Enzyvant Announces First-Ever Data on Burden of Illness and Costs of Supportive Care for Pediatric Congenital Athymia

On average, pediatric congenital athymia patients spent 150.6 days each year in the hospital with a mean total cost of $5,534,121 for supportive care over three years

Mean total costs for patients with annual inpatient stays of 365 days are $11,763,320 over three years

When treated with supportive care, patients with congenital athymia endure numerous, severe medical consequences and caregivers experience intense emotional, social, and financial burdens

CAMBRIDGE, Mass. and BASEL, Switzerland, Aug. 26, 2021 (GLOBE NEWSWIRE) — Data from two first-ever studies reveal extreme clinical, emotional, social, and financial burdens on patients with pediatric congenital athymia and their families, and extraordinary costs of supportive care to healthcare systems. Congenital athymia is an ultra-rare condition in which children are born without a thymus, leading to profound immunodeficiency, life-threatening immune dysregulation, and high susceptibility to potentially fatal infections. Estimated incidence of congenital athymia in the U.S. is ~17 to 24 live births each year.¹ Currently, there are no FDA-approved treatments for congenital athymia.

Manifestations of congenital athymia are frequent and multidimensional. Supportive care is used to prevent potentially fatal infections and manage other symptoms of immunodeficiency and immune dysregulation due to congenital athymia. In addition to strict isolation protocols in the hospital and at home, supportive care involves a broad scope, volume, and intensity of diagnostic and medical interventions. With only supportive care, patients with congenital athymia typically die by age two or three.

To evaluate the burdens of congenital athymia on patients and families, and the total medical costs associated with supportive care, two separate studies were conducted. Posters of each of the studies were presented at the Clinical Immunology Society 2021 Annual Meeting. A burden of illness study (n=18), published in Advances in Therapy, investigated the complicated and traumatic medical journey pediatric patients with congenital athymia face, as reported by their caregiver(s).¹ A study (n=10) of congenital athymia supportive care costs, published in the Journal of Medical Economics, looked at real-world healthcare resource utilization as reported by treating physicians based on actual patient medical charts.²

Pediatric patients with congenital athymia face lengthy hospital stays, life-threatening clinical manifestations, and acute medical interventions.

Congenital athymia patients are recommended to be placed in isolation immediately after diagnosis. In the hospital, isolation may involve specialized air flow rooms or intensive care settings (Neonatal Intensive Care Unit/NICU or Pediatric Intensive Care Unit/PICU), infection prevention protocols for hospital staff, and restricted visitation from family and friends. In the study, patients spent an average of 150.6 days a year in the hospital, with two patients experiencing the highest annual stay of 365 days.

Clinical manifestations of congenital athymia reported in both studies were acute and frequent:

• Patients experienced frequent and multiple types of infections and immune dysregulation events
• In an average year, 80% of patients had two or more types of infections
• 40% of patients experienced sepsis with an average frequency of 3.5 times a year
• 60% had respiratory infections on average 3.3 times a year
• 60% of patients had skin manifestations of immune dysregulation at an average frequency of 5.8 times a year

Patients receive multiple medications prophylactically and for the treatment of infections. They also may receive immunosuppression for autologous graft versus host disease and are frequently monitored with medical tests to evaluate immune function. Patients may also endure invasive procedures. Ninety percent of patients required placement of a feeding tube and 70% needed a central line. Caregivers characterized the medical procedures as repeated trauma for patients.

Isolation required for infection control places severe burden on patients and their families.

At home, caregivers of pediatric congenital athymia patients and family members, are instructed to maintain strict isolation and hygiene procedures. Any interactions by the family with individuals outside the immediate household can potentially expose the patient to pathogens that can lead to fatal infections.

In the burden of illness study, caregivers described the severe consequences of congenital athymia and how strict isolation required to protect a congenital athymia patient presents daily challenges that require many sacrifices for parents and siblings:

• Caregivers ranked the most significant impacts on their families
  • Living in isolation (100% of respondents)
  • Fear of death, infection, and worries about the future (100%)
  • Financial hardship (78%)
  • Inability to meet family/friends (72%)
  • High burden of medical care (67%)
  • Negative impact on siblings/families (67%)
• Isolation for infection control causes patients to miss out on social interactions needed for emotional and social development
• There are also impacts of isolation on caregivers’ lives, including the feeling of separation from their support system of family and friends
• The significant consequences of congenital athymia extend to siblings’ lives as they may be home-schooled and restricted from interacting with peers, participating in sports, or joining in social activities for extended periods of time
• As stated in the publication, caregivers communicated the emotional toll of caring for a patient with congenital athymia, describing a constant fear that their child would die

Healthcare systems bear extraordinarily high costs for pediatric congenital athymia patients requiring supportive care.

As a result of strict isolation requirements, profound immunodeficiency, and immune dysregulation, patients with congenital athymia can have prolonged hospital stays of weeks, months, and beyond. Within the medical chart review study, 79% of the total costs associated with supportive care were for inpatient hospital stays. Patients spend an average of 150 days a year in the hospital with a mean total cost for supportive care of $5,534,121 over three years. For congenital athymia patients who spend 365 days in the hospital each year, the total costs over three years were $11,763,320.

About the Congenital Athymia Burden of Illness and Cost of Supportive Care Studies

Both the congenital athymia caregiver-assessed burden of illness and cost of supportive care studies were fully supported with funding from Enzyvant.

To explore burdens of congenital athymia, a cross-sectional study was conducted among caregivers of 18 congenital athymia patients: five patients currently receiving supportive care and 13 patients who had received supportive care in the past. The study used a quantitative survey and qualitative interviews.

Authors for the burden of illness study include:

• Cathleen Collins, M.D., Ph.D., Rady Children’s Hospital and University of California San Diego
• Julie J. Kim-Chang, M.D., Duke University School of Medicine
• Abigail Silber and Matthew O’Hara, Trinity Life Sciences
• Sarah Kulke, M.D., Enzyvant Therapeutics, Inc.
• Elena Hsieh, M.D., University of Colorado, Anschutz School of Medicine; Children’s Hospital Colorado

Healthcare resource utilization data were gathered from 10 patient medical charts and analyzed. The medical chart audit study was conducted among U.S. board-certified/eligible healthcare practitioners (HCPs) who had previously treated at least one patient with congenital athymia. A web-enabled questionnaire was used to abstract medical chart data. Medical chart data were required to be available for at least 12 continuous months prior to three years of age while receiving supportive care.

Costs were gathered from literature, national cost databases, consumer retail websites, or publicly available hospital chargemaster data. As stated in the publication, costs for inpatient room charges were derived from the 2020 chargemaster data from Children’s Hospital, Colorado, which is representative of a real-world care setting for congenital athymia patients based on clinical experts’ direct experience.

The study estimated the mean annual utilization of each medical resource. A mean annual cost per patient was estimated across medical chart visibility, then multiplied by three to determine the total direct medical costs per patient for the first three years of life. A scenario analysis was conducted comparing two real-world patient scenarios based on inpatient hospital stays, high inpatient utilizers, and low inpatient utilizers.

Authors for the cost of congenital athymia supportive care study include:

• Megan Cooper, M.D., Ph.D., Washington University, St. Louis
• Cathleen Collins, M.D., Ph.D., Rady Children’s Hospital and University of California San Diego
• Julie J. Kim-Chang, M.D., Duke University School of Medicine
• Abigail Silber and Matthew O’Hara, Trinity Life Sciences
• Sarah Kulke, M.D., Enzyvant Therapeutics, Inc.
• Elena Hsieh, M.D., University of Colorado, Anschutz School of Medicine; Children’s Hospital Colorado

About the Thymus and Congenital Athymia

The “T” in T cell stands for thymus because it is where T cells are selected to fight infections or are destroyed if they have the potential to attack the body instead of invaders. Congenital athymia is an ultra-rare condition in which children are born without a thymus, causing profound immunodeficiency, vulnerability to potentially fatal infections, and life-threatening immune dysregulation. With only supportive care, children with congenital athymia typically die by age two or three. Athymia is initially detected by T-cell deficiency observed in newborn screening for SCID (severe combined immune deficiency), which is now required in all 50 U.S. states. SCID and congenital athymia are both primary immunodeficiency disorders but they are distinct conditions. The estimated incidence of pediatric congenital athymia in the United States is 17 to 24 live births each year.

About Enzyvant

Enzyvant, a wholly owned subsidiary of Sumitovant Biopharma Ltd. (wholly owned by Sumitomo Dainippon Pharma Co., Ltd.), is a biotechnology company dedicated to developing novel, transformative regenerative therapies for people with devastating rare diseases. Enzyvant’s lead asset is the investigational tissue-based regenerative therapy, RVT-802, for congenital athymia, an ultra-rare and life-threatening pediatric immunodeficiency. RVT-802 has been granted multiple regulatory designations, including the U.S. Food and Drug Administration designation as a Regenerative Medicine Advanced Therapy (RMAT). The RVT-802 Biologics Licensing Application (BLA) was resubmitted this year and the expected action date provided by the FDA under the Prescription Drug User Fee Act (PDUFA) is October 8, 2021. The European Medicines Agency (EMA) has granted Orphan Drug designations and the Advanced Therapy Medicinal Product (ATMP) designation for RVT-802. For more information about Enzyvant, visit Enzyvant.com. Follow @Enzyvant on Twitter, Facebook, and LinkedIn.

About Sumitovant Biopharma Ltd.
Sumitovant is a global biopharmaceutical company with offices in New York City and London. Sumitovant is the majority shareholder of Myovant (NYSE: MYOV) and wholly-owns Urovant, Enzyvant, Spirovant, and Altavant. Sumitovant’s promising pipeline is comprised of early-through late-stage investigational medicines across a range of disease areas targeting high unmet need. Sumitovant is a wholly-owned subsidiary of Sumitomo Dainippon Pharma. For further information about Sumitovant, please visit https://www.sumitovant.com. Follow Sumitovant on LinkedIn.

Media Contacts:

Enzyvant
Eliza Schleifstein
6 Degrees
(917) 763-8106
Eliza@schleifsteinpr.com

Sumitovant Biopharma
Maya Frutiger
VP, Head of Corporate Communications
media@sumitovant.com

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¹Hsieh, E.W.Y., Kim-Chang, J.J., Kulke, S. et al. Defining the Clinical, Emotional, Social, and Financial Burden of Congenital Athymia. Adv Ther (2021). https://doi.org/10.1007/s12325-021-01820-9

²Collins, C., Kim-Chang, J.J., Hsieh, E. et al. Economic burden of congenital athymia in the United States for patients receiving supportive care during the first 3 years of life. J Med Econ. (2021). https://doi.org/10.1080/13696998.2021.1962129