in the U.S. are pediatric. Signs and symptoms of ASMD can present in infancy, childhood, or adulthood, and may include enlarged spleen or liver, difficulty breathing, lung infections, and unusual bruising or bleeding, among other disease manifestations.
Until now, management of ASMD included supportive care to address the impact of individual symptoms and careful monitoring to detect potential disease complications.
David Guy, parent to Kaila, 16, who has the disease, said: “As young parents, it was initially devastating to me and my wife when our daughter, Kaila, received her diagnosis of ASMD. We faced so many unknowns when we first heard the diagnosis: what does this mean, how will this affect her, and most importantly what hope is there for a treatment option? We were grateful to find hope when we enrolled Kaila in the clinical trials for olipudase alfa.”
Xenpozyme under Priority Review
In the U.S., Xenpozyme received Breakthrough Therapy designation, which expedites the development and review of drugs intended to treat serious or life-threatening diseases and conditions. The FDA evaluated Xenpozyme under Priority Review, which is reserved for medicines that represent potentially significant improvements in efficacy or safety in treating serious conditions.
In March 2022, Xenpozyme was approved in Japan under the SAKIGAKE (or pioneer) designation, marking the first approval for olipudase alfa anywhere in the world. In June 2022, the European Commission (EC) approved Xenpozyme for use in Europe.
ASMD represents a spectrum of disease, with two types that may represent opposite ends of a continuum referred to as ASMD type A and ASMD type B. ASMD type A/B is an intermediate form that includes varying degrees of central nervous system (CNS) involvement.
ASCEND and ASCEND-Peds clinical trials showed that Xenpozyme improved lung function and reduced spleen and liver volumes in adults and children
Positive data for Xenpozyme
The approval is based on positive data from the ASCEND and ASCEND-Peds clinical trials, in which Xenpozyme showed clinically relevant improvement in lung function (as measured by diffusing capacity of the lung for carbon monoxide, or DLco) and platelet count, and reduction of spleen and liver volumes, with a demonstrated safety profile.
Melissa Wasserstein is a pediatric genetic medicine at Albert Einstein College of Medicine and the Children’s Hospital at Montefiore. She said: “ASMD is an extremely rare, progressive, and potentially fatal genetic disease that impacts children and adults around the world.
“Until now, those living with ASMD have had no FDA-approved treatment to combat this devastating condition. I’m proud of the work that has been done and look forward to witnessing the impact that this treatment may have on those living with ASMD.”
Xenpozyme, a hydrolytic lysosomal sphingomyelin-specific enzyme replacement therapy, is designed to replace deficient or defective acid sphingomyelinase (ASM), an enzyme that allows for the breakdown of the lipid sphingomyelin.
In individuals with ASMD, the deficiency in the ASM enzyme leads to sphingomyelin accumulation in various tissues. Xenpozyme is not expected to cross the blood-brain barrier or modulate CNS manifestations of ASMD. Xenpozyme has not been studied in patients with ASMD type A.
Xenpozyme is adminstered intravenously every two weeks, and its administration requires a dose escalation phase followed by a maintenance phase. It is expected to be available in the U.S. in the coming weeks.